RADIOLOGICALASSESSMENTREPORTSSERIESRadiological
Conditions in the
Dnieper River Basin
Assessment by an international expert teamand recommendations for an action plan

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RADIOLOGICAL CONDITIONS IN THE
DNIEPER RIVER BASIN
Assessment by an international expert teamand recommendations for an action plan

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ARGENTINA
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AUSTRALIA
AUSTRIAAZERBAIJANBANGLADESH
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RADIOLOGICAL ASSESSMENT REPORTS SERIESRADIOLOGICAL CONDITIONS IN THE
DNIEPER RIVER BASIN
Assessment by an international expert teamand recommendations for an action plan

INTERNATIONAL ATOMIC ENERGY AGENCY
VIENNA, 2006

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STI/PUB/1230

IAEA Library Cataloguing in Publication Data
Radiological conditions in the Dnieper River basin : assessment by aninternational expert team and recommendations for an action plan.
— Vienna : International Atomic Energy Agency, 2006.
p. ; 29 cm. — (Radiological assessment reports series,
ISSN 1020–6566)
STI/DOC/1230
ISBN 92–0–104905–6
Includes bibliographical references.
1. Radioactive pollution — Dnieper Basin (Ukraine). 2. Radioactive
pollution — Ukraine — Chornobyl. 3. Radioactive waste sites —Cleanup. I. International Atomic Energy Agency. II. Series.
IAEAL

06–00423

FOREWORD
Various locations around the world have been affected by radioactive residues, sometimes from peacefulactivities, such as the mining and milling of uranium ores, and sometimes from military activities, such as nuclear
weapon testing. In some cases, governments have considered it to be socially and politically desirable to obtain
independent expert opinions on the radiological conditions caused by the residues. As a result, the IAEA has
been requested by the governments of a number of Member States to provide assistance in this context. The
assistance has been provided by the IAEA under its statutory obligation “to establish… standards of safety forprotection of health… and to provide for the application of these standards… at the request of a State”.
In 1986, in the Dnieper River basin, a densely populated area in the middle of eastern Europe, the most
severe nuclear accident in human history happened at the Chernobyl nuclear power plant in Ukraine. The
accident destroyed a high power nuclear reactor and resulted in the release of large amounts of radionuclides
into the environment. In other areas of Ukraine adjacent to the middle reaches of the Dnieper River, uranium
mining and milling facilities have been in operation since 1948, which have left substantial tailings containing
naturally occurring radioactive material. These events resulted in the contamination of substantial areas withradioactive residues, and some associated health effects. More questions arose regarding the possible
radiological consequences of the radioactive residues for local populations and the environment, and thegovernments of the affected States were obliged to respond.
After the Ministers of the Environment of the three riparian countries (i.e. Belarus, the Russian Federationand Ukraine) expressed in June 1996 their intention to develop an international programme for theenvironmental rehabilitation of the Dnieper River basin, the first transboundary diagnostic analysis (TDA) was
developed in 1997. In assessing the Dnieper River basin, the United Nations Development Programme — Global
Environment Facility (UNDP–GEF) identified radioactive contamination as one of the significant issues.
Subsequently, the IAEA was requested to contribute its expertise in radiation and environmental protection toa more detailed analysis involving a revision of the TDA and preparation of a strategic action plan.
The present project was started in 2001 within the framework of the Dnieper Basin Environmental
Programme (DBEP) under the UNDP–GEF. The project was executed by the IAEA as Regional TechnicalCooperation Project RER/9/072, Preparation of Strategic Action Plan (SAP) for the Dnieper River Basin andDevelopment of SAP Implementation Mechanism.
The international expert team for this study assembled by the IAEA included scientists from Belarus, theRussian Federation and Ukraine familiar with radioactive contamination in the Dnieper River basin andexperienced in radiological assessments; the team was led by D. Levins from Australia. This report includes thefindings and conclusions of the international expert team and recommendations to the Governments of Belarus,
the Russian Federation and Ukraine.
The IAEA project officer for this project was M. Samiei of the Division for Europe, Latin America andWest Asia and the technical officer was M. Balonov of the Division of Radiation, Transport and Waste Safety.

EDITORIAL NOTE
Although great care has been taken to maintain the accuracy of information contained in this publication, neither the
IAEA nor its Member States assume any responsibility for consequences which may arise from its use.
The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as
to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries.
The mention of names of specific companies or products (whether or not indicated as registered) does not imply any
intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the
IAEA.

CONTENTS
1.

2.

3.

4.

SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

1.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2. Radioactive source terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3. Chernobyl affected areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1. Transboundary migration of radionuclides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.2. Behaviour of caesium-137 and strontium-90 in the environment . . . . . . . . . . . . . . . . . . . .
1.3.3. Chernobyl exclusion zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.4. Contaminated floodplain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.5. Chernobyl cooling pond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.6. Chernobyl shelter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4. Nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5. Uranium mining and processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6. Radioactive waste storage and disposal sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.7. Non-power sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.8. Human radiation exposure from environmental sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.9. Analysis of hot spots and possible accidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10.1. Chernobyl affected areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10.2. Nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10.3. Uranium mining and milling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10.4. Other radiological sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10.5. Human exposure to radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10.6. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.11. Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.11.1. Chernobyl affected areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.11.2. Nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.11.3. Uranium mining and processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.11.4. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References to Section 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1
1
1
2
2
3
3
3
3
4
4
6
6
6
8
8
8
9
9
9
9
10
10
10
11
11
11
12

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13

References to Section 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14

RADIOACTIVITY IN THE DNIEPER RIVER BASIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15

3.1. Areas affected by the Chernobyl nuclear accident . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2. Nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3. Uranium mining and processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4. Radioactive waste storage and disposal sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5. Non-power sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References to Section 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15
18
18
19
19
19

CHERNOBYL AFFECTED AREAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

4.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2. Distribution of fallout from the Chernobyl accident . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3. Monitoring of radioactivity in the environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21
21
26

5.

4.3.1. Types of environmental monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1.1. Airborne monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1.2. Surface waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1.3. Bottom sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2. Monitoring sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2.1. Belarus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2.2. Russian Federation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2.3. Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3. Databases on surface waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.4. Data quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.5. Storage, publication and use of monitoring data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4. Characteristics of radionuclide runoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.1. Radionuclide dynamics in catchment areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.2. Characteristics of runoff in Belarus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.3. Characteristics of runoff in the Russian Federation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.4. Chernobyl exclusion zone, Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5. Analysis of key processes governing the long term dynamics of radioactive contaminationof the Dnieper water system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6. Transboundary fluxes of radionuclides in the Dnieper River basin . . . . . . . . . . . . . . . . . . . . . . . .
4.7. Radionuclides in the Dnieper reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7.1. Assessment of radionuclide influx into the cascade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7.2. Current state of the radioactive contamination of the reservoirs . . . . . . . . . . . . . . . . . . . .
4.7.3. Current state of radioactive contamination of the bottom sediments . . . . . . . . . . . . . . . .
4.8. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References to Section 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

26
27
27
27
28
28
28
29
31
33
36
36
37
39
40
42

NUCLEAR POWER PLANTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65

5.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2. Nuclear reactors in the region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.1. Russian reactors within the Dnieper River basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.1.1. Kursk nuclear power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.1.2. Smolensk nuclear power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.2. Ukrainian reactors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.2.1. Zaporozhe nuclear power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.2.2. Rovno nuclear power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.2.3. Khmelnitski nuclear power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.2.4. South Ukraine nuclear power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.3. Ignalina nuclear power plant, Lithuania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3. Safety features of nuclear reactors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.1. Russian Federation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2. Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4. Licensing status of nuclear facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.1. Russian Federation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.2. Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5. System for environmental radiation monitoring in the vicinity of nuclear power plants . . . . . . .
5.5.1. Russian Federation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.2. Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.3. Belarus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6. Releases from nuclear reactors in the Dnieper River basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.1. Releases from the Kursk and Smolensk nuclear power plants . . . . . . . . . . . . . . . . . . . . . .
5.6.2. Radioactive contamination in the vicinities of the Kursk and Smolensk
nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65
65
65
65
65
66
66
66
67
67
67
68
68
69
71
71
72
74
74
75
75
75
75

49
51
53
53
54
57
61
62

76

6.

7.

5.6.2.1. Soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.2.2. Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.2.3. Natural water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.3. Releases from Ukrainian nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7. Management of radioactive waste and spent fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.1. Russian nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.2. Ukrainian nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.2.1. Zaporozhe nuclear power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.2.2. Rovno nuclear power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.2.3. Khmelnitski nuclear power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8. Overview of safety analyses performed for nuclear reactors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8.1. Russian Federation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8.2. Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.9. Status of the implementation of safety improvement programmes for nuclear facilities . . . . . . .
5.9.1. Russian Federation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.9.2. Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.9.3. Emergency preparedness and response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.10. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.11. Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References to Section 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

76
77
78
78
81
81
82
82
83
83
84
84
85
86
86
90
91
93
93
94

URANIUM MINING AND ORE PROCESSING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

96

6.1.
6.2.
6.3.
6.4.

96
96
97
98
98
98
100
101
103
103
103

Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overview of uranium mining and processing in the Dnieper River basin . . . . . . . . . . . . . . . . . . .
Systems for monitoring pollution from the uranium industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sources of potential contamination at the Zhovti Vody site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.1. Tailings KBZh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2. Tailings Sch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.3. Tailings R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.5. Assessment of the sources of contamination of natural waters in the Zhovti Vody area . . . . . . .
6.6. Effect of in situ leaching of uranium on contamination of natural waters . . . . . . . . . . . . . . . . . . .
6.6.1. Devladovo site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.6.2. Forecast of the long term potential contamination of the Saksagan River . . . . . . . . . . . .
6.7. Impact of the former Pervomayskaya uranium mining operation on radioactive
contamination of natural waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.8. Radioactive waste from former uranium processing in Dniprodzerzhinsk . . . . . . . . . . . . . . . . . .
6.8.1. Tailings Zapadnoye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.8.2. Tailings Centralny Yar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.8.3. Tailings Yugo-Vostochnoye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.8.4. Tailings Dniprovske (D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.8.5. Base C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.8.6. Tailings C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.8.7. Other contaminated areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.9. Assessment of the impact of waste from the Prydniprovsky chemical plant . . . . . . . . . . . . . . . . .
6.10. Plans for future restoration of radioactive waste sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.11. Conclusions and recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References to Section 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

105
106
107
108
108
108
110
110
110
111
114
114
115

OTHER RADIOLOGICAL SOURCES WITHIN THE DNIEPER RIVER BASIN . . . . . . . . . . . .

116

7.1. Research reactors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2. Medical and industrial uses of radioisotopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3. Buried waste of Chernobyl origin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

116
116
117

8.

9.

7.3.1. Storage and disposal sites in Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.2. Waste from decommissioning of Chernobyl nuclear facilities . . . . . . . . . . . . . . . . . . . . . . .
7.3.3. Chernobyl contaminated waste in Belarus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.4. Disposal sites in the Russian Federation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4. Storage/disposal of radioactive waste from non-power applications . . . . . . . . . . . . . . . . . . . . . . .
7.4.1. Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.2. Belarus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.5. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References to Section 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

117
118
119
120
121
121
123
124
125

ASSESSMENT OF HUMAN EXPOSURE TO RADIATION WITHIN THE
DNIEPER RIVER BASIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

126

8.1. Overview of radiation doses and associated health effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.1. Doses of ionizing radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.2. Radiobiological effects and health risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.3. International system of radiation protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.4. Radionuclides in the Dnieper River basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2. Major sources and pathways of human exposure in the Dnieper River basin . . . . . . . . . . . . . . . .
8.3. Models of external and internal exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.3.1. Model for external exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.3.2. Model for internal exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.4. Dose from natural radionuclides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.4.1. General public . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.4.2. Population of the Ukrainian uranium mining and milling areas . . . . . . . . . . . . . . . . . . . . .
8.5. Present and future human exposure levels caused by Chernobyl fallout . . . . . . . . . . . . . . . . . . . .
8.5.1. General public . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.5.2. Inhabitants of contaminated areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.5.2.1. External exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.5.2.2. Internal exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.5.2.3. Total dose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.6. Contribution of aquatic pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.6.1. General public . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.6.1.1. Consumption of drinking water from the Dnieper reservoirs . . . . . . . . . . . . . . .
8.6.1.2. Consumption of fish taken from the Dnieper reservoirs . . . . . . . . . . . . . . . . . . .
8.6.1.3. Consumption of agricultural products grown on lands irrigated using
water from the Dnieper reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.6.2. Hot spots: closed lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.7. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References to Section 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

126
126
126
128
129
130
131
131
132
134
134
135
137
138
138
139
139
140
143
143
143
143

RADIOLOGICAL HOT SPOTS IN THE DNIEPER RIVER BASIN . . . . . . . . . . . . . . . . . . . . . . . .

149

9.1. Concept of radiological hot spots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.2. List of the candidate radioactive hot spots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3. Assessment of the hot spots in the Chernobyl affected areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.1. Pripyat River floodplain upstream of the Chernobyl nuclear power plant . . . . . . . . . . . .
9.3.2. Chernobyl cooling pond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.3. Chernobyl shelter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

149
150
150
150
154
156

143
145
146
147

9.3.3.1. Assessment of Dnieper River basin contamination due to surface
water transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.3.2. Radionuclide flux from the shelter to the Pripyat River via groundwater . . . .
9.3.3.3. Scenario 1: Shelter without the new safe confinement . . . . . . . . . . . . . . . . . . . . .
9.3.3.4. Scenario 2: Shelter with the new safe confinement . . . . . . . . . . . . . . . . . . . . . . . .
9.3.4. Chernobyl exclusion zone (Ukrainian and Belarusian parts) . . . . . . . . . . . . . . . . . . . . . . .
9.3.5. Affected areas outside the Chernobyl exclusion zone: closed lakes . . . . . . . . . . . . . . . . . .
9.3.5.1. Russian Federation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.5.2. Belarus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.5.3. Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.5.4. Overall assessment of closed lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.6. Affected areas outside the Chernobyl exclusion zone: Kiev reservoir . . . . . . . . . . . . . . . .
9.4. Uranium processing sites in Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5. Waste storage/disposal facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.1. Ecores facility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.2. RADON radioactive waste storage sites in Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.3. Waste storage facilities at nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.6. Potential accidents at nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.7. Final classification of hot spots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References to Section 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

157
160
161
162
163
163
164
165
166
167
167
168
171
171
171
173
173
176
177

MAJOR CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

180

10.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.2. Chernobyl affected areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.3. Nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.4. Uranium mining and milling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.5. Other radiological sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.6. Human exposure to radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.7. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.7.1. Classification of hot spots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.8. Possible accidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

180
180
180
180
181
181
182
182
182

RECOMMENDATIONS TO THE GOVERNMENTS OF BELARUS,
THE RUSSIAN FEDERATION AND UKRAINE FOR THE STRATEGIC ACTION PLAN
AND NATIONAL ACTION PLANS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

183

11.1. Chernobyl affected areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.2. Nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.3. Uranium mining and processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.4. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

183
183
183
184

CONTRIBUTORS TO DRAFTING AND REVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

185

10.

11.

1. SUMMARY
1.1. INTRODUCTION
As a contribution to the Dnieper Basin
Environmental Programme (DBEP), an international team of scientists, under the direction of the
IAEA, carried out an assessment of radioactive
contamination in the Dnieper River basin. The
DBEP is being carried out under the United
Nations Development Programme — Global
Environment Facility (UNDP–GEF).
The current phase of the DBEP involved amajor revision of the previous transboundary
diagnostic analysis (TDA) for the Dnieper Riverbasin and preparation of a strategic action plan
(SAP) and national action plans (NAPs). This
report is a detailed technical report of the IAEA’s
contribution to this programme and elaborates
upon a summary document provided to the UNDP–GEF in November 2002. The IAEA assessment
involved two fact finding missions, two meetings ofthe international expert team and participation byteam members in a number of workshops organizedby the UNDP–GEF.

1.2. RADIOACTIVE SOURCE TERMS
The main sources (actual and potential) ofradioactivity and radiation exposure within the
Dnieper River basin were identified as follows:
(a)
(b)
(c)
(d)
(e)

Areas affected by the Chernobyl nuclear
accident;
Nuclear power plants;
Uranium mining and ore processing;Radioactive waste storage and disposal sites;
Non-power sources (e.g. from the use ofradiation and radioisotopes in medicine,industry and research).

The study considered the public exposurelevels (past, present, projected and potential) andassociated adverse effects of these sources onhuman health and the environment.
Of the above sources, Chernobyl affectedareas currently produce transboundary effects.
Nuclear power plants have the potential to produce
major transboundary impacts in the event of a
nuclear accident. The transboundary impacts of theother source terms are likely to be small, although
their impact could be considerable within a local
region or a single country.

1.3. CHERNOBYL AFFECTED AREAS
The Chernobyl nuclear power plant site lies innorthern Ukraine within the Dnieper River basin
and very close to the border with Belarus. The
Chernobyl accident on 26 April 1986 released large
amounts of radioactivity into the air: 1760 PBq1 of
131
I, 85 PBq of 137Cs, 54 PBq of 134Cs, 10 PBq of 90Sr
and 0.07 PBq of 239,240Pu, as well as many shorter
lived radionuclides of lesser radioecological significance. The fallout of this activity was dependent on
the vagaries of the wind direction and rainfall overthe period of the releases. The deposition was
greatest in the three countries (Belarus, the RussianFederation and Ukraine) that lie within the Dnieper
River basin.
The most serious consequences of theChernobyl accident to the public were caused byexposure to short lived radionuclides, especially 131I,
which resulted in many thyroid cancers [1.1]. Other
health effects may be expected in the future fromthe exposures received by some individuals during
the accident phase.
This assessment is concerned with the current
and future exposures resulting from contaminationof the Dnieper River basin with radionuclides. Of
those radionuclides still remaining from the
Chernobyl accident, 137Cs (half-life 30 years) and90
Sr (half-life 29.1 years) are the most importantfrom an environmental and public healthperspective. Caesium-137, with its short lived
daughter, 137mBa, emits beta and gamma radiation;
90
Sr, with its short lived daughter, 90Y, emits strong
beta radiation.
Caesium is volatile at the high temperaturesthat were experienced during the Chernobyl
accident. Consequently, it tended to travel
substantial distances before being deposited. Bothin the environment and in the human body, caesium
radionuclides behave like potassium. Strontium,
however, is not particularly volatile and was mainly
associated with fuel particles, which were deposited
1

1 PBq = 1 × 1015 Bq ≈ 27 000 Ci.

1much closer to the release point. In the environment
and in the human body, strontium radionuclides
behave like calcium (hence strontium is a ‘boneseeker’).
Within the catchment area of the Dnieper
River basin, an area of about 85 000 km2 has asurface contamination of 137Cs above 37 kBq/m2(1 Ci/km2). On the territory of Belarus, the worst
affected areas are the Gomel and Mogilev regions.
Within the Russian Federation, the south-west partof the Bryansk region was the most affected. In
Ukraine, contamination was particularly high in theKiev, Zhytomyr and Chernihiv regions.
The Pripyat basin within Belarus and Ukraine,and especially the Chernobyl exclusion zone
(CEZ), received the highest contamination of 90Sr
and plutonium isotopes.
1.3.1.

Transboundary migration of radionuclides

One of the more serious long term ecologicaleffects of the Chernobyl fallout was the secondary
runoff (‘wash-off’) of radionuclides from theinitially contaminated areas through the river
networks of Belarus, the Russian Federation andUkraine into the Dnieper reservoir system, thereby
expanding the spatial scale of the accident andexposing the millions of people who use thedownstream resources of the Dnieper River.
Since the Chernobyl accident, water
monitoring stations have been established within
the CEZ and along the major rivers to determine
the concentration of radionuclides and their total
flow. Although these stations are not ideally suitedfor monitoring transboundary fluxes, estimates havebeen made for 137Cs and 90Sr (see Table 1.1).

The transboundary migration of 137Cs has
decreased markedly with time. However, the transboundary migration of 90Sr has fluctuated from year
to year, depending on the extent of annual flooding
along the banks of the Pripyat River. The extent of
washout of radionuclides is, however, only a verysmall percentage of the total inventory in thecatchment area (see Table 1.1).

1.3.2.

Behaviour of caesium-137 andstrontium-90 in the environment

The migration characteristics of 137Cs and 90Sr
can be understood from an appreciation of thechemistry of their respectively elements, caesium
and strontium. Caesium has an affinity for clay
minerals frequently occurring in natural soils.
Binding of caesium to soil retards its lateral andvertical migration. Strontium is less firmly bound tomineral sites and is consequently more mobile in
the environment. The soils of the CEZ are heavily
contaminated with 90Sr, and some is washed off
during flood events when the low lying areas
become inundated.
The chemistry of the respective elements also
explains their behaviour upon entering the Dnieper
cascade. Caesium-137 tends to become fixed to clay
sediments, which are deposited in the deeper
sections of the reservoirs, especially the Kiev
reservoir. Very little 137Cs flows through thecascades because of this process and consequently
the present concentration entering the Black Sea is
indistinguishable from background. However,
although 90Sr concentration decreases with distancefrom the source (mainly due to dilution), about

TABLE 1.1.
ESTIMATES OF TRANSBOUNDARY TRANSPORT OF CAESIUM-137 AND
STRONTIUM-90 BY MAJOR RIVERS FLOWING THROUGH CHERNOBYL AFFECTED REGIONS
Years
SectionBorderCaesium-137 outflow(TBq)

1987–1999

Caesium-137(% catchment inventory)
Strontium-90 outflow(TBq)
Strontium-90(% catchment inventory)

2

1990–1999

Iput River

Besed River

Pripyat River

Dnieper River

DobrushBelarus–RussianFederation

Svetilovichi
Belarus–RussianFederation

Belaya Soroka
Belarus–Ukraine

Nedanchichi
Belarus–Ukraine

9.1

1.9

31.3

43.1

0.4

0.1

0.7

0.56

0.9

0.7

52.6

34.3

2.2

1.9

4.3

3.6

40-60% passes through the cascade and reaches theBlack Sea.
The concentrations of 137Cs and 90Sr in flowing
rivers are now well below the permissible levels set
by the national authorities and below internationalguideline levels for drinking water. However, lakes
with no regular outflows still present a radiologicalproblem that will continue for some time. In such
systems, which are usually associated with
underlying peat deposits, there is no mechanism for
fixation of 137Cs. Consequently, 137Cs concentrations
in water are close to the permissible levels fordrinking water, while the levels in fish exceed thepermissible levels by one to two orders ofmagnitude. Moreover, higher than permissible
radionuclide levels are measured in forest foods(wild game, mushrooms, berries) as well as in milk
and beef produced by cattle grazing on contaminated floodplains. These areas were identified as
possible local ‘hot spots’ for more detailed
consideration.

Chernobyl reactor units. It was completed in 1982,
covers an area of approximately 23 km2 andcontains approximately 149 × 106 m3 of water. The
cooling pond is located less than 1 km from the
Chernobyl nuclear power plant; a dam separates thepond from the Pripyat River.
The pond was heavily contaminated during
the Chernobyl accident and by subsequent dumpingof radioactive liquid waste into it. The total
inventory of radionuclides is estimated to be atpresent in excess of 200 TBq, with the deep
sediments containing most of this activity.
Currently, the water level is kept artificially high;however, this will change when the cooling systems
at the Chernobyl nuclear power plant are finallyshut down and pumping of water into the pond is
terminated. This will leave the sediments partly
exposed and subject to dispersal. Contamination of
the Pripyat River could also occur if the dam werebreached or otherwise damaged.

1.3.3.

1.3.6.

Chernobyl exclusion zone

The CEZ contains a number of discrete
contamination sources that represent separate
problems: flood prone land along the banks of the
Pripyat River, the Chernobyl nuclear power plantcooling pond, waste burial sites and the shelter thathouses the crippled Chernobyl reactor.
1.3.4.

Contaminated floodplain

The floodplain along the Pripyat River ishighly contaminated from the Chernobyl accident,
especially with 90Sr, where concentrations exceed
4000 kBq/m2 over large areas. This area is regularly
inundated, especially during spring floods.
Moreover, some of the waste burial sites are locatedwithin the floodplain. Engineering works have been
undertaken to mitigate the flooding but have notbeen completed because of financial problems.
Radioactivity, especially 90Sr, is washed off thefloodplain during times of high flood andtransported via the Pripyat River to the Dnieper
reservoir system.
1.3.5.

Chernobyl cooling pond

The cooling pond of the Chernobyl nuclear
power plant is an artificial lake built to provide thecooling water for the condensers of the four

Chernobyl shelter

The Chernobyl shelter was constructed upon
the ruins of the destroyed reactor building of
Chernobyl unit 4 and was completed in November
1986. This containment was erected under difficult
circumstances in very high radiation fields using
remote construction methods. Unfortunately, as aresult of construction difficulties, there are now
openings and breaks in the walls and the roof of the
shelter, which is estimated to total about 1200 m2 inarea.
The shelter contains between 173 and 200 t of
nuclear fuel with an activity of up to 750 PBq(20 MCi) of 238U and 235U and their daughter
products, as well as long lived fission and neutron
activation products, including 137Cs, 90Sr, plutonium
radionuclides and 241Am. Most of the fuel is now
contained in a lava-like matrix containing many
inclusions of various uranium compounds, finely
dispersed high level active fuel dust, and aerosols.
Contamination of the environment by radioactive
substances from the shelter may occur in two
principal ways: (a) release of fuel dust into theatmosphere through openings in the shelter if there
is a collapse of internal structures; and (b) migrationof radionuclides through the subsurface together
with water that is inside the shelter. A new safe
confinement is planned above the existing shelter
after 2007.

3

1.4. NUCLEAR POWER PLANTS
There are 17 operating nuclear power reactors
in the Dnieper River basin, ten in Ukraine at threesites (Zaporozhe, Rovno and Khmelnitski) andseven in the Russian Federation at two sites (Kursk
and Smolensk). In addition, there are three nuclear
power reactors (South Ukraine nuclear power
plant) in the southern Bug River basin. Ukraine isheavily dependent on nuclear power, which supplies
about 45% of its electricity needs. The Zaporozhe
nuclear power plant, comprising six 1000 MW(e)units adjacent to the Kakhovka reservoir, is one of
the largest in the world. Currently, one 1000 MW(e)nuclear power reactor is being commissioned at
Rovno, while another is under construction at
Khmelnitski.
Our examination of discharge and monitoringdata for nuclear power plants in Ukraine and in the
Russian Federation shows that routine discharges
are generally well below authorized limits and do
not contribute to significant contamination of theenvironment. Waste management facilities (including
spent fuel storage) do not present a problem,
although storage facilities in several cases are close
to capacity and new facilities are required in
Ukraine to accommodate the increasing quantity ofspent fuel. Previously, spent fuel was sent to theRussian Federation for reprocessing, and a policy
for the long term management of spent fuel needs
to be developed. The provision of dry storage
facilities, as at the Zaporozhe nuclear power plant,
is an acceptable midterm strategy.
A major accident at a nuclear power plant can
result in major transboundary impacts. The accident
at Chernobyl nuclear power plant unit 4, which wasa high power channel type (RBMK) reactor, is an
example of the transboundary effects of a nearworst case nuclear disaster. Since that accident,
Russian built reactors have been subject to many
internal and international reviews, and upgrades
have been undertaken with the aim of improving
nuclear safety.
Immediately after the Chernobyl accident,
urgent measures were taken to improve theinherent safety of the first generation RBMKs.
These measures included reduction of the positive
void effect and increased neutron absorbers. Thiswas followed by the first stage of modernization,
which took place in the 1990s. The second stage ofmodernization is ongoing. These engineering
upgrades have been complemented by increased
licensing requirements and regulatory scrutiny.
4

The Ukrainian reactors are water cooled,water moderated units (WWERs), which belong to
the category of pressurized water reactors (PWRs),
the most common reactor type in the world. The
main WWER design criteria are consistent withcurrent international safety practices. Efforts areunder way to improve emergency operatingprocedures and to develop accident management
guidelines. An international in-depth safetyassessment process is under way to optimize theimprovement programmes.
The system for emergency preparedness andresponse in Ukrainian and Russian nuclear power
plants is based on the recommendations of the
IAEA. Strengthening of this system requires
further development of the automatic monitoring(early warning) system around each nuclear power
plant and of the real time decision support systemfor off-site emergency management. The enhanced
decision support system should include modules
that forecast post-accident contamination of water
bodies after accidental fallout or direct releases into
the water. Information exchange between nuclear
power plant emergency units and regional
authorities should also be improved.

1.5. URANIUM MINING AND PROCESSING
The only uranium mining and ore processingin the Dnieper River basin is in Ukraine. Uranium
exploration started in 1944 and led to the discovery
of 21 deposits. Many of the deposits are within thewatershed of the Dnieper River basin, while someare within the basins of the southern Bug andSeversky Donets Rivers.
The first uranium processing plant was thePrydniprovsky chemical plant, which started
operations in 1948 using ores shipped fromcountries in central Europe. It is situated a few
kilometres from the Dnieper River in the city of
Dniprodzerzhinsk and ceased operations in 1991.
The Zhovti Vody hydrometallurgical plantcommenced production in January 1959 to processores from the region. Current production is about1000 t U/a. Most of the current production comesfrom the Ingulsky mine, developed on theMichurynske deposit.
There are plans to mine the Severinske
deposit, which has reserves of 64 000 t U at an
average grade of 0.1% uranium. Doubling of thecapacity of the ore processing plant to 2000 t U/a isenvisaged.

Three ore bodies — Bratske, Devladovske
and Safonovske — have been exploited by the insitu leaching method. This involves injection ofsulphuric acid into the ore body and avoids the
problems of tailings management, but, underunfavourable conditions, can result in contamination of groundwater.
Uranium mining and milling has a number ofpotential impacts on human health and theenvironment. They include:
(a)
(b)
(c)
(d)
(e)
(f)
(g)

Contamination of mine water with uraniumand other radionuclides;
Release of mill wastewaters to surface waters(usually after treatment);
Runoff of water from contaminated areas ofthe mine or mill;Radon release from mines, waste rock dumps
and mill tailings piles;
Leaching of radionuclides from tailings andtheir subsequent transport in water;
Erosion of tailings storage systems, leading todispersal of tailings by wind and water;
Contamination of underground and surface
waters by toxic non-radioactive substancessuch as heavy metals and the chemicals used inprocessing.

The most important waste from the milling of
uranium is the finely divided solid residue known as
tailings. Tailings typically contain 70% of the radioactivity in the original ore, including the long lived
radionuclides 230Th (half-life 80 000 years) and 226Ra(half-life 1600 years). Radium is a continual sourceof 222Rn (half-life 3.8 days), which, being a gas, isreadily dispersed. Radon daughters are a source ofradiation exposure and a known cause of lungcancer in uranium miners.
The mining and processing of uranium ores at
Zhovti Vody has negatively affected theenvironment as well as the sanitary state of the town
since the start of operations in the 1950s. The main
sources of radioactive contamination are thefollowing three tailings sites:(i)

Tailings site KBZh has an area of 55 ha andcontains 19 × 106 t of radioactive waste,
deposited from 1964 until 1982. Restoration of
the site began in 1991 and is still incomplete
because of financial problems. At present,
most of the tailings are covered with 0.4 m ofclay to prevent dispersion of tailings dust.

(ii)

Tailings site Sch consists of two sections with a
total area of 250 ha and contains about 45 ×
106 t of radioactive waste. The new section wascommissioned in 1979 and is still operating.
(iii) Tailings site R has an area of 230 ha. It was
originally used as a storage pond for iron ore
milling sludge and was also used as a settling
pond for uranium mine drainage waters.
Runoff and seepage from the tailings, mines
and other contaminated sites leads to elevatedlevels of radionuclides in local rivers; however,levels are below the permissible levels for drinking
water.
The former Prydniprovsky chemical plant islocated alongside the Dnieper River on a large
industrial complex with other industries, such as
coke, and other metallurgical plants. During
operation of the plant, nine tailings dumps werecreated containing about 42 × 106 t of radioactive
waste with a total activity of about 4 × 1015 Bq(≈100 000 Ci).
Of the tailings dumps in the area, tailings D is
considered to have the greatest potential forpollution of the environment. The group has
assessed this site as a potential major hot spotbecause of the large amount of radioactivity(1500 TBq), the long half-life of the main radionuclides, the proximity to the Dnieper River, theevidence of current seepage and the possibility ofcatastrophic failure of the impoundment.
The Prydniprovsky chemical plant and related
facilities are responsible for elevated levels of
uranium and its daughters in the Konoplyanka andDnieper Rivers. In order to determine the effects ofuranium mining and ore processing in the region, it
is necessary to carry out a pathway analysis. Such ananalysis requires information on radioactivity levels
in air, vegetation and food products. Currently suchinformation is lacking and needs to be obtained
before remedial actions are prioritized andundertaken.
There is a need to stabilize tailings impoundments against failure over long time periods basedon international consensus, having regard for thelong half-lives of the radionuclides in the tailings. It
is also in accord with Principle 4 (Protection of
Future Generations) and Principle 5 (Burden on
Future Generations) of Ref. [1.2].

5

1.6. RADIOACTIVE WASTE STORAGE ANDDISPOSAL SITESRadioactive waste disposal sites in the
Dnieper River basin include:
(a)

(b)

(c)

The Ecores State facility near Minsk, which
comprises two closed trenches and two repositories that are being progressively filled. Thisfacility accepts radioactive waste from the
nearby Institute of Radiation Physics andChemistry Problems, National Academy of
Sciences of Belarus (Sosny), and from morethan 100 organizations from the industrial,
research and medical sectors. The facility is
2 km from the Slouch River; the nearest pond
is 1.6 km away. This facility is below current
international standards for engineered
disposal of low and intermediate level waste.
However, the repository is remote from theDnieper River and any environmental impact
in the future will be localized.
Two disposal sites operated by the RADON
State enterprise at Kiev and Dnipropetrovsk.
These sites handle both radioactive waste andspent radiation sources from the non-nuclear
power plant sector, including the industrial,
medical and agricultural sectors.
Many disposal or ‘temporary’ storage sites inBelarus and Ukraine for waste from the
Chernobyl nuclear power plant. The largest ofthese is the Buriakovka repository, which
consists of 30 trenches with a 1 m thick bottom
isolation clay.

These facilities have the potential for
moderate impact within the local area. There are no
significant radioactive waste disposal sites in the
Russian section of the Dnieper River basin.
Waste storage sites are not considered to havea major impact because of the high degree ofengineered
containment.
However,mostradioactive waste storage sites at nuclear power
plants are close to capacity.

1.7. NON-POWER SOURCES
Non-power sources include research reactors
and those arising from the application of radioisotopes and radiation in medicine, industry andresearch.
6

The research reactors at the Sosny Institutenear Minsk and the Institute for Nuclear Researchat Kiev are shut down. The decommissioning ofthese reactors will be a significant source ofradioactive waste. However, in their current state
they do not directly impact on the environment.
Disused radiation sources are a potential
source of exposure if not properly managed. They
are often very intense sources of radiation, and in
the past poor management has resulted in highexposures of individuals in several countries.
Regulatory authorities need to maintain a registerof sources and ensure that they are properly
licensed and managed.
Overall, non-power sources have a limited andlocalized impact on the environment and publichealth.

1.8. HUMAN RADIATION EXPOSURE
FROM ENVIRONMENTAL SOURCES
Exposure to radiation at low doses, which istypical for public exposure from environmental
sources, can cause stochastic detrimental healtheffects (i.e. malignancies and hereditary effects).
The fundamental quantity used in radiation
protection to characterize the level of human
exposure associated with stochastic health effects isthe ‘effective dose’. The unit of effective dose is thesievert (Sv), but the smaller unit of millisievert(mSv) is more appropriate for normal exposures.
The worldwide level of annual natural
background exposure, including external exposure,consumption of food and water containing naturalradionuclides, and inhalation of radon with its
daughter products, amounts on average to 2.4 mSv,
with a range from 1 to 10 mSv. In Ukraine the mean
background exposure is about 2.5 mSv, which is inline with worldwide levels.
The internationally recommended annual
dose limit for controlled exposures of the generalpublic is equal to 1 mSv. For prolonged exposure
situations from all environmental radioactive
sources, including natural and human-made sources,
the International Commission on RadiologicalProtection (ICRP) recently recommended a genericintervention level of existing annual dose equal to
10 mSv as the level below which intervention isunjustified, taking into account radiological,
economic and social factors.
Radiation exposure of the population of the
Dnieper River basin is caused by both naturallyoccurring radionuclides and human-made radionuclides, mainly nuclear fission products (137Cs, 90Srand some others). The pathways of long term
environmental human exposure include external
exposure with gamma radiation and internal
exposure via ingestion of contaminated food anddrinking water as well as inhalation of airborne
radionuclides.
Whereas natural radiation accompanies thewhole human history, significant environmental
contamination with human-made radionuclides
occurred during two time periods: first in the 1950s
and 1960s as a result of global stratospheric fallout
from worldwide nuclear weapons tests and later in1986 when a large radioactive release occurred
directly into the Dnieper River basin due to theChernobyl accident. Local contamination of the
Dnieper River basin in 1986 led to the highest
population doses caused by the Chernobyl accident
in Europe.
In the long term after the Chernobyl accident,
the inhabitants of areas contaminated with radionuclides in 1986 are still subjected both to external
exposure from 137Cs gamma radiation and tointernal exposure due to consumption of local
foodstuffs containing 137Cs and, to a lesser extent,
90
Sr. Inhalation of plutonium radionuclides and241
Am does not significantly contribute to humandoses. In accordance with the environmental
behaviour of 137Cs and 90Sr, external exposure
prevails in areas with dominantly black soils, andthe contribution of internal exposure to the total(external and internal) dose does not exceed 10%.
In contrast, in areas with light sandy soils, thecontributions due to internal and external exposure
are comparable, and, in areas with peaty soils, theinternal exposure dominates. At present, along with
consumption of local agricultural vegetable andanimal (milk and meat) foods, consumption ofnatural foods (lake fish, forest mushrooms andberries, game), which is typical for the Dnieper
River basin population, significantly contributes (upto 50–70%) to 137Cs intake in the human body andthe associated internal dose.
After 1995, average total annual doses of
inhabitants of settlements located in the Chernobyl
accident areas, caused by environmental 137Cs and90
Sr, ranged from 0.1 to about 5 mSv; the contribution of 90Sr being usually below 5%. The
inhabitants of the settlements of the Gomel andMogilev regions of Belarus and the Bryansk regionof the Russian Federation, where 137Cs soil

contamination exceeds 1 MBq/m2, are subjected tothe highest exposure levels. In many tens of settlements, the average annual exposure level still
exceeds the national action level of 1 mSv.
The contribution of freshwater pathways topublic exposure is dependent on the direct
consumption of water and fish containing radionuclides as well as on the flooding of land used forlivestock grazing/haymaking and utilization of riverwater for irrigation of agricultural land, which leads
to subsequent human exposure via terrestrial
pathways. In the lower Dnieper River reaches,
which were not subjected to direct radionuclide
contamination in 1986, almost all the Chernobyl
exposures are attributed to water pathways;
however, the dose itself is very low. In most of thedirectly Chernobyl contaminated areas the humandose is much higher (see previous paragraph), but it
is mostly attributable to terrestrial pathways.
The exception is a number of ‘closed’ lakes(without a regular outflow) located in peaty areas,in which the concentration of 137Cs (and to a lesser
extent of 90Sr) in water and fish is much higher thanin the nearest rivers. These concentrations do notsignificantly decrease with time, and in many lakes
still exceed the permissible levels for drinking waterand especially for fish. The consumption of contaminated fish prevails as the pathway of internal
exposure of the inhabitants of the nearest settlements. In some of these settlements the averageannual human dose exceeds 1 mSv, and therefore
closed lakes and their inhabited surroundings are
considered in this report as actual local hot spots.
Another source of internal exposure of the
inhabitants of some Ukrainian riparian settlements
via consumption of river water and fish is therelease of uranium radionuclides and their daughter
products from mining and milling facilities locatedin the Dnipropetrovsk region. Significantly elevatedlevels of 234U, 238U and 210Po in water have recently
been detected in rivers downstream of Zhovti Vody
and of the uranium tailings dumps of the Prydniprovsky chemical plant. For people drinking waterfrom contaminated rivers, an associated annualinternal dose of the order of 0.1 mSv has been
estimated. However, there are insufficient datafrom other pathways (contaminated food, radon,etc.) to determine the total exposure of individuals
living in these areas. As the uranium concentrationin river water approaches or could approach thenational action level, both sites are identified as
local hot spots.

71.9. ANALYSIS OF HOT SPOTS AND
POSSIBLE ACCIDENTS
Following the UNDP Hot Spots Workshop in
Kiev, the following definitions, which take account ofradiation protection methodology, were proposed.
Hot spot. A technical facility, object or local
natural site that is contaminated with radionuclides
or, in the future, could become a source of environmental radioactive contamination above reference
levels or could result in human or biota exposure
above radiological criteria.
Transboundary hot spot. A hot spot that is, orin the future could become, a source of environmental radioactive contamination above reference
levels or could result in human or biota exposure
above radiological criteria on the territory of
another country.
National hot spot. A hot spot that occupies, orin the future could occupy, a substantial national
territory and that has no significant transboundary
impacts.
Local hot spot. A hot spot that occupies a
local area.
Initially, the group made a list of candidate hot
spots. A screening process was then applied, basedon the above criteria, to determine the final list as
follows.
Actual hot spots:
(a)

(b)

(c)

The Pripyat floodplain area within the CEZ.
This is assessed to be a transboundary hot spotwith a current impact and a greater impact
during times of high flooding.
The radioactive waste dumps on the former
Prydniprovsky chemical plant site in
Dniprodzerzhinsk and of the uranium
processing operation in Zhovti Vody. These
are actual national hot spots with a potential
for a major impact over a very long period if
impoundment structures erode or failcatastrophically.
Inhabited areas in the three countries withhigh levels of Chernobyl caused radioactive
contamination, including closed lakes in which
concentrations of 137Cs in fish or drinking
water exceed the permissible levels. These are
local hot spots but occur in all three countries.

(ii)

The Chernobyl cooling pond in the event of
dam failure (national hot spot).
(iii) The Ecores and RADON facilities at Kiev andDnipropetrovsk, until reconstruction iscomplete (local hot spots).
Possible accidents: in addition to these actualand potential hot spots, an accident at a nuclear
power plant was considered. A major accident at anuclear power plant is considered to be of very low
probability, having regard for major and ongoing
improvements at nuclear power plants in the
Russian Federation and Ukraine. However, a large
release would have considerable transboundary
impacts, especially in the Black Sea if the source
were in the south of Ukraine.

1.10. CONCLUSIONS
1.10.1. Chernobyl affected areas
(1)

(2)

(3)

(4)

(5)
Potential hot spots:(i)

8

The Chernobyl shelter in the event of its
collapse (transboundary hot spot);

High levels of radioactivity remain within the
CEZ. Important hot spots within this zone are
the floodplain along the Pripyat River, theChernobyl nuclear power plant cooling pond
and the Chernobyl shelter.
There is still transboundary transfer of radionuclides (mainly 90Sr) by rivers within the
Dnieper River basin. The most importantsource is the floodplain of the Pripyat River
within the CEZ.
The concentrations of 137Cs and 90Sr in riverwaters of the Dnieper River basin havedecreased significantly and are now below the
maximum permissible levels set by thenational authorities and recommended byexpert international organizations. Almost all
the 137Cs washed out of contaminated areas isimmobilized in bottom sediments within thereservoirs of the Dnieper River. The impact ofthese sediments is low and will decline further
with decay and further deposition of
sediments on top of the contaminatedsediments.
Lakes with no regular outflows still present a
radiological problem arising from higher
levels of 137Cs in water and fish.
The levels of radioactivity in forest foods (wildgame, mushrooms, berries) in some Chernobyl
affected areas are above permissible levels, as
are those in milk and beef produced by cattle
grazing on contaminated floodplains.

1.10.2. Nuclear power plants
(6)

(7)

(8)

Routine discharges from nuclear power plants
in the Russian Federation and Ukraine are
generally well below authorized limits and do
not contribute to significant contamination of
the environment.
A legislative and regulatory basis establishedin both the Russian Federation and Ukraine
ensures that all nuclear power plants operatewith a valid licence. A legal mechanism exists
for regulatory body review and assessment ofplant safety and renewal of plant licences on aregular basis.
In recent years the safety of RBMK and
WWER reactors has been subject to considerable regulatory and international scrutiny.
Major engineering upgrades have been
undertaken to improve safety. An international in-depth safety assessment process isunder way to optimize the improvement
programmes. There is room for improvement
in emergency preparedness and response.

1.10.3. Uranium mining and milling(9)

Uranium mining and milling in Ukraine has
had a negative impact on the environment.
The most serious problem is caused by about
100 × 106 t of tailings and other radioactive
waste from past and current operations. Mostof the tailings dumps have not been properly
rehabilitated and will pose a long term
problem unless they are properly stabilized.
Tailings D at Dniprodzerzhinsk is considered
to have the greatest potential for pollution of
the environment because of its proximity to
the Dnieper River, the evidence of current
seepage and the possibility of catastrophic
failure of the impoundment. The situation in
the region of tailings C and adjacent to it
needs regular control, and decisions on further
use should be taken with regard to IAEA
recommendations and on the basis of a cost–benefit analysis.
(10) There is a paucity of data on the levels ofradionuclides in the vicinity of uranium mines
and mills and radioactive waste impoundments. Consequently, it is not possible toestimate the current or future dose rates fromthese sources with any degree of accuracy.
(11) There is a need to urgently start thedevelopment of modern standards on theprotection of the environment, radiation
safety and monitoring in the zone of influenceof the uranium sites, consistent with therequirements of Ukrainian law and the recommendations of international organizations
such as the IAEA.
1.10.4. Other radiological sources(12) Medical and industrial uses of radioisotopes
do not pose significant risks to the populationof the Dnieper River basin. Radioactive
sources with a high radioactivity could be asource of local exposure. Regulatory
authorities should ensure that they areproperly licensed and managed.
(13) There are many disposal or temporary storagesites for Chernobyl waste in Belarus, theRussian Federation and Ukraine. There is aneed to continue to monitor and characterize
the most hazardous of these sites; however,their impact appears to be quite localized anddoes not represent a major source of contamination of surface waters.
(14) There are two RADON type waste storage
facilities at Kiev and Dnipropetrovsk in the
Ukrainian section of the Dnieper River basin.
Further safety assessments need to beundertaken to assess their environmental
impact.
(15) The Ecores State facility near Minsk does notcomply with international standards for the
storage or disposal of radioactive waste. Thisfacility is a potential source of radioactive
contamination of the local population, but notof the Dnieper River basin as a whole.
1.10.5. Human exposure to radiation(16) The average dose rate to Ukrainian citizens
from natural radiation sources is about
2.5 mSv/a, which is close to the global average.
This value is also considered to be areasonable estimate of the average dose rate
to the population of the Dnieper River basin
as a whole.
(17) The inhabitants of areas contaminated withradionuclides from the Chernobyl accident in1986 are still being subjected both to external
exposure from 137Cs gamma radiation and tointernal exposure due to consumption of local
foodstuffs containing 137Cs and, to a lesser
extent, 90Sr. The most important factors
9controlling the mean external dose are thesettlement type (rural or urban) and the levelof 137Cs soil deposition (in kBq/m2). Forinternal exposures, the most important factors
are the soil type and the level of 137Cs soil
deposition. On average, effective doses to the
inhabitants of rural settlements are higher
than those to urban dwellers.
(18) The average total annual doses to the
inhabitants of settlements located in the
Chernobyl accident areas, caused by environmental 137Cs and 90Sr, range from 0.1 to about
5 mSv. In many tens of settlements the averageannual exposure level still exceeds thenational action level of 1 mSv.
(19) Dosimetric models have been developed andtested to estimate past, present and futureradiation exposures from all Chernobyl
related pathways. The models predict that, by
2001, people in affected areas had alreadyreceived at least 75% of their lifetime internal
dose due to 137Cs, 134Cs, 90Sr and 89Sr in
Chernobyl fallout. Dose rates will decrease
slowly with time over the next 50 years as
deposited 137Cs (half-life 30 years) decays andis made less available by soil redistribution
processes.
(20) For critical groups in Chernobyl contaminatedareas, wild foods (e.g. forest mushrooms,
game, forest berries and fish) can make animportant contribution to dose; for example,
in one study in the Bryansk region of theRussianFederation,‘natural’foods
contributed from 50% to 80% of 137Cs intake.
The average annual internal dose due to 137Cs
was estimated to be 1.2 mSv for men and
0.7 mSv for women.
(21) In most cases, aquatic pathways (drinking
water, fish consumption and irrigation) makeonly a small contribution to the total dosefrom Chernobyl sources. At times of floodingof the Pripyat floodplain, dose rates increase
somewhat due to washout of 90Sr.
Furthermore, in some closed lakes the concentration of 137Cs remains high, and high levelsof contamination are found in fish species.
People who illegally catch and eat contaminated fish may receive internal doses in excess
of 1 mSv/a from this source.
(22) Routine releases of radionuclides fromoperating nuclear reactors in the Dnieper
River basin do not contribute significantly to10radiation exposure of communities living intheir vicinity.
(23) More data are required in order to makereliable estimates of exposures of people
living in uranium affected areas. Estimates of
exposure from the drinking water pathway
suggest low dose rates, except in small areasthat are unlikely sources of drinking water.
(24) Further work is needed to assess the potential
short term and long term doses that might bereceived if uranium tailings impoundments
adjacent to waterways in Ukraine were to failand release tailings and/or contaminatedwater into adjacent rivers.
1.10.6. General(25) Monitoring data are collected by various
agencies for different purposes; different
methodologies are used, some of which are
outdated. There needs to be harmonization of
results between the various organizations
engaged in monitoring.

1.11. RECOMMENDATIONS
1.11.1. Chernobyl affected areas
Within the CEZ:
(1)

(2)

(3)

(4)

(5)

(6)

The engineering works on the right bank of
the Pripyat River within the CEZ should becompleted. The works were started in 1998 but
were suspended due to lack of funding.
A diversionary canal should be constructedalong the Belarus–Ukraine border between
the settlements of Krasne and Zimovische toprevent inundation of the heavily contaminated areas on the Pripyat River’s left bank.
After 2007 the heavily contaminatedChernobyl cooling pond should be safely
decommissioned.
Appropriate measures need to be taken tomonitor and prevent releases of radioactivity
from the Chernobyl shelter.
Technical measures should be taken toprevent significant radionuclide dispersion
from the sites of temporary radioactive waste
storage in the floodplain of the Pripyat River.
The monitoring system for surface andunderground waters in the CEZ should be
improved and optimized.

(7)

(8)

(9)

Within inhabited areas:

1.11.3. Uranium mining and processing

In order to reduce population exposure in themost contaminated areas, the following
measures should be considered:(i) Restrict consumption of local foods (wildgame, fish, berries, mushrooms, etc.);(ii) Restrict grazing and use of vegetation on
floodplains;(iii) Provide safe water to rural communities.
The monitoring system for surface andunderground waters should be optimized. In
particular, screening studies on closed lakes in
the most contaminated areas should be
performed and their impact on population
exposure assessed.
The radiological criteria in the Chernobyl
affected countries should be harmonized.

(16) An ongoing system for radioecologicalmonitoring of the environment (water, soil,
vegetation, air and food products) in theaffected regions (Zhovti Vody, mining areas
and Dniprodzerzhinsk) needs to be established. This should involve provision of
appropriate equipment and coordination of
the efforts of the external monitoring organizations.
(17) The pollution resulting from past and present
operations in the Dniprodzerzhinsk industrial
complex needs to be considered holistically inorder to understand its respective contribution to pollution of the Dnieper River basin
and the effects of interactions between the
major waste storage areas. Essentially, there
needs to be an overall plan for the site, which
will include rehabilitation of sites along withpossible further industrial development.
(18) Rehabilitation of non-operational uranium
tailings impoundments at Zhovti Vody andDniprodzerzhinsk needs to be completed inorder to ensure that they provide long term
containment. In any rehabilitation plan,
particular attention should be given to tailings
D and to the Konoplyanka River, which isacting as a conduit for the transfer ofpollutants from the tailings impoundment into
the Dnieper River.
(19) Current and future operations need to be
carried out in accordance with an environmental plan that includes funding provisions
to ensure progressive rehabilitation of closed
mines, dumps and other facilities.

1.11.2. Nuclear power plants(10) Rules and regulations should be harmonizedwithin the Dnieper River basin and madeconsistent with international best practice.
(11) Cooperation and information exchange
between regulatory organizations should be
strengthened to make use of experience
gained in implementing safety upgrade
programmes.
(12) To improve preparedness for a possible
nuclear accident, technical measures (early
warning systems, decision support systems),
institutional measures (logistics) and links
between nuclear power plant and regional
administrative units should be improved.
(13) The scope of safety analysis reports should becompliant with national requirements andconsistent with the IAEA safety standards
and current international practice.
(14) Comprehensive plant specific probabilistic
safety assessments need to be finalized for all
nuclear power plants in the region andsubjected to thorough regulatory review. The
countries with nuclear power plants would
benefit from participation in activities
organized by the IAEA on comparison ofprobabilistic safety assessment studies for
similar reactors.
(15) Plans established for safety improvements
should be carried out as a matter of urgency.

1.11.4. General(20) Existing laws, regulations and guidelines
should be reviewed and revised:(i) To ensure that radiation safety provisions
are consistent within the region andcompliant with the latest international
standards;(ii) To apply risk assessment methodologies
to account for radioactive, chemical andbiological contamination.
(21) More detailed impact analysis of actual andpotential hot spots should be undertaken
within the framework of a specialized project.

11(22) Monitoring of the environmental radioactive
contamination in the Dnieper River basinshould be improved and harmonized among
Belarus, the Russian Federation and Ukraine.
(23) Scientific research that contributes to theassessment, understanding and solution ofradiological problems in the Dnieper Riverbasin should be supported.

12

REFERENCES TO SECTION 1
[1.1]

[1.2]

UNITED NATIONS, Sources and Effects of
Ionizing Radiation (Report to the General
Assembly), Annex J: Exposures and Effects of theChernobyl Accident, United Nations ScientificCommittee on the Effects of Atomic Radiation(UNSCEAR), UN, New York (2000).
INTERNATIONALATOMICENERGYAGENCY, The Principles of Radioactive Waste
Management, Safety Series No. 111-F, IAEA,
Vienna (1995).

2. INTRODUCTION
The Dnieper is the third largest river in Europe(after the Volga and the Danube). It drains an area of
511 000 km2 and has a total length of 2200 km.
Twenty per cent of the river basin lies within the
territory of the Russian Federation, 23% in Belarus
and the largest portion, 57%, in Ukraine. Thirty-two
million people live in the Dnieper River basin [2.1].
Most of the land is arable and many crops (wheat,sugar beet, barley, rye, sunflower, flax, soybean,
fruits and vegetables) are grown in the region.
Over 84% of the total annual river flow (about
45 km3) is collected in the upper parts of the basin(within Belarus and the Russian Federation).
However, most of this water is consumed byindustrial and agricultural activities in Ukraine,where there is a series of large reservoirs. About
8.5 km3 discharges into the Black Sea, which isbordered by six countries (Bulgaria, Georgia,
Romania, Russian Federation, Turkey andUkraine). The Dnieper River contributes asignificant fraction of the total freshwater input tothe Black Sea, along with various pollutants andcontaminated sediments collected along the way[2.2–2.4].
Figure 2.1 shows the extent of the Dnieper
River basin in Belarus, the Russian Federation andUkraine. Major tributaries and towns are also
shown.

FIG. 2.1. Map of the Dnieper Basin showing the network of rivers (courtesy of the UNDP).

13

The river has suffered severe pollution andwater quality deterioration during the past decades,
which has affected access to safe drinking water forthe millions of people living in the three riparian
countries. The basin is no longer considered a selfregulating river ecosystem and is a serious threat tobiota species and their habitats. As a result,assistance was requested from the international
community to develop a strategic action plan (SAP)
to protect the river in a sustainable manner, andthrough this to contribute to the protection ofregional and global international waters [2.3].
This report is a contribution to the Dnieper
Basin Environmental Programme (DBEP) by aninternational team of scientists under the directionof the IAEA. The DBEP is being carried out under
the United Nations Development Programme —Global Environment Facility (UNDP–GEF).
In assessing the Dnieper River basin, theUNDP–GEF has identified radioactive contamination as one of the significant issues. A preliminarytransboundary diagnostic analysis (TDA) was
published for the Dnieper River basin in 1997 [2.3].
Subsequently, the IAEA was requested tocontribute its expertise in radiation and environmental protection to a more detailed analysis
involving a revision of the TDA and the preparationof a SAP. A summary report by the international
expert team was provided to the UNDP in
November 2002 [2.5]; this included scientificfindings and conclusions derived from theassessment material (see Section 10 of this report),
as well as a list of recommendations for the SAP
and the national action plans (NAPs) (seeSection 11). This report is a detailed radiologicalassessment in support of the statements, conclusions
and recommendations provided in that summary
report.
The international expert team for this study
included scientists from Belarus, the RussianFederation and Ukraine familiar with radioactive
contamination in the Dnieper River basin andexperienced in radiological assessments. A list ofinternational expert team members and othercontributors is given at the end of this report. To
gather information for the study, two fact finding
missions were undertaken. One of these wasconcerned with radiation and waste safety issues

14and the other with the safety of nuclear power
plants. Meetings and discussions were held in
Belarus, the Russian Federation and Ukraine with
scientific specialists, plant operators, regulatory
personnel, representatives of ministries and local
administrators. Inspections were carried out at the
Chernobyl site, at uranium tailings managementsites near Dniprodzerzhinsk and at the Ecores State
waste management facility near Minsk. There were
two meetings of the international expert team, andteam members participated in a number ofworkshops organized by the UNDP–GEF.
This report includes 11 sections. Following thisintroduction, Section 3 identifies the major radiological sources within the Dnieper River basin.
Each of these sources is assessed in subsequent
sections (Chernobyl in Section 4, nuclear power
plants in Section 5, uranium mining and processingin Section 6, other sources, including waste disposalsites and research facilities, in Section 7). Section 8
deals with an assessment of human exposure toradiation within the Dnieper River basin andSection 9 assesses radiological hot spots. The
conclusions and recommendations are presented in
Sections 10 and 11, respectively.

REFERENCES TO SECTION 2
[2.1]

[2.2]
[2.3]

[2.4]

[2.5]

UNITEDNATIONSDEVELOPMENT
PROGRAMME, Diagnostic Analysis for the
Dnieper Basin, UNDP, New York (2003).
BABCOCK, K., BARICA, J., Why the Dnieper?
Water Qual. Res. J. Canada 33 (1998) 453–455.
UNITEDNATIONSDEVELOPMENT
PROGRAMME,Transboundary
Diagnostic
Analysis for the Dnipro River Basin: Synthesis
Report, UNDP–GEF, UNDP, New York (1997).
UNITEDNATIONSDEVELOPMENT
PROGRAMME, The Dnipro: Partnership forEnvironmental
Rehabilitation,
Information
Bulletin of the UNDP–GEF Dnieper Basin Environment Programme, No. 1 (1998).
INTERNATIONALATOMICENERGYAGENCY, Radioactive Contamination of the
Dnieper River Basin: Contribution to the Transboundary Diagnostic Analysis and Recommendations for the Strategic Action Plan, Summary
Report, Regional Technical Co-operation Project
RER/9/072 (UNDP Project RER/98/G31), IAEA,
Vienna (2002).

3. RADIOACTIVITY IN THE DNIEPER RIVER BASIN
Radioactivity is the property of unstableatoms (called ‘radionuclides’) that spontaneously
disintegrate with emission of radiation. Everyone is
exposed to radiation from radioactivity in thenatural environment. In addition, human activities
involving the use of radiation and radioactive
substances cause radiation exposure. Some of these
activities, such as the mining of radioactive ores andthe burning of coal containing radioactive
substances, enhance exposure to natural radiation.
Nuclear power plants and other nuclear installations release radioactivity into the environment andproduce radioactive waste, which is a potential
source of radiation exposure. Another source is theuse of radiation and radioisotopes in medicine,industry and research. The medical use of radiationis the largest human-made source of radiation
exposure [3.1].
Exposure to ionizing radiation can damage
living organisms and cause health effects in humans,
including leukaemia and other cancers. The effectsof radiation on human health are discussed in
Section 7.
This report deals only with the assessment of
those sources of radiation and radioactivity that areof special concern in the Dnieper River basin. The
first task of the project team was to identify themain sources (actual and potential) of radiation
exposure meeting this criterion. The identified
sources are:
(a)
(b)
(c)
(d)
(e)

Areas affected by the Chernobyl nuclear
accident;
Nuclear power plants;
Uranium mining and ore processing;Radioactive waste storage and disposal sites;
Non-power sources (e.g. from the use ofradiation and radioisotopes in medicine,industry and research).

Figure 3.1 shows the locations of the mostimportant sources. Each is assessed in detail inseparate sections of this report. The following
sections give a brief introduction to each of thesesources.

3.1. AREAS AFFECTED BY THE
CHERNOBYL NUCLEAR ACCIDENTThe Chernobyl nuclear power plant is locatedalongside the Pripyat River in northern Ukraine,
about 130 km north-east of Kiev. It is 12 km fromthe border with Belarus and 140 km from theborder with the Russian Federation (see Fig. 3.1).
On 26 April 1986 the worst ever nuclear accident
occurred at unit 4 of the plant. Following a criticality
excursion, two major steam explosions destroyed
the reactor and badly damaged the reactor building
and other structures (see Fig. 3.2). A major releaseof radioactivity occurred as a result of the
explosions. Subsequent burning of the graphite
moderator resulted in continued release of radioactivity over a period of ten days. Overall, about
50% of the 131I and 30% of the 137Cs in the reactor
core were released [3.1, 3.2].
The fallout of this radioactivity was dependent
on the vagaries of the wind direction and rainfall
over the period of the releases. The most serious
consequences of the Chernobyl accident to the
public were caused by exposure to short lived radionuclides, especially 131I, which resulted in many
thyroid cancers [3.1]. Other health effects are
expected in the future from the exposures received
by some individuals during the accident phase. A
large number of studies have been carried out on
the health effects arising from exposure of reactor
personnel, emergency workers and the generalpublic during the immediate period after theaccident [3.1, 3.3–3.8].
This assessment is concerned mainly withcurrent and future exposures to radiation. Of thoseradionuclides still remaining from the Chernobyl
accident, 137Cs (half-life 30 years) and 90Sr (half-life
29.1 years) are the most important from an environmental and public health perspective. Caesium-137,
with its short lived daughter, 137mBa, emits beta andgamma radiation; 90Sr, with its short lived daughter,90
Y, emits beta radiation.
Caesium is volatile at the high temperaturesthat were experienced during the Chernobyl
accident. Consequently, it tended to travel
substantial distances before being deposited. Bothin the environment and in the human body caesium
radionuclides behave like potassium. However,strontium is not particularly volatile and was mainly
15

associated with fuel particles deposited much closer
to the release point. In the environment and in thehuman body, strontium radionuclides behave like
calcium (hence strontium is a ‘bone seeker’).
The area in the immediate vicinity of theChernobyl nuclear power plant was the mostcontaminated. In 1986 the 30 km Chernobyl
exclusion zone (CEZ) was established around theChernobyl nuclear power plant and the public wasevacuated from the area. Within the CEZ are anumber of important sources:(a)

The damaged nuclear reactor. In May 1986 adecision was taken to enclose the area aroundunit 4 to prevent the further spread of radioactivity into the environment and to reduce theexposure of personnel working on the
Chernobyl nuclear power plant site. An(b)enclosing building, known as the shelter or‘sarcophagus’, was completed in November
1986 (see Fig. 3.3)It was erected under difficult
circumstances in very high radiation fields
using remote construction methods. Unfortunately, as a result of construction difficulties,
there are now openings and breaks in the walls
and roof of the shelter, which is estimated tototal about 1200 m2 in area.
The Chernobyl cooling pond. The coolingpond is an artificial lake built to provide thecooling water for the condensers of the four
Chernobyl reactor units. The pond covers an
area of approximately 23 km2 and contains
approximately 149 × 106 m3 of water. The
cooling pond is less than 1 km from the
Chernobyl nuclear power plant; a dam
separates the pond from the Pripyat River.

FIG. 3.1. Location of major nuclear facilities and sources of radioactivity within the Dnieper River basin.

16

(d)

FIG. 3.2. The damaged unit 4 of the Chernobyl nuclear
power plant (from Ref. [3.2]).

FIG. 3.3. Construction of the Chernobyl shelter (fromRef. [3.2]).

(c)

The pond was heavily contaminated during
the Chernobyl accident and by subsequent
dumping of radioactive liquid waste into it.
Waste burial sites. After the Chernobyl
accident, contaminated material, including
debris, structures, equipment, dead trees andcontaminated soil, were buried within the

CEZ in trenches and under mounds. The
purpose was to reduce radiation levels near
the Chernobyl nuclear power plant and toprevent dispersion of radioactivity. Leaching
into groundwater and migration from thesesites is a potential source of contamination ofwaterways.
Contaminated floodplain. The floodplain
along the Pripyat River is highly contaminatedfrom the Chernobyl accident, especially with90
Sr; concentrations exceed 4000 kBq/m2 overlarge areas. This area is regularly inundated,
especially during spring floods. Moreover,some of the waste burial sites are locatedwithin the floodplain. Engineering works havebeen undertaken to mitigate the flooding but
have not been completed due to financial
problems. Radioactivity, especially 90Sr, iswashed off the floodplain during times of highflood and transported via the Pripyat River tothe Dnieper system.

Although the deposition of radioactivity was
highest in the CEZ, significant fallout occurred
throughout much of Europe. However, deposition
was greatest in the three countries (Belarus,
Russian Federation and Ukraine) that lie within the
Dnieper River basin. Figure 3.1 shows the areas ofhighest contamination. On the territory of Belarus
the worst affected areas are the Gomel and Mogilev
regions. Within the Russian Federation the southwest part of the Bryansk region is the most affected.
In Ukraine contamination is particularly high inthe Kiev, Zhytomyr and Chernihiv regions. In total,
about 85 000 km2 of the Dnieper River basin
received a surface contamination of 137Cs above
37 kBq/m2 (1 Ci/km2)1. Section 4 gives detailed
information on the deposition of radioactivity.
One of the more serious long term ecologicaleffects of the Chernobyl fallout was the secondary
runoff (wash-off) of radionuclides from the initiallycontaminated areas through the river networks of
Belarus, the Russian Federation and Ukraine into
the Dnieper reservoir system, thereby expanding
the spatial scale of the accident and exposing
1

Radioactivity is measured in units of becquerel(Bq), which is one disintegration per second. An older
unit called the curie (Ci), equivalent to 3.7 × 1010 Bq, isstill in common use. The becquerel is a very small unit andhence large units are commonly used, for example 1 kBq= 103 Bq, 1 MBq = 106 Bq, 1 GBq = 109 Bq, 1 TBq = 1012
Bq and 1 PBq = 1015 Bq.

17

millions of people who use the downstream
resources of the Dnieper River. Section 4 discusses
the water-borne dispersal of radionuclides in detail.

3.2. NUCLEAR POWER PLANTS
There are 17 operating nuclear power reactors
in the Dnieper River basin (Fig. 3.1), ten in Ukraine
at three sites (Zaporozhe, Rovno and Khmelnitski)
and seven in the Russian Federation at two sites(Kursk, Smolensk). In addition, there are three
nuclear power reactors (South Ukraine nuclear
power plant) in the Bug River basin. The
Zaporozhe nuclear power plant, comprising six
1000 MW(e) units, is one of the largest in the world(see Fig. 3.4). Currently, one 1000 MW(e) nuclear
power reactor is being commissioned at Rovno,
while another is under construction at Khmelnitski.
Nuclear power plants can release radioactivity
to the environment in a number of ways:
(a)
(b)
(c)
(d)
(e)

By routine releases to air and water;
By releases from spent nuclear fuel storage
facilities;
By releases from radioactive waste storage
facilities;
By transport accidents;
By major accidents affecting the nuclear core,
where releases are difficult to control.

Under normal conditions, nuclear power
plants release small amounts of radioactivity into
the air and sometimes into cooling water systems.
However, such releases do not result in significant

FIG. 3.4. Zaporozhe nuclear power plant and the coolingpond and Kakhovka reservoir on the Dnieper River.

18

radiation exposures of the general public. Data on
normal releases from nuclear reactors in the
Dnieper River basin are presented in Section 5.
Radioactive material resulting from reactor
operations (such as spent nuclear fuel andradioactive waste) is stored in specially designatedfacilities that are subject to regular inspection by
regulatory authorities. Release of radioactivity ispossible, especially from liquid waste storage
facilities, but would normally require a breakdown
in a number of barriers. Monitoring systems aredesigned to detect any release of radioactivity at an
early stage.
Accidents can occur during transport, buttransport containers are designed to withstand themost serious credible accidents. Worldwide, thenuclear industry has a very safe record in thetransport of nuclear material.
A major reactor accident (such as occurred at
Chernobyl) can have very serious consequences.
The adequacy of ongoing measures taken to prevent
nuclear accidents in the Dnieper River basin is
assessed in Section 5, while Section 9 reports on theconsequences of a hypothetical accident affecting
the Dnieper River basin and the Black Sea.

3.3. URANIUM MINING AND PROCESSING
The only uranium mining and ore processingin the Dnieper River basin is in Ukraine. Uranium
exploration started in 1944 and led to the discovery
of 21 deposits. Many of the deposits are within thewatershed of the Dnieper River basin, while someare within the basins of the southern Bug andSeversky Donets Rivers. Figure 3.1 shows thelocations of the deposits and the ore processing
operations. The effects of uranium mining andprocessing are localized and only affect the Dnieper
River basin in southern Ukraine.
The first uranium processing plant in Ukraine
was the Prydniprovsky chemical plant, whichstarted up in 1948 using ores shipped from countries
in central Europe. It is situated a few kilometresfrom the Dnieper River in the city of
Dniprodzerzhinsk and ceased operations in 1991.
The Zhovti Vody hydrometallurgical plantcommenced production in January 1959 to processores from the region. Current production is about1000 t U/a. Most of the current production comesfrom the Ingulsky mine developed on theMichurynske deposit.

Uranium mining and milling have a number ofpotential impacts on human health and theenvironment. These include:
(a)
(b)
(c)
(d)
(e)
(f)
(g)

Contamination of mine water with uraniumand other radionuclides;
Release of mill wastewaters to surface waters(usually after treatment);
Runoff of water from contaminated areas ofthe mine or mill;Radon release from mines, waste rock dumps
and mill tailings piles;
Leaching of radionuclides from tailings andtheir subsequent transport in water;
Erosion of tailings storage systems, leading todispersal of tailings by wind and water;
Contamination of underground and surface
waters by toxic non-radioactive substancessuch as heavy metals and the chemicals used inprocessing.

The most important waste from the milling of
uranium is the finely divided solid residue known as
tailings. Tailings typically contain 70% of the radioactivity in the original ore and remain radioactive
for hundreds of thousands of years. The main long
lived radionuclides are residual uranium, 230Th(half-life 80 000 years) and 226Ra (half-life
1600 years). Radium is a continual source of 222Rn(half-life 3.8 days), which, being a gas, is readily
dispersed. Radon daughters are a source ofradiation exposure and a known cause of lungcancer in uranium miners.
Section 6 gives information on uranium
mining and processing in Ukraine and on theirimpact on the environment and public health.
Where available, monitoring data are presented andan assessment is made of the long term stability ofthe tailings and the need for countermeasures.

(b)

(c)

These sites are assessed in Section 7.

3.5. NON-POWER SOURCES
Non-power sources include research reactors
and those arising from the application of radioisotopes and radiation in medicine, industry andresearch. Radioisotopes are used in medicine fordiagnosis and treatment in all three countries.
Nuclear research facilities in the Dnieper
River basin are limited. The research reactors at the
Sosny Institute near Minsk and the Institute for
Nuclear Research at Kiev are shut down.
Radioactive waste from these facilities is stored in
dedicated waste storage sites.
Non-power sources of radioactivity are
discussed briefly in Section 7.

REFERENCES TO SECTION 3
[3.1]

[3.2]

3.4. RADIOACTIVE WASTE STORAGE ANDDISPOSAL SITES[3.3]

Radioactive storage and disposal sites in the
Dnieper River basin include:

[3.4]

(a)

The Ecores State facility near Minsk, which
comprises two closed trenches and two repositories that are being progressively filled. Thisfacility accepts radioactive waste from the
nearby Sosny Institute and from more than

100 organizations from the industrial, research
and medical sectors.
Two disposal sites operated by the RADON
State enterprise at Kiev and Dnipropetrovsk.
These sites handle both radioactive waste andspent radiation sources from the non-nuclear
power plant sector, including the industrial,
medical and agricultural sectors.
Many disposal or ‘temporary’ storage sites for
Chernobyl waste in Belarus and Ukraine.

[3.5]

UNITED NATIONS, Sources and Effects of
Ionizing Radiation (Report to the General
Assembly), Annex J: Exposures and Effects of theChernobyl Accident, United Nations ScientificCommittee on the Effects of Atomic Radiation(UNSCEAR), UN, New York (2000).
DE CORT, M., Atlas of Caesium Deposition on
Europe after the Chernobyl Accident, Rep. 16733,
Office for Official Publications of the European
Communities, Luxembourg (2001) CD-ROM.
INTERNATIONALATOMICENERGYAGENCY, Summary Report on the Post-accident
Review Meeting on the Chernobyl Accident,
INSAG Series No. 1, IAEA, Vienna (1986).
INTERNATIONALATOMICENERGYAGENCY, The International Chernobyl Project:
Assessment of the Radiological Consequencesand Evaluation of Protective Measures, IAEA,
Vienna (1991).
INTERNATIONALATOMICENERGYAGENCY, The Chernobyl Accident: Updating of
INSAG-1, INSAG Series No. 7, IAEA, Vienna(1992).

19

[3.6][3.7]

20

One Decade after Chernobyl: Summing up theConsequences of the Accident (Proc. Int. Conf.
Vienna, 1996), IAEA, Vienna (1996).
Fifteen Years after the Chernobyl Accident:
Lessons Learned (Proc. Int. Conf. Kiev, 2001),
United Nations, New York (2001).

[3.8]

WORLD HEALTH ORGANIZATION, HealthConsequences of the Chernobyl Accident: Resultsof the IPHECA Pilot Projects and Related
National Programmes (SOUCHKEVITCH, G.N.,
TSYB, A.F., Eds), Rep. WHO/EHG 95-19, WHO,
Geneva (1996).

4. CHERNOBYL AFFECTED AREAS
4.1. SCOPE
This section presents detailed information on
the distribution of radioactivity from the Chernobyl
accident, the systems used to monitor the dispersionof the radioactivity, the characteristics of radioactivity in water-borne runoff, the fate of radionuclides in the Dnieper reservoirs and thetransboundary movement of radioactivity from
Chernobyl affected areas.
The storage and/or disposal by burial ofChernobyl contaminated waste is discussed in
Section 7. Section 8 assesses current and future
exposure to radiation from Chernobyl affectedareas. Section 9 describes the identification andanalysis of Chernobyl hot spots.

4.2. DISTRIBUTION OF FALLOUT FROMTHE CHERNOBYL ACCIDENT
As a result of the Chernobyl accident, about
85 PBq of 137Cs, 54 PBq of 134Cs, 1760 PBq of 131I,
10 PBq of 90Sr and 0.07 PBq of 239,240Pu werereleased, as well as many shorter lived radionuclidesof lesser radioecological significance [4.1]. Major

releases occurred over a period of ten days, during
which time there were a number of changes in winddirection. As a consequence, fallout was depositedover most of Europe; however, the largest areas ofcontamination were in Belarus, the RussianFederation and Ukraine (see Table 4.1). Much of
the fallout in these three countries was deposited in
the Dnieper River basin.
After the Chernobyl accident, the responsible
agencies in many countries gathered data on soil
contamination in their territories. These data were
published in the form of reviews, maps and lists ofcontamination density in populated areas. Much of
the data applies to areas within the Dnieper Riverbasin. In 1992–1995 a European Union–Commonwealth of Independent States programme wascarried out to study the consequences of theChernobyl accident [4.2], and within that
programme data on soil contamination density weregathered, processed and published as an atlas [4.3],
including a CD-ROM version [4.4]. The maps wereprepared using the geographic information system
ARC/INFO, Version 6.1. The information fromparticipating countries was received in the form ofgeographically located data for about 400 000
sampling sites selected in 31 European countries,

TABLE 4.1. AREAS IN EUROPE CONTAMINATED BY CHERNOBYL FALLOUT IN 1986 [4.1, 4.4]
Area with 137Cs deposition density range (km2)
37–185 kBq/m2

185–555 kBq/m2

555–1480 kBq/m2>1480 kBq/m2

Russian Federation

49 800

5 700

2100

300

Belarus29 900

10 2004200

2200

Ukraine37 200

3 200

900

600

Sweden

12 000———Finland

11 500———Austria

8 600

—

—

—

Norway

5 200

—

—

—

Bulgaria

4 800

—

—

—

Switzerland

1 300

—

—

—

Greece

1 200

—

—

—

Slovenia

300

—

—

—

Italy

300

—

—

—

Republic of Moldova

60

—

—

—

21

Scale 1: 2 500 000
Projection: Lambert Azimuthal
0 kilometres

25
25

100

200

50

0 miles

100

Total caesium-137 (nuclear weapons test, Chernobyl, ...) deposition
kBq/m2
2

Ci/km

1

2

4

10

20

40

0.027 0.054 0.1 0.27 0.54 1.08

100 185555 1480

2.7

15

5

40

© EC/IGCE, Roshydromet (Russia)/Minchernobyl (Ukraine)/Belhydromet (Belarus, 1998)

FIG. 4.1. Distribution of deposited 137Cs in the Russian part of the Dnieper River basin (May 1986) [4.4].

including 19 058, 176 971 and 11 569 sampling points
in Belarus, the Russian Federation and Ukraine,
respectively.
Figures 4.1–4.3 show 137Cs deposition in the
Russian Federation, Belarus and Ukraine areas of
the Dnieper River basin based on these sources1.
Figure 4.4 is a closer view showing the areas of
22

greatest 137Cs contamination. Radionuclide fallout
was concentrated in the upper Dnieper watershedin Russian and Belarusian territory and in the whole
Pripyat watershed. Of the 137Cs deposited in the1

See Fig. 3.1 for the boundaries of the Dnieper
River basin.

Scale 1: 1 500 000
Projection: Lambert Azimuthal
0 kilometres

25

25

50

100

50

0 miles

Total caesium-137 (nuclear weapons test, Chernobyl, ...) deposition
kBq/m2
Ci/km2

40

100

185

555 1480

0.027 0.054 0.1 0.27 0.54 1.08

1

2

4

10

20

2.7

5

15

40

© EC/IGCE, Roshydromet (Russia)/Minchernobyl (Ukraine)/Belhydromet (Belarus, 1998)

FIG. 4.2. Distribution of deposited 137Cs in the Belarusian part of the Dnieper River basin (May 1986) [4.4].

Scale 1: 2 500 000
Projection: Lambert Azimuthal
0 kilometres

25

100

0 miles

25

200

50

100

Total caesium-137 (nuclear weapons test, Chernobyl, ...) deposition
kBq/m2
Ci/km21

20.027 0.054

4

10

20

40

100

185

555

1480

0.1

0.27 0.54

1.08

2.7

5

15

40

© EC/IGCE, Roshydromet (Russia)/Minchernobyl (Ukraine)/Belhydromet (Belarus, 1998)

FIG. 4.3. Distribution of deposited 137Cs in the Ukrainian part of the Dnieper River basin (May 1986) [4.4].

23

ep

r

Te

te

re

v

Des

na

Goryn

St y

r

’

St o

kho

d

Desna

Dn

Dn

Roska

ep

r

FIG. 4.4. Distribution of deposited 137Cs in the most contaminated areas of the Dnieper River basin (December 1989)[4.1].

Dnieper River basin, approximately 30% was in theCEZ (see Fig. 4.5), 30% in the far zone of theBelarusian and Ukrainian sections of the Pripyat
River basin and about 40% in the basins of the Sozh
and Iput Rivers, in the so called Gomel andBryansk–Tula hot spots. Table 4.2 shows data on
contamination levels in the administrative regionsof Belarus, the Russian Federation and Ukraine
within the Dnieper River basin.
More detailed information on these three
countries is contained in the atlas of the radioactive
contamination of the European part of the RussianFederation, Belarus and Ukraine [4.5]. The maps
were generated from the databases and electronic
maps of the hydrometeorological service organizations of the three countries.
There are also maps and databases of theradionuclide deposition density in specific regions
contaminated following the Chernobyl accident.
Less data are available for radionuclides other than137
Cs because they are not as easily measured andbecause they were deposited closer to their source,

24

FIG. 4.5. Distribution of 137Cs within the CEZ, 1986 [4.1].

due to their lower volatility under the accident
conditions.

TABLE 4.2. AREAS (THOUSANDS OF km2) WITH ELEVATED CAESIUM-137 DEPOSITION IN THE
REGIONS WITHIN THE DNIEPER RIVER BASIN (AS OF 1993–1995)
Caesium-137 soil deposition (MBq/m2)
0.04–0.2

0.2–0.6

0.6–1.5>1.5

Total >0.04

Belarus
Gomel

16.9

6.7

2.8

1.6

28.0

Minsk

2.0

0.05

—

—

2.1

Mogilev

5.5

2.9

1.5

0.5

10.4

Subtotal

24.4

9.7

4.2

2.1

40.4

1.9

0.3

11.6

Russian Federation
Bryansk

6.7

2.7

Kaluga

3.4

1.4

—

—

4.8

Kursk

1.4

—

—

—

1.4

Smolensk

0.08

—

—

—

0.08

Subtotal

11.6

4.1

1.9

0.3

17.9

UkraineCherkassy

3.2

0.07

—

—

3.3

Chernihiv

2.2

0.14

—

—

2.3

Dnipropetrovsk

0.04

—

–

—

0.04

Kiev

7.7

1.0

0.6

0.4

9.7

Nikolaev

0.02

—

—

—

0.02

Rovno

0.2

—

—

—

0.2

Zhytomyr

9.2

1.8

0.3

0.15

11.5

3.0

0.9

0.6

27.1

16.8

7.0

3.0

85.4

Subtotal
Total

58.6

Figure 4.6 shows the distribution of deposited
Sr; of the 90Sr deposited in the Dnieper Riverbasin, about 70% was deposited on the catchments
and floodplain areas of the CEZ within Belarus andUkraine, and the remainder was deposited in the far
catchment areas of the basin. The Russian part of
the Dnieper River basin received less than 10% of
the 90Sr inventory of the Dnieper River basin as awhole. This explains the importance of the CEZ as asource of 90Sr contamination. Plutonium, which was
associated with fuel particles that became airborne,
was even more localized (see Fig. 4.7). The only
areas with plutonium levels exceeding 4 kBq/m2 arelocated within the CEZ.
A significant portion of the point type data on
soil contamination density in the Dnieper Riverbasin obtained by organizations within Belarus, the90

Russian Federation and Ukraine from 1986 to thepresent day was entered into the databases ofsubprojects of Project 2, Radioecology, of theFrench–German Chernobyl Initiative [4.6]. The
database contains several thousand determinationsof 137Cs and 90Sr densities on agricultural land; dataon contamination density, speciation and vertical
distribution of 137Cs and 90Sr in soils on thecatchments of the rivers flowing in the Dnieper
River basin; and data on 137Cs and 90Sr soil contamination density in population centres. As part ofthese projects a series of electronic maps was
generated for the six most contaminated regions ofBelarus, the Russian Federation and Ukraine(Gomel, Mogilev, Bryansk, Kaluga, Kiev andZhytomyr regions), including maps of 137Cs contamination density.

25

Scale 1: 2 500 000

Scale 1: 2 500 000

25
25

Projection: Lambert Azimuthal

Projection: Lambert Azimuthal

0 kilometres

0 kilometres

25

100
25

50

0 mileskBq/m2 3.7

kBq/m2 37.0 74.0 111.0
Ci/km

1.0

2.0

50

0 miles
Deposition zones

Deposition zones

2

100

Ci/km23.0

0.1© EC/IGCE, Roshydromet (Russia)/Minchernobyl (Ukraine)/Belhydromet (Belarus, 1998)© EC/IGCE, Roshydromet (Russia)/Minchernobyl (Ukraine)/Belhydromet (Belarus, 1998)

FIG. 4.6. Distribution of deposited 90Sr (December 1989)[4.4].

FIG. 4.7. Distribution of deposited 239,240Pu (December
1989) [4.4].

4.3. MONITORING OF RADIOACTIVITY IN
THE ENVIRONMENT

stations. Soil sampling for further radionuclide
analysis is carried out during special surveys.
The methods recommended for implementation and used by the monitoring networks of theRussian Federation, Belarus and Ukraine and aredescribed in Refs [4.7–4.12]. The recommended
sampling methods provide for:Radioactivity deposited in the Dnieper Riverbasin is subject to dispersal in the environment by
airborne and water-borne processes. The
monitoring of radioactivity in the environment isimportant in understanding these processes and in
estimating radiation exposure to individuals and the
population. Following the Chernobyl accident, an
extensive monitoring network was established in
the three countries, focusing on water-borne
pathways.
4.3.1.

(b)

Types of environmental monitoring

The hydrometeorological services of Belarus,
the Russian Federation and Ukraine carry out
monitoring for radioactivity in air, atmosphericprecipitation and surface waters. Determination ofenvironmental contamination is based on similar
methods and equipment. Gamma radiation is alsomeasured on a regular basis at meteorological
26

(a)

(c)

Selection of an appropriate strategy to locate
representative monitoring sites, sampling sites
and methods, and to ensure the required
accuracy of laboratory measurements;
Correct selection and location of measuringsections in conformity with the programme ofhydrological monitoring and allowing forspecific geometrical and hydrological characteristics of water bodies (river, lakes,
reservoirs);
Fulfilment of the requirements for proper
averaging of measurements in time and space
for a given water body, taking into accountspecific monitoring goals;

Monitoring of radioactive contamination innear surface air is based on round the clock
sampling of aerosol particles using FPP-15-1.5 air
filters. Collected samples are subject to analysis
for:Precise determination of 137Cs in water requires
sampling an even greater volume (up to 500 L).
With this in mind, in 1986 the Midiya systemdeveloped by SPA Typhoon was adopted for
filtration and concentration of radionuclides on tosorbents (Fig. 4.8).
Spectrometric measurements are carried out
separately on the sorbent (to determine dissolved
nuclides) and on the filters (to determine suspended
matter). A fairly low detection limit for samplers of
the Midiya type makes it possible to determine, withsatisfactory accuracy, the concentration of radionuclides in rivers over the whole territory
contaminated after the Chernobyl accident.
Reference [4.12] provides recommendations on
how to use this system under field conditions.

(a)4.3.1.3. Bottom sediments

(d)

(e)

(f)

Proper filtration of natural waters, using
systems for concentration of natural waters
where appropriate;
Compliance with the requirements ofanalytical procedures involving radiospectrometric and radiochemical measurements;
Selection of appropriate sampling methods tostudy radionuclides in bottom sediments.

4.3.1.1. Airborne monitoring

(b)
(c)

Total beta activity, one and four days after
sampling, using a thin film scintillation
detector or a Geiger counter;
Radionuclide composition of samples using
gamma spectrometry;
Measurement of radioactivity of plutonium
isotopes and 90Sr by radiochemical methods.

Atmospheric fallout is collected on gauze
collectors after a sampling time of one day. The
methodologies for sample preparation andmeasurement are similar to those used for aerosol
particles.
4.3.1.2. Surface waters
In surface waters, 90Sr, 137Cs and tritium areroutinely monitored. Sampling and preconcentration for 90Sr analysis are undertaken at hydrological stations and radiometric network stations,whereas radiochemical analysis is done in regional
laboratories.
One of the key tasks in the design phase ofwater monitoring, given water bodies with different
contamination levels, is to estimate correctly thevolumes of samples to be collected for radiometricmeasurements.
The appropriate sample volume depends onthe concentration of a specific radionuclide; forexample, for 137Cs determination in the Kiev
reservoir the sample volume should be not less than
20 L. For water bodies at a greater distance from thecontamination source, where contamination levels
are low (Dnieper reservoirs, sea areas, etc.), thewater volume should be at least 100 L for confident
determination of a given radionuclide in water.

The experience gained in studies of bottom
sediment contamination after the Chernobyl
accident has shown that it is critical to select theright type of sampler for bottom sediments,
depending on the required task. Most discrepancies
in measurements by different specialists withrespect to the amount and pattern of the distribution of radionuclides on sediments are due tofailure to select appropriate sampling equipment,
differences in methods of averaging individual dataover the whole water area and/or differences ininterpretation of results.
The samplers used in the first year after theaccident had design shortcomings that precluded
sampling of undisturbed cores, leading to loss ofmaterial during lifting of the cores to the surface.
Better sampling systems began to be used from

FIG. 4.8. Midiya sampling system. 1: pipe; 2: filter block;
3: chamber for sorbent with flow meter; 4: portable electric
power station.

27

1990. The DTSh-3 sampler (manufactured by
Ecotechnics in the Russian Federation) enables
sampling of any undisturbed core 30 cm long, and amore sophisticated pneumatic sampling systemmanufactured by McKereth in the UK permits
sampling of silt cores up to 1 m long. Using thesesamplers it is possible to determine sedimentcontamination density and specific activity as afunction of depth.

4.3.2.

Monitoring sites

The monitoring of radioactive aerosols in the
Dnieper River basin is carried out daily at six points
in Belarus (Minsk, Gomel, Mogilev, Pinsk, Mozyr
and Mstislavl), eight points in Ukraine (Kiev,
Baryshevka,
Odessa,Rakhov,
Sevastopol,
Chernobyl, Shepetovka and Shchors) and 40 points
in the Russian Federation, among them Kursk,
Kurchatov and Bryansk. Deposited radioactivity ismonitored at a larger number of points, numberingfrom 30 in Belarus to more than 300 in the RussianFederation. Recommendations on how to use
different samplers for various types of bottom
sediment (mud, sand, etc.) at different depths aredescribed in Ref. [4.12].
4.3.2.1. Belarus
The monitoring of surface waters for radioactivity is carried out mainly in five rivers in Belarus:
Dnieper (at Rechitsa), Sozh (at Gomel), Pripyat (atMozyr), Iput (at Dobrush) and Besed (at Svetilovichi). Until 1990, the hydrometeorologicalservice of Belarus conducted monitoring in therivers Chechera (at Derbichi) and Pokot (at Krasny
Dubok). Sampling is organized on a monthly basis
and, simultaneously, river water discharge ismeasured. Samples of surface water are analysedfor 137Cs (monthly), 90Sr (quarterly) and total beta
activity (monthly).
Belarus Hydromet and a number of otheragencies carry out monitoring. Belgiprovodkhoz
conducts radiation monitoring of surface waters inthe small rivers of Belarus (20 points) and water
reservoirs (three points) with a frequency of one to
two times per year. Water samples are collected,
water discharges are measured and 137Cs isdetermined in samples.
The Institute of Radiobiology (IRB) is
involved in radiation monitoring of the surface
waters of small rivers, including those flowing
28

through the CEZ. Water sampling is organized one
to two times per year. Belarusgeologia is in chargeof radiation monitoring of groundwater. Currently,
attention is focused on monitoring of the radiation
status of underground waters used for thecentralized water supply of the major population
centres in the contaminated areas (Gomel, Mozyr,
Kalinkovichi, Narovlya, Khoiniki, Rechitsa,
Slavgorod,
Zhlobinand
Dobrush).
The
Republican Center of Hygiene and SanitaryService, Ministry of Health of Belarus, is engaged
in monitoring of the radioactivity in drinking waterin the populated areas of the Chernobyl contamination zone. Minzhilcomunkhoz carries out
monitoring of 137Cs in wastewaters and aeration
zones of the major populated areas of theChernobyl contaminated zone. Table 4.3
summarizes information on the frequency ofsampling at existing and closed observation
stations.
The Republican Center of Radiation andEnvironment Monitoring (RCREM) monitors theradioactive contamination of soils. The monitoring
network includes 181 sites at which measurementsof gamma dose rate are performed with varying
frequency, depending on radioactive contaminationlevels. Soil samples are collected for subsequent
analysis of 137Cs and 90Sr. Studies of the verticalmigration of radionuclides are carried out at
18 locations having different types of soils anddifferent radioecological and physicogeographicalconditions. Migration studies are conducted withrespect to 137Cs, 90Sr, plutonium isotopes andamericium.
4.3.2.2. Russian Federation
Within the Russian Federation there are no
stations on the Dnieper River that continuously
monitor surface water for radioactivity. However,the contamination levels of rivers and lakes aremonitored through special purpose surveys within
national and international programmes.
In the Russian Federation during 1987–1988
the concentrations of 137Cs and 90Sr were measured
several times each year, mainly during periods offlooding on the rivers Iput (two measuringsections), Snov (one measuring section) and Besed(one measuring section). During 1991–1993
specialized studies were performed on the Iput
catchment area. The content of 137Cs and 90Sr inriver water was measured several times a year ateight sections.

TABLE 4.3. AVAILABILITY OF DATA ON RADIOACTIVE CONTAMINATION OF RIVERS IN THE
BELARUSIAN PART OF THE DNIEPER RIVER BASIN
Measuring
sectionMonitoringorganization

Frequency per year

Observation
periodCaesium-137

Strontium-90

Dnieper

Rechitsa

RCREM

1987–2002

12

4

Sozh

Gomel

RCREM

1987–2002

12

4

Iput

DobrushRCREM

1987–2002

12

4

Besed

Svetilovichi

RCREM

1987–2002

12

4

Pripyat

Mozyr

RCREM

1987–2002

12

4

Braginka

BtraginBelgiprovodkhoz

1991–1997

2—

Slovechno

Nesvich
Senna

Pirki

IRB

1991–2002

2

2

Gden

IRB

1991–2002

2

2

KuzmichiIRB

1991–2002

2

2

GazhinIRB

1991–2002

2

2

Belyi Bereg

IRB

1991–2002

2

2

KulazhinIRB

1991–2002

2

2

Posudovo

IRB

1991–2002

2

2

Chudyany

IRB

1991–2002

2

2

PilnyaBelgiprovodkhoz

1991–1997

2

—

Lipa

Lipa

IRB, National
Academy of Scienceof Belarus

1991–2001

2

2

Kolpita

VydrinkaBelgiprovodkhoz

1991–1997

2—

The latest large scale study of radioactive
contamination of the rivers in the Bryansk region
was performed in 1998–1999 as part of a UNDP
project [4.13]. The activity of 137Cs and, in somecases, 90Sr was determined in the rivers Iput (sevenmeasuring sections), Snov (three measuringsections) and Besed (two measuring sections) and innine other rivers and canals (one to two measuringsections).
Following the Chernobyl accident, themonitoring of the radioactive contamination levels
in surface water and wastewater of some selected
enterprises became the responsibility of the waterinspection authorities. In the Bryansk region there
were 52 measuring sections, of which 14 wereoperating continuously up to the early 1990s. Data
were transmitted to the Civil Defence Headquartersof the region and to Minvodkhoz of the USSR.
During floods, samples were collected on aquarterly basis. Starting from the early 1990s, thenumber of hydrological sections of continuous
monitoring was cut back and the frequency was
reduced to annual testing.

Radioecological surveys of the state ofgroundwater contamination after the Chernobyl
accident have been conducted in the RussianFederation since 1988. Joint work on this project isnow under way involving Bryanskgeologia, the AllRussian Research Institute for Hydrogeology andEngineering Geology (VSEGINGEO) and the AllRussian Research Institute for Mineral Resources(VIMS). The observational network includes
35 boreholes and 26 wells.
4.3.2.3. Ukraine
The Hydrometeorological Service of Ukraine
conducts radioactivity monitoring of surface waters
in 13 measuring sections, of which 11 are in the
Dnieper River basin. The concentrations of 137Cs
and 90Sr are monitored at different time intervals,
depending on the season, in two measuring sections
on the Pripyat River (at Belaya Soroka andChernobyl), one measuring section on the Uzh
River (at Cherevach), one section on the Desna
River (at Litki) and ten measuring sections on the29

FIG. 4.9. Surface water monitoring stations under observation by CREM in the near zone of the Chernobyl nuclear power plant.

Dnieper River located over the stretch from
Nedanchichi to the Dnieper–Bug estuary.
Radiation monitoring of surface and groundwaters in the CEZ is undertaken by the Center ofRadiationandEnvironmental
Monitoring(CREM), part of the Chernobyl RadioecologicalCenter. Monitoring of surface and ground waters in
the CEZ includes the following:
(a)
(b)
(c)
(d)
(e)

(f)

30

The Pripyat River and its tributaries;
The north-east part of the Kiev reservoir;
The Chernobyl nuclear power plant coolingpond;
The off-take point at unit 4 of the Chernobyl
nuclear power plant;
Lakes and backwaters on the right bankfloodplain that are cut off from the primarychannel of the Pripyat River;
Water bodies of the left bank floodplain andgroundwater within the CEZ.

The locations of surface monitoring points
are shown in Fig. 4.9. Monitoring covers 22
watercourses and ten water bodies, the total numberof monitoring points being 40. The monitoring
programme provides for measurement of hydrological characteristics, the dynamics of radioactive
contamination
characteristics andhydraulicstructures (e.g. water levels and discharge rates).
Water sampling is carried out in accordancewith the methodologies recommended by the
Ministry of Emergencies of Ukraine and theDepartment of the Hydrometeorological Service
and Monitoring. Hydrometric activities arecarried out using the volume necessary forreliable determination of water runoff flow andradionuclide outflow. The frequency of measurements is established by relevant protocols andvaries from weekly to quarterly. During floods
and emergencies the frequency of sampling isincreased.

All water samples are analysed for 90Sr and
Cs. In addition, the specific activities of 241Am,
238
Pu and 239,240Pu are determined in water bodies
with higher concentrations of 90Sr and 137Cs andthose of key importance.
Monitoring of groundwater near the Chernobyl
nuclear power plant is performed in the Quaternary,
Eocene and Senoman–Cretaceous horizons. The
Quaternary aquifer is monitored as a priority, as it lies
closer to the surface and is more subject to radioactive
contamination. Groundwater from the Eocene
deposits (used for the centralized water supply of theChernobyl nuclear power plant) is monitored at the
point of water intake of the Chernobyl nuclear power
plant (Pripyat), and groundwater of the Senoman–
Cretaceous deposits (used for centralized watersupply of the town of Chernobyl) is monitored at thewater intake at Chernobyl.
The monitoring of the radiation status ofgroundwater in the Quaternary deposits is arranged
within specific sites (radioactive waste disposal sites,
sites of temporary containment of radioactive
waste, cooling pond) and on a regional basis.
At the beginning of 2002 the groundwater
monitoring system included 158 observation wells.
The frequency of observations in dug wells isgoverned by the extent of radionuclide migration,
allowing for the specificity of their accumulationin geological rocks. In areas with significant
groundwater contamination, observations are
conducted on a monthly basis, whereas in otherareas they take place on a quarterly or six monthly
basis. At present, for seven wells located within
the Red Forest in the area of the Yanov dam andStaraya Stroibaza, measurements are made on amonthly basis, for 25 wells of the regional network
on a six monthly basis and for the remaining
126 wells on a quarterly basis. Measurements ofthe groundwater level are made using a belt typelevel gauge, the accuracy of measurements being
about 1 cm.
Monitoring of radioactive contamination ofrivers and reservoirs of the middle and lower
Dnieper River is the responsibility of theHydrometeorological Service of Ukraine and the
UkrainianHydrometeorological
Institute(UHMI). The protocol of observations ispresented in Table 4.4.
137

4.3.3.

Databases on surface waters

All organizations operating as part of hydrometeorological services (RCREM, SPA Typhoon,

UHMI) maintain their own databases. The principal
shortcoming of these databases is that they mainlycontain results of radionuclide determinations insurface waters obtained by the national institutions.
The exceptions are results derived prior to 1991,
which are partly available in the databases of neighbouring countries. This drawback has been
overcome in the RUNOFF database, which wasdeveloped within subproject SP-3c of Project 2,
Radioecology, of the French–German Initiative on
Chernobyl [4.6]. This database contains data for all
three countries from 1986 to the present. Using thedatabase, the following tasks can be addressed:
(a)

(b)

(c)

(d)
(e)

Reconstruction of radiation doses received by
the population of contaminated areas throughthe aquatic pathway;
Testing and validation of models of radionuclide wash-off to rivers from contaminatedwatersheds, of models of radionuclidetransport to river systems, of models ofvertical migration and transformation ofradionuclide species in soils, and of hydrological models and methods for estimating
parameters of the above models;
Studying of physicochemical mechanisms todescribe the behaviour of radionuclides inrivers;Calibration of model parameters using experimental data;
Calculation of transborder movement ofradionuclides by rivers.

The RUNOFF database includes the following
information arrays:
(i)

(ii)

Radionuclide concentrations in river water.
Data on the concentration of 137Cs and 90Sr in
solution and on suspended matter in 20 rivers
flowing through the territory contaminatedafter the Chernobyl accident are available.
These data were obtained in the period from1986 to 1999 from national monitoring
programmes and special experiments byorganizations of Belarus, the RussianFederation and Ukraine.
Experiments on runoff plots. Results areavailable from nearly 100 experiments tostudy radionuclide wash-off by rainfall andsurface runoff from melting snow. Theseexperiments were conducted in the contaminated territories in the period from 1986 to
1998 on runoff plots of 1–1000 m2. The data
31

TABLE 4.4. SCHEDULE OF CONTROL OF SURFACE WATER RADIOACTIVE CONTAMINATIONBY THE UKRAINIAN HYDROMETEOROLOGICAL SERVICE
Observation point

Sampling periodicity

Organization responsible for sampling

Dnieper: Nedanchichi

Twice per month (more than twice per month
during spring flooding)

Chernihiv centralhydrometeorological station

Desna: Chernihiv

Twice per month (more than twice per month
during spring flooding)

Chernihiv hydrometeorologicalobservatory

Southern Bug: Gurievka

Monthly (more than once per month during
spring flooding)

Nikolaev central hydrometeorologicalstationKiev reservoir: Vyshgorod(power station)

April–October: three times per month;
November–March: twice per month

Hydrometeorological station, Kiev

Kiev reservoir: Kiev (hydropark)

Monthly

Hydrometeorological station, Kiev

Kiev reservoir: Kanev(power station)

April–October: twice per month; November– Hydrometeorological station, Kanev
March: once per month

Kremenchug reservoir: Svetlovodsk(power station)

April–October: twice per month, 90Sr;
November–March: once per month, 90Sr

Svetlovodsk hydrometeorologicalobservatory

Zaporozhe reservoir: Zaporozhe(power station)

Monthly, 90Sr

Zaporozhe hydrometeorologicalstationKakhovka reservoir: Novaya
Kakhovka (power station)

April–October: twice per month;
November–March: once per month

Novaya Kakhovkahydrometeorological station

Dnieper (southern Bug estuary):
Ochakov

Four times per year

Nikolaev hydrometeorologicalobservatory

Cascade of Dnieper reservoirs

Twice per year

UHMI, central geophysicalobservatory

include the properties and content of 137Cs and
Sr in soil, rain and runoff hydrographs, theconcentration of 137Cs and 90Sr in solution andon suspended matter in the runoff, thechemical composition of runoff and the radionuclide species in soil for selected runoff plots.
(iii) Hydrological and meteorological data. Results
are available from hydrological and meteorological observations conducted in the contaminated areas by the hydrometeorologicalservices of Belarus, the Russian Federationand Ukraine. Both mean characteristics (overseveral years) and daily measurements at
meteorological and hydrological stations in
the Chernobyl contaminated territories areentered into the database.
(iv) Radionuclide characteristics. Data are alsoavailable on the content, species and vertical
distribution of radionuclides in soils and on
soil properties of river watersheds in contaminated territories.
90

The RUNOFF database contains about
10 000 filled lines on 137Cs and 90Sr activity concen32

tration in 20 rivers. Table 4.5 lists these rivers, theobservation periods and a number of measuringsections for which data are available. For most of
the measuring sections, data on the radioactive
contamination of river water up to the present time
are available from the hydrometeorological serviceof each country.
The RUNOFF database contains almost allavailable data on radioactive contamination of riverwater in the basin of the upper Dnieper River,including data on the rivers involved in the transboundary transport of radionuclides (except the
Desna and Seim Rivers). Data on the Desna Riverand the lower Dnieper River are available in the
UHMI database, Cascade of the Dnieper Reservoirs.
Since contamination of lakes and reservoirs(excluding the nuclear power plant cooling ponds)
is not monitored on a continuous basis, such data
are more limited as compared with the rivers.
Results of determinations of the radioactive
contamination of some Belarusian, Russian andUkrainian lakes can be found in the databasegenerated in the course of the INCO-Copernicus
Project Aquascope and the database of subprojectTABLE 4.5. RIVERS, OBSERVATION PERIODS AND NUMBER OF CROSSSECTIONS FOR WHICH DATA ARE AVAILABLE IN THE RUNOFFDATABASE
Cross-sectionsa

Period of observations

Dnieper3

1986–1999

Sozh

1

1987–1998

Besed

1

1987–2000

Iput

9

1986–2000

Pripyat4

1986–1999

Glinitza1

1987–1999

Sakhan2

1986–1999

Slovetchno

2

1992–1998

Uzh

3

1986–1999

Ilya

1

1986–1999

Vialcha

1

1988

Ilcha

1

1988

Rudava1

1988

Braginka

4

1986–1999

Nesvich2

1988–1998

Right tributary of Braginka

1

1992–1999

Irpen

1

1987–1999

Teterev

1

1987–1992

Lipa

2

1992–1998

Senna

2

1992–1998a

Number of cross-sections on the river for which data on radionuclide concentrations areavailable.

SP3d, Project 2, Radioecology, of the French–
German Initiative on Chernobyl [4.14].
The database of subproject SP3d also contains
data on fish contamination (predatory and preyspecies), as well as on a wide range of macrophite
algae, phytoplankton and periphyton, and on
contamination of bottom sediments and benthic
organisms. In addition are recommended
parameters for the validation of mathematicalmodels and the prediction of migration of radionuclides through the food chain of aquatic
ecosystems affected by the Chernobyl accident[4.14].

of data. Scientific methods must also be developed
to identify and reject untrustworthy data. Laboratories involved in routine monitoring need to
implement external controls to ensure that data
continue to be of a high quality. For this purpose,the following external control tools are used in thethree countries:
(a)
(b)

(c)
4.3.4.

Data quality

One of the most important functions of theorganizations (such as the UHMI, the RCREM and
SPA Typhoon) responsible for the gathering andscientific analysis of data is evaluation of the fidelity(d)Intercalibrations (national and international);
Intercomparison of data obtained by the
UHMI, the RCREM and SPA Typhoon withdata of other monitoring laboratories (parallel
sampling);
Control measurements in the laboratories of
the UHMI, the RCREM and SPA Typhoon
using samples measured earlier in the laboratories of different agencies;
Scientific evaluation of monitoring data.

The quality of data on the radionuclide
content in rivers depends on the quality of sampling33

and on analysis. Analysis of errors that may arise in
the course of such procedures and how they
influence the uncertainty in radionuclide data are
discussed below.
Sampling is the most crucial stage ofmeasurement. Correct sampling procedures andallowance for hydrological factors are critical if
representative samples are to be obtained. If there
is adequate mixing across a cross-section, it makes
no difference which point of the cross-section isused for sampling. Therefore, samples collectedfrom the water surface near the bank are fairly
representative of the whole cross-section for determination of 137Cs and 90Sr concentrations in the
dissolved phase.
It is more difficult to collect a suspended
sediment sample that is representative with respect
to the radionuclide content. The distribution ofsuspended sediment concentrations across a crosssection is extremely non-uniform and is determinedby the complexities of the turbulent river flow.
Generally, concentrations of suspended sediments
increase from the river bank towards the river
middle and from the water’s surface to the bottom[4.15, 4.16]. Water samples collected in the surface
layer near the bank contain the minimum amount ofsuspended sediments and are not representative of
the whole cross-section. Therefore, in rivers with afairly high level of radioactive contamination (given
50 L of water or less is enough for gamma spectrometric measurements), sampling for determinationof 137Cs concentrations on suspended sediments
should be based on the methodology used formeasuring discharges of water and suspended
sediments. This can involve either the detailed or
the basic procedure of sampling at a minimum of
two points for every velocity, using a bottle sampler
or vacuum sampler; in other words, the same
standard means as used in the measurement of
sediment discharges in rivers. It is generally takenthat the accuracy of these methods of measuring
sediment discharges is not less than 20%.
To illustrate the importance of representative
sampling, a data sample was taken from the
RUNOFF database of 137Cs determinations in riverbank samples with the same date and of samples
averaged over the whole effective cross-section. It
can be seen from Table 4.6 that the discrepancy
between the activities on the bank and the averaged
samples occurs during the flood period andoccasionally can be as high as an order ofmagnitude. It is worth noting that the volumetricconcentration of 137Cs in the bank sample was never34

higher than in the sample averaged over the flowcross-section and collected on the same day.
In many cases, the laboratories involved in themonitoring of watercourses carry out water
sampling by submerging a container in water. Even
though a container is filled gradually, most of thelarge fractions of the suspended matter do not enter
the container and, consequently, both the quantity
and the radionuclide activity on suspended
sediments are underestimated.
Table 4.7 compares the turbidity andvolumetric activity of suspended 137Cs in samples
collected with a bottle sampler averaged over theriver flow cross-section and samples collected
directly in the container at several points across thechannel. Using the second sampling technique gives
rise to two errors that result in underestimation of
turbidity and volumetric activity: (a) water samples
collected from the flow surface contain lesssuspended material than those averaged over thewhole effective cross-section; (b) during water
sampling directly in a container most of the sandfraction does not enter the sample.
It is well known that the details of thesampling method are important. With this in mind,
the RUNOFF database and the Cascade of the
Dnieper Reservoirs database include a descriptionof the sampling method along with the measured
concentrations. This facilitates assessment of theuncertainty in the data.
The procedures for primary treatment of thesamples and their preparation for radionuclide
analysis are described in Refs [4.8, 4.9, 4.17, 4.18].
All the laboratories involved in observations on thewatercourses in the Chernobyl zone base theirprocedures on these guidelines. Application ofthese methodologies, given appropriate sampling,
qualified personnel and sensitive instrumentation,
makes it possible to determine the concentration
with an accuracy of not less than 20% for 90Sr andnot less than 10% for 137Cs. In reality, however, thisis not always the case, mostly due to lack ofappropriate equipment.
The monitoring services rely on sanitary
norms prescribed by law, such as the maximum
permissible
concentrations,thetemporary
permissible levels (TPLs) and the control levels.
Many department laboratories perform monitoring
to check whether the radionuclide content in waterused for municipal water supply (drinking andindustrial water supply, irrigation, recreation, etc.)
agrees with the applicable sanitary standards. It is
worth noting that since 1987 there have been only

TABLE 4.6. COMPARISON OF VOLUMETRIC ACTIVITY (Bq/L) OF CAESIUM-137 ON
SUSPENDED SEDIMENTS IN BANK SAMPLES WITH THE SAMPLES AVERAGEDOVER THE FLOW CROSS-SECTION
Date of sampling

Sample averaged
over cross-section

Bank sample

Ratio average/bank

26 March 1988

0.151

0.112

1.3

26 March 1988

0.570

0.256

2.2

29 March 1988

0.529

0.241

2.2

26 March 1988

0.307

0.218

1.4

1 April 1988

0.215

0.174

1.2

6 April 1988

0.418

0.168

2.5

8 April 1988

0.272

0.159

1.7

9 April 1988

0.470

0.210

2.2

11 April 1988

0.781

0.258

3.0

12 April 1988

0.574

0.210

2.7

16 April 1988

0.403

0.038

10.7

19 April 1988

0.407

0.189

2.2

21 April 1988

0.297

0.245

1.2

24 April 1988

0.496

0.167

3.0

28 April 1988

0.218

0.152

1.4

18 May 1988

0.268

0.127

2.1

14 June 1988

0.426

0.122

3.5

individual cases of levels above the sanitary
standards in the Pripyat and Dnieper Rivers. From1990 onwards, the concentrations of these radionuclides were one or two orders of magnitude below
the TPL, and beyond the CEZ two to three ordersof magnitude below. Such a big difference in thecontrol and actual concentrations of radionuclides
has led to less attention being given to measurement
accuracy in many laboratories.
The fact that the monitoring system is still far
from optimal can be illustrated by the results ofmonitoring 137Cs in the Dnieper River at themeasuring section at Vyshgorod, Ukraine, obtainedby different laboratories in 1999 (Fig. 4.10). It is
obvious that determination of the actual 137Cs
content with such a wide spread is quite problematicwithout knowing the specifics of sampling andmeasurement in each laboratory.
After department guidelines were prepared,
the scientific and methodological control of data
quality by the Hydrometeorological Service of
Ukraine was put in place and its local units were

TABLE 4.7. COMPARISON OF THE TURBIDITY AND CONTENT OF SUSPENDED CAESIUM-137
IN SAMPLES COLLECTED BY DIFFERENT METHODS
Turbidity (g/m3)

Caesium-137 (Bq/m3)

Date ofsampling

AOCa

AOSb

Ratio
AOC/AOS

AOCa

AOSb

Ratio
AOC/AOS16 April 1999

104

10.8

9.5

96.0

16.0

6.0

24 April 1999

86.6

2.4

36

81.6

8.0

10

7 October 1999

30.2

6.45

5

73.0

21.0

3.5

a
b

AOC: averaged over the river flow cross-section.
AOS: sample collected at several points across the channel at the surface (averaged over the flow surface).

35

0.20

the total content of radionuclides in water is close to
the uncertainty of the normally dominating 90Sr
dissolved form.
In summary, for the reasons indicated, datafrom different sources are often inconsistent, whichmakes it difficult to harmonize monitoring ofradioactive contamination in surface waters within
the Dnieper River basin.

Caesium-137 total (Bq/L)

Kievvodokanal
CGO
0.15

Goskomwodhoz
CREMEZ

0.10

UHMI

0.05

0.00
27/09/98 16/11/98

5/01/99

24/02/99 15/04/99

4/06/99

24/07/99

12/09/99

1/11/99

21/12/99

137

FIG. 4.10. Results of determinations of Cs in water bydifferent laboratories in the Dnieper–Vyshgorod measuringsection [4.19].

equipped with systems for sampling the concentration of radionuclides contained in large water
volumes, observational results became closer to thereference values considered to be the actual 137Csconcentrations.
The most common causes of systematic errors
in many agencies are the following:
(a)
(b)

(c)
(d)
(e)

(f)

Insufficient qualification of personnel;
Outdated technology for sampling andfiltration and sample preparation unsuitable
for measuring low levels of radioactivity;
Samples are measured with low sensitivity
gamma spectrometers or scintillators;
Spectra are processed manually or inappropriate software is used;
Requirements for the correction of results forradiation background in the laboratory andshielding instrumentation are not observed;
Lack of consistency in the radiochemical
preparation of samples and in determining theefficiency of strontium chemical yield (for 90Sr
analysis).

Owing to high variability in data on radionuclide content in river water, results are not very
informative unless they have uncertainty estimates.
Therefore, in the RUNOFF and Cascade of Dnieper
Reservoirs databases, the bulk of the data on radionuclide concentrations in rivers are accompanied byexpert judgements on uncertainty made by UHMI
specialists, with allowance for errors in sampling
and analysis. Most radionuclide concentrations in
the dissolved form have uncertainties of not lessthan 30%. The uncertainty in volumetric activities
of radionuclides associated with suspended particles
is normally not less than 50%. The uncertainty of

36

4.3.5.

Storage, publication and use ofmonitoring data

Storage, analysis and publication ofmonitoring data are carried out by the following
organizations in each of the three countries:
(a)
(b)
(c)

In Belarus: the RCREM.
In the Russian Federation: the Institute ofExperimental Meteorology of SPA Typhoon.
In Ukraine: the UHMI.

These organizations also use the data tounderstand the physicochemical processes involved
and to forecast changes with time.
The users of the radiation monitoring
information are concerned ministries and agencies,
regional authorities, institutes of national hydrometeorological services and academies of the three
countries. Within inter-State agreements (Belarus,
the Russian Federation and Ukraine), continuous
exchange of data occurs. Data from Belarus andUkraine are supplied on an annual basis to SPA
Typhoon and published in the annual collection
Radiation Situation in the Territory of the RussianFederation and Adjacent Countries. These
collections are the main source for informing the
public about the results of radiation monitoring in
Belarus, the Russian Federation and Ukraine
carried out by the hydrometeorological services ofthese countries.

4.4. CHARACTERISTICS OF
RADIONUCLIDE RUNOFF
Table 4.8 shows the estimated inventories of
Cs and 90Sr in the main rivers and tributaries of
the Dnieper River catchment area. In total, about
19 PBq (500 kCi) of 137Cs and 2.2 PBq (60 kCi) of
90
Sr were deposited within the Dnieper system
within the limits of the main river basins.
137TABLE 4.8. ESTIMATE OF INVENTORIESa (1986) OF CAESIUM-137 AND STRONTIUM-90 IN SOILSOF THE DNIEPER RIVER CATCHMENT AREA UPSTREAM OF KIEV [4.20]
Catchment area (103 km2)

Inventory (PBq)

Total

Activity>37 kBq/m2

Caesium-137

Strontium-90

Upper Dnieper (upstream of Kiev reservoir)

105

29

10.2

0.22

Pripyat, mouth

115

27

6.7

1.5

Braginka and area between Dnieper and Pripyat Rivers

2

2

2.1

0.44

Desna

89

6

0.3

0.04

a

Does not include the radionuclide inventory at the industrial site of the Chernobyl nuclear power plant.

4.4.1.

Radionuclide dynamics in catchment areas

The extent to which the source term
contributes to the contamination of water bodies
depends not only on the initial inventory but also on
factors affecting the dynamics and availability ofeach radionuclide. These factors include:
(a)
(b)

(c)

(d)

The extent of radioactive decay;
The reduction of radionuclide activity in theupper layer of the soil as a result of verticalmigration;
The transformation of the initial physical andchemical forms of radionuclides in the soils of
the watersheds and floodplains of the rivers;
Local and climatic factors affecting waterrunoff and erosion.

In the earliest phase after the accident — fromhours to weeks — fallout of short lived radionuclides (especially 131I) dominated the dose rate. In
the period from weeks to a few years, 106Ru, 144Ceand 134Cs were important. From a few years to a few
hundred years, secondary transport processes
become increasingly important and the dominantradionuclides are 137Cs and 90Sr. The dose rate is
reduced by radioactive decay so that, as of
September 2003, the activity of 137Cs and 90Sr is
about 33% less than in 1986. Finally, for periods
beyond a few hundred years, most of the 137Cs and90
Sr will have decayed and other radionuclides suchas 241Am and 239Pu will become relatively more
important, although the overall impact will be much
lower.
Since radionuclides are transferred into thesurface runoff mainly from the upper layer of thesoil, the extent of radioactive contamination ofwaterways depends on the vertical distribution ofradionuclides in the soil. Depending on thechemical properties of the radionuclide, soil type,landscape and geochemical factors, the activity will
have migrated to a greater or lesser extent into thesoil over the past 17 years. Thus the inventory ofradionuclides available for migration by surface
transport decreases with time.
The chemical and physical forces that bindradionuclides to the soil determine the extent of
their transfer to water. The nature of the binding
depends on both the characteristics of the radionuclide and the properties of the soil, and hence willvary with soil type. The traditional way of experimentally determining the type of binding is themethod of sequential extraction [4.21]. In thismethod, the water soluble form is first extracted
from the soil using distilled water. The
exchangeable form is then extracted using a concentrated solution of an electrolyte, usually
1M CH3COONH4. The portion remaining in thesolid phase after the two extractions is considered tobe the non-exchangeable form.
Table 4.9 shows data for the sequential
extraction of 137Cs and 90Sr from contaminated soilsof the Gomel and Bryansk regions collected in the
mid-1990s as determined by SPA Typhoon. The data
demonstrate that, independent of soil type, thefraction of 137Cs that is exchangeable is much lower
than that of 90Sr. Some generalized data on the formof 137Cs in soils of the CEZ are presented inTable 4.10.
Analysis of these data allows a better understanding of why, ten or more years after theaccident, radionuclides have different rates of
release depending on the specific radionuclide, thesoil type and region; for example, even when mostcontaminated lowland of the Chernobyl zone wascovered by water during the highest flood
37

TABLE 4.9. PER CENT CONTENT OF FORMS OF CAESIUM-137 AND STRONTIUM-90 IN SOILS OF
THE BRYANSK AND GOMEL REGIONS IN THE MID-1990s
Water extract

Extract 1M CH3COONH4

Soil
typea

Caesium-137

Strontium-90

Caesium-137

Strontium-90

Sod–podzol

10.2 ± 0.2

6.1 ± 1.4

2.8 ± 0.7

67.1 ± 2.8[4.22]Sandy2

0.2 ± 0.1

1.9 ± 0.2

2.6 ± 0.4

51.4 ± 4.2[4.22]

Soil

Ref.

Loamy sand2

0.5 ± 0.1

5.2 ± 3.1

8.3 ± 0.2

69.0 ± 0.5[4.22]

Sod–podzol loamy sand30.2 ± 0.1

1.7 ± 0.8

4.2 ± 0.2

71.9 ± 3.4[4.6]

Sod–podzol

10.5 ± 0.5

8.3 ± 6.7

23.2 ± 2.4

57.3 ± 9.3[4.22]

On moraine2

0.7 ± 0.1

1.7 ± 0.1

25.6 ± 1.4

57.4 ± 3.8[4.22]

Sod–podzol

1

0.4 ± 0.3

5.8 ± 7.6

7.2 ± 1.4

67.3 ± 9.6[4.22]

On sand

2

0.5

1.1

23.3

64.4

[4.22]

Sod–podzol gley loamy sand1

1.4 ± 0.6

1.9 ± 1.2

16.1 ± 2.0

60.5 ± 6.9[4.23]

Grey forest soil

1

0.8

1.9

10.3

58.7

[4.22]

Grey forest soil

1

0.9

1.5

3.2

42.9

[4.22]

Marsh low lying

1

0.3 ± 0.1

2.2 ± 1.7

1.0 ± 0.2

40.8 ± 3.8[4.22]

Marsh low lying humus peaty

30.1 ± 0.02

1.3 ± 0.5

1.9 ± 0.7

53.2 ± 7.9[4.23]

Boggy soils

1

7.4 ± 1.2

5.6 ± 3.8

16.7 ± 3.0

57.5 ± 6.6[4.22]b

Peaty podzol–gley4

9.4[4.24]

Peaty sod–podzol

4

18.1b

[4.24]

Humus–peaty

4b[4.24]

Alluvial sod acid loamy sand

1

a
b

24
0.1 ± 0.05

2.8 ± 1.1

0.8 ± 0.2

68.8 ± 7.8[4.6]

1: non-arable; 2: agricultural; 3: arable; 4: forest.
Sum of water soluble and exchangeable forms.

TABLE 4.10. EXCHANGEABLE FORMS OF CAESIUM-137 IN SOILS OF THE
CHERNOBYL EXCLUSION ZONE
Type of soil

Sector (distance from
nuclear power plant)

Per cent exchangeable form

Automorphic

Northern (2–15 km)

6–15

Automorphic

Northern (15–50 km)

15–30

Hydromorphic

Northern (2–15 km)

2–9Hydromorphic

Northern (15–50 km)

2–28

Peat–bog soil

Northern (15–50 km)

6–9

Podzol–sandy soil

Northern (3–4 km)

2–13

Peat–podzol soil

Western (3–4 km)

1–10

Podzol–sandy soil

Western (4–5 km)

3–6

inundation in 1999, the flux of 137Cs into the
Pripyat River was much less than that of 90Sr. At
present, the percentage of mobile caesium in theupper contact layer of CEZ soils does not exceed
2–3%. The same data and the nature of 90Sr distri38

bution (see Fig. 4.6) demonstrate that the only
significant source of 90Sr wash-off at present is thefloodplain territories and watercourses crossing
the near zone of the Chernobyl nuclear power
plant.

0.14

10
9
8

0.1

Dnieper River upstream at Rechitsa

Annual flux 137Cs (TBq)

Caesium-137 wash-off (%)

0.12

Sozh River at Gomel
0.08

0.06

0.04

7

Besed
Dnieper
Iput
Sozh

6
5
4
3

0.02

2
0
0

1

2

3

4

5

6

7

8

9

Years since accident

137

FIG. 4.11. Reduction in Cs wash-off from the watershedssof the Dnieper River (upstream of the Rechitsa observation
point) and of the Sozh River at Gomel [4.26].

4.4.2.

1
0
1986

1988

1990

1992

1994

1996

1998

2000

2002

Year

FIG. 4.12. Annual fluxes of 137Cs in the Dnieper River andits tributaries from the far zone of radioactive fallouti[4.25].

Characteristics of runoff in Belarus

In the Belarusian section of the Dnieper Riverbasin about 40 000 km2 was contaminated withfallout of 137Cs in excess of 37 kBq/m2 (seeTable 4.2). The worst affected areas were the Gomel
and Mogilev regions (see Fig. 4.4). The contamination of the watershed areas is characterized byextreme heterogeneity. The levels of contaminationof soils with 137Cs generally ranged from 37 to 1480
kBq/m2 (1–40 Ci/km2), with some localized areas
above this range. Thus in the Kolyban settlement of
the Bragin district in the Gomel region, the levels ofcontamination with 137Cs vary from 170 to2400 kBq/m2. The maximum concentration of 137Cs
in the soils of the far zone was 5100 kBq/m2,
occurring at the Chudyany settlement of theCherikov district in the Mogilev region. The mainpart of 137Cs fallout entered the watersheds of therivers Sozh, Iput, Besed, Chechera, Pokot andBraginka (all in the Dnieper River basin).
The left side tributaries of the Pripyat Riverrelease radionuclides mainly from the territory of
Belarus, whereas the right side tributaries mainly
carry radionuclides from the Ukrainian part of thewatershed. The key points of observation ontransfer from watersheds is Mozyr for the Pripyat
River and Mogilev and Gomel (Sozh River) for theupper Dnieper River basin.
The contamination of the watersheds of theupper Dnieper and Pripyat Rivers with 90Sr is muchless (1–100 kBq/m2) than that recorded within the
Belarusian part of the CEZ (e.g. the Hoiniki districtof the Gomel region has a concentration of 1800
kBq/m2). High soil concentrations of 90Sr were also
recorded in the watersheds of the Sozh River at a

distance of about 250 km from the Chernobyl
nuclear power plant (e.g. the watershed of the
Senna River received a 90Sr contamination of about
30 kBq/m2, compared with about 140 kBq/m2 in theGomel region). However, most 90Sr contamination
occurred in the catchments of the CEZ, including
both the Ukrainian and Belarusian parts of this area(see Fig. 4.6).
The monitoring data from Belarus indicatethat the radionuclide fluxes into the Dnieper Riversystem have stabilized over the past 7–10 years andare now relatively low. The mean annual concentrations of 137Cs during the period 1987–2001 in thewater of the large and medium rivers of Belarus wasless than 0.01% of the total radionuclide inventories
in the watersheds (see Fig. 4.11). At present, 137Cs
runoff from the Belarus watershed does not
represent a substantial contribution to contamination of the Dnieper reservoirs.
The level of water contamination also does
not pose any significant risks for water use because,
according to the data of Belhydromet, the 137Csconcentration in surface waters during the past five
years remained at the level of 0.01–0.03 Bq/L, whichis over 100 times lower than the provisional national
limit for drinking water (10 Bq/L) for 137Cs and theequivalent limit (2 Bq/L) established in Ukraine.
Although the wash-off of radionuclides should
continue to be monitored, there is no justification
for remedial actions in the upper Dnieper Riversystem from a radiation safety viewpoint.
Figure 4.12 shows the annual fluxes of 137Csfrom the tributaries of the Dnieper River. The total
releases of 137Cs from the rivers of the upper
39

Dnieper River basin during the period 1987–2000
were as follows [4.25]:
(a)
(b)
(c)
(d)

hundred such water bodies of both natural andartificial origin. To date, detailed studies have been
carried out on only a few lakes. Analysis of available
data (see Table 4.11) for Lakes Svyatskoe(watershed of the Besed River) and Revucheye(watershed of the Iput River) shows that the current
radionuclide levels in water of 137Cs (8–9 Bq/L) and90
Sr (0.4–0.6 Bq/L) are close to the national
provisional permissible levels for drinking water(137Cs =10 Bq/L, 90Sr = 0.37 Bq/L) [4.27]. This topic
is discussed further in Section 9.3.5.

Sozh (Gomel): 22.2 TBq.
Dnieper (Rechitsa): 12.6 TBq.
Iput (Dobrush): 9.5 TBq.
Besed (Svetilovichi): 1.9 TBq.

The total releases of 90Sr from the rivers of theupper Dnieper River basin during the period 1990–
2000 were as follows:
(i)
(ii)
(iii)
(iv)
(v)

Sozh (Gomel): 3.4 TBq.
Dnieper (Rechitsa): 2.9 TBq.
Iput (Dobrush): 0.9 TBq.
Besed (Svetilovichi): 0.7 TBq.
Pripyat (Mozyr): 4.2 TBq.

4.4.3.

Characteristics of runoff in the
Russian Federation

Within the Russian Federation, the Bryansk
region has suffered most from Chernobyl fallout(see Fig. 4.4 and Table 4.2). The most contaminatedareas are five administrative districts in the southwest of the region (Gordeyevsky, Zlynkovsky,
Klintsovsky, Krasnogorsky and Novozybkovsky). In
August 1995 the sites with levels of 137Cs contamination of 37–185 kBq/m2 (1–5 Ci/km2) covered anarea of 6680 km2, those with 185–555 kBq/m2 (5–15
Ci/km2) an area of 2700 km2, those with 555–
1500 kBq/m2 (15–40 Ci/km2) an area of 1900 km2
and those with more than 1500 kBq/m2 (40 Ci/km2)
an area of 310 km2 [4.13].

By comparison, the wash-off of 90Sr from theterritory of the near zone of the Chernobyl nuclear
power plant during 1999 was about 3.7–4.4 TBq(100–120 Ci). From the above data, we conclude
that the near zone of the Chernobyl nuclear power
plant contributes the major fraction of total washoff of 90Sr to the Dnieper River system.
Although 137Cs concentrations in the surface
waters of the upper Dnieper River have reduced
markedly, those in the lakes have remained high.
Within the territory of Belarus there are several

TABLE 4.11. CONCENTRATIONS OF CAESIUM-137 AND STRONTIUM-90 IN THE WATERS OF
LAKES SVYATSKOE AND REVUCHEYE
Caesium-137 (Bq/L)

Strontium-90 (Bq/L)

Date of sampling
Svyatskoe

Revucheye

40

Water, solution

Water, suspension

Water, solution

5 September 1995

6.8

0.12

—

6 June 1996

4.5

0.07

—

9 October 1996

4.9

0.07

—

25 May 1998

4.7

0.06

0.3

25 May 1998

5.8

0.08

0.4

5 June 1998

1.5

0.23

—

5 June 1998

1.6

0.16

—

15 June 1999

9.0

0.008

0.007

8.0

0.05

0.02

5 June 1996

8.1

0.1

—

9 July 1997

5.4

—

—

9 July 1997

5.2

—

—

5 June 1998

6.0

—

—

Determination of 90Sr and plutonium isotopes
in the soil was performed mainly in the settlementsof the Bryansk region with the highest 137Cs depositions. In August 1995 there were 163 settlements inareas with 90Sr contamination of less than 3.7 kBq/
m2 (0.1 Ci/km2), 281 settlements within the range
3.7–18.5 kBq/m2 (0.1–0.5 Ci/km2), 40 settlements
within the range 18.5–37 kBq/m2 (0.5–1 Ci/km2) andseven settlements within the range 37–55.5 kBq/m2(1–1.5 Ci/km2) [4.13]. The areas most contaminatedwith 90Sr are seven settlements in the Zlynkovsky
district. The density of contamination of soil with
239,240
Pu in most investigated settlements was within
the range 37–185 Bq/m2 (0.001–0.005 Ci/km2), andnone exceeded 740 Bq/m2 (0.02 Ci/km2) [4.13].
There are no natural radiation abnormalities
in the Bryansk region. In the central regions of theEuropean part of the USSR, the level of soil
contamination from global fallout prior to theChernobyl nuclear power plant accident was, on
average, about 2.5 kBq/m2 of 137Cs, and about
1.6 kBq/m2 of 90Sr [4.1, 4.5]. Within the Bryansk
region there are several watersheds that drain into
tributaries of the Sozh and Iput Rivers. These
remained the main sources of radionuclide wash-offfrom Russian territory after the Chernobyl
accident. Caesium-137 was considered to be the key
radionuclide washed out from this catchment. Its
release into the rivers decreased with time, firstly
because of a gradual reduction in the mobile formsof 137Cs in the soil and secondly because of verticalmigration into the deeper soil layers.
Prior to the Chernobyl nuclear power plant
accident in 1986, the State Hydrometeorological
Service of the USSR carried out regular monitoringof the content of 90Sr and tritium in surface waters
and individual measurements of 137Cs concentrations. Based on the results of these measurements,
the pre-Chernobyl concentrations in river waters of
the Bryansk region were assumed to range from 14
to 20 Bq/m3 for 90Sr and from 0.2 to 1.3 Bq/m3 for137

Cs [4.13]. After the accident, the radioactive
contamination of the rivers in the territories of thesouth-western districts of the Bryansk region
increased markedly. During the period of the springinundation of 1987, the content of 137Cs in the Iput
and Besed Rivers reached 5000 Bq/m3 andexceeded the pre-Chernobyl level by three to fourorders of magnitude [4.28]. At present, the concentrations of 137Cs in the rivers of the Bryansk region
have reduced significantly and, as a rule, do not
exceed 10 Bq/m3 [4.13].
The main rivers that flow through the mostcontaminated territory (Bryansk region) of the
Dnieper River basin are the Iput, Besed and Snov.
Their main characteristics are presented in Tables
4.12 and 4.13. The Iput and Besed Rivers aretributaries of the Sozh River, and the Snov is atributary of the Desna River (see Fig. 2.1). The SnovRiver originates in the Bryansk region and runs into
the territory of Ukraine. The sources of the Besed
and Iput Rivers are situated in Belarus and theSmolensk region of the Russian Federation, respectively. Both rivers empty into the Sozh in the
territory of Belarus. The main part of the Besed
River runs through Belarus, the main part of the
Iput River is in the Bryansk region.
Assessment studies show that, just as in
Belarus, the levels of contamination in the rivers
flowing through the affected areas of the RussianFederation have decreased with time and now
approach pre-Chernobyl levels. Consequently, there
are now no limitations on local water use from the
Sozh and Iput Rivers.
The most contaminated areas after the
Chernobyl accident have been, and remain, theclosed lakes. Thus in lake Svyatoe, located in thefloodland of the river Besed, the 137Cs concentration
at the beginning of the 1990s was twice the national
intervention level for drinking water (11 Bq/L), andin 2000 it remained at about 10 Bq/L [4.13, 4.30,
4.31].

TABLE 4.12. MAIN RIVERS OF THE CONTAMINATED DISTRICTS OF THE BRYANSK REGION[4.13, 4.29]
Total length(km)

Length in theregion (km)Total watershedarea (km2)

Watershed in theregion (km2)

Annual flow
(km3)

Iput

475

290

10 694

7520

1.00

Besed

256

54

5 406

1610

0.33

Snov

253

125

8 700

2620

0.16

41

TABLE 4.13. RADIONUCLIDE INVENTORY IN THE WATERSHED OF THE IPUT RIVER IN
INDICATED SECTIONS IN THE RUSSIAN FEDERATION
Distancefrom the Chernobyl
nuclear power plant(km)

Watershed area
(km2)

Iput–Krutoyar

170

Iput–Belovodka

230

Iput–Kazarichi
Iput–Tvorishino

Inventory in watershed(1012 Bq)
Caesium-137

Strontium-90

4 019

34

2.2

5 356

48

3.3

250

5 864

64

4.1

260

6 041

122

4.9

Iput–Uscherpie

300

8 319

604

13.7

Iput–Bobovichi

330

9 174

1265

24.1

Iput–Vyshkov

360

9 614

1676

33.2

Iput–Dobrush (Belarus)405

10 1002240—

4.4.4.

Chernobyl exclusion zone, Ukraine

During the initial accident release period after
26 April 1986, the neighbouring areas (water
catchments, floodplains and surface water bodies
around the Chernobyl nuclear power plant (seeFig. 4.5))
weredirectly
contaminatedbyatmospheric fallout. Surface water contamination
was characterized by a high level of radiation from awide spectrum of short lived radionuclides. The
total beta contamination of the open water bodies
near the Chernobyl nuclear power plant reachedapproximately 37 000 Bq/L (1 mCi/L). The beta
activity of the Pripyat River water downstream of
the Chernobyl nuclear power plant in early May
1986 exceeded 370 Bq/L. The range of radioactivity
in the Dnieper River near the main water intake ofKiev city (130 km downstream from the Chernobyl
nuclear power plant) was 3.7–370 Bq/L in May andJune 1986. The largest contribution to watercontamination in the first months after the accident
was caused by 131I. Since 1987, 137Cs and 90Sr havebecome the most important radionuclides in termsof contamination and dose to the population.
Detailed studies of pollution from watersheds
have shown that the most contaminated areas that
could be flooded are portions of the left and rightbanks of the Pripyat River floodplain upstream of
the Chernobyl nuclear power plant (Fig. 4.13).
Figure 4.14 shows the contaminated zones andcatchment areas; the activity of 90Sr in each area isgiven in Table 4.14.
In the first phase of the mitigation of theconsequences of the Chernobyl accident, considerable effort and resources were spent on actions to
reduce contamination of surface waters. In
42undertaking these actions, emphasis was placed on
the prevention of secondary contamination of water
systems due to wash-off of radionuclides fromcatchments and transport of radionuclides by river
systems from the near zone of the Chernobyl
nuclear power plant to relatively clean areas. The
primary countermeasures undertaken included:
(a)
(b)

(c)
(d)
(e)
(f)
(g)

Dispersion of sorbents in the Pripyat River(1986);
Building an embankment along the Pripyat
River in the near zone of the Chernobyl
nuclear power plant (1986);
Setting up bottom traps (1986–1987);
Building filter systems for dams (1986–1987);
Setting up a drainage barrier around thecooling pond (1987–1988);
Establishing the left bank flood control dyke
(1993);
Establishing the right bank flood control dyke
(1998).

The soil in this area is heavily contaminatedwith Cs and isotopes of plutonium. Figure 4.15
shows 137Cs and 239,240Pu spatial contamination of
the most contaminated catchments in the CEZ.
These radionuclides are firmly bound to soil
particles and their wash-off from the floodplain
areas of the CEZ is of much less importance interms of secondary contamination and human dose
via aquatic pathways.
The contribution of all possible sources of137
Cs runoff from the far zone into the Pripyat Riverbasin has stabilized at a level of about l TBq/a (25–
30 Ci/a). This represents about 80–85% of the total
input of 137Cs into the Kiev reservoir over the past137

kBq/m2

20 000
7500
4000
2000
750
400
200
75
40
20
0

Scale 1:200 000· State border· Railway· Road· Towns and villages· Rivers and lakes· Exclusion zone border© UIAR, 1998

90

FIG. 4.13. Contamination density of Sr within the floodplain areas near the Chernobyl nuclear power plant [4.32].

2
1

9

13

4

7

12

11
15

16

10
8
3
6
5

14

15

FIG. 4.14. Contaminated zones and catchment areas in the vicinity of the Chernobyl nuclear power plant.The 90Sr activities inareas 1–16 are listed in Table 4.14.

43

TABLE 4.14. ACTIVITY OF STRONTIUM-90 (1997) IN THE CONTAMINATED ZONES AND
CATCHMENT AREAS SHOWN IN FIGURE 4.14
Area

Description of area

Size ofarea(km2)

Strontium-90
activity(TBq)

1

Left bank water reclamation area

71.5

138

2

Braginka River catchment (upper part)

37.1

24

3

Pripyat water reclamation system

147

31

4

Area inside of the left water protective dyke and flood control dyke (polder)

14.7

72

5

Left bank floodplain area

61.3

22

6

Kopaci water reclamation system

79.6

212

3.86

24

7

Catchment of the Yanov River (Pripyat Bay)

8

Sakhan River catchment

204

78

9

Benevka floodplain area

45.6

17

10

Chernobyl nuclear power plant industrial site

6.89

50

11

Sandy plateau waste storage site

13.4

23

12

Catchment of Lake Azbuchin

2.81

32

13

Catchment of Rozhave River

71.0

1

14

Chernobyl city

15.8

4

15

Uzh River catchment

803

53

16

Braginka River catchment (middle part)

39.4

4

Total

10–12 years. The contribution of sources located in
the near zone of the Chernobyl nuclear power plantincreases in high water years (e.g. 1999), in periodsof continuous showers (e.g. 1993) and during otherextreme hydrological events (such as occurred in1991 and 1994) that result in flooding of the mostcontaminated zone. In contrast, the main contribution of 90Sr contamination (60–75%) comes fromthe contaminated floodplains of the Pripyat River in
the near zone of the Chernobyl nuclear power plantand from direct drainage from the contaminatedwater bodies and polder systems.
At present, the CEZ zone may be considered
as a regional hot spot from which the main flux ofradioactive contamination into the Pripyat Riveroriginates. The radioactive contamination of the
Pripyat River arises from several sources. The
contributions of various sources based upon observations by Ecocentre are presented in Table 4.15 fora typical low water year (1997), a high water year
(1999) and an average water year (2001).
Drainage from the left bank polder throughthe water protective structure No. 7 depends on
the water flow and constitutes 10–16% of the total.
44

1617

786

As a result of engineering works performed at thepolder in 2001 (cleaning of the waterbed of thereclamation channels and reconstruction of theinlet facility for water discharge into the Pripyat
River), the average water level at the polder was
reduced by 1.8 m, and the specific activity of 90Sr
was reduced by a factor of two. As a consequence,
it is expected that radionuclide release from thepolder into the Pripyat River will continue todecrease. The release from the Chernobyl nuclear
power plant cooling pond can be determined frommeasurements at the filtration streams, thesouthern drainage canal and the Glinnitsa River.
This release is the most stable when measured in
activity units (GBq or Ci); in percentage terms it
increases during low water periods and constitutes
from 8% during a high water year up to 15%
during a low water year. Annual releases to the
Pripyat River are shown in Fig. 4.16. The main
source of water contamination is the radionuclides
in the bottom sediments. The activity of the major
radionuclides in the sediments (as of 2001) is asfollows: 137Cs = 160 ± 25 TBq, 90Sr = 24 ± 5 TBq,
239,240
Pu = 0.52 ± 0.15 TBq, 238Pu = 0.26 ± 0.07 TBq,

(a)kBq/m220 000
7500
4000
2000
750
400
200
75
40
0

Scale 1:200 000· State border· Railway· Road· Towns and villages· Rivers and lakes· Exclusion zone border(b)kBq/m21000.0
400.0
200.0
100.0
40.0
20.0
10.0
4.0
1.0
0.4
0.0
0.0

Scale 1:200 000· State border· Railway· Road· Towns and villages· Rivers and lakes· Exclusion zone border© UIAR, 1998

FIG. 4.15. Spatial radioactive contamination by 137Cs (a) and 239,240Pu (b) within the CEZ.

45

TABLE 4.15. MAIN SOURCES OF STRONTIUM-90 TRANSFER INTO THE PRIPYAT RIVER
DURING TYPICAL YEARS
Strontium-90 migration (TBq)

Relative contribution (%)

1997

1999

2001

1997

1999

2001

Pripyat River: entrance into the CEZ

0.80

3.21

1.29

26.1

29.9

36.2

Drainage from the left bank polder

0.33

1.39

0.57

10.8

12.9

16.0

Surface wash-off, groundwaters

1.18

5.21

0.92

38.6

48.5

25.8

Filtration streams of the cooling pond

0.13

0.08

0.10

4.2

0.7

2.8

Glinnitsa River

0.22

0.27

0.21

7.2

2.5

5.9

Sakhan River

0.02

0.04

0.05

0.7

0.4

1.4

Uzh River

0.17

0.27

0.20

5.6

2.5

5.6

Braginka River

0.21

0.28

0.22

6.9

2.6

6.2

Total within the limits of the CEZ

2.26

7.54

2.27

73.9

70.1

63.8

Total migration beyond the limits of the CEZ

3.06

10.75

3.56

100

100

100

241

Am = 0.67 ± 0.19 TBq and 241Pu = 20 ± 5 TBq.
The cooling pond is assessed as a hot spot in
Section 9.3.2.
The total contribution of Pripyat Rivertributaries (Uzh, Braginka, Sakhan) over the past
five years did not exceed 9–13% (see Table 4.15).
Accordingly, remedial measures in the floodland of
the Braginka River and at the reclamation systems in
the CEZ are not considered nowadays as a priority.
The annual contribution into the river ofvarious groundwater and surface sources fromlocalized areas within the Chernobyl nuclear power
plant zone may contribute from 25% to 50% of the90
Sr release, depending on the water flow that year
and the peculiarities of the flooding of the contaminated territory.
Thus the main potentially regulated sources of
the current secondary contamination are thefollowing:(i)Flood prone sections along the river in thenear zone of the Chernobyl nuclear power
plant that have yet to be dyked;(ii) Areas of the first over-floodplain terrace
along the Chernobyl nuclear power plantcooling pond;(iii) Seepage into the river;(iv) Controlled surface creeks from the polder
reclamation system of the left bank within the
CEZ.
According to the assessments of Ecocentre,
the present transfer of 90Sr via groundwater(without consideration of the Chernobyl nuclear
46

power plant industrial site, the Chernobyl shelter orthe cooling pond) does not exceed 0.04 TBq/a.
Taking into account the transfer of the filtrationwaters from the water body and the groundwaterflow under the shelter, the contribution of theunderground waters may constitute 0.2–0.4 TBq/a.
As noted in Section 3, some contaminatedmaterial from the Chernobyl site was buried within
the CEZ. During periods of inundation of thefloodplain, the waste disposal sites contribute to therelease into the Pripyat River. Further informationon these burial sites is provided in Section 7, and adetailed description is available in the documents of
the administration of the CEZ, in the annual reportson the results of radiation monitoring in the CEZ
and in the literature (e.g. Refs [4.33–4.35]). This
literature indicates that, at present, the need forredisposal of the majority of the dumps in the
Chernobyl nuclear power plant zone is notapparent, since the total release of the most mobile
radionuclide, 90Sr, from all disposal sites into the
Pripyat River does not exceed 0.04–0.08 TBq/a. The
only concern is direct flooding of the near surface
disposal pits located along Yanov Creek.
The Institute of Geological Science of the
National Academy of Science of Ukraine has madea long term conservative prediction of 90Sr transferfrom the waste disposal sites into Pripyat Bay andLake Azbuchin. On the territory between the bay
and the lake there are point sources such as the Red
Forest, Stroibaza, Yanov and Neftebaza radioactive
waste temporary storage sites (see Section 7 forfurther information on these sources). The groundwaters from the Chernobyl nuclear power plant

The annual total inputs of 137Cs and 90Sr into
the cascade of reservoirs from the Pripyat andDnieper catchments after the accident are as
follows:

70.0

Strontium-90 (Ci/a)

60.0
50.0
40.0

— 0.59 TBq and 0.7 TBq, respectively, in 1986;— 0.49 TBq and 7.7 TBq, respectively, in 1989;— 0.30 TBq and 7.8 TBq, respectively, in 1991;— 0.03 TBq and 8.2 TBq, respectively, in 1999.

30.0
20.0
10.0

2000

2001

1999

1998

1996

1997

1995

1993

1994

1991

1992

1989

1990

1988

0.0

Year
90

FIG. 4.16. Annual Sr radionuclide releases from thecooling pond to the Pripyat River. Data of the CREM
(Chernobyl Ecocentre). Note: 1 Ci = 37 GBq.

industrial site and the shelter are released into Lake
Azbuchin. The results of the simulation arepresented in Table 4.16. Conservative modelling
predicts that the total amount of 90Sr transferredfrom the disposal sites over 300 years will not
exceed 15 TBq.
Thus, according to the forecasts, theunderground fluxes from the disposal sites and themost contaminated spots within the near zone of theChernobyl nuclear power plant will, even in 60–
100 years’ time, release relatively small quantities of90
Sr into the Pripyat River (i.e. a maximum of
130 GBq/a). The transfer from the CEZ as a whole
may reach 0.8 TBq/a. The maximum 90Sr contamination from underground waters is expected in the20th to 30th year after the accident, and thereafter
the contribution from underground sources will
decrease due to radioactive decay.
It should be noted that there is considerable
uncertainty in the assessment of the contribution of
the Chernobyl nuclear power plant industrial site
and the shelter to groundwater contamination, due
to many factors, including the complexity of theradionuclide migration conditions. Section 9.3.3
gives a detailed assessment of potential
groundwater contamination from the shelter.
The main feature of radionuclide release fromthe contaminated watersheds to the Kiev reservoir
over the 17 years since the accident is the significant
decrease in 137Cs influx to the reservoir; however,90
Sr release to the river network continues to besignificant. Since 1992 the rate of 90Sr release to the
Pripyat River has been reduced due to water
protection measures (dyke construction) on thefloodplain near the Chernobyl nuclear power plant.

The differences in the behaviour of the radionuclides are also apparent in the fact that a largepart of the 137Cs, as well as some other radionuclides, is associated with suspended particles in thewater, whereas essentially all the 90Sr is in the
dissolved state.
After the spring and summer of 1986 (whendirect radioactive fallout on to the surface of water
bodies took place), the most significant sources of
surface water contamination of the Dnieper River
have been surface runoff from the contaminatedfloodplains and catchment areas as well as infiltration of heavily contaminated water from thecooling pond and other water bodies into the river.
The first flood period in 1987 showed that the main
sources were the whole catchment of the upper partof the Pripyat River basin and a significant part of
the upper Dnieper River catchment (mainly the
Sozh River). From 1996 to the present, more than
70% of annual radionuclide input has been due tosources situated inside the CEZ.
Since the Chernobyl accident, no long periodsof high river water or flooding have occurred in thecontaminated areas. The spring water flow of the
Pripyat River, with discharges of 800–2200 m3/s, has
not exceeded the normal flood condition. The
maximum possible Pripyat River discharge canexceed 5000 m3/s (as occurred in 1979). Afterflooding of the riverplain in 1988 and 1991, it
became clear that, unless mitigation actions were
implemented in the contaminated area, thefloodplain would remain a potential hazard wellinto the future. For this reason, after 1992 remedialactions focused on the prevention of further
significant removal of radionuclides from the
Pripyat River floodplain. Significant flood events
took place in 1994 and during the spring of 1999,
when the maximal water discharge reached about3000 m3/s. In particular, during the high flood of1999 the heavily contaminated terraces of the riverfloodplain near the Chernobyl nuclear power plant
were inundated significantly (the flooding event
lasted for about two weeks), and radionuclide
47

TABLE 4.16. FORECAST OF STRONTIUM-90 RELEASE VIA GROUNDWATERS TO SURFACEWATERS IN THE NEAR ZONE OF THE CHERNOBYL NUCLEAR POWER PLANT [4.36]
Receivingwater body

Watershed
area
(km2)

Strontium-90
inventory(TBq)

Maximalrelease(GBq/a)Time tomaximal release(a)Integral releaseover 300 years(TBq)

Watershed of
Pripyat Creek

Pripyat
Creek

7

111

63

65

4.2

Watershed of
Lake Azbuchin

Lake
Azbuchin

1.8

37

63

33

3.9

Watershed of
Semikhody Creek

Semikhody
Bay

8

19

6.3

65

0.4

Red Forest
radioactive waste
temporary storagesite

Pripyat
Creek

1

74

3.3

200

0.23

Yanov radioactive
waste temporarystorage site

Pripyat
Creek

4

15

0.22

220

0.015

Stroibaza radioactive
waste temporarystorage site

Pripyat
Creek

1.8

222

81.4

110

5.3

Chernobyl nuclear
power plant
industrial site

Lake
Azbuchin

0.25

59

37

145

1.4

23.85

537

129.5

Total

releases occurred mainly from the right bank (seeFig. 4.17). Figure 4.18 shows peaks corresponding tosignificant wash-off of 90Sr during the spring floodsof 1988, 1991, 1994 and 1999.
In the initial period after the accident, 90Sr
wash-off from the far water catchments was higher
than from the Chernobyl nuclear power plant
accident zone. This can be explained by the

15.4

relatively low mobility of 90Sr in fuel particles
during that period. Subsequently, as the fuelparticles disintegrated, the mobility of radionuclidesof 90Sr increased. In contrast, 137Cs quickly became
fixed to the soil minerals (especially clays). Overtime, the relative contribution of 90Sr increased, and
it is now the most important radionuclide in termsof contamination of the Dnieper water system.
Figure 4.19 shows the ratio of dissolved 90Sr todissolved 137Cs as a function of time. Again, the

Bq/L

10.0

1.00

3
I

0.10
2

1987 1988 1989 1990 1991 1992 1993

1994 1995 1996 1997 1998 1999

Year

FIG. 4.17. Dyke at Pripyat Bay and inundated riverside
land within the CEZ during the spring flood, April 1999.

48

FIG. 4.18. Radionuclide concentration (10 day averages) in
the Pripyat River. 1: 137Cs, dissolved; 2: 137Cs, particulate
phase; 3: 90Sr.

50
45
40
Sr, soluble/Cs, soluble

35
30
25
20
15
10
5

0
1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999

Year
90

FIG. 4.19. Ratio of Sr to 137Cs activity concentration in
Pripyat River water in the city of Chernobyl.

spring flood events in 1991, 1994 and 1999 areclearly discernible as sharp peaks when thefloodplains became inundated.
Significant reduction in 90Sr release from the
CEZ is expected after completion of a whole seriesof flood control (water protective) measures on theright bank of the river, drying-up of the coolingpond and completion of the water runoff control
system on the left bank polder. In particular, during
2001, 10 km of canals of the left bank polder (reclamation) system were dredged and manyengineering works such as flow gates, drains andothers were restored and repaired. These works
allowed better control of runoff from the polder
system.
Recently, the water management authorities
in Belarus and Ukraine agreed to justify actions
concerning construction of a bypass channel along
the Belarusian–Ukrainian border in the CEZ. The
construction of a 10 km long channel (between thesettlements of Krasne and Zimovishche) would
direct surface runoff from Belarusian catchments
during high water periods straight to the Braginka
River, which flows into the Kiev reservoir, thus
avoiding the most contaminated lowland areas
within the CEZ. This proposal has considerable
merit, since it would reduce the downstream 90Sr
source term during flood conditions.

4.5. ANALYSIS OF KEY PROCESSESGOVERNING THE LONG TERM
DYNAMICS OF RADIOACTIVECONTAMINATION OF THE
DNIEPER WATER SYSTEM
The initial radioactive contamination after the
Chernobyl accident resulted from direct fallout on
the water surface. Thereafter, the dynamics ofradioactivity in river water were controlled by theredistribution of radionuclides between the waterand the bottom sediments. In the following period,
which started approximately one year after the
fallout [4.37], the contamination of river water
depended on inflow of radionuclides from thecatchment areas. The model proposed in Ref. [4.37]
assumes that the radionuclide concentration in riverwater during this time period is directly proportional to the average concentration of its
exchangeable form in the surface soil layer on thecatchment. This means that the key processes
responsible for the long term dynamics of radionuclides in river water are vertical migration andexchange of radionuclide species in soils on thecatchment. For the case where the bulk of the radionuclides deposited on the catchment are in the formof condensation particles, the time dependence ofradionuclide concentration in the dissolved phasecan be expressed as follows:Cw =Ê Ê u2ˆˆd ˆ
Ê
+ lt˜ ˜
exp
1
+
Á-Á
˜¯
ÁË
¯¯
pDE t
t
Ë Ë 4 DE
K

(4.1)
where
K
DE
u
d
l
t

is a site specific parameter (Bq/m2);
is the effective diffusion coefficient insediments (m2/a);is the effective velocity of convective transport(m/a);
is the kinetic parameter of radionuclide
fixation in soil (a0.5);
is the radioactive decay constant (a–1);
is the time (a).

Equation (4.1) predicts with adequate
accuracy the long term dynamics of 137Cs in thethree rivers (Irpen, Teterev and Uzh) flowing acrossthe southern part of the radioactive trace formed
after the Chernobyl accident [4.37]. It also yields
satisfactory results for the rivers flowing throughother territories with similar soil and fallout characteristics. As an illustration, Fig. 4.20 shows
calculated and experimental dependences of themean annual concentration of 137Cs in the Iput
River (at the Dobrush measuring section). Goodagreement of the calculated and measured concentrations suggests that the underlying assumptions
regarding the physicochemical mechanisms arevalid.
490.3

Caesium-137 (Bq/L)

Caesium-137 (Bq/L)

2

1.5

1

y = 1.2271x
R2 = 0.9406

0.2

0.1

0.5
0
0

0
0

2

4

6

8

10

12

Time after the accident (years)

FIG. 4.20. Predicted (line) and measured (points) activity
concentration of 137Cs in the Iput River (cross-section at
Dobrush). Experimental data were taken from Ref. [4.39].

Caesium-137 (Bq/L)

1
0.8
0.6
0.4
0.2
0
0

5

10

15

20

Time after the accident (years)

FIG. 4.21. Reconstructed activity concentration of 137Cs in
the Snov River (cross-section at Khoromnoe).

The advantage of Eq. (4.1) is that a prediction(or reconstruction) of the long term dynamics ofradionuclide concentration in river water can bemade based on measurements made over a
relatively short period of time. In particular, for the
Snov River, along which transboundary transport ofradionuclides from the Russian Federation to
Ukraine occurs, only fragmentary results ofmeasurements of 137Cs specific activity made in 1998
are available [4.13]. Based on these data, and using
Eq. (4.1), the dynamics of the contamination of thisriver over the period starting from 1987 to thepresent day can be reconstructed (see Fig. 4.21).
Equation (4.1) can also, most probably, beused for estimating the distribution of radionuclides
over the whole length of the river, provided data forone or several measuring sections and a catchment
contamination map are available. Earlier studies
suggest that the radionuclide concentration in ameasuring section is directly proportional to theaverage contamination density of that part of theriver catchment upstream of the given measuringsection (see Fig. 4.22).
50

0.05

0.1

0.15

0.2

Contamination density (MBq/m2)

14

FIG. 4.22. Concentration of 137Cs in the Iput River in 1991–
1993 as a function of upstream watershed contamination
density. Experimental data were taken from Ref. [4.40].

During the years after the Chernobyl accident
the radiocaesium activity concentration in mostcontaminated aquatic ecosystems decreased
markedly. Lakes with no permanent inflows andoutflows (closed lakes), however, still present a
radioecological problem that is expected tocontinue for some time. This is explained by the factthat the main mechanism underlying the reductionof the radionuclide concentration in the water ofsuch lakes is a fairly slow migration to the lower
layers of bottom sediments. Given negligible runoff
and sedimentation, the dynamics of radiocaesium inlake water is described by a simple equation with
only one unknown parameter [4.38]:

C w (t ) =s
K d pDE texp( - l t ) =Atexp( - l t )
(4.2)

where
Cw
A
Kd

is the radionuclide activity concentration in
the water layer (Bq/m3);
is a constant for a given lake and radionuclide;is a dimensionless distribution coefficient thatis equal to the ratio of radionuclide activity
concentration in the water to that in thesurface of the sediments (on a volume basis).

Equation (4.2) was tested against 137Cs
activities measured between 1993 and 1999 in Lake
Svyatoe in the Bryansk region of the RussianFederation (see Fig. 4.23). It can be seen that the137
Cs concentration in the lake is actually equal tothe intervention level effective in the RussianFederation today (11 Bq/L) and will remain high formany years. Given the fact that the 137Cs

concentration in fish in these lakes is also quite high,it may be concluded that, as a result of theChernobyl accident, the lifestyle of the local
inhabitants has been affected for a considerable
time. Hence, the lakes without outflow, in a sense,
can be considered to be significant hot spots (seeSection 9.3.5).

Caesium-137 in water (Bq/L)

30
25
20
15
10
5
0
6

8

10

12

14

Time after the accident (years)

FIG. 4.23. Measured versus modelled 137Cs activity
concentration in Lake Svyatoe water. Modelled activity
dynamics are given by the solid line, measured values bycircles. Standard deviations of the mean for measured
values are also shown.

4.6. TRANSBOUNDARY FLUXESOF RADIONUCLIDES IN THE
DNIEPER RIVER BASIN
The transboundary movement of radionuclides in rivers is determined by water discharge
rates and radionuclide volumetric activity at theborder crossing. Table 4.17 gives the average the

TABLE 4.17. AVERAGE TRANSBOUNDARY FLOW OVER MANY YEARS OF THE MAJOR
RIVERS OF THE UPPER DNIEPER RIVER BASIN MOST CONTAMINATED BY THE CHERNOBYLACCIDENT [4.29]
Annual runoff (km3)
Flow from

Flow toProbability
Mean
75%

90%

95%

Dnieper

RussianFederation

Belarus

3.65

2.96

2.51

2.25

Dnieper

Belarus

Ukraine

18.6

15.0

12.5

11.2

Pripyat

Belarus

Ukraine

12.2

9.16

7.25

6.29

Braginka

Belarus

Ukraine

0.09

—

—

—

Sozh

RussianFederation

Belarus

1.84

1.41

1.14

1.00

Iput

RussianFederation

Belarus

1.57

1.19

0.94

0.81

Besed

Belarus

RussianFederation

0.52

0.41

0.33

0.29

Besed

RussianFederation

Belarus

0.76

0.60

0.49

0.43

Snov

RussianFederation

Ukraine

0.35

0.27

0.22

0.20

Seim

UkraineRussianFederation

0.27

0.21

0.16

0.14

Seim

RussianFederation

Ukraine

2.61

2.03

1.64

1.44

Desna

RussianFederation

Ukraine

5.11

4.24

3.61

3.30

51

characteristics over many years of the transboundary water flow of major rivers in the regions
most contaminated after the Chernobyl accident
and of rivers flowing through the areas surrounding
the Smolensk and Kursk nuclear power plants.
The average values in Table 4.18 can be used
to forecast transboundary fluxes of radionuclides.
For retrospective estimates it is better to use datafrom routine observations for a given time period.
Radionuclide concentration in rivers isnormally measured in cross-sections lying several
tens of kilometres from the border. The exceptions
are two measuring sections on the Belarusian–
Ukrainian border (Belaya Soroka on the Pripyat
River and Gden on the Braginka River) and the
Vyshkov measuring section on the Iput near theRussian–Belarusian border. For the latter crosssection, however, only limited data are available.
Systematic monitoring of radioactive contaminationin rivers flowing through the areas around the
Kursk and Smolensk nuclear power plants (theDesna and Seim Rivers) is carried out only atmeasuring sections in the immediate proximity of
the nuclear power plants. Therefore, in most cases
to estimate radionuclide concentrations at theborder, extrapolation methods are required, such as
the concentration dependence on catchment
contamination density (see Fig. 4.22). In those cases
when limited observational series are available,
extrapolation of concentration over time can beused.
Estimates of the transboundary transport ofradionuclides in the Dnieper River basin have been

made starting from the early phase of the accident.
It was shown that, in 1987, the transport of 137Csfrom the Sozh catchment was about 80% of its flow
to the Kiev reservoir with the water of the Dnieper
River [4.28]. In turn, about half of the 137Cs wastransported to the Sozh River via the Iput River,whereas the input from the Besed River was only
about 8%.
The concentration of radionuclides in rivers
has decreased significantly with time. The
dependence of annual outflow of 137Cs from theterritory of the Russian Federation to Belarus via
the Iput River suggests that most of the radionuclides were transported across the border in the firstfew years after the accident. Table 4.18 contains
estimates of transboundary flows of 137Cs and 90Sr
for the period 1987–1999 based on the data derived
from the measuring sections closest to the borders.
It can be seen that over the 12 year period the transboundary transport of 137Cs did not exceed 1% of
the amount of radionuclides deposited on thecatchment area in 1986. The transboundary
movement of 90Sr was somewhat higher, but did notexceed 5% for the same period.
Figures 4.24 and 4.25 show the annual fluxes
on the Pripyat, Iput and Besed Rivers near theborders. The transboundary migration of 137Cs has
decreased markedly with time. However, the transboundary migration of 90Sr has fluctuated from year
to year depending on the rainfall and extent offlooding (see Figs 4.24(b) and 4.25(b)).
The above analysis indicates that the existing
system of monitoring of radioactive contamination

TABLE 4.18.
ESTIMATES OF TRANSBOUNDARY TRANSPORT OF CAESIUM-137 AND
STRONTIUM-90 IN MAJOR RIVERS FLOWING THROUGH CHERNOBYL AFFECTED REGIONS[4.26, 4.41]
Years

Iput River

Besed River

Pripyat River

Dnieper River

SectionDobrushSvetilovichi

Belaya Soroka

Nedanchichi

BorderRussianFederation–
Belarus

RussianFederation–
BelarusBelarus–
UkraineBelarus–
Ukraine

9.1

1.9

31.3

43.1

0.4

0.1

0.7

0.56

0.9

0.7

52.6

34.3

2.2

1.9

4.3

3.6

Caesium-137 outflow(TBq)

1987–1999

Caesium-137 (per centcatchment inventory)
Strontium-90 outflow(TBq)
Strontium-90 (per centcatchment inventory)

52

1990–1999

9

Belaya Soroka
Chernobyl(a)7

Chernobyl

9

Caesium-137 (TBq)

Caesium-137 (TBq)

8

6
5
4
3

(a)

8

Border

7
6
5
4
3
2
1

2

0

1

1987 1988 1989 1990 1991 1992 1993 1994

1995 1996 1997 1998 1999 2000

Year

01987 1988 1989 1990 1991 1992 1993 1994

1995 1996 1997 1998 1999

2000

Year
Strontium-90 (TBq)

18

(b)

16

Strontium-90 (TBq)

Chernobyl
Border

20

20

14
12
10

18

(b)

16
14
12
10
8
6
4
2

8

0
6

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Year

4
2
0
1987 1988 1989 1990 1991 1992 1993 1994

1995 1996 1997 1998 1999 2000

Year

FIG. 4.25. Annual fluxes of (a) 137Cs and (b) 90Sr in the Iput
and Besed Rivers near the Russian Federation–Belarus
border.

FIG. 4.24. Annual fluxes of (a) 137Cs and (b) 90Sr in the
Pripyat River near the Belarus–Ukraine border and at
Chernobyl.

4.7. RADIONUCLIDES IN THE
DNIEPER RESERVOIRS
4.7.1.

Assessment of radionuclide influx into
the cascade

The current state of radioactive contaminationof the Dnieper reservoirs is determined first by theamount of radionuclides transferred by the rivers
from the contaminated territories. From themoment that direct aerosol fallout on to the water
surface ceased, the runoff from the contaminatedCaesium-137
Strontium-90

10.000Bq/L

in the Dnieper River basin is not geared towards
monitoring transboundary fluxes. In order toestimate these fluxes, various methods of time andspace extrapolation have to be used. The accuracyof these methods seems to be sufficient for thecurrent purpose, given that the transport of radioactivity across the borders of Belarus, the RussianFederation and Ukraine is very low. However,should an accident or incident occur, thedeficiencies of the monitoring systems in the
Dnieper River basin may preclude obtaining correct
estimates of transboundary fluxes of radionuclides
by the water pathway.

100.000

1.000

0.100

0.010

0.001
1986

1988

1990

1992

1994

1996

1998

2000

2002

Year

FIG. 4.26. Dynamics of radionuclide concentration in themeasuring section of the Kiev hydropower plant, 1986–
2001.

watersheds on the Pripyat and upper Dnieper
Rivers was the only significant source of radionuclide input into the reservoirs. The radionuclides
enter these rivers mainly during periods of rain andsnow melting in the contaminated territories (seeFig. 4.26) and during the periods of flooding of theriver floodplain in the near zone of the Chernobyl
nuclear power plant. The influence of othertributaries is unimportant.
The waters of the upper Dnieper River,though transporting some 137Cs and 90Sr, also dilutethe more contaminated runoff waters of the Pripyat
River. Another significant tributary influencing thedilution of contamination released from the
Chernobyl nuclear power plant zone is the Desna
River. Calculations showed that, on account ofcomplete mixing of waters from the Pripyat River53

was no trend in the migration of 90Sr, although there
were fluctuations from year to year. Accordingly,
the structure of the radioactive runoff has changed:
the contribution of 90Sr has increased relative to137
Cs (in 1987 the activity ratio 90Sr:137Cs was 0.8; in
1994 it was 4.0).
Figure 4.26 shows the trends in 90Sr and 137Csconcentration at the Kiev hydroelectric power
station. Figure 4.27 shows corresponding data at themouth of the Desna River. The large scatter in datafor 137Cs from the mid-1990s partly reflects thestatistical errors in analysis at near-backgroundconcentrations.

and from the Dnieper River in the bowl of the Kiev
reservoir, the concentration of 137Cs in the water isreduced by a factor of two, and that of 90Sr by afactor of almost three (mean annual assessments
over a 15 year period of observations).
Table 4.19 shows annual data on the influx of137
Cs and 90Sr from various rivers into the Dnieper
cascade.
The data on the dynamics of contamination of
the above rivers show that the discharge of radioactivity with these rivers has significantly reduced
over time, and substantial increases of radionuclide
content (mainly 90Sr) in the reservoir are observed
only during periods of flooding.
Analysis of monitoring data reveals certain
trends in radioactive contamination of the watersfrom the post-accident period. The main trend is the
reduction of total radionuclide migration into thecascade of the Kiev reservoirs (Table 4.19). From1987 until 1994, total 137Cs migration via the Pripyat
River decreased by a factor of 4.5; however, there

4.7.2.

Current state of the radioactive
contamination of the reservoirs

The current state of the radioactive contamination of the Dnieper reservoirs is determined by
the combined effect of the following factors:

TABLE 4.19. INFLUX OF CAESIUM-137 AND STRONTIUM-90 INTO THE CASCADE OF THE
DNIEPER RESERVOIRS WITH RIVER WATER (TBq) (1986–2001)
Pripyat River

Dnieper River

Desna River

Uzh River

Braginka, Teterev
and Irpen Rivers

Caesium- Strontium- Caesium- Strontium- Caesium- Strontium- Caesium- Strontium- Caesium- Strontium137
90
137
90
137
90
137
90
137
90
1986
(Jun.–Dec.)

21.8a

3.7a

15.4a

3.8a

(2.7a)(0.63)(1.30)(0.26)(1.41)(0.19)

1987

12.7

10.4

13.8

8.0

2.11

1.85

0.63

0.70

0.67

0.37

1988

9.5

18.7

9.3

5.1

1.33

2.44

0.56

0.48

0.70

0.37

1989

6.4

8.9

7.1

3.6

1.15

1.26

0.26

0.37

0.48

0.30

1990

4.6

10.1

5.1

3.7

0.85

1.78

0.30

0.70

0.30

0.26

1991

2.7

13.9

2.0

4.5

0.63

1.11

0.26

0.67

0.52

0.85

1992

1.7

4.4

1.3

0.7

0.26

0.74

0.22

0.15

0.22

0.30

1993

3.9

13.5

1.0

1.2

0.04

0.48

0.15

0.56

(0.2a)(0.2a)

1994

3.3

11.0

1.0

2.8

0.04

0.56

0.22

0.67

(0.3a)(0.4a)

1995

1.1

3.2

0.6

0.7

0.04

0.22

0.07

0.15

(0.1a)(0.2a)

1996

1.4

2.8

—

—

—

—

—

—

—

—

1997

1.0

3.5

—

—

—

—

—

—

—

—

1998

1.4

5.9

—

—

—

—

—

—

—

—

1999

3.3

10.3

—

—

—

—

—

—

—

2000

1.6

3.3

—

—

—

—

0.09

0.19

—

0.1

b

0.1b

b

0.2b
3.33

2001

1.5

3.3

—

—

—

—

0.09

0.27

0.2

Total

67.1

101.5

56.6

34.1

9.18

11.1

3.96

4.70

4.81

a

Ref. [4.42].
Braginka only.
Note: Data in parentheses are an approximate assessment.

b54

100.000

Caesium-137
120

0.000
1986

20

Kakhovka

40
0.001

Zaporozhia

60

0.010

Dniprodzerhinsk

80

Kremenchug

Bq/m3

Bq/L

0.100

Kanev

100

1.000

Vyshgorod

10.000Strontium-90

140

Caesium-137
Strontium-90

0
1988

1990

1992

1994

1996

1998

2000

Year

0

100

200

300

400

500

600

700

800

Distance from Vyshgorod (km)FIG. 4.27. Dynamics of 137Cs and 90Sr concentration at themouth of the Desna River.

FIG. 4.28. Changes in concentration of 137Cs and 90Sr along
the Dnieper River, July 2000.

(a)sorption of the radionuclides on to the bottom
sediments.
The reservoirs of the Dnieper cascade are
essentially huge sedimentation tanks. The slow
passage of water through the cascade creates ideal
conditions for accumulation of radionuclides andother pollutants in all components of the ecosystemof the reservoirs.
As a consequence, the 137Cs concentration in
the river water is reduced by two orders ofmagnitude along the way from the upper part of the
Dnieper cascade to the Dnieper mouth. According
to data of the Hydrometeorological Service of
Ukraine, from 1994 onwards the levels of 137Cs
contamination decreased to the levels of the preaccident years (less than 1 Bq/m3). Hence, due tothe self-cleansing processes, practically all the 137Cs
entering the Dnieper reservoirs from 1994 isdeposited in the bottom sediments. For the entire
post-accident period in the ecosystem of thereservoirs and the Dnieper–Bug estuary, more than
99% of the 137Cs that entered the Pripyat and upper
Dnieper Rivers was removed on to sediments.
Figure 4.28 shows the results of monitoring in 2000,
which confirm the current trend in 137Cs and 90Sr
concentrations through the reservoir cascade.
Data on the dynamics of radioactive contamination of the Dnieper reservoirs during the postaccident years are presented in many publishedworks [4.7, 4.12, 4.44]. The main result of theseworks was the synthesis of data on the temporal andspatial dynamics of radionuclides of Chernobyl
origin in the reservoirs as a basis for justification of
the water protection works in the basin and forfurther use in radioecological research. Figure 4.29
shows the trend in 137Cs concentration with time inthe upper (at Vyshgorod) and lower (at Kakhovka)
reservoirs of the cascade. The activity of 137Cs in the

(b)

(c)

(d)

Continued wash-off of radionuclides ofChernobyl origin from the surface of thewatersheds into the Dnieper River basin and,in particular, the discharge of the contaminated water from the Chernobyl nuclear
power plant zone into the Pripyat River,which remains the main source of contamination of the Dnieper aquatic system.
The peculiarities of the water balance within
reservoirs in specific years and the regulationof flow through the cascade.
Within reservoir processes that lead to redistribution of the radionuclides between themain components of the water ecosystem (thewater solution, suspended alluvium, bottom
sediments and biota).
Other factors, including both self-cleaning of
the water masses and their secondary contamination from sediments.

With regard to the system of the Dnieper
reservoirs and the Dnieper estuary as a whole, theradionuclides in the soils and the rivers located in
the CEZ may be called concentrated, since the maincontamination enters the upper part of the Dnieper
cascade via the Pripyat and upper Dnieper Rivers.
Not more than 10% of the residual radioactivity
from Chernobyl fallout enters the Dnieper
reservoirs from the side tributaries. Of these, themost important is the influx from the Desna River.
Insignificant quantities of radionuclides ofChernobyl origin enter the Dnieper River below
Kiev.
The radioactivity that enters the upper part of
the Dnieper cascade reaches the Black Sea after
approximately one year [4.43]. Along the way theconcentration of radionuclides is reduced due todilution from clean side tributaries and due to

55

1.5

Strontium-90 (Bq/L)

500
400

Bq/m3

Vyshgorod
Kakhovka

300
200
100
0
1986

Vyshgorod
Kakhovka

1.0

0.5

0.0
Jan.
1988

1990

1992

1994

1996

1998

Feb. Mar. Apr. May Jun.

2000

Month

Year

waters of the Dnieper mouth in 2000–2001 was 0.3–
0.9 Bq/m3. This corresponds to the values existing
before the Chernobyl accident [4.45]. Generally,
more than 90% of 137Cs was in the dissolved form.
Owing to the higher mobility of 90Sr, thedegree of its deposition (50–70%) within the
Dnieper reservoirs is significantly lower than that of137
Cs. One of the main reasons for the nonexchangeable behaviour of 90Sr from the watercolumn is its strong chemical fixation in the shells of
growing molluscs (strontium is the chemical
analogue of calcium). This is why the maximum
content of 90Sr in the bottom sediments wasobserved on the sites of mollusc colonies and in
sediments containing shell debris.
The 90Sr concentration in Dnieper River water
is reduced by a factor of 1.5–3 from Chernobyl to
the Kakhovka reservoir (according to data averaged
over a year). This is determined mainly by the
dilution of Pripyat waters with clean waters fromthe upper Dnieper River and the side tributaries.
The mixing action of the Dnieper reservoirs as the90
Sr passes along the cascade becomes apparent by
the gradual reduction of the peak concentrations
and by the offset of this peak with time. Even very
high peak concentrations of 90Sr in the waters of the
Pripyat River and Kiev reservoir are suppressed by
the time the peak reaches the Kremenchug
reservoir, and in the Kakhovka reservoir one may
observe only gradual fluctuations in the concentration of 90Sr.
Over recent years the amplitude of the withinyear variations of 90Sr activity concentrations at themouth of the Dnieper River has significantly
changed. This is a result of the reduction of releaseof 90Sr into the Dnieper cascade due to naturalprocesses (radioactive decay, migration into the soil
depth, etc.) and the effectiveness of engineering
works in isolating the most contaminated sites on
the Pripyat floodplain within the CEZ [4.46].
56

FIG. 4.30. Strontium-90 activity concentration movement in
the Kiev and Kakhovka reservoirs in 1999.

600

Strontium-90 (Bq/m3)

FIG. 4.29. Changes in Сs concentration in the upper andlower parts of the Dnieper cascade.
137

Jul. Aug. Sep. Oct. Nov. Dec.

Vyshgorod

500

Kakhovka

400
300
200
100
0
1986

1988

1990

1992

1994

1996

1998

2000

Year

FIG. 4.31. Changes in average annual 90Sr concentration in
the upper (Vyshgorod) and lower (Novaya Kakhovka)
parts of the cascade of the Dnieper reservoirs over time.

The situation observed in 1999 was an
exception to this trend. In that year, significant
quantities of 90Sr were washed out into the cascadefrom regions of significantly contaminated floodprone sites beside the Pripyat River in the near zoneof the Chernobyl nuclear power plant. The signal ofradioactively contaminated waters was followed to
the Kakhovka reservoir during 1999. Owing to thehigh river flow rates in March–June 1999, fast
movement of the contaminated water down the
Dnieper River was observed, and, by mid-July 1999,
this front had reached the Black Sea (Fig. 4.30). The
maximum value of 90Sr activity measured duringthat period in the Dnieper River at Novaya
Kakhovka was 287 ± 60 Bq/m3, being three to fourtimes higher than the levels of contamination
observed during the previous years. Thisobservation further demonstrates that the modern
source of radioactive contamination of the Dnieper
waters is the flood prone territories of the Pripyat
River and other sources of contamination in thenear zone of the Chernobyl nuclear power plant.
However, the repetition of such situations, which
only happen at times of major flooding, occurs only
once in 10–15 years on average.
Figure 4.31 shows the trend in average annual90
Sr concentration in the Dnieper reservoirs sinceinto the Dnieper–Bug estuary and then into theBlack Sea.

the Chernobyl accident. To some extent it reflects
the effect of various events that affected thefloodplains in the near zone of the Chernobyl
nuclear power plant, viz.:
(i)
(ii)
(iii)
(iv)
(v)

4.7.3.

Rain inundation in July 1988;
Ice jam and winter inundation in 1991;
Rain inundation in July 1993;
Ice jam and winter inundation in 1994;
High spring flooding in 1999.

Current state of radioactive contaminationof the bottom sediments

The bottom sediments of the reservoirs are an
important component that, in some respects,
determines the aquatic ecosystem. The accumulated
data on the distribution of radionuclides in thesystem (water suspension–bottom sediments) after
the Chernobyl nuclear power plant accident
revealed the leading role of the sedimentation
processes in the self-cleaning of the water column.
On one hand, these processes positively influence
the water quality; on the other hand, sedimentaccumulation is the main factor in the formation of
the secondary contamination of the bottom
sediments in which the radionuclides and otherpollutants are deposited.
In recent years, as the influx of radionuclides
into the system has decreased, the role of thebottom sediments as a potential source of secondary
contamination of the Dnieper waters has become
more important. For our purposes, the main characteristics of the bottom sediments are the radionuclide content per unit of dry mass (Bq/kg), thedensity of contamination (expressed in Bq/m2 orBased on regular measurements of 137Cs and90
Sr concentrations performed by the Hydrometeorological Service of Ukraine at the cascade of the
Dnieper reservoirs, the mean monthly and meanannual concentrations of these radionuclides in thereservoirs, and mean monthly and mean annual
values of radionuclide outflow, have been
calculated. This enables reliable estimates to bemade of radionuclide transport along the river, andtimely forecasting of water quality and issuing ofrecommendations to water consumers, who arelocated predominantly in the middle and lower partof the Dnieper water system. Table 4.20 contains an
example of such a calculation for the lower part of
the Kakhovka reservoir (the Dnieper–Novaya
Kakhovka station), while the data in Table 4.21
show the yearly average concentrations and flows

TABLE 4.20. MEAN MONTHLY CONCENTRATIONS (Bq/m3) AND VALUES OF MONTHLYOUTFLOW (GBq) OF CAESIUM-137 AND STRONTIUM-90 THROUGH THE MEASURING SECTION
OF THE DNIEPER–NOVAYA KAKHOVKA STATION IN 1999
Caesium-137

Strontium-90

Dnieper Riverdrainage (km3)

Bq/m3

GBq

Bq/m3

GBq

January

5.62

0.65 ± 0.09

3.65

131 ± 24.0

736.5

February

5.62

0.43 ± 0.26

2.42

79.0 ± 30.0

444.1

March

7.16

0.32 ± 0.08

2.29

95.5 ± 19.0

683.7

April

8.28

0.64 ± 0.09

5.30

77.0 ± 30.0

637.5

May

8.97

0.77 ± 0.13

6.91

82.5 ± 17.0

740.0

June

4.04

0.68 ± 0.07

2.75

167 ± 65.0

675.3

July

2.78

1.15 ± 0.37

3.20

200 ± 40.0

556.6

August1.42

0.75 ± 0.08

1.06

157 ± 35.0

222.5

September

1.42

0.60 ± 0.06

0.85

263 ± 50.0

372.9

October

3.00

0.40 ± 0.08

1.20

272 ± 55.0

817.4

November

3.88

0.38 ± 0.10

1.49

229 ± 40.0

888.5

December

4.81

0.30 ± 0.03

1.44

285 ± 70.0

1370.9

Total

57

0.57

32.6

142.8

8183

57

TABLE 4.21. ESTIMATED VALUES OF CAESIUM-137 AND STRONTIUM-90 INFLOW TO THE
BLACK SEA (DNIEPER–BUG ESTUARY) FROM THE DNIEPER RIVER
Strontium-90

Caesium-137

Dnieper runoff
(km3)

Bq/m3

TBq

Bq/m3

TBq

1986
(Jun.–Dec.)

20.6

34.1 ± 5.5

0.7

28.4 ± 4.3

0.59

1987

36.4

349 ± 5212.7

9.1 ± 0.5

0.33

1988

45.8

256 ± 18

11.7

25.2 ± 1.5

1.15

1989

34.1

225 ± 147.68

14.3 ± 1.4

0.49

1990

37.1

160 ± 105.93

10.3 ± 0.4

0.38

1991

43.4

179 ± 23

7.78

6.8 ± 0.7

0.30

1992

24.9

208 ± 215.20

2.8 ± 0.2

0.070

1993

39.3

104 ± 54.07

1.8 ± 0.3

0.070

1994

48.9

129 ± 106.30

2.3 ± 0.3

0.063

1995

36.3

51.7 ± 6.7

1.88

1.3 ± 0.2

0.048

1996

29.0

57.6 ± 6.9

1.67

0.77 ± 0.18

0.022

1997

36.6

64.5 ± 7.1

2.36

0.82 ± 0.17

0.030

1998

58.5

90.1 ± 20.4

5.27

0.57 ± 0.28

0.034

1999

57.0

143 ± 17

8.18

0.57 ± 0.17

0.033

2000

40.9

95.1 ± 30.0

3.89

0.56 ± 0.08

0.023

Note: The data include regular measurements carried out by laboratories of the Hydrometeorological Service of Ukraine,
the Ministry of Health and the Water Management State Committee of Ukraine (total 700 samples). To refine theestimates of radionuclide outflow from the Dnieper River into the Black Sea, data from irregular observations of the
UHMI (1986–1999), SPA Typhoon (1986–1987), the Institute of Biology of the Southern Seas (1986–1988) and theInstitute of Hydrobiology of the National Academy of Sciences of Ukraine (1987–1989) were also used.

Ci/km2), the sediment composition, the particle size
distribution and the rate of silt accumulation.
The first investigations of the radioactive
contamination of the Kiev reservoir bottom were
performed in May 1986 by experts from theInstitute of Hydrobiology of the Academy of
Sciences of Ukraine. These first surveys showed theextremely heterogeneous nature of the radioactive
contamination of the bottom. According to thepreliminary assessments, the total inventory of 137Cs
in the bottom sediments of the reservoir was
estimated as up to 81 TBq, and that of 90Sr was
about 30 TBq.
The UHMI started investigations of theradioactive contamination of the bottom of thereservoirs in 1987, and completed mapping in the
period 1989–1991 [4.47]. These maps are still thebasis for the current understanding of the content ofradiocaesium in the bottom sediments. Additional
studies of the vertical structure of radionuclide distribution in the bottom sediments were performed by
the UHMI in the period 1991–1996 [4.7].
58

Examples of the maps of the bottom contamination of the Kiev, Kanev and Kremenchug
reservoirs are presented in Figs 4.32–4.34 (note thatthe units of measurement are Ci/km2). Contamination of the reservoirs in the lower part of the
Dnieper River is significantly less, and nowadays isdifficult to map due to redistribution of thesediments.
Due to insufficient data and extreme heterogeneity of the spatial distribution, mapping of 90Sr
was not performed and only estimates of the total
activity of this radionuclide in the reservoirs wereobtained.
Analysis of data on the distribution of radionuclides with depth in the bottom sediments, thegranulometric distribution and composition of thebottom sediments, and the forms of radionuclides
contributes to an understanding of the scales andregularities of the formation of radioactive contamination of the bottom. As has already been noted,
the initial radioactive contamination of the bottom
occurred in the period of the intensive fallout on the

Caesium-137 density (Ci/km2)<0.5
0.5–1.0
1.0–2.0

2.0–5.0
5.0–10.0
10.0–15.0

Caesium-137 density (Ci/km2)
<1

10–15

1–2

15–25

2–5

>25

FIG. 4.33. Distribution of 137Cs (Ci/km2) in the bottom
sediments of the Kanev reservoir, 1995.

5–10

FIG. 4.32. Distribution of 137Cs (Ci/km2) in the bottom
sediments of the Kiev reservoir, 1990.

Caesium-137 density (Ci/km2)<0.1

0.5–1.0

0.1–0.2

1.0–2.0

0.2–0.5

water surface and the further fast (within severaldays) deposition on the bottom. For sites far down
the cascade, such as the Kakhovka reservoir,
aerosol fallouts became the main factor ofradioactive contamination since, starting in 1987,
insignificant amounts of 137Cs were transported
from the upper part of the basin.
The main radioactive contamination of thebottom sediments was completed in 1988, when the
migration of radionuclides with the waters of themain tributaries dropped off significantly. The
process of redistribution of the radioactive contamination along the bottom then became apparent.
This process occurs due to hydrodynamic factors(drainage and drift fluxes, storm impact on thebottom) that remove the fine sediments with thehighest contamination from shallow water into thezones of stable sediment accumulation. In suchzones of all reservoirs, the maximum densities of thebottom sediment contamination are observed.
Analysis of the 137Cs vertical distribution within the

FIG. 4.34. Distribution of 137Cs (Ci/km2) in the bottom
sediments of the Kremenchug reservoir, 1994.

bottom sediments shows that, in all reservoirs in thezones of stable sediment accumulation, the layer ofmaximum contamination in 1986 is gradually being
buried. Thus, in the deep parts of the Kiev,
Kakhovka and Kremenchug reservoirs, the peaks of137
Cs activity in 1986–1987 are presently located at
depths of 40 cm or more below the bottom surface(Fig. 4.35). The possibility of radionuclides
returning to the water column is reduced with time.
The ability of 137Cs to be strongly sorbed byfinely dispersed mineral and organic substances
prevents its diffusion and penetration into thedeepest sediments. Even at those parts of thebottom consisting of well penetrating sandy
deposits, the activity of 137Cs quickly reduces withdepth from the surface (Fig. 4.36).
59

Activity of 137Cs (Bq/kg)

Activity of 137Cs (Bq/kg)
0

5000

10 000

15 000

20 0000

25 000

200

400

600

0

0-2
4-6
8-10

2

12-14
16-18

Depth (cm)

20-22

4

24-26

Depth (cm)

28-30
32-34
36-38
40-42
44-46

6
8

48-50
52-54

10

56-58
60-62

12

FIG. 4.35. Caesium-137 in the deep silt deposits in the upper
part of the Kiev reservoir, July 2000.

The current activity of 137Cs radionuclides inthe bottom sediments can be determined from thesurveys. Table 4.22 shows the dynamics of 137Cs
inventories in the bottom sediments of the Kiev andKakhovka reservoirs. The calculations show that,since 1991, the 137Cs inventories in the bottom
sediments of the Kiev reservoir are falling, since theannual input does not compensate for the losses due

14

FIG. 4.36. Caesium-137 depth distribution in the sanddeposits of the Kiev reservoir, May 1991.

to radioactive decay. In the Kakhovka reservoir,
where the contamination occurred mainly fromaerosol fallout on the water surface in 1986, theinventories of 137Cs in the bottom sediments havebeen steadily declining since 1987.

TABLE 4.22. CALCULATIONS OF THE TOTAL INVENTORY (TBq) OF CAESIUM-137 IN THE
BOTTOM SEDIMENTS OF THE KIEV AND KAKHOVKA RESERVOIRS
Kiev reservoir

Kakhovka reservoir

AffluxIntegral inventory(no decay)

Inventory consideringdecay

AffluxIntegral inventory(no decay)

Inventory considering
decay

1986

59.2

59.2

58.9

7.22

7.22

7.14

1987

11.9

71.1

69.3

0.63

7.84

7.62

1988

5.9

77.0

73.5

0.06

7.92

7.51

1989

4.8

81.8

76.6

0.10

8.03

7.44

1990

4.7

86.5

79.6

0.08

8.10

7.33

1991

1.7

88.2

79.4

0.04

8.14

7.22

1992

1.6

89.8

79.1

0.05

8.21

7.10

1993

2.1

91.9

79.4

0.06

8.25

6.99

1994

2.0

93.9

79.6

0.10

8.36

6.92

1995

0.7

94.7

78.5

0.07

8.44

6.85

1996

1.0

95.7

77.7

0.03

8.44

6.70

1997

0.6

96.3

76.6

0.01

8.47

6.55

1998

1.3

97.6

76.1

0.05

8.51

6.48

1999

2.4

100.0

76.8

0.07

8.58

6.40

2000

1.3

101.3

76.3

0.06

8.62

6.29

60

TABLE 4.23. CAESIUM-137 IN THE BOTTOM SEDIMENTS OF THE DNIEPER
RESERVOIRS (JANUARY 1995)
Inventory (TBq)

Averaged density of contamination (kBq/m2)

Kiev

80 ± 1786 ± 6Kanev

18 ± 331 ± 25

Reservoir

Kremenchug

26 ± 313 ± 1

Dniprodzerzhinsk

4.3 ± 0.4

7.4 ± 0.7

Dnieper

2.2 ± 0.7

5.6 ± 1.9

Kakhovka

6.8 ± 0.7

3.1 ± 0.4

Total in cascade

136 ± 26—

Table 4.23 shows the inventory of 137Cs in thebottom sediments of the Dnieper reservoirs and theaveraged densities of the bottom contamination ofeach reservoir as of January 1995.
As noted above, the mapping of the bottom
sediment contamination with 90Sr was problematic.
Owing to the low sorption of 90Sr on to solid
particles, no regularities in its spatial distribution on
the bottom of the reservoirs were discovered.
However, where there is an accumulation of shellsof molluscs and other carbonate deposits on thebottom, there are higher levels of 90Sr. It is not
excluded that the strong fixation of 90Sr in the
carbonate structure of folds is one of the main
factors of irretrievable removal of this radionuclide
from the water column on to the bottom.
At present, the contaminated bottom
sediments in the reservoirs do not influence significantly the secondary radioactive contamination of
the water and aquatic organisms. In all places thedeposition of cleaner sediments over the morecontaminated ones is observed. Thus the generalrule for exploitation of the reservoirs (mainly Kiev)
is to minimize scooping and mechanical operations
at the places with increased bottom contamination.
The natural processes of self-cleaning are working
in all the reservoirs. As a consequence, there is a
gradual reduction in the radionuclide levels in fish
and other aquatic species living in the reservoirs.
Results of modelling of the sediment redistribution following a major flood are given in Section
9.3.6.

(b)

(c)

(d)

(e)

(f)

4.8. CONCLUSIONS(a)

The levels of 137Cs and 90Sr in flowing rivers
are now well below the permissible levels set(g)by the national authorities and below internationally acceptable levels for drinking water.
Surface water runoff from watersheds andfloodplains contaminated with 90Sr remains
the major contributor to contamination of the
Dnieper reservoirs. The main sources contributing to radionuclide releases into the
Dnieper cascade are located within the CEZ.
The water remedial actions carried out during
recent years (1993–2000) significantly reduced
actual and potential fluxes into the river.
Almost all the 137Cs washed out of contaminated areas is immobilized in bottom
sediments within the reservoirs of the Dnieper
River. The impact of these sediments is low
and will decline further with decay and further
deposition of sediments on top of the contaminated sediments. The overall strategy should
be to leave these sediments as is and avoid
processes that will lead to their resuspension.
Identification of the main sources within the
Chernobyl zone shows that the heavily
contaminated floodplain areas still remain themain source for releases. The waste disposalsites in the flood prone areas are of secondarypriority for possible remedial actions.
Monitoring systems have been developed forthe river systems and are important inputs tothe decision making process on possible
further water protection measures in the
Chernobyl area.
Monitoring data are collected by various
agencies for different purposes; different
methodologies are used, some of which are
outdated. There needs to be harmonization of
results between the various organizations
engaged in monitoring.
Mathematical models have been developed todescribe the wash-off of radioactivity from61

contaminated land. These models can be used
to predict the discharge of radioactivity intorivers and reservoirs from knowledge of therainfall distribution.
(h) Only a small fraction of the radioactivity
deposited on ground via fallout has entered
the Dnieper River system, and most of the137
Cs and 90Sr will decay in the ground.
(i) Levels of 137Cs in the lower sections of the
Dnieper River have returned to preChernobyl accident levels. Strontium-90 ismore persistent because it does not adsorb as
readily on to sediments.
(j) Lakes with no regular inflows and outflows
still present a radiological problem that willcontinue for some time. There is a need for
improved
understandingofprocesses
occurring within lakes, especially transfer tofish.
(k) Transboundary movement of radionuclides
from the Chernobyl accident was greatest
prior to 1990. The annual flows of 137Cs acrossnational borders have continued to decline
steadily, whereas those of 90Sr continue tofluctuate, depending on the extent of floodingof contaminated land (especially thefloodplain area of the CEZ). Currently, theannual flow of 137Cs into the Black Sea isnegligible, whereas 1–8 TBq of 90Sr reaches
the Black Sea.
(l) There is a need for improved understanding of
the 90Sr inventory in sediments and 90Sr
fixation processes. Strontium-90 becomes
more important with time because of its
greater mobility.
(m) The large database developed by SPA
Typhoon, the UHMI and the RCREM is very
useful in understanding and interpreting data,and should be maintained. Ideally it should be
expanded to include aquatic species data anddata from the lower parts of the Dnieper
River.

REFERENCES TO SECTION 4[4.1] UNITED NATIONS, Sources and Effects of
Ionizing Radiation (Report to the General
Assembly), Annex J: Exposures and Effects of theChernobyl Accident, United Nations ScientificCommittee on the Effects of Atomic Radiation(UNSCEAR), UN, New York (2000).

62[4.2] DE CORT, M., TSATUROV, Y., Atlas of Caesium
Deposition on Europe after the Chernobyl
Nuclear Power Plant Accident, Final Report of
Joint Study Project No. 6, Rep. 16542, Office for
Official Publications of the European Communities, Luxembourg (1996).
[4.3] DE CORT, M., Atlas of Caesium Deposition on
Europe after the Chernobyl Accident, Rep. 16733,
Office for Official Publications of the European
Communities, Luxembourg (1998).
[4.4] DE CORT, M., Atlas of Caesium Deposition on
Europe after the Chernobyl Accident, Rep. 16733,
Office for Official Publications of the European
Communities, Luxembourg (2001) CD-ROM.
[4.5] Atlas of Radioactive Contamination of European
Part of Russia, Belarus and Ukraine, Federal
Service of Geodesy and Cartography of Russia,
Moscow (1998).
[4.6] KONOPLEV, A.V., DEVILLE-CAVELIN, G.,
VOITSEKHOVICH, O.V., ZHUKOVA, O.M.,
Transfer of Chernobyl 137Cs and 90Sr by surface
runoff, Radioprotection-Colloques 37 C1 (2002)
315–318.
[4.7] KANIVETS, V., Main tendencies in the Dnieper
water system radioactive contamination during
the period after the Chernobyl accident, Visnik
Agro. Nauki N-4 (1996) 40–56 (in Russian).
[4.8] MAKHONKO, K.P. (Ed.), Instructions for
Hydrometeorological Stations and Posts, Issue 12,
Monitoring of Radioactive Contamination of theEnvironment,
Hydrometeoizdat,
Leningrad(1982) (in Russian).
[4.9] MAKHONKO, K.P. (Ed.), Manual on Organization of Monitoring of the State of theEnvironment in the Area of NPP, Hydrometeoizdat, St. Petersburg (1990) (in Russian).
[4.10] NIKITIN, A.I. (Ed.), Manual on Control ofRadioactive Contamination of Water Bodies, SPA
Typhoon, Obninsk (1996) (in Russian).
[4.11] NIKITIN, A.I. (Ed.), Manual on Control of
Tritium Content in Water Bodies, SPA Typhoon,
Obninsk (1996) (in Russian).
[4.12] VOITSEKHOVITCH, O.V., KANIVETS, V.V.,
Manual on Carrying out Observations of Radioactive Pollution of the Environment, Ukrainian
Hydrometeorological Institute, Kiev (2001) (inUkrainian).
[4.13] UNITED
NATIONSDEVELOPMENT
PROGRAMME, Water Quality Evaluation andPrediction in Areas Affected by the Chernobyl
Accident (Bryanskaya Oblast), Rep. RUS/95/004,
UNDP, Moscow (2001).
[4.14] DEVILLE-CAVELIN, G., BIESOLD, H.,
BRUN-YABA, C., CHABANYUK, V., The
consequences of the Chernobyl accident: First
results in the radioecology project of the FrenchGerman initiative, Radioprotection-Colloques 37
C1 (2002) 1043–1048.

[4.15] KARAUSHEV, A.V., Problems of Dynamics of
Natural
Water
Flows,
Hydrometeoizdat,
Leningrad (1960) (in Russian).
[4.16] VELIKANOV, M.A., Dynamics of Channel
Flows, Hydrometeoizdat, Leningrad (1949) (inRussian).
[4.17] VAKULOVSKY, S.M. (Ed.), Guidelines on
Determination of Radioactive Contamination of
Water Bodies, Hydrometeoizdat, Leningrad(1986) (in Russian).
[4.18] Instructions and Guidelines on Evaluation of the
Radiation Situation in the Contaminated Territory, Goscomhydromet, Moscow (1989) (inRussian).
[4.19] KANIVETS, V., et al., Results of determinationsof 137Cs in water by different laboratories in themeasuring section Dnieper–Vyshgorod, unpublished data.
[4.20] VOITSEKHOVITCH, O.V., KANIVETS, V.V.,
LAPTEV, G.V., Analyses of the Dnieper aquatic
system radioactive contamination since five years
passed since the accident, Proc. Ukrainian
Hydrometeorological Inst. 245 (1993) 106–125 (inRussian).
[4.21] PAVLOTSKAYA, F.I., Migration of Radioactive
Products of Global Fallout in Soils, Atomizdat,
Moscow (1974) (in Russian).
[4.22] OSIPOV, V.B., Physical and Chemical Behavior of137
Cs and 90Sr and their Stable Isotopes in Soils of
Different Ecosystems in Bryansk Region in the
Chernobyl Accident Area, PhD thesis, Russian
Institute of Agricultural Radiology and Radioecology, Obninsk (1996) (in Russian).
[4.23] BULGAKOV, A.A., KONOPLEV, A.V., “Basictransformation processes of chemical species in soil
and bottom sediments”, Modelling and Study of
the Mechanisms of the Transfer of Radioactive
Material from Terrestrial Ecosystems to and in
Water Bodies Around Chernobyl, Final Report(SANSONE, U., VOITSEKHOVICH, O., Eds),
Office for Official Publications of the European
Communities, Luxembourg (1996) 122–135.
[4.24] KONOPLEV, A.V., et al., “Modelling radiocaesium bioavailability in forest soils”, ContaminatedForests: Recent Developments in Risk Identification and Future Perspectives (LINKOV, I.,
SHELL, W.R., Eds), Kluwer, Dordrecht (1999)
217–230.
[4.25] SHEVCHOUK, V.E. (Ed.), 15 Years After the
Chernobyl Catastrophe: Consequences in the
Republic of Belarus and their Overcoming,
National Report, Committee on the Problems of
the Consequences of the Accident at the
Chernobyl NPP, Minsk (2001).
[4.26] KUDELSKY, A.V., SMITH, J.T., ZHUKOVA,
O.M., MATVEENKO, I.I., PINCHUK, T.M., Therole of river runoff in natural 137Cs decontamination of contaminated areas, J. Rep. NASB 42(1998) 90–94 (in Russian).

[4.27] MINISTRY OF PUBLIC HEALTH OF THE
REPUBLIC OF BELARUS, Republican Permissible Levels of Cesium-137 and Strontium-90
Content in Food Products and Drinking Water,
Rep. RPL-99, Ministry of Public Health of the
Republic of Belarus, Minsk (1999).
[4.28] VAKULOVSKIY, S.M., et al., “Dynamic of radioactive contamination of rivers of Ukraine, Russia
and Belarus due to the accident at the Chernobyl
NPP”, Proc. 1st All-Union Conf. on Radiation
Aspects of the Chernobyl Accident (IZRAEL,
Y.A., Ed.), Hydrometeoizdat, St. Petersburg(1993) 324–331 (in Russian).
[4.29] Water Resources and Water Budget in the
Territory of the Soviet Union, Hydrometeoizdat,
Leningrad (1967) (in Russian).
[4.30] AQUASCOPE, Final Report: Aquifers andSurface Waters in the Chernobyl Area: Observations and Predictive Evaluation, Project IC15
CT98-0205, Centre for Ecology and Hydrology,
Grange-over-Sands, UK (2002).
[4.31] KONOPLEV, A.V., et al., Study of 137Cs and 90Sr
behavior in lakes Svyatoe and Kozhanovskoe,
Bryansk region, Meteorologiyai Gidrologiya 11(1998) 45–53 (in Russian).
[4.32] KASHPAROV, V., et. al., Contamination of 30
km Chernobyl exclusion zone, Radiochem. 42(2001) 550–559 (in Russian).
[4.33] ANTROPOV, V.M., et al., Review and analysis ofsolid long-lived and high level radioactive waste
arising at the Chernobyl nuclear power plant andthe restricted zone, DG Environment Project No.
B7-5350/99/51983/MAR/C2, Office for Official
Publications of the European Communities,
Luxembourg (2001) 370.
[4.34] Report on the Study Development of PVLRO
Conservation Projects Within the 30-km Exclusion
Zone, Phase 17, Assessment of Disposal Safety in
PVLRO Kompleksny and Evaluation of the Environmental Impact, Contract No. 247-/96, Zhovti
Vody (1996) (in Ukrainian).
[4.35] PANASYUK, N.I., et al., Assessment of theRadiological Contamination of the Geosphere
and Calculation of the Radwaste Quantities
Localised in the Technogenic Soils and Adjacentto the Unit Shelter, ISTC Shelter Preprint 99-2,
ISTC, Chernobyl (1999) (in Ukrainian).
[4.36] BUGAI, D., DJEPO, S., SKALSKY, A., “Prediction of radionuclide migration in geological media,
risk assessment and principles of water remedialactions related to groundwater radioactive
contamination in the Chernobyl exclusion zone”,
Radiogeoecology of the Water Bodies at the
Chernobyl Accident Affected Areas, Vol. 2(VOITSEKHOVITCH, O., Ed.) Chernobylinterinform, Kiev (1998) 218–252.
[4.37] BULGAKOV, A.A., et al., Modelling the longterm dynamics of radiocaesium in closed lakes, J.
Environ. Radioact. 61 (2002) 41–53.

63

[4.38] BULGAKOV,A.A.,
KONOPLEV,
A.V.,
KANIVETS, V.V., VOITSEKHOVICH, O.V.,
Modelling the long-term dynamics of radionuclides in rivers, Radioprotection-Colloques 37
C1 (2002) 649–654.
[4.39] TSATUROV, Y.S., et al., Levels and dynamics ofthe contamination with the Chernobyl-origin
radionuclides of surface water and catchment
territory in the western areas of the Bryansk
region, Geol. Bull. Cent. Reg. Russia, No. 2 (2001)
5–9.
[4.40] NOVITSKY, M.A., NIKITIN, A.I., Prediction ofradioactive contamination of water bodies after
the Chernobyl accident, Radiat. Prot. Dosim. 64(1996) 29–32.
[4.41] ZHUKOVA, O., SHIRYAEVA, N., SHAGALOVA, E., “Water migration of Chernobyl
radionuclides in rivers of Belarus”, Radioprotection-Colloques 37 C1 (2002) 723–728.
[4.42] VAKULOVSKY, S.M., et al., Cs-137 and Sr-90
contamination of water bodies in the areas
affected by releases from the Chernobyl nuclear
power plant accident: An overview, J. Environ.
Radioact. 23 (1994) 103–122.

64[4.43] NOVIKOV, B.I., TIMCHENKO, V.M., Hydrological conditions of radionuclide migration
through the Dnieper’s reservoir, J. Water Resour.
N-1 (1992) 95–102.
[4.44] VOITSEKHOVITCH,O.,LAPTEV,G.,
KANIVETS, V., Radioactive contamination of thewater bodies in the Chernobyl exclusion zone,
Bull. Ecol. Status Chernobyl Exclusion Zone, No.
6 (1996) 37–44.
[4.45] BOCHKOV, L.P., VAKULOVSKY, S.M.,
NIKITIN, A.I., TERTYSHNIK, E.G., CHUMICHEV, V.B., Activity concentration of 137Cs interrestrial
surfacewaters,
Meteorologiyai
Gidrologiya 8 (1983) 79–83.
[4.46] VOITSEKHOVITCH, O.V., Water Quality
Management at the Area Affected by the
Chernobyl Accident, Ukrainian Hydrometeorological Institute, Kiev (2001) (in Russian).
[4.47] OGORODNIKOV, V., KANIVETS, V., Bottom
sediment of the Kiev Reservoir, Proc. Ukrainian
Hydrometeorological Institute, No. 245 (1994)
180–194.

5. NUCLEAR POWER PLANTS
vertical steel tubes surrounded by graphite blocks.
The steam is separated and flows directly to theturbines. The reactor loading is about 200 t of 2–4%
enriched uranium.

5.1. SCOPE
Section 3.2 gives general information on thelocation and potential radiological impacts ofnuclear power plants in the Dnieper River basin.
This section is an overview of the nuclear
power plants in, and in the vicinity of, the Dnieper
River basin. It contains a description andassessment of operational characteristics, safety
features, licensing status, management of spent fueland radioactive waste, normal releases to theenvironment and the status of safety improvements
and emergency preparedness.
Section 8.2 provides information on radiation
doses received by the general public living in thevicinity of operating nuclear power plants. Section
9.6 considers releases from a hypothetical severe
nuclear accident at a reactor close to the Dnieper
River.

5.2.1.1. Kursk nuclear power plant
The Kursk nuclear power plant, comprisingfour reactors, is located on the left bank of the Seim
River, in its middle course (see Fig. 3.1). The energy
workers’ town is Kurchatov. It is situated in thecentral Chernozem area, 30 km to the west of Kursk
city. The climate in the region is temperatecontinental with a mean annual air temperature of
5.3°C. Eastern winds prevail during winter; the restof the time southern, south-eastern and southwestern winds prevail.
A cooling pond constructed on the Seim River
provides the water supply for the power plant. Its
average volume, area, depth and water level are
94.6 × 106 m3, 21.5 × 106 m2, 4.4 m and 154.5 m,
respectively. The water level in the pond ismaintained by pumping water from the Seim River
with a maximum flow rate of 14 m3/s [5.2]. The
design parameters of a second cooling pond,
which is under construction for the fifth reactor, are45.7 × 106 m3 (volume), 8.9 × 106 m2 (area), 5.1 m(depth) and 155 m (water level).

5.2. NUCLEAR REACTORS IN THE REGION
5.2.1.

Russian reactors within the
Dnieper River basin

In the Russian part of the Dnieper River basin
are seven reactor units in operation at two locations:
Kursk and Smolensk (see Table 5.1). All reactors
are graphite moderated, light water cooled reactorsof the RBMK type (the same type as the reactors at
Chernobyl) with a nominal capacity of 1000 MW(e).
In this design the fuel elements are contained within

5.2.1.2. Smolensk nuclear power plant
The Smolensk nuclear power plant is locatedon the left bank of the Desna River in its upper

TABLE 5.1. OPERATING NUCLEAR POWER REACTORS IN THE DNIEPER RIVER BASIN
REGION OF THE RUSSIAN FEDERATION [5.1]

Kursk

SmolenskaUnit number

Generation

Year of commissioning Planned shutdown year

1

I

1976

2006–2011a

2

I

1979

2009–2014a

3

II

1983

2013

4

II

1985

2015

1

II

1982

2012

2

II

1985

2015

3

II

1990

2020

Exact time of shutdown is yet to be decided.

65

course (see Fig. 3.1). The energy workers’ town is
Desnogorsk. It is situated in a subzone of mixed
forests. It lies near the upper reaches of the Dnieper
River. The climate in the region is temperate continental. The mean monthly temperature of thewarmest month (July) is +17.9°C; the mean monthly
temperature of the coldest month (January) is –8.5°C.
The mean annual precipitation is 610 mm, two thirdsof which falls during ice free periods. Sustainablesnow cover is formed on average in the beginning ofDecember and breaks during the first days of April.
A cooling pond constructed on the Desna
River provides the water supply for the power plant.
Its average volume, area and depth are 210 × 106 m3,
32.2 × 106 m2 and 6.5 m, respectively. The waterexchange constant is about 0.8 a–1.

5.2.2.

Ukrainian reactors

Currently there are 13 nuclear power reactors
operating in Ukraine at four locations (seeTable 5.2); ten are in the Dnieper River basin (seeFig. 3.1). These reactors supply 43–45% of
Ukraine’s electricity. Following the shutdown of thelast of the Chernobyl reactors in December 2000, alloperating reactors are PWRs of Russian design.
There are three nuclear power reactors (at theSouth Ukraine nuclear power plant) in the Bug
River basin, which adjoins the Dnieper River basin.
The South Ukraine nuclear power plant is includedin this discussion because of its possible impact on
the Dnieper River basin via airborne releases in theevent of a nuclear accident.

Additionally, one 1000 MW(e) nuclear powerreactor is being commissioned at Rovno, while
another is under construction at Khmelnitski.
5.2.2.1. Zaporozhe nuclear power plant
The Zaporozhe nuclear complex, shown in
Fig. 3.4, comprises six 1000 MW reactors, making it
one of the largest nuclear power plants in the world.
The Kiev Energoproject Institute developed thedesign. The plant site is situated on the left bank of
the Kakhovka reservoir opposite the town of
Nikopol. The energy workers’ town is Energodar.
The water source for the nuclear power plantis the Kakhovka reservoir. Water is provided by a
combination of a cooling pond, cooling towers and aspray evaporation system. The cooling pond has anarea of 8.2 km2 and a volume of 47 × 106 m3. The
cooling pond is connected to the Kakhovka
reservoir by entrance and discharge canals 4 km
long and 130 m wide (see Fig. 3.4). Water losses are
replenished by make-up water drawn from thereservoir. In 1999 the cooling ponds werereplenished with 143 × 106 m3 of water from thereservoir, and 88 × 106 m3 was discharged back to
the reservoir to prevent an accumulation ofdissolved salts.
5.2.2.2. Rovno nuclear power plant
The Rovno nuclear power plant is located in
the north of the Rovno region, close to the energy
workers’ town, Kuznetsovsk. It is the only nuclear
power plant in Ukraine that employs cooling towers

TABLE 5.2. OPERATING NUCLEAR POWER REACTORS IN UKRAINE
Gross capacity (MW(e))

Type

Commissioning date

Zaporozhe 1

1000

WWER-1000

10 October 1984

Zaporozhe 2

1000

WWER-1000

2 July 1985

Zaporozhe 3

1000

WWER-1000

10 December 1986

Zaporozhe 4

1000

WWER-1000

24 December 1987

Zaporozhe 5

1000

WWER-1000

31 August 1989

Zaporozhe 6

1000

WWER-1000

19 October 1995

Rovno 1

402

WWER-440

31 December 1980

Rovno 2416

WWER-440

30 December 1981

Rovno 31000

WWER-1000

24 December 1986

Khmelnitski 1

1000

WWER-1000

31 December 1987

South Ukraine 1

1000

WWER-1000

22 December 1982

South Ukraine 2

1000

WWER-1000

6 January 1985

South Ukraine 3

1000

WWER-1000

20 September 198966

as the sole form of cooling. One cooling tower isused for the two smaller units (Rovno 1 and 2),
while two are used for the largest unit (Rovno 3).
The Rovno 4 unit has been underconstruction, with interruptions, since 1986.
The water flow for the reactors is obtained
directly from the Styr River without any regulating
construction on the river. The average volume ofreplenishment is 36–38 × 106 m3/a. According to an
environmental impact assessment [5.3], theinfluence of the four reactors on the river flow will
be small and the water supply is guaranteed.
5.2.2.3. Khmelnitski nuclear power plant
At present, the Khmelnitski nuclear power
plant consists of only one reactor, but another isunder construction. The design was developed by
the Kiev Energoproject Institute. The site is locatedon the right bank of the Horyn River in the northwest part of the Khmelnitski region, almost on theboundary with the Rovno region. The energy
workers’ town is Neteshin.
The water supply for the Khmelnitski nuclear
power plant is a specially constructed cooling pond
located on a small river, the Gniloy Rog, that is atributary of the Viliya River, which, in turn, flows
into the Horyn River and finally the Pripyat River.
The surface area of the cooling pond is 20 km2 andthe working volume is 88 × 106 m3.
The water is replenished from the HorynRiver. In order to reduce the negative influence ofthe Khmelnitski nuclear power plant on the HorynRiver, the water intake for replenishment is carriedout when the river flow exceeds 6 m3/s during theperiod from October until April.
After commissioning of Khmelnitski nuclear
power plant unit 2, the reduction of the HorynRiver discharge will be about 33 × 106 m3/a, which isequivalent to an average expenditure of 1.05 m3/s.
Investigations performed for the environmental
impact assessment for Khmelnitski nuclear power
plant unit 2 showed that this value is not large incomparison with the average river flow rate
(16.4 m3/s) [5.3].
5.2.2.4. South Ukraine nuclear power plant
The design of this nuclear power plant wasdeveloped by the Kharkov Energoproject Institute.
The plant is located on the left bank of the southern

Bug River approximately midway between
Pervomaisk and Voznesensk. The energy workers’
town is Yuzhnoukrainsk.
The water supply for the power plant isprovided by a specially constructed cooling pond
built on the small Tashlyk River, which flows into
the southern Bug River. The cooling pond has anarea of 8.6 km2 and a storage volume of 86 × 106 m3.
The pond is quite deep, up to 38 m, and there is aconsiderable difference in temperature between thelower and upper layers.
Initially it was envisaged that the nuclear
power plant would function as a component of anenergy complex that included the Tashlyk hydroelectric power station. According to the concept,
water from the cooling pond would be discharged
through the hydroelectric station. However, theaccident at Chernobyl caused a revision of thedesign. In particular, it was decided not to allow
discharge of water from the cooling pond. Due tothis decision, the thermal load on the cooling pond
was quite high, and the discharge temperaturereached 38–40°C. Owing to this restriction, theoverall nuclear power plant capacity has been
restricted to 1.8 GW.
5.2.3.

Ignalina nuclear power plant, Lithuania

There are no nuclear power plants in the
Republic of Belarus; however, the Ignalina nuclear
power plant is located about three miles from thewestern border of Belarus. Consequently, the 30 km
zone extends into Belarusian territory. The power
plant is constructed on the southern side of Lake
Drukshiai, 40 km from the town of Ignalina.
There are two nuclear reactors (Ignalina 1 and2), both Soviet designed RBMK-1500 reactors witha nominal gross power of 1500 MW. These are thelargest nuclear power reactors in the world. The
safety of the reactors has been a cause of concern in
Europe, and a number of international safety
studies have been undertaken, resulting in manysafety upgrades. In return for funding from theEuropean Union, it has been decided to shut down
unit 1 in 2005 and unit 2 in 2009.
Releases to surface waters from the Ignalina
nuclear power plant do not enter the Dnieper Riverbasin; however, for about 100 days per year winds
from the north-west and west prevail, so thatradioactive fallout could reach the Dnieper
catchment in the event of an accident.

675.3. SAFETY FEATURES OF NUCLEAR
REACTORS
This section gives an overview of the main
safety features of the nuclear reactors in the
Dnieper River basin.
5.3.1.

Russian Federation

Figure 5.1 shows the important features of
RBMK type reactors. Instead of a reactor pressure
vessel containing the reactor core with the fuelelements and cooling water, the core is made up ofeither 1693 (first generation) or 1661 (second
generation) pressure tubes. This design allows foron-load refuelling and thus high availability. The
pressure tubes contain the fuel elements, which arecooled by water flowing through the channels.
These channels are contained in a large volume ofgraphite, which is capable of absorbing and storinglarge amounts of energy. The water passing throughthe pressure tubes is heated to a water–steam
mixture. The steam is separated from the water infour large steam drums and then passed on to theturbine for electricity production (see Fig. 5.2). This
arrangement means that, similar to boiling water
reactors, there is no secondary circuit and the water
passing through the core also passes through theturbine in the form of steam.
The original design suffered from a substantial
positive reactivity coefficient under certain
conditions, exacerbated by an insufficient negative
reactivity insertion capability, allowing a runaway
effect of neutron power. Overpressurization from asimultaneous multiple pressure tube rupture could
cause lifting of the reactor cavity cover, leading toLegend
1. Reactor core
2. Steam to water pipes
3. Drum separator
4. Main circulation pumps
5. Group dispensing headers
6. Water pipelines
7. Upper biological shield
8. Refuelling machine
9. Lower biological shield

FIG. 5.1. Main features of the RBMK-1000 reactor.

68

rupturing of all the remaining pressure tubes. These
two effects are the basic physical phenomena thatcaused the Chernobyl accident.
After the Chernobyl accident, the positive
reactivity coefficient was reduced in all RBMK
reactors, the reactor shutdown system was
improved and the venting capacity of the reactor
cavity was increased.
Another specific feature of RBMKs is thatinstead of a containment structure they have acompartment system for the purpose of localizing
accident conditions. This feature has a very limited
capability in the first generation plants.
The first two units (Kursk 1 and 2) are first
generation reactors based on designs developed in
the 1960s, while the remainder belong to the second
generation, with improved safety features. Since theChernobyl accident a considerable amount of work
has been undertaken to improve the safety of
RBMK reactors and to exclude the possibility of an
accident like the one at Chernobyl [5.4].
The first generation RBMKs had a very
limited range of primary pipe break design basis
accidents (DBAs), which was recently extended tocover breaks up to 300 mm. In contrast, it waspossible to extend the DBA for second generation
RBMKs to a diameter of 900 mm. The accident
localization system (ALS) for first generation plants
is limited to the reactor cavity, whereas for second
generation plants it includes all pressure bearing
components up to the steam drums, which areoutside of the ALS. Improvements can be made to
first generation RBMKs by providing for steam
venting through a water bubbler system. Anotherimportant difference relates to the capacity of thereactor cavity to cope with rupture of the pressure
tubes without lifting the cavity cover. For all plants
the venting capacity has now been increased tohandle simultaneous rupture of about nine tubes.
As mentioned above, RBMK reactors posses
a compartment system instead of a containment
structure. Originally, first generation plants would
vent steam from pipe ruptures to the atmosphere;
this was improved by filtering the steam through abubbler tank system. Second generation plants were
provided by the original design with a bubbler
condenser system for condensing and containing
steam and radioactivity from DBAs. The limited
capacity of first generation RBMK reactors to copewith pipe breaks contributed, together with thepositive reactivity feedback under certain
conditions, and other factors, to the decision madeto limit the power to 70% of the design capacity.

Concrete shield

Control
rods
Steam
drums
TurbineGraphitemoderator
Pressure
tubes
Fuel elements

Pump

FIG. 5.2. The water/steam flow in RBMK reactors.

5.3.2.

UkraineAll the operational nuclear reactors in
Ukraine are WWER (water cooled and watermoderated) reactors, which belong to the categoryof PWRs. This is the most common reactor type in
the world, comprising more than 50% of all powerreactors. All of the Ukrainian WWER reactors
belong to the second generation of Soviet built
reactors. Rovno 1 and 2 are WWER-440/213
reactors with a capacity of about 400 MW(e) (seeFig. 5.3), whereas the other reactors belong to thelarger WWER-1000 category (see Fig. 5.4) with acapacity of 1000 MW(e). Two reactors, South
Ukraine 1 and 2, belong to an earlier version of thereactors called the small series. Both reactors underconstruction at the Rovno and Khmelnitski sites areof the WWER-1000 series.
The main WWER design criteria areconsistent with current international safety
practices. The enveloping DBA is the break of amain coolant pipe (diameter of 500 mm for
WWER-440, 850 mm for WWER-1000). Safetysystems have been designed with a 3 × 100%
redundancy; however, separation of trains is notalways totally effective. In particular, all steam andfeed water pipes at the 28.7 m level in WWER-1000
reactors are installed in parallel. Efforts are under
way to improve emergency operating procedures

and to develop some accident management
guidelines.
Specific design characteristics of WWER
reactors are horizontal steam generators (versus theusual vertical steam generators) and a hexagonal
design of the fuel elements with the fuel containedin tubes (‘cassettes’). The design of the horizontal
steam generators introduces the possibility ofcollector breaks, of which a large one could lead to asevere accident. The later designs have been
modified and manufacturing techniques have been
improved to practically exclude the possibility oflarge primary to secondary circuit breaks (larger
than 100 mm diameter equivalent). Safety and relief
valves of the primary circuit are being replaced withvalves designed for water or water–steam mixtures.
A relatively low power density in the core andlarge water inventories in the primary andsecondary coolant circuits characterize the WWER440/213 reactors. They have six steam generatorsand coolant loops that can be individually (but notvery reliably) isolated in the event of an emergency.
This provides for large safety margins and possibilities for accident management measures in theevent of an accident. Without power and coolant
water supply, natural circulation of the primary loop
can cool the core for more than five hours. All
coolant pipes are made of austenitic steel, making
pipe breaks very unlikely.
69

Pool type pressure
suppression system

Reactor building

50 m

Middle building

Turbine hall

Confinement
systemboundary

0m

0m

15 m

24 m

12 m

3

18 m

18 m

24 m

FIG. 5.3. WWER-440 reactor as used at Rovno units 1 and 2. 1: reactor pressure vessel; 2: steam generator; 3: refuellingmachine; 4: spent fuel pit; 5: confinement system; 6: make-up feedwater system; 7: protective cover; 8: confinement system; 9:
sparging system; 10: check valves; 11: intake air unit; 12: turbine; 13: condenser; 14: turbine block; 15: feedwater tank with degasifier; 16: preheater; 17: turbine hall crane; 18: electrical instrumentation and control compartments.

For the WWER-440/213 reactors, in contrast
to standard western PWR designs, there is nocontainment. Instead they have a compartment
structure and a bubbler condenser tower. This
tower consists of floors or ‘shelves’ filled with water(see Fig. 5.3) that can condense the steam andcontain radioactivity. Final experiments are under
way within the umbrella of the OECD/NEA toexperimentally confirm the functioning and physicalstability of the bubbler condenser towers.
The larger WWER-1000 reactors areequipped with containments more similar in design
to those of western reactors (see Fig. 5.4). The main
parameters, such as power density or number ofsteam generators and water inventory, are also quite
similar to the usual PWR design. In comparison tothe ‘oversized’ WWER-440 design, safety margins
have as a result been reduced to normal levels andhave to be compensated for by the capacity of thesafety systems. In order to facilitate transport byrail, reactor pressure vessels were kept rather slim
(but long). This poses special requirements when
considering the doubling of power between the
WWER-213 and WWER-1000 types, in particular
for monitoring the neutron flux sustained by the70

vessel walls and for the loading patterns necessary
for low neutron leakage cores.
The standard WWER-1000 has some
improvements over the small series reactors,
including a stricter separation of redundant trains,

FIG. 5.4. WWER-1000 reactor. 1: horizontal steam generator; 2: reactor coolant pump; 3: containment building; 4:
refuelling crane; 5: control rod assemblies; 6: reactor vessel.

improvements in instrumentation and control,
extended ranges of high pressure and low pressure
injection of the emergency core cooling system andthe possibility to switch to the containment sump toallow for feed and bleed operation.
Safety improvement programmes have either
already been implemented or are still under way for
all reactors. These have significantly improved thelevel of safety of the reactors but have the potential
for further improvement.

5.4. LICENSING STATUS OF
NUCLEAR FACILITIES
5.4.1.

Russian Federation

In the Russian Federation the law thatgoverns all nuclear activities was enacted in 1995
(Federal Law on the Use of Atomic Energy, 1995,
RF FL 170-FZ). It establishes the legal basis andprinciples for the regulation and licensing ofactivities related to the use of atomic energy. The
law also contains principles for safeguarding healthand life and protecting the environment andproperty. It has provisions concerning:
(a)
(b)

(c)

(d)

The safe use of atomic energy;
Free access to information on the use of
atomic energy (unless such information
constitutes a State secret);
The participation of citizens, commercial
enterprises and corporate bodies in the reviewof State policy and the drafting of legislation
relating to the use of atomic energy;
Compensation for damage caused by theeffects of radiation.

The Federal Law on the Use of Atomic
Energy is complemented by the Federal Law on
Environmental Protection (RF FL 2060-1 of 19
December 1991) and by the Federal Law on
Radiation Safety of the Population (RF FL 3FZ 09
of 1 January 1996). In line with internationallyrecognized safety standards, the latter legislation
sets out key principles for radiation safety, as well asa mechanism for their implementation. These are:
(i)

(ii)

The standardization of permissible dose limitsof radiation for the population at large and for
personnel working at nuclear installations;
The prohibition of all activities using sourcesof ionizing radiation for which the benefit tohumans and society in general does not exceed
the risk posed by such activities;(iii) Ensuring that individual doses and thenumber of people exposed to ionizing
radiation are kept to the lowest possible level,taking into account the social and economic
factors involved in the use of atomic energy(as low as reasonably achievable (theALARA principle)).
The Russian legislation affirms the priority ofhuman health and environmental protection in thecontext of the operation of nuclear installations andthe use of radioactive substances and other sourcesof ionizing radiation.
The main State regulatory bodies set up to
enforce compliance with the legislation, as of 2003,
were the:— Federal Nuclear and Radiation Safety
Authority of Russia (Gosatomnadzor);— Federal Sanitary and Epidemiological Inspectorate (Gossanepidnadzor);— Federal Mining and Industrial Inspectorate of
Russia;— State fire service.
Gosatomnadzor is the organization that
regulates nuclear and radiation safety. It establishes
conditions that ensure the protection of workers,
the public and the environment from undue harmfrom radiation. As such, it is charged with the tasksof defining safety principles, standards and criteria,
as well as with licensing, inspection andenforcement of all activities related to the use of
nuclear energy.
In 1997 Gosatomnadzor updated the General
Provisions Governing the Safety of Nuclear Power
Stations (OPB-88). This regulation contains
objectives, safety goals, basic criteria and principles,and, in some cases, details of engineering and organizational measures needed to meet the nuclear andradiation safety standards.
The concept of defence in depth has beenfurther developed in OPB-88, which requires that:“[A] nuclear power plant design andoperation shall ensure that exposure of
personnel, the public, and the environment toradiation during normal operation or during
any abnormal operational occurrences,including design basis accidents, does not
result in radiation doses that exceed those71

prescribed for personnel and the public, as
well as the standards governing releases,
discharges, and the content of radioactive
substances in the environment. In the case of
beyond design basis (BDB) accidents, such
exposure should be limited as far as possible.”
The permissible personal radiation dose limits
and dose limits for the public as a result of releases
and discharges of radioactive substances from anuclear power plant are defined in Russian
Radiation Protection Rules NRB-99 (SP 2.6.1.75899). It is required that the maximum dose for a
DBA be less than the intervention levels set for offsite contamination, which at present are 5 mSv
individual whole body dose within the first ten days
after an accident.
OPB-88 also establishes the requirements forpreventing, controlling and mitigating the consequences of BDB and severe accidents. It also
includes a probabilistic safety goal for severe coredamage of a frequency less than 10–5 per reactor
year. OPB-88 recommends that every attempt be
made to ensure that the estimated frequency oflarge unacceptable radioactive releases does notexceed 10–7 per reactor year. Accident management
systems are required to cope with BDB accidents.
The Law on the Use of Atomic Energy,
supported by a governmental decree, requires that alicence be obtained for some 35 prescribed
activities. These include the siting, construction,commissioning, operation, modification and decommissioning of nuclear power plants. For a licence tobe issued by Gosatomnadzor, a given activity should
be in compliance with the standards and rules
prescribed by the applicable legal and regulatory
documents.
The units of the Kursk and Smolensk nuclear
power plants have had their safety justification
documents submitted to the regulatory body inaccordance with the requirements of the licensing
process. The current validity of the licences isdifferent, dependent upon the age and design typeof the unit. The present practice is that, for first
generation units, a licence is granted on an annual
basis, while for second generation units the licenceis valid for five years.

Energy and Radiation Safety, No. 39/95, wasenacted in 1995. There were subsequent
amendments to this law in 1996 and 1997, and sincethen a significant number of relevant subordinate
regulations and regulatory guides have beendeveloped. This legislation establishes theframework for the regulation of activities related tothe use of atomic energy and includes provisions forthe following:
(a)

(b)

(c)

(d)
(e)

(f)

(g)

The Law on Human Protection Against
Ionizing Radiation (dated January 1998) sets out
the requirements for the radiation protection ofworkers and the public. This law is supported byrelevant regulations and standards developed by the
Ministry of Health.
In January 2000 the Law on Permissible
Activity in the Area of Nuclear Energy Utilization
established the following principles:(i)

5.4.2.

Ukraine(ii)

In Ukraine the overarching law that governs
all nuclear activities, the Law on Use of Nuclear

72

Setting up agencies to carry out the control
and State regulation of safety in the use of
nuclear energy in accordance with the law.
Making decisions on the safe siting, planning,
construction, operation and decommissioningof uranium ore mining enterprises, nuclear
installations
andradioactive
waste
management facilities.
Administration of nuclear installations,
ionizing radiation sources, nuclear material
and radioactive waste management facilities
that are the property of the State.
Protecting the public and the environment
from the harmful effects of ionizing radiation.
Preparing measures connected with theaccountancy and monitoring of nuclear
material and ionizing radiation sources andwith the physical protection of nuclear installations, ionizing radiation sources, nuclear
material and radioactive waste management
facilities.
Defining the procedure for drafting andadopting regulations, rules and standards
regarding nuclear and radiation safety.
Defining the types of activities that should belicensed.

The prioritization of maintenance of nuclear
and radiation safety above other interests;
A varied approach to activities commensuratewith the potential nuclear and radiation
danger associated with them;(iii) The independence and objectivity of
regulatory bodies and acceptance of theirdecisions;(iv) The validity of established criteria, requirements and conditions for safety, having regard
for all ecological, economic and social factors;(v) The responsibility of regulatory bodies toensure that licensing conditions are observed.
The procedure for licensing was established by
the Order for Licensing Various Kinds of Activity in
the Field of Nuclear Energy Use, which wasapproved by the Cabinet of Ministers (No. 1782 on
6 December 2000). The order establishes theconditions of licensing, the list of documents
required, the conditions and procedures forrenewal, cessation and cancellation of licences,
procedures for the registration of the given licences
and control over the observance of the licenceconditions.
The Ukrainian legislation represents acomprehensive basis for ensuring nuclear andradiation safety, including protection of the
population and the environment. It affirms thepriority of human health and environmental
protection in the context of the operation of nuclear
installations and the use of radioactive substancesand other sources of ionizing radiation.
The main State regulatory bodies set up to
enforce compliance with the legislation are the:— State Nuclear Regulatory Committee of
Ukraine (SNRCU);— Ministry of Environment and Natural
Resources of Ukraine (MENRU);— Ministry of Health of Ukraine;— Ministry of Emergencies.
In December 2000 the President of Ukraine
issued a decree (1303/2000, Decree on State
Regulation of Nuclear and Radiation Safety) that
established the SNRCU as the prime independent
regulatory body for the safety aspects of nuclear
activities. As such, it is charged with the tasks ofdefining safety principles, standards and criteria,
as well as with licensing, inspection andenforcement of all activities related to the use of
nuclear energy.
The SNRCU has made use of OPB-88 insetting its objectives, safety goals, basic criteria andprinciples for nuclear safety. The standards and dose
rate limits are set in Norms of Radiation Safety of
Ukraine, Supplement: Radiation Protection from

Potential Ionizing Radiation Sources (NRBU-97/D2000). Maximum occupational and public exposure
dose limits for the whole body are set at 20 mSv and1 mSv, respectively. The principle of ALARA is also
set down in the law, which follows the latest IAEA
and ICRP recommendations.
Within the Law on Permissible Activity in the
Area of Nuclear Energy Utilization, enacted in
January 2000, the function of issuing licences was
assigned to the SNRCU, and a requirement todefine and attach conditions to a licence was also
given. The scope of the licensing regime in Ukraine
covers all significant facilities and activities,
including: nuclear power plant design, construction
and operation; uranium ore processing; radioactive
waste storage and treatment; transport ofradioactive material; decommissioning of nuclear
facilities; closure of radioactive waste disposal sites;
and nuclear power plant operator training.
In accordance with the law mentioned above,the scope and format of the documents that shall be
submitted by the licence applicant in order to obtaina licence are to be determined by the SNRCU. It has
defined two strategies in relation to its reactor
licensing process: one for nuclear power plants
under operation and the other for nuclear power
plants under construction.
For the reactor units on the four operating
nuclear power plant sites, the SNRCU has decided
to give site licences, as it is allowed to do under thelaw. For this purpose the contents of the safety
analysis report (SAR) required from theoperators were specified in a guide prepared by
the SNRCU.
It was recognized by the SNRCU that theprocess for the completion of comprehensive SARs
will take several years, and therefore to speed up
the licensing process it was decided to issue licences
based on partially developed or basic SARs. All thelicences have now been issued; however, they arevalid for only one year and have stringent
conditions attached, including timescales for thecompletion of comprehensive SARs. This annual
licence renewal procedure will remain until all theplant specific SARs have been submitted by theoperators to the SNRCU for regulatory review andassessment. Once satisfied, permanent licences will
be granted to the nuclear power plants by the
SNRCU. However, one of the conditions attachedto these licences will be for the operators to perform
a full periodic safety review on a ten year cycle.
For Rovno 4 and Khmelnitski 2, which are
currently under construction/commissioning, a full73

scope safety assessment based on a SAR containing
BDB and severe accident analyses as well as a plant
specific probabilistic safety assessment (PSA) is
required as a condition for active commissioning of
the units.

5.5. SYSTEM FOR ENVIRONMENTAL
RADIATION MONITORING IN THE
VICINITY OF NUCLEAR POWER
PLANTS
5.5.1.

Russian Federation

The radiation situation in the 30 km zone of
Russian nuclear power plants is monitored by theirinternal services in accordance with the Proceduresfor Radiation Monitoring. Included is monitoring of
the:
(a)

(b)

(c)
(d)

(e)

(f)

Space–time distribution of gamma radiationdose rate and spatial distribution of annual
absorbed dose in the area;
Volumetric activity of radioactive aerosols inthe surface atmospheric layer and of theradioactive deposition density;
Radionuclide content in soil, vegetation andlocal food;Volumetric activity of radionuclides in waterin discharge pipelines, at industrial andmunicipal sewage sites, in open water bodies,in fish and in other aquatic organisms;
Leakage (if any) to groundwater from liquid
waste storage sites and storage facilities
containing spent nuclear fuel;Sources of drinking water supply and thewater network used for district heating.

In the 100 km zone around nuclear power
plants, regional units of the hydrometeorologicalservices conduct monitoring.
A process is now under way to set up at all
Russian nuclear power plants automated systems
for radiation monitoring (ASKRO), which areplanned to be integrated in future into the unified
State automated system for radiation monitoring(EGASKRO) [5.5]. The ASKROs of nuclear power
plants incorporate [5.6]:(i)

74

Stations to measure the radiation dose rate in
the sanitary zone and observation zone;(ii)

Facilities for emergency monitoring of
releases through the ventilation stacks ofnuclear power plants;(iii) Meteorological stations;(iv) Central points of data collection fromdifferent subsystems engaged in the gatheringand primary processing of information from
instrumentation;(v) Central monitoring posts to receive andprocess information from the central points ofall subsystems and its transmission to theinformation network of nuclear power plants
and the emergency centre of Rosenergoatom.
ASKROs are designed to provide [5.5, 5.6]:— Continuous monitoring of the radiation
situation on the site and in the sanitary zone
and observation zone;— Prognosis of the evolution of the radiation
situation and doses to the population andpersonnel in the normal operation of nuclear
power plants and in the event of an
emergency;— Information and analytical support to nuclear
power plant management, the operatingorganization and territorial authorities;— Information to the public about the radiation
situation in the observation zone aroundnuclear power plants through the media anddisplay boards.
The existing monitoring system is primarily
geared towards an emergency response in the eventof an accident involving an atmospheric release ofradioactivity. There is no doubt that this system
serves its purpose, and will more so after ASKROs
are fully put into operation. On the other hand,monitoring of contamination of surface waters andgroundwaters is currently conducted on a monthlyor quarterly basis, and it cannot be excluded thatleakage of a considerable amount of radioactive
substances to surface waters or groundwaters could
occur, precluding timely and effective countermeasures.
This possibility is exemplified by the leak froma liquid waste storage facility that occurred at the
Novovoronezh nuclear power plant in 1985 [5.7]. By
the time the leak was detected, only 137Cs was foundat the leak site, whereas 60Co, in the form of a nonsorbable complex, had migrated to groundwater.
From 1995 onwards elevated concentrations of 60Co
were detected in bottom sediments of the Don

River (up to 5 kBq/kg) as a result of uncontrolled
discharge of this radionuclide. In 2000 a significant
level of 60Co was measured in soil on the Don Riverbank near the mouth of the wastewater discharge
pipeline of the nuclear power plant (dose rate up to
30 μSv/h). Thus the failure to detect the leak quickly
made it impossible to contain it within a localized
area. The above example shows that the system ofmonitoring leaks of radioactive substances tonatural waters from nuclear power plant sites needs
to be improved.
5.5.2.

(b)(c)

5.5.3.

5.6. RELEASES FROM NUCLEAR
REACTORS IN THE DNIEPER RIVER
BASIN
5.6.1.

Releases from the Kursk and Smolensk
nuclear power plants

UkraineIn the vicinity of the operating Ukrainian
nuclear power plants, environmental monitoring isorganized as follows:(a)monitored on a regular basis. The monitoring of
surface waters and bottom sediments is conducted,
however, only on Lake Drisvyaty in the zone
influenced by the Ignalina nuclear power plant.

At the facilities of nuclear power plants andwithin the 10 km zone, the safety and environmental departments of nuclear power plantsmonitor releases. The following aremonitored: releases from ventilation stacks,
air and soil at nuclear power plant sites and intheir vicinity, waste water discharge and water
intake points, cooling ponds and undergroundwaters.
Within the 30 km zones around nuclear power
plants and the zones of potential impact,
monitoring is carried out by units of theHydrometeorological Service of Ukraine andGossanepidnadzor.
Sampling near water intakes and other watersupply facilities and estimation of radioactive
contamination levels is the responsibility of
Gosvodkhoz. In addition to Gosvodkhoz,
surface and underground waters aremonitored by other entities, as prescribed byagency protocols and rules. The system formonitoring groundwater contamination levels
in Ukraine is described in Ref. [5.8].

Gaseous and aerosol releases at the Kursk andSmolensk nuclear power plants are discharged
through ventilation stacks with a height of 150 m
and through small stacks with a height of 60 m. The
gases are detained for a certain time prior torelease, to allow for decay of short lived radionuclides, and are then partially cleaned ofradioactive aerosols and radio-iodine.
During the whole period of operation of theSmolensk and Kursk nuclear power plants, thepermissible rate of radionuclide releases into theatmosphere both of groups of and individual radionuclides as prescribed by the Sanitary Rules on
Design and Operation of Nuclear Power Plants(SPAES-68 and SPAES-79) have not been exceeded[5.1, 5.7, 5.9–5.12]. Actual releases have been much
lower than the requirements of SPAES-88.
In the latest revision of the Sanitary Rules(SPAES-99), the permissible releases into theatmosphere were further reduced. Table 5.3
compares the actual and permissible releases for the
Kursk and Smolensk nuclear power plants for theperiod 1995–2000. The releases were greatest for
the inert radioactive gases (isotopes of xenon,
krypton and argon), but well below the permissible
limits in all cases.
Discharge of radionuclides from nuclear
power plants into surface water occurs via thefollowing wastewaters:

Belarus

There are no nuclear power plants in Belarus,
but the 100 km zones of four nuclear power plants(Chernobyl, Ignalina, Rovno and Smolensk) in theneighbouring countries extend into the territory of
the republic. The RCREM and its network units
carry out radiation monitoring in the nuclear power
plant impact zones in Belarus. The radiation dose
rate is monitored continuously, and radioactive
contamination of the air and atmospheric fallout is

(a)
(b)
(c)
(d)
(e)

Excess (debalanced) water;
Cooling water from the heat exchangeequipment in the reactor compartment;
Industrial and shower sewage water;
Special laundry and shower room water;
Utility sewage water.

During the first years of nuclear power plant
operation, the release of radionuclides was attributable mainly to debalanced waters and, thereafter,75

TABLE 5.3. ANNUAL GASEOUS AND AEROSOL RELEASES OF RADIONUCLIDES AS A
PERCENTAGE OF PERMISSIBLE RELEASES [5.7, 5.13]
Radionuclide

Kursk

Smolenska

IRGa

Actual release as per cent of permissible limit

Permissible release
(Bq)

1995

1996

1997

1998

1999

2000

3.7 × 1015

13

14

10

30

32

17

Iodine-131

109.3 × 10

7.5

11

12

8.3

9.1

2.0

Cobalt-60

2.5 × 109

5.2

32

16

8.8

1.9

—

Strontium-90

2.4 × 108

<0.1

<0.1

<0.1

<0.1

<0.1

—

Caesium-134

9

1.4 × 10

0.86

0.61

3.4

1.6

0.66

—

Caesium-137

9

0.60

0.93

2.8

1.6

1.3

—

IRG

4 × 10

3.7 × 1015

27

18

19

17

16

14

Iodine-131

109.3 × 10

6.8

6.0

27

15

5.7

8.9

Cobalt-60

92.5 × 10

4.0

3.0

2.8

2.7

2.3

4.0

Strontium-90

82.4 × 10

6.0

5.0

5.0

4.2

17

17

Caesium-134

9

1.4 × 10

1.6

0.16

4.8

3.2

1.9

1.2

Caesium-137

9

2.2

0.78

4.3

3.5

1.8

1.6

4 × 10IRG: inert radioactive gases.

cooling water and industrial and shower sewage
water [5.12]. A typical radionuclide composition ofthese waters for nuclear power plants of the RBMK
type is presented in Table 5.4.
Deviations from the above norms were notobserved at the Kursk or Smolensk nuclear power
plants. The permissible and actual releases of radionuclides into surface waters during 1998–2000 are
presented in Table 4.5. The actual releases are lower
than the permissible releases by several orders ofmagnitude.

5.6.2.

Radioactive contamination in the vicinitiesof the Kursk and Smolensk nuclear power
plants

5.6.2.1. Soil
Before the Chernobyl accident, the level ofsoil contamination in the central regions of theEuropean part of the USSR was, on average, 137Cs =3.0 kBq/m2 and 90Sr = 1.9 kBq/m2. The density of137
Cs contamination in the soil in the vicinity of the
Kursk and Smolensk nuclear power plants wasdetermined by the global background, and it waspractically the same as in the reference regions (seeTable 5.6).

TABLE 5.6. DENSITY OF CONTAMINATION OF SOIL WITH CAESIUM-137 IN THE VICINITY OF
THE SMOLENSK AND KURSK NUCLEAR POWER PLANTS [5.16]
Caesium-137 (kBq/m2)
Year

Nuclear power plantsurroundings

Monitored territory

Kursk

1978

2.8 ± 0.1

2.70 ± 0.03

Smolensk

1981

2.8 ± 0.1

2.61 ± 0.02

Smolensk

1983

3.1 ± 0.2

2.61 ± 0.02

76

TABLE 5.4. TYPICAL RADIONUCLIDE COMPOSITION OF RELEASED WATERS FROM RBMKTYPE NUCLEAR POWER PLANTS [5.12]
Debalanced waters (Bq/L)

Waters of industrial andshower sewage (Bq/L)

Operation year

Operation year

Waters of reactor
department(Bq/L)

1–5

>5

1–5

>5

Caesium-134

4–15(4–7) × 10–3

0.04–0.185

1.85 × 10–3

3.7 × 10–3

Caesium-137

3.7(0.4–4) × 10–3

7.4 × 10–2

—

—

1.85

–4

(7–15) × 10

3.7 × 10

7.4 × 10–3

–3

–2

7.4 × 10—

7.4 × 10–3

Strontium-90(1.5–2.2) × 10

–3

–4

Cobalt-60

15–30(0.4–1.85) × 10

Cobalt-58

11–33

3.7 × 10–4

3.7 × 10–3—

1.5 × 10–3

Argon-41

40–3000(0.4–1.85) × 10–3

0.4–4

—

3.7 × 10–2

2–11

(0.4–1.1) × 10–3

(0.4–3.7) × 10–2—

7.4 × 10–3

15—

7.4 × 10–3

—

—

—

Manganese-54–3

Iron-59

15–300(0.4–1.85) × 10

Iodine-131

7–15(0.4–4) × 10–2

TABLE 5.5. PERMITTED AND ACTUAL RELEASES FROM THE KURSK AND SMOLENSKNUCLEAR POWER PLANTS INTO SURFACE WATERS [5.7, 5.11]

Kursk

Smolensk

1998

1999

2000

Cobalt-60

3.0 × 1011

7.0 × 107

1.05 × 108

2.5 × 107

Strontium-90

3.2 × 1010

3.6 × 107

3.92 × 107

1.82 × 106

Caesium-137

2.4 × 1011

1.2 × 108—

6.0 × 107

Cobalt-60

4.81 × 1011

6.4 × 105

4.05 × 107

4.09 × 107

Strontium-90

1.81 × 109

1.27 × 106

2.98 × 106

3.7 × 106

Caesium-137

2.85 × 109

4.0 × 1065.25 × 107

3.03 × 107

After 1986 the level of soil contamination with
Cs in the vicinity of the Smolensk and Kursk
nuclear power plants was determined mainly byfallout from Chernobyl (see Section 3). To thenorth-east of Smolensk, the density of fallout was
18.5–37 kBq/m2 (0.5–1 Ci/km2); in other areas thelevels reached 37–74 kBq/m2 (1–2 Ci/km2). In thesouth-west direction, the densities of contamination
were lower than 18.5 kBq/m2 (0.5 Ci/km2).
The Kursk nuclear power plant is located in
territory with a general level of contamination of
7.4–18.5 kBq/m2 (0.2–0.5 Ci/km2); at a distance ofabout 10 km to the south-west there is a spot with ahigher concentration, viz. 18.5–37 kBq/m2 (0.5–1 Ci/
km2). According to the assessment in Ref. [5.14],
during 16 years of operation of the Kursk nuclear
power plant, 0.2 Bq/m2 of 90Sr and 0.8 Bq/m2 of 137Cs
137

Actual release (Bq/a)

Permitted release(Bq/a)

Radionuclide

were deposited in the area of Kurchatov town. Thisis three to four orders of magnitude lower than thelevel of contamination as a result of global releases.
It is not possible to discern any statisticallysignificant contribution from releases of theSmolensk and Kursk nuclear power plants into thesoil [5.12, 5.14, 5.15]. Firstly, the necessary
information on the initial contamination of theregions is absent or insufficiently complete andqualitative. Secondly, the contribution of thenuclear power plants is negligibly low.
5.6.2.2. Air
During the whole period of their operation,
gaseous and aerosol releases from the Kursk andSmolensk nuclear power plants did not lead to any
77TABLE 5.7. CAESIUM RADIONUCLIDE ACTIVITY CONCENTRATION IN SURFACE WATERS IN
THE VICINITY OF THE KURSK NUCLEAR POWER PLANT [5.18]
Observation period

Caesium-134(mBq/L)

Caesium-137(mBq/L)

Cooling pond

1980–1985, 1987–1993

25

35

1986

55

63

Seim River

1980–1985, 1987–1993

23a

32a

1986

37

72

Reut River

1980–1985, 1987–1993

23a

32a

1986

88

140

Sampling locationaMedian value of concentrations in the Seim and Reut Rivers in 1986.

significant contamination of the air; they were lower
than the effective norms. In 1983–1985 the content
of 137Cs in the area of the Smolensk nuclear power
plant was (1–4) × 10–6 Bq/m3. After the Chernobyl
accident it significantly increased, and in 1988–1989
was tens of mBq/m3 [5.15]. In 2000 the maximum
concentration of 137Cs in the area of the Smolensk
nuclear power plant equalled 3 × 10–5 Bq/m3. At a
distance of 35 km from the nuclear power plant it
was approximately the same as at the plant site.
In the vicinity of the Kursk nuclear power
plant the content of 137Cs in the air increased by 104
times during 1986 and reached (2–4) × 10–4 Bq/m3[5.14]. In 2000 at the Kursk nuclear power plant sitethe mean annual content of 137Cs in the air equalled
8 × 10–5 Bq/m3 [5.7]. Releases from the Kursk
nuclear power plant were proposed as an
explanation for a small increase in the airborne
concentration of 137Cs in Kursk city compared withthe average over the whole of the RussianFederation [5.11]; however, this may be a result ofcontamination from the Chernobyl releases.
5.6.2.3. Natural water
The concentrations of radionuclides in thesurface waters of the Bryansk region may be used toassess the pre-Chernobyl concentrations in rivers in
the territories of the Kursk and Smolensk regions,
namely 14–20 mBq/L for 90Sr, 4–8 Bq/L for tritiumand 0.2–1.3 mBq/L for 137Cs [5.17]. Before 1986 thecontent of radionuclides in the surface waters in thearea of the Smolensk nuclear power plant did notexceed these ranges. In 1983–1985 the concentrations in this area were 0.4–1.2 mBq/L 137Cs and 1.5–
5.6 Bq/L tritium [5.15]. The median value of 137Cs
activity in the water of the Smolensk cooling pond
during the operational period up until the beginningof the 1990s, excluding 1986, was 0.7 mBq/L [5.18].

78

Concentrations of 137Cs are a little higher in
the Smolensk cooling pond and in the Seim andReut Rivers in the area of the power plant (seeTable 5.7). In 1986 they increased 2.5–3 times, but in1988 they were back to the pre-Chernobyl level[5.18].
At present, the concentrations of 137Cs in thesurface waters in the vicinity of nuclear power
plants remain at low levels that do not require intervention, although they are a little higher than the
pre-Chernobyl concentrations caused by global
releases. In 1999 the activity of 137Cs in the Desna
River and the Desnogorsk reservoir was 13 mBq/L[5.11] and in the Seim and Reut Rivers up to
20 mBq/L (see Table 5.8).
Since there were no significant releases of 90Sr
from the Chernobyl nuclear power plant in theareas of the Kursk and Smolensk plants, its present
concentrations in surface waters are approximately
the same as before 1986.
Thus the operation of the Kursk and Smolensk
plants has not led to significant releases of radionuclides into the environment. The influence of
nuclear power plants on the radioactive contamination of soil, air and natural water becomesapparent mainly at certain times in a few samples,
where trace quantities of radionuclides of reactor
origin, such as 51Cr, 54Mn and 58,60Co, are detected.
The only detectable influence of the nuclear power
plants on the radioactive contamination of theenvironment is apparently a small increase(compared with the global level) in the 137Csconcentration in surface waters in the vicinity of the
Kursk nuclear power plant.
5.6.3.

Releases from Ukrainian
nuclear power plants

Release of radioactivity from nuclear power
plants can occur via either the air or water pathway.

TABLE 5.8. CONCENTRATION OF RADIONUCLIDES IN THE WATER OF INDUSTRIAL AND
OPEN WATER BODIES IN THE AREA OF THE KURSK NUCLEAR POWER PLANT IN 1996–2000[5.1, 5.7, 5.10, 5.11]
Strontium-90 (mBq/L)

Sampling location

1996 1997 1998 1999 2000

Caesium-137 (mBq/L)

Total beta activity (mBq/L)

1996 1997 1998 1999 2000

1996 1997 1998 1999 2000

Cooling pond
Outlet canal

1.5

8

7.4

8

7

—

—

100

—

—

200

200

250

240

230

Inlet canal

3

8.5

13

7.8

8

—

—

—

—

80

200

200

240

230

220

10

10

—

200

200

280

260

230

6

—

—

200

200

250

260

230

—

—

—

200

200

220

230

230

Seim Rivera

ISS release

2.8

3.2

98

5

5

—

Upstream ISS release

4.2

16

12

15

15

—

Downstream ISS release

1

10

1

11

11

—

20
10

Reut Riverb

WK release

70

4

9

16

16

50

120

90

70

—

200

200

280

250

220

Upstream WK release

1.6

14

6

12

12

—

20

—

—

—

200

200

290

250

220

Downstream WK release

1.3

9

7

13

13

—

10

10

—

—

200

200

240

250

220

a
b

ISS: interim storage site.
WK: wastewater treatment works, Kurchatov.

After cleaning, ventilation air is released to theatmosphere via tall stacks. Gaseous and aerosol
releases may also enter the atmosphere via ejectors
when there is a leak of coolant from the primary to
the secondary circuit. In the turbine condenser,
separation of non-condensable gases takes place,which then are exhausted by the ejectors. The gases
are exhausted into the outlet canal of the circulatingwater and then into the cooling ponds.
The permissible release of radioactivity to theenvironment is determined for each nuclear power
plant taking account of the stack height, average
meteorological conditions at the site and location of
the sanitary and protective zones. Table 5.9 showsthese permissible releases for Ukrainian nuclear
power plants. Before 2000, ischarges from all nuclear

power plants were below the requirements set out instandard SPAS-88.
In 1997 new radiation safety regulations wereintroduced (NRBU-97) based on the Basic Safety
Standards [5.19] and the recommendations of the
IAEA. Under these regulations, the permissible
release is calculated on the basis of a dose quotientthat takes account of all exposure routes to a criticalgroup of the population. For nuclear power plants,
the dose limit is 40 mSv/a, which represents 4% of
the allowable dose to the general population fromall sources (1 mSv/a).
In addition to the permissible limits, more
restrictive control levels for releases to air andwater are set following discussions with the State
Sanitary Supervisory Agency.

TABLE 5.9. PERMISSIBLE RELEASES FROM NUCLEAR POWER PLANTS IN UKRAINE

Zaporozhe

Permissible releases(TBq/d)Long lived radionuclides(MBq/d)Iodines(MBq/d)

148

3330

1480

South Ukraine

55.5

1660

1110

Rovno

34.8

1040

695

Khmelnitski

18.5

555

370

79

TABLE 5.10. RADIONUCLIDE RELEASES FROM NUCLEAR POWER PLANTS DURING 1997–2001
Caesium-137 (MBq/a)

Cobalt-60 (MBq/a)

Zaporozhe

Rovno

Khmelnitski

South
UkraineZaporozhe

Rovno

Khmelnitski

South
Ukraine

1997

254

1345

0.7

15.8

40.2

84.0

0.9

28.3

1998

615

3627

0.0

31.4

116

152

11.9

159

1999

213

1220

2.0

65.1

57.5

61.8

0.0

158

2000

157

633

130

47.6

121.8

45.6

0.5

38.7

2001

153

628

39.2

151

63.9

8.2

0.4

223

TABLE 5.11. RADIONUCLIDE RELEASES INTO THE ZAPOROZHE NUCLEAR POWER PLANT
COOLING POND (2000)
Radioactivity (MBq)

Released water(106 m3)

Caesium-137

Caesium-134

Manganese-54

Cobalt-60

Blowdown from spray
ponds

1.36

135

59

52

104

Chemical water cleaning

0.17

22

12

5

17

Total effluents

1.53

157

71

57

121

Control level (MBq/a)

—

930

370

1900

2600

Release index (%)

—

16.9

19.1

Effluent source

3.0

4.7

TABLE 5.12. RADIONUCLIDE RELEASES INTO THE KHMELNITSKI NUCLEAR POWER PLANT
COOLING POND (2000)
Radioactivity (MBq)

Releasedwater(103 m3)

Tritium(GBq)

Spray ponds

333

5300

2.3

8.8

15.3

0.4

—

Desalting installation

18

—

—

1.3

1.3

—

0.3

Chemical water cleaning

317

430

1.5

2.8

7.7

0.1

—

Total

668

5720

3.8

129.7

24.3

0.5

0.3

Effluent source

Strontium-90 Caesium-137 Caesium-134

The main releases of radioactivity to water
occur via primary circuit leaks, blowdown of coolingwater systems, drainage from active areas, spent fuelpond operations, decontamination and maintenance
operations, and drains from washrooms, showers,
etc. Table 5.10 shows the radionuclide releases fromall Ukrainian nuclear power plants for the five years
from 1997.
Tables 5.11–5.13 show releases to the coolingponds. In all cases the release rates are only a small
80

Cobalt-60

Manganese-54

fraction of the maximum permissible releases or thecontrol level.
Tables 5.14 and 5.15 show the concentrationsof the key radionuclides, 137Cs and 90Sr, in the ponds
and receiving waters of Ukrainian nuclear power
plants. These data demonstrate that, at least underpost-Chernobyl conditions, it is impossible todistinguish the influence of nuclear power plantreleases. Actual releases are significantly lower thanpermissible releases.

TABLE 5.13. RADIONUCLIDE RELEASES INTO THE ROVNO NUCLEAR POWER PLANT
COOLING POND (2000)
Radioactivity (MBq)
Releasedwater(106 m3) Cobalt-60 Caesium-134 Caesium-137 Strontium-90 Silver-110m Cobalt-58 Manganese-54
Industrial water andshower sewage

15.6

<45.0

Domestic sewage

0.2

2.3

Maximum permissible
release—Index of maximum
permissible release (%)—

63 000

327

755

76.6

<90

<73

<63

13

0.3

<1

<1

<1

6

93

190 000

360 000

230 000

1.30

0.08

6.3
34 000

<0.08

0.98

<0.05

<0.02

<0.03

TABLE 5.14. CONCENTRATION (Bq/m3) OF RADIONUCLIDES IN SURFACE WATERS NEARZAPOROZHE NUCLEAR POWER PLANT (2000–2001)
Cooling pond

Caesium-137
Strontium-90
aKakhovka reservoir

2000

2001

Backgrounda

2000

2001

9.3

3.7

2.6

8.9

3.7

74

24.3

161

113

57

Background refers to measurements taken before reactors were commissioned.

TABLE 5.15. CONCENTRATION (Bq/m3) OF RADIONUCLIDES IN SURFACE WATERS NEAR
SOUTH UKRAINE NUCLEAR POWER PLANT (2000–2001)
South Bug River

Treatment pond fordomestic sewage

Outlet canals

2000

2001

2000

2001

2000

2001

Caesium-137

22

22

29

36

31

38

Strontium-90

30

30

21

40

31

38

5.7. MANAGEMENT OF RADIOACTIVE
WASTE AND SPENT FUEL
5.7.1.

Russian nuclear power plants

The spent fuel from RBMK reactors iscurrently stored under water at each plant site. The
specific activity of the fuel after unloading from thereactor is as high as 1018–1019 Bq/t, but after three
years of storage it decreases to (2–4) × 1016 Bq/t
[5.16].
Several thousand tonnes of spent fuel haveaccumulated from operation of the Kursk andSmolensk reactors. Existing storage facilities arealmost full [5.20, 5.21]. To solve this problem, a plan
has been developed, viz. Concept of Spent FuelManagement, and approved by Minatom. It
prescribes the following successive actions for theperiod until 2020 [5.20]:
(a)
(b)
(c)

Extension of existing storage facilities;
Construction of interim dry storage facilities
using a container type design;
Removal of all the spent fuel from nuclear
power plants to the centralized storage facility
near Krasnoyarsk.
81

A brief description of the waste management
practices at Ukrainian nuclear power plants within
the Dnieper River basin is given below.

At present, these actions are carried out inaccordance with the Work Programme of Rosenergoatom for Spent Fuel Management, 2002–2005[5.20]. Extension of the existing storage facilities,
currently under way at the Kursk nuclear power
plant, will increase storage capacity by 67%.
Construction of interim dry storage facilities has
also commenced. A metal–concrete container thatcan be used for both dry storage and transport of
RBMK spent fuel has been designed and iscurrently undergoing trials.
In addition to the spent fuel, tens of thousandsof cubic metres of both liquid and solid radioactive
waste is stored at the Kursk and Smolensk nuclear
power plants. The volume of stored waste is close to
the storage capacity, especially for solid waste[5.16]. For this reason, new waste treatment
facilities will be established at the nuclear power
plants. Such facilities are under construction at theSmolensk plant, while at the Kursk plant they arebeing designed [5.20].
5.7.2.

5.7.2.1. Zaporozhe nuclear power plant
The management of radioactive waste iscarried out within the main facilities of the reactor
units and in special buildings designed for theprocessing and storage of solid radioactive waste.
Liquid radioactive waste is collected at the placeof production and transported to a chemical treatment
plant, where it is processed to reduce its volume. The
resulting liquid is stored and pumped into anothertreatment process involving deep evaporation tofurther reduce the volume. The end product of suchtreatment is a salt concentrate (density about 2000 kg/m3), which is deposited into 200 L drums. Upon
cooling, the liquid solidifies into a salt monolith. The
drums are then stored on the site as solid waste.
Solid radioactive waste is collected at theplace of production. It is then sorted into
combustible and non-combustible waste. The
combustible waste is incinerated in an on-sitefacility. The non-combustible waste is compacted
and stored on the site. A programme to minimize
waste production is in progress. Table 5.16 shows
the downward trend in the production of liquid andsolid radioactive waste in recent years.
As of 1 January 2002 the volume of solid andliquid radioactive waste in storage at the Zaporozhe
nuclear power plant was approximately 7831 m3 and3002 m3, respectively. The radioactive waste
management programme at the plant includes new
facilities for transporting, reprocessing and decontaminating liquid radioactive waste.

Ukrainian nuclear power plants

The radioactive waste resulting from theproduction of nuclear power includes gases, liquids
and solids. Very low level gaseous and liquid waste
is monitored and discharged to the environment inaccordance with the licensing conditions. Liquidand solid waste is treated to reduce volume andthen stored at each plant. Although there have been
problems with the treatment and storage ofradioactive waste and spent fuel at nuclear power
plants in Ukraine, there is no evidence of significant
radioactive releases to surface waters or groundwaters in the vicinity of the plants.

TABLE 5.16. VOLUME AND ACTIVITY OF RADIOACTIVE
WASTE PRODUCED AT THE ZAPOROZHE NUCLEAR POWER
PLANT DURING THE PERIOD OF IMPLEMENTATION OF THE
WASTE MINIMIZATION PROGRAMME (1998–2001)

1998
1999
2000
2001

82

Liquid waste

Solid waste

1695 m3

487 m3

5.9 × 108 Bq

1.4 × 109 Bq

31145 m

466 m3

1.7 × 1010 Bq

1.2 × 1010 Bq

893 m3575 m3

1.7 × 1010 Bq

3.0 × 109 Bq

3

761 m

380 m3

6.7 × 106 Bq

9.6 × 108 Bq

TABLE 5.17. VOLUME OF RADIOACTIVE WASTE (m3)
PRODUCED AT THE ROVNO NUCLEAR POWER PLANT
DURING THE PERIOD OF IMPLEMENTATION OF THE
WASTE MINIMIZATION PROGRAMME (1998–2001)
Liquid waste

Solid waste

1998

1904

280

1999

1860

262

2000

1522

190

2001

1330

110

The Zaporozhe nuclear power plant is uniquein Ukraine in that practical measures have beentaken to solve the problem of the long term safe
storage of spent nuclear fuel. Since 1993 work has
been undertaken on the dry storage of spent nuclear
fuel. Having analysed the various design options, it
was decided to use concrete containers as
developed in the USA. A positive feature of thisdesign is its low cost.
5.7.2.2. Rovno nuclear power plant
The radioactive waste management system at
the Rovno nuclear power plant is similar to that at
the Zaporozhe nuclear power plant. Liquidradioactive waste processing at the Rovno nuclear
power plant includes pretreatment, evaporation andbituminization. The procedure for solid radioactive
waste treatment includes sorting the waste followed
by on-site storage. Table 5.17 shows the reduction in
waste volumes with time due to implementation of
the waste minimization programme at the Rovno
nuclear power plant.
Waste minimization initiatives have included
improvement of existing systems and installation ofa bituminization plant and a facility to immobilize
evaporated salts in a bitumen matrix. There areplans for a new facility for sorting, drying andcompacting solid waste, and another forevaporation of liquid radioactive waste to dryness.
At the beginning of 2002 the accumulated volumesof radioactive waste were estimated as 3838 m3 ofsolid waste and 6216 m3 of liquid waste.
The previous waste management programme
expired in 2001 and a new programme is being
developed that will take into account the operationof the fourth reactor at the Rovno nuclear power
plant.
The safe storage of spent fuel remains animportant issue at the Rovno nuclear power plant as
at other sites in Ukraine. Previously the spent fuelwas exported to the Russian Federation. The designof a temporary storage facility for spent fuel iscurrently under development.
5.7.2.3. Khmelnitski nuclear power plant
Waste management operations at the
Khmelnitski nuclear power plant include sorting,purification and evaporation of liquid waste to forma salt mixture. The conditioned waste is stored on
the site.
A radioactive waste management programme
was implemented from 1998 to 2001. Table 5.18

TABLE 5.18. VOLUME OF RADIOACTIVE WASTE (m3)
PRODUCED AT THE KHMELNITSKI NUCLEAR POWER
PLANT DURING THE PERIOD OF IMPLEMENTATION OF
THE WASTE MINIMIZATION PROGRAMME (1998–2001)
Liquid waste

Solid waste

1998

140

196

1999

114

184

2000

158

204

2001

98

175

83

shows the trend in waste volumes over this period.
The lowest waste volumes were achieved in the final
year of the programme. The National Nuclear
Regulatory Body of Ukraine has approved thewaste management action plan for 2002.
At the beginning of 2002 the accumulated
volumes of radioactive waste were estimated as
3363 m3 of solid waste and 530 m3 of liquid waste.
The capacity of storage facilities at the
Khmelnitski nuclear power plant is currently
stretched; for example, five of the six tanks in use forstorage of the highest category solid radioactive
waste are full. New facilities for the temporarystorage of spent fuel are under development.

5.8. OVERVIEW OF SAFETY ANALYSESPERFORMED FOR
NUCLEAR REACTORS
5.8.1.

Russian Federation

The first efforts to assess the safety of theSmolensk and Kursk nuclear power plants weremade during the phase of preparing the environmental impact assessment. The environmental
impact assessment analyses all impacts of significance, including releases of radioactive substances
during normal operation and in the event of design
and BDB accidents.
Since 1990 all industrial facilities, including
nuclear power plants, have been obliged to have anenvironmental ‘passport’ approved by the USSR
Goscompriroda or, after the collapse of the USSR,
the Russian Ministry of Natural Resources (Minpriroda). The environmental passport includes, interalia, a brief description of the facility and its
location, data on actual (including emergency) andmaximum permissible discharges and releases to theenvironment (all media), and information on water
treatment facilities and quantities and methods ofwaste storage. When modifications are made totechnology, equipment, standards, etc., appropriatechanges are made in the environmental passport.
As part of the regulatory licensing regime
described above, the operators of nuclear facilities
must also provide a written SAR in order to justify
construction, operation or continuation ofoperations. The scope and content of thesesubmissions are outlined in a regulatory guideissued by Gosatomnadzor. This guide has been
recently amended and the current requirements on
the content and format of the SARs in the Russian
84

Federation are in line with best international
practice.
Over the last few years a programme of SAR
production/enhancement has taken place to thepoint where the expectation is that a fully
developed safety report or justification for eachreactor unit will be provided, the content and scopeof which should meet Gosatomnadzor requirements
and international standards.
Specifically, for the first generation RBMK
plants, which did not have a modern SAR, an ‘indepth safety assessment’ (IDSA) was required,primarily within the scope of the European Bankfor Reconstruction and Development (EBRD)
activities in support of nuclear safety improvementsin eastern Europe. The aim of the IDSA is toprovide the operator and the regulator with acomprehensive analysis on which safety decisions,such as continued plant operation and the need forfurther plant safety upgrades, can be based. Most of
the IDSAs have now been completed, or are
nearing completion for the older designs of nuclear
power plant.
As mentioned in Section 5.3.1, at the Kursk
nuclear power plant two of the reactor units are of
the first generation and two are of the second
generation. An IDSA was completed for unit 1 in
2000. This was the first IDSA for an RBMK in the
Russian Federation. The accident analyses
performed within the scope of this assessment
justified the new design basis for the plant, which
has been extended to cover primary pipe breaks up
to 300 mm. A number of BDB and severe accidents
have also been considered, and measures toimprove accident management have been
elaborated. The impact on safety of all safety
improvement measures implemented at the site has
been evaluated. The report has been reviewed by
the regulatory body and amended to take accountof its comments. In the preparation of the IDSA
report for Kursk nuclear power plant unit 2, therelevant experience gained at Kursk 1 is being taken
into account.
The first version of the PSA for Kursk 1,
which considers internal initiators during normal
power operation, has also been recently
completed. The preliminary results show that the
expected core damage frequency might be in therange of 6.0 × 10–5, but it is understood that the
study needs to be revised and completed before
taking any safety related decisions.
The unit 2 IDSA is planned for completion by
the end of 2003. Units 3 and 4 have a basic SAR.

TABLE 5.19. ESTIMATES OF EXTERNAL RADIATION DOSESTO THE CRITICAL POPULATION GROUP FOR DESIGN AND
BEYOND DESIGN BASIS ACCIDENTS AT THE FIFTH UNIT OF
THE KURSK NUCLEAR POWER PLANT
Radiation dose for the whole body (mSv/a)
From plume

From soil surface

Design

0.15

0.08

BDB

0.65

0.24

special protection measures, even in the event of a
BDB accident.
The report of ISTC Project 503 [5.23] provides
a review of models for the transport of radionuclides in the accident confinement systems(ACSs) and their release to the environment.
Analysis of ACSs was performed for units 1–3 of theSmolensk nuclear power plant. Assessments havebeen made for releases of radionuclides from ACSs
to the environment under different scenarios ofaccident evolution, involving rupture of thepressure header in the event of loss of tightness in
10% and 100% of fuel elements.

However, work is planned to enhance the scope ofthe safety analyses for these units to also include a
PSA by the end of 2005.
At the Smolensk nuclear power plant thethree units are of the second generation and have
had basic SARs for some years. However, as for
Kursk units 3 and 4, a programme is in place toenhance the safety analyses to include a PSA by theend of 2005.
In the meantime, all nuclear power plants
annually submit a report on operational safety toGosatomnadzor. The scope of these reports is set
out in guidelines jointly produced by Gosatomnadzor and Minatom. The annual assessments
check on plant physical condition, report on
progress with modification programmes, review
operational experience feedback and identify any
additional measures to improve operational safety
in the forthcoming year.
In Ref. [5.22] the dose rates to the critical
population group resulting from design and BDB
accidents at the fifth unit of the Kursk nuclear
power plant (then under construction) are
estimated. The critical group was the residents of
the western edge of the town of Kurchatov, lying
3 km from the plant. The derived estimates arepresented in Tables 5.19 and 5.20. The doses to thecritical population group do not necessitate any

5.8.2.

UkraineFor each of the nuclear plants in Ukraine, abasic SAR (hereafter referred to as a safety
substantiation report) exists. These reports now
form the basis on which the SNRCU grants annual
permits for continued operation of the units. The
safety substantiation report includes an analysis of anumber of anticipated operational occurrences and
DBAs that have been considered in the justificationof plant design safety and in development of thedesign operating limits and conditions. This substantiation report stipulates the fulfilment of the safety
standards and codes that are effective at the time ofdevelopment of the document.

TABLE 5.20. ESTIMATES OF DOSES TO THE CRITICALPOPULATION GROUP VIA INHALATION FOR DESIGN AND
BEYOND DESIGN BASIS ACCIDENTS AT THE FIFTH UNIT OF
THE KURSK NUCLEAR POWER PLANT
Radiation dose for organs (mSv/a)
GonadsLungs

Thyroid

Design

0.10

0.11

18

BDB

0.28

3

21

85

Over the past few years Energoatom and thenuclear power plants have devoted considerable
effort to reassessing the safety of the units inoperation in order to comply with the SNRCU’s
requirements for the development of comprehensive SARs. A programme has been established
for the gradual completion of the work andsubmission to the SNRCU of all the documents
needed to obtain a permanent licence in accordancewith the new regulatory body licensing policy.
The strategy of the safety reassessment isfocused on combining a periodic safety review by
the end of a specified date with an IDSA using
modern analysis techniques (such as probabilistic
safety analysis and BDB accident analysis). Thissafety reassessment is being undertaken now for
three reference units, representing each of the three
types of reactor in operation. These are:
(a)
(b)
(c)

Zaporozhe unit 5, WWER-1000 (B-320), large
series;South Ukraine unit 1, WWER-1000 (B-302),
small series;
Rovno unit 1, WWER-440 (B-213).

In accordance with the SNRCU’s regulation,at the first stage of a safety reassessment theanalysis should contain an extended (supplementary to the original design) safety substantiation
report, additional material on safety analysis related
to the evaluation of operational safety and ageing
mechanisms and a new design basis analysis andprobabilistic safety analyses at level 1 for internal
initiators at nominal power. Based on the results ofthese analyses, the SNRCU will take a decision as towhether to grant a permanent licence for each of
the plants and will set up the priorities for further
nuclear power plant safety improvements.
During the second stage of the safety
reassessment, the PSA analysis at level 1 should becomplemented with analyses for external initiators
and a low power and shutdown PSA. It is planned
also to perform level 2 PSAs and BDB accident
analyses, which will allow completion of theevaluation and preparation of comprehensive SARs
in accordance with best international practice.
The first part of the safety reassessment forSouth Ukraine 1 and Rovno 1 has recently been
completed and submitted to the regulatory body.
The work for completion of that for Zaporozhe 5 isalso at an advanced stage. Similar analyses will be
performed for the remaining units; however, it isunderstood that their scope will be limited to86

consideration of the differences between thereference plant and each individual plant.
The results of the first versions of the PSAlevel 1 studies for the South Ukraine 1, Zaporozhe 5
and Rovno 1 units are in line with the results for
similar types of nuclear power plant in othercountries, and the estimated core damage frequency
is reported to be 1.5 × 10–4, 4.5 × 10–5 and 8.1 × 10–5,
respectively. The iterative process adopted by theregulatory body for the review of these studies isscheduled for completion by the end of 2002.
The second part of the safety reassessment for
the reference plants is expected to be ongoing until
the end of 2003/2004. Once completed, results fromsevere accident analyses and PSA level 2 studies canserve as a basis for improvement of the accident
management guidelines and emergency preparedness for the nuclear power plants in the Dnieper
River basin.
For future construction work and commissioning of the new units at Khmelnitski and Rovno,
the preparation of a comprehensive SAR, in
accordance with best international practice, isenvisaged.

5.9. STATUS OF THE IMPLEMENTATION OF
SAFETY IMPROVEMENTPROGRAMMES FOR
NUCLEAR FACILITIES
5.9.1.

Russian Federation

After the Chernobyl accident an improvement
programme began for the RBMK reactors. The
most urgent safety improvements required for the
first generation RBMKs were completed in 1986 to
exclude the possibility of another accident like thatat Chernobyl [5.4, 5.24]. There are six RBMK units
in total: Leningrad units 1 and 2, Kursk units 1 and 2
and Chernobyl units 1 and 2 (now closed down).
Some further general improvements have been
completed but others remain to be implemented.
The first stage of modernization took place in the
1990s. The second stage of modernization is
ongoing.
The urgent measures were carried out toimprove both the inherent behaviour of the reactor
and operational safety. In particular, the following
measures were implemented:(a)Increased enrichment of theincreased neutron absorbers;

fuel

and

(b)

(c)

(d)
(e)
(f)

Reduction of the positive void effect byimproving reliability of the water supply of thecontrol and protection system (CPS) cooling
circuit and reducing the water volume within
the core part of the CPS circuit;
Improvement of the efficiency and reliabilityof the CPS by modifying the design of thecontrol rods, increasing the worth and the
speed of the shutdown system, andimprovement of the monitoring of theoperational reactivity margin (ORM);
Monitoring of the margin of the main coolingpump cavitations;
Implementation of improved in-service
inspection of pipes and components;
Improvement of operational documentation.

Following the urgent upgrading programme,
the first stage of modernization was performed in
the middle and late 1990s; some of it is still ongoing.
Where necessary this included replacement of thefuel channels to avoid closure of the gap between
the channels and the surrounding graphite. In
particular, the following measures were taken:
(a)

(b)

(c)

(d)

Enhancment of the pressure boundary
integrity by:(i) Replacement of some reactor coolant
circuit pressure components;(ii) Increased in-service inspection of themain coolant components.
Improvement of the load bearing capability ofthe building structure by improving thereactor cavity venting system (simultaneous
rupture of about nine fuel channels).
Enhancement of the core structure andcontrol and shutdown systems:(i) Introduction of uranium–erbium fuel;(ii) Introduction of 12 additional CPS manualrods as a shutdown system backup;(iii) Replacement of CPS drives and flux
distribution monitoring (high frequency
sensors);(iv) Interlock
systemstoprevent
unauthorized withdrawal of CPS rods.
Improvement of emergency core cooling:(i) Two additional emergency feedwater
pumps for the emergency core coolingsystem (ECCS-1) (first generation
nuclear power plants);(ii) Possibility of emergency makeup of themain cooling circuit by service and firefighting water.

(e)

Installation of a temporary emergency control
panel (as a preliminary solution for the
emergency control room).

At present, the safety of nuclear installationsin the Russian Federation is being improved inaccordance with the programme of development of
atomic energy in the Russian Federation in 1998–
2005 and to 2010 (Decree of the Government of theRussian Federation of 21 July 1998) and the federal
targeted programme on nuclear and radiation safety
in the Russian Federation (Decree of theGovernment of the Russian Federation 149 of
22 February 2000). Within the last programme, in
2000–2001, a number of research institutions andother organizations further developed the scientific,
normative, methodological and organizationalframework. It is envisaged that in the second stage(2002–2003) all subunits of the programme will be
performed in a consistent way. In the final stage(2004–2006) the key tasks will be implemented andfuture activities will be identified. Specifically, thesection on nuclear installations and facilities ofradiation hazard provides for the following
activities:
(a)

(b)

(c)

(d)

(e)

(f)
(g)

Improving the quality of maintenance andrepair of the equipment of nuclear power
plants;Setting up systems for warning and mitigationof emergencies at nuclear power plants andothernuclearinstallations,
includingemergency centres and consulting andresearch centres;
Enhancing the logistical and organizationalbase of the emergency rescue units of Minatom
to improve preparedness for emergencies;
Conducting research and design activities toimprove the nuclear and radiation safety offuel cycle activities in the nuclear industry
using fast breeder reactors;
Development and adoption of guidelines andtraining aids, including full scale simulators intraining centres at nuclear power plants;
Updating
technologies
forhandling
radioactive waste and spent nuclear fuel;Setting up disposal sites and storage facilities
for radioactive waste and spent nuclear fuel.

A second stage of modernization is being
undertaken in order to bring the state of RBMKs
into compliance with the current requirements.
Where applicable this includes:
87

(a)

Integrated instrumentation for monitoring,
control and protection of the reactor with two
redundant and diverse trains.
(b) ECCS with two redundant trains, one
upgraded and one new (ECCS-2).
(c) A physically separated and protected
emergency building to house an emergency
control room (from where reactor shutdown
and core cooling can be controlled).
(d) Completion of the ACOTT leak detection
system with three diverse types of sensor train(one measure of the leak before breakconcept, which should compensate for thelimited cooling and load bearing capability,
since the first generation of nuclear power
plants can not sustain pipe ruptures larger
than 300 mm).
(e) Introduction of a confinement safety system
activated at fuel channel rupture.
(f) Introduction of a reactor protection trip signal
caused by a group distributor header (GDH)
flow rate decrease.
(g) Implementation/replacement of GDH checkvalves.
(h) Installation of a modern operational
information support system (SKALA);(i) Introduction of an automated radiation
monitoring system (ASKRO).
(j) Upgrade of the service water system.
(k) Introduction of a bypass pipe between thereactor coolant pump pressure header and theECCS.
(l) Upgrade of the drum separators.
(m) Upgrade of the AC/DC emergency power
supply.
(n) Upgrade of fire protection, for example
replacement of flammable turbine hall roof
lagging.
(o) Improvement in the area of operational safety
by restructuring of the nuclear power plant
management and improvements in training,
including simulator training.
Further planned improvements will take into
account operational experience feedback andrecommendations of the updated SAR and plant
specific PSA.
Emphasis will be given to further enhancements at all levels of the defence in depth safetyconcept, in order to compensate for the absence of afull containment (especially for nuclear power
plants of the first generation). Furthermore, work
will include the enhancement of emergency
88

operating procedures (and development of asymptom based emergency operating procedure(EOP) and accident management guidelines) andthe introduction of a systematic ageing management
programme.
The additional planned improvements will be
influenced by any decision on possible life extensionof the reactors to more than 30 years, which was theoriginal design life.
Table 5.21 summarizes the current status of
implementation of the main safety upgrades for theRussian reactors. The table has been preparedbased on the available information and may not be
fully up to date.
A series of actions are also under way tofurther protect the public and operating personnel
at nuclear power plants. These measures areespecially important for the Kursk and Smolensk
nuclear power plants, as the personnel exposures atplants with RBMK reactors are twice as high as atother Russian nuclear power plants. The personnel
exposure levels will be reduced through thefollowing initiatives:
(a)
(b)
(c)

Organizational actions including study andapplication of the ALARA concept;
Measures to improve the radiation situation;
Measures to reduce the time spent by
personnel in ionizing radiation fields.

A comparative analysis of personnel exposure
at the Kursk and Smolensk nuclear power plants
over many years indicates that organizational
improvements only are possible at the Kursk
nuclear power plant, whereas at the Smolensk
nuclear power plant technical changes are needed.
Some technical changes are proceeding, in spite oflimited funding. In particular, a series of remote
automated instruments has been developed formaintaining the RBMK-1000 reactors operating at
the Kursk and Smolensk nuclear power plants.
One of the important activities within thefederal law section Protection of the Population,
Rehabilitation of Contaminated Areas andMonitoring of the Radiation Situation is technicaland organizational support for the federal
automated system for monitoring the radiation
situation (ASKRO) (see Section 5.5.1). At present,
there are 14 stations for automated monitoring of
the dose rate around the Smolensk nuclear power
plant and 11 stations around the Kursk nuclear
power plant. The ASKRO for the Kursk nuclear
power plant began operation on a test basis in 2002.

TABLE 5.21. SUMMARY OF THE STATUS OF THE MAIN SAFETY UPGRADES FOR THE KURSK AND
SMOLENSK NUCLEAR POWER PLANTS
Improvement measure

Kursk

Smolensk

1

2

3

4

1

2

3

New fuel (enrichment, erbium asburnable absorber)

P

P

P

P

—

—

—

CPS channel and coolingmodifications

Y

—

—

—

—

—

—

Modification of control rods andspeed of insertion

Y

Y

Y

Y

Y

Y

Y

Interlock to prevent unauthorized
control rod withdrawal

Y

—

a

a

Y

Y

Y

Monitoring of ORM

Y

Y

Y

Y

Y

Y

Y

Addition of fast acting shutdown
system

Y

Y

Y

Y

Y

Y

Y

Redundant, diverse and physicallyseparated shutdown system

Y

—

—

—

—

—

—

Reactor protection signal caused by
GDH flow rate decrease

Y

—

—

—

—

—

—

Replacement of fuel channels(channel–graphite gaps)

Y

Y

P/2002

P/2003

P/2002

P/2006

P/2010Capacity of reactor cavity venting
system (simultaneous rupture ofabout nine channels)

Y

—

Y

Y

Y

Y

Y

Bubble condenser for ALS (first
generation)

Y—

Inspection of intergranular stresscorrosion of lower water lines

Y

Y

Upgrading of existing ECCS

Y—

Included in the original design

Redundant and physically separated
ECCS

Y

—

Included in the original design

Steam drum modification toincrease water inventory for
emergency coolingY—

Water volume is enlarged by design

Implementation of check valve ingroup distribution headers

Y

2002

Y

Y

Y

Y

Y

Emergency control room

Y

—

a

a

a

a

a

Upgrade of AC/DC emergency
power supply

Y

—

a

a

a

a

a

SKALA-micro (modernized
operational information support
system)

Y

—

—

—

—

—

—

ACOTT leak detection system(leak before break concept)

Y

—

a

a

a

a

a

Introduction of ASKRO
automated radiation monitoring
system

Y

—

—

—

—

—

—

Significant upgrading of fire
protection

Y

P

P

P

P

P

P

Included in the original design
Y

Y

Y

Y

Y

89

TABLE 5.21. SUMMARY OF THE STATUS OF THE MAIN SAFETY UPGRADES FOR THE KURSK AND
SMOLENSK NUCLEAR POWER PLANTS (cont.)
Improvement measure

Kursk

Smolensk

1

2

3

4

1

2

3

Improvement in operator training
and licensing

Y

Y

Y

Y

Y

Y

Y

Full scope simulator

—

—

Y

Y

Y

Y

Y

Status of IDSA

P

—

TOB

TOB

TOB

TOB

TOB

Plant specific PSA

June 2003

—

—

—

—

—

Issue and expiry date of theoperational licence

October
2000–
October
2003

April
2002–
April
2003

November
1999–
November
2003

November
1999–
November
2003

February
January
1999–
1999–
December January 2004
2003—
January
2002–
April
2007

a

Information on the implementation status not publicly available.
Y: Implemented.
P: Partly implemented.
TOB: Technical substantiation of safety (basic SAR).
—: No.

5.9.2.

UkraineA design review of the second generation
WWER reactors did not identify any safety
deficiencies of the highest significance (as, forexample, were found for the first generation
reactors). Safety improvements, however, havebeen made to these plants in relation to:
(a)
(b)

(c)
(d)

Control rod insertion reliability;
Prevention of containment sump filter
clogging (to ensure recirculation of the ECCS
in the event of a loss of coolant accident(LOCA));
Reliability of overpressure protection devices;
Capacity of accumulator batteries.

There are several other issues that require
resolution, and measures to address these are still
under way. These issues include, inter alia, thefollowing:(i)

Quality and reliability of individual safety
related equipment (e.g. instrumentation andcontrol);(ii) Reactor pressure vessel embrittlement;(iii) Steam generator integrity (protection against
primary to secondary leaks);(iv) Vulnerability with regard to hazardous
systems interactions, including protection

90

against common cause failures (e.g. highenergy pipe breaks, fire and internal flooding);(v) Monitoring for vibration and water leaks;(vi) Control room design in conjunction withaccident monitoring equipment;(vii) Installation of a safety parameter display
system in order to provide the most relevant
information on critical safety parameters
under accident conditions.
At present, an international IDSA process isunder way to optimize improvement programmes.
Further analyses are being carried out in relation to:— Design criteria of containment integrity
assessment for simultaneous occurrence of alarge break LOCA and an earthquake;— Periodicity of and methods for containment
integrity and tightness tests;— Stability of reactor pressure vessel internals in
the event of a large break LOCA;— Estimated frequency and size of large steam
generator collector leaks and the possible
impact on pipes and supports of dynamic
loads;— Total loss of service water (input and resultsfrom PSAs);— Extreme natural phenomena and an aircraft
crash;— Integrity of the suction line of the ECCS.

Feedback of operating experience is a major
contributory factor to the development of improved
plant safety. The most important sources for
feedback of experience are abnormal occurrencesand deficiencies revealed during operation, as well
as experience gained from maintenance andinspection activities.
Table 5.22 summarizes the current status of
implementation of the main safety upgrades for
Ukrainian reactors. The table has been preparedbased on the available information and may not be
fully up to date.
5.9.3.

Emergency preparedness and response

The Chernobyl accident demonstrated theneed for the development and constantmaintenance of systems for emergency preparedness and response.
The systems for emergency preparedness andresponse in the Ukrainian and Russian nuclear
power plants are based on IAEA recommendations[5.25–5.27] (i.e. they include a set of technical andorganizational measures). The State Committee of
Nuclear Regulation of Ukraine and Goskomnadzor
in the Russian Federation control the levels of a
nuclear power plant’s emergency preparedness.
Special procedures define the interaction of thenuclear power plant’s emergency units with theregional branches of the Ministries of Emergencies
in the Russian Federation and Ukraine forpopulation protection in the event of an emergency.
Specialized drills and exercises for the emergency
units of nuclear power plants and their interaction
with the emergency units of other institutions are
performed on a regular basis. Information crisis
centres with various levels of equipment andtelecommunications exist at the SCNRU,
Goskomatomnadzor, the Ministries of Emergenciesof Ukraine and the Russian Federation,
Energoatom in Ukraine and Rosenergoatom.
In Ukraine all measures for emergency
preparedness and response are integrated into the
Uniform State System for Prevention and Response
to Man-induced and Natural Emergencies (USSE).
In 2001 a plan of response to State levelemergencies was developed by the Ministry of
Emergencies and approved by Resolution No. 1567
of the Cabinet of Ministers of Ukraine [5.28]. The
plan specifies the performance of work to mitigate
the consequences of any human-made or natural
emergency, the responsibilities of the various

control authorities and the required financial,material and other resources. The development of a
specific plan for nuclear and radiation accidents wasapproved by Resolution No. 122 of the Cabinet of
Ministers of Ukraine. The plan will be developed
taking into account recommendations of the IAEA
[5.29].
The technical bases for emergency response
are monitoring systems around nuclear power
plants. Each plant has its own system of automatic
control of radioactive contamination in the 30 km
zone (ASKRO) as well as systems for monitoring
releases from the stacks. In Ukraine, with thesupport of the European Commission, and within
the framework of the Technical Assistance toCommonwealth of Independent States (TACIS)
programme, the early warning system GAMMA-1
was developed around the Zaporozhe and Rovno
nuclear power plants. The information fromGAMMA-1 is transmitted to the emergency centresof the Ministry of the Environment of Ukraine andMinistry of Emergencies of Ukraine, with
duplication to the SCNRU.
Each nuclear power plant uses computercodes for the simulation of atmospheric dispersionof radionuclides after atmospheric releases. A realtime, on-line decision support system (RECASS)
was developed by SPA Typhoon and is under implementation now for the Kursk and Smolensk nuclear
power plants. In Ukraine a real time, on-line
decision support system for off-site nuclear
emergency
management(RODOS)
was
implemented in 2002. It was customized for the
Zaporozhe nuclear power plant site and linked withGAMMA-1 and the system of real time meteorological forecasting. In Belarus, RODOS has beenused in the off-line mode to simulate fallout on
Belarusian territory from an accidental release fromthe Ignalina nuclear power plant.
Strengthening of the system of emergency
response in all countries requires further
development of the automatic monitoring (early
warning) systems around each nuclear power plantand further development of the real time decision
support system for off-site emergency management.
The decision support system should include
modules for forecasting post-accident contamination of water bodies after accident fallout or
direct releases into water. The system for
information exchange between nuclear power plant
emergency units and regional authorities should be
improved.

91

TABLE 5.22. SUMMARY OF THE STATUS OF THE MAIN SAFETY UPGRADES FOR UKRAINIAN
NUCLEAR POWER PLANTS
ZaporozheSouth Ukraine

Khmelnitski

Rovno

Improvement measure
1

2

3

4

5

6

1

2

3

1

3

1

2

Control rod insertion reliability

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

n.a. n.a.

Prevention of sump filter
clogging

—

—

—

—

—

—

P

—

P

—

—

P

P

Reliability of overpressure
protection devices

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Equipment qualification (e.g.
instrumentation and control)

A programme for equipment qualification has been prepared by Energoatom; work to be
implemented in the near future for each of the units

Reactor pressure vessel
embrittlement (monitoring,measures)

P

P

P

P

P

P

P

P

P

P

P

n.a. n.a.

Heating system

—

—

—

—

—

—

P

P

P

Y

Y

Y

Y

Steam generator integrity

P

P

P

P

P

P

P

P

P

P

P

P

P

Safety analyses are in progress to evaluate the necessity of additional plant upgrades

28.8 m (14.7 m for WWER-440)
platform; vulnerability withregard to hazardous systems
interactions; high energy pipe
breaksModification of feedwater supply
system

P

P

P

P

P

P

P

Y

—

—

Y

P

P

Upgrade of emergency power
supply

Y

P

P

P

P

P

P

P

P

P

P

P

P

Significant upgrading of fire
protection

Y

Y

Y

Y

Y

Y

P

P

P

P

Y

P

P

Leak detection system (leakbefore break concept)

—

—

—

—

—

—

—

—

—

—

P

—

P

Introduction of automatedradiation monitoring system

P

P

P

P

P

P

P

P

P

P

P

P

P

Installation of a safety parameter
display system (SPDS)

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Ageing management (fatigue
monitoring)

P

P

P

P

P

P

P

P

P

P

P

P

P

Symptom based EOP

—

—

P

—

P

—

P

—

—

—

P

—

—

Full scope simulator

Y

P

—

—

—

—

Y

—

Y

Y

Y

P

—

Severe accident guidelines

—

—

—

—

—

P

P

—

—

P

P

—

—

First stage

—

—

—

—

P

—

Y

—

—

—

—

Y

—

Second stage

—

—

—

—

2004

—

2004

—

—

—

—

2005 —

Plant specific PSA

—

—

—

—

Y

—

Y

—

P

P

Y

Y

Status of safety reassessment

Issue and expiry date of theoperational licence
Y: Implemented.
P: Partly implemented.
n/a: Not applicable.
—: No.

92

Issued on an annual basis—

5.10. CONCLUSIONS

5.11. RECOMMENDATIONS

(a)

(a)

(b)

(c)

(d)

(e)

(f)

(g)

The Russian and Ukrainian legislation affirms
the priority of human health and environmental protection in the context of theoperation of nuclear installations.
A legislative and regulatory basis establishedin both the Russian Federation and Ukraine
ensures that all nuclear power plants operatewith a valid licence. A legal mechanism exists
for regulatory body review and assessment ofplant safety and renewal of plant licences on aregular basis.
In the Dnieper Basin within the RussianFederation there are two nuclear power plants
in operation. They comprise seven reactor
units of the RBMK type. Following theChernobyl
accident,
modernization
programmes have been put in place that havesignificantly increased the safety of thesereactors.
In Ukraine there are 13 WWER units inoperation, of which ten are in the Dnieper
River basin. These reactors belong to thecommon PWR type. Significant improvements
have been made to these reactors and areongoing.
During normal operation the radioactive
emissions from the reactors in the Dnieper
River basin represent a small fraction of theauthorized discharge limits. The contributionof these emissions to the atmosphericradioactive burden and to the aquatic
environment are negligible for the Dnieper
River basin.
For potential severe accidents, a set of intervention criteria that are consistent with the
Basic Safety Standards [5.19] and the relevant
ICRP recommendations [5.30] has been
established by the countries of the region.
Over the past few years considerable effort
has been made to complete the IDSA forreference units, covering all types of thereactors operating in the river basin. This
assessment includes analyses of DBAs and
BDB and severe accidents, as well as PSAs.
These studies have been performed inaccordance with current international
practice.

(b)

(c)

(d)

(e)

(f)

Rules and regulations governing the safety ofthe operation of nuclear power plants should
be further developed with a view toharmonizing them within the Dnieper Riverbasin region, consistent with international
practice and the standards of the IAEA.
Cooperation and information exchange
between regulatory organizations should be
strengthened to make use of the experience
gained in implementing the safety upgrading
programmes and lessons learned fromoperating experience.
The scope of SARs for each of the nuclear
power plants should be in compliance with
the national requirements and be consistent
with the IAEA safety standards and current
international practices. The experience gained
in developing the assessments for thereference units should serve in future as asound basis for these reports. It would bedesirable to exchange information on the
results.
Comprehensive, plant specific PSAs should be
finalized for all nuclear power plants in theregion and subjected to thorough regulatory
review. This would provide the basis to usethem for identifying priorities for safety
improvements and risk informed decision
making. The countries could benefit fromparticipation in the activities organized byinternational organizations such as the IAEA
on comparison of PSA studies for similar
reactors.
To improve preparedness for a possible
nuclear accident, technical measures (early
warning systems, decision support systems),
institutional measures (logistics) and links
between nuclear power plants and regional
administrative units should be improved.
Plans established for safety improvements
should be carried out as a matter of highpriority. Exchange of experience in implementing safety improvement programmes for
similar plants will help to harmonize the levelof safety in the region and minimize thepotential for radioactive releases fromoperational nuclear power plants.

93

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[5.3] VISHNEVSKIY, V., River and Water Bodies of
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Accident (Bryanskaya Oblast), Rep. RUS/95/004,
UNDP, Moscow (2001).
DROVNIKOV, V.V., et al., “Radionuclides inecosystem components of the Kursk NPP coolingpond”, Ecology of the Regions of Nuclear Power
Plants, Atomenergoproekt, No. 4 M (1995) 295–
320 (in Russian).
FOOD AND AGRICULTURE ORGANIZATIONOF
THE
UNITEDNATIONS,INTERNATIONALATOMICENERGYAGENCY,INTERNATIONALLABOURORGANISATION,OECD
NUCLEAR
ENERGY AGENCY, PAN AMERICANHEALTHORGANIZATION,WORLDHEALTH ORGANIZATION, International
Basic Safety Standards for Protection against
Ionizing Radiation and for the Safety of Radiation
Sources, Safety Series No. 115, IAEA, Vienna(1996).
DAVYDENKO, N., NPP closure, spent fuel andradioactive waste management, Bull. Rosenergoatom 32 8 (2002) 8–11 (in Russian).
KOZLOV, Y.V., SAFUTIN, V.D., TIKHONOV,
P.S., TOKARENKO, A.I., SPICHEV, V.V., Longterm storage and transportation of spent nuclear
fuel, At. Ehnerg. 89 (2000) 273–284 (in Russian).
EGOROV, Y.A., RYABOV, S.E., CHIONOV,
V.G., “Doses for population in vicinity of Kursk
NPP”, Ecology of the Regions of Nuclear Power
Plants, Atomenergoproekt, No. 5 M (1996) 31–43(in Russian).
INTERNATIONAL SCIENCE AND TECHNOLOGY CENTER, WWR-K Conversion,
Project K-503, ISTC, Moscow (2002).
GALICH, V., Russian NPPs are among the safest
in the world, Bull. At. Energy, No. 3–4 (2001) 17–
22 (in Russian).
INTERNATIONALATOMICENERGYAGENCY, Method for the Development ofEmergency Response Preparedness for Nuclear orRadiological Accidents, IAEA-TECDOC-953,
IAEA, Vienna (1997).
INTERNATIONALATOMICENERGYAGENCY, Generic Assessment Procedures for
Determining Protective Actions During a Reactor
Accident, IAEA-TECDOC-955, IAEA, Vienna(1997).

[5.27] INTERNATIONALATOMICENERGYAGENCY, Generic Procedures for Monitoring ina Nuclear or Radiological Emergency, IAEATECDOC-1092, IAEA, Vienna (1999).
[5.28] Nuclear and Radiation Safety in Ukraine: Annual
Report 2001, State Nuclear Regulatory Committeeof Ukraine, Kiev (2002) (in Ukrainian).
[5.29] INTERNATIONALATOMICENERGYAGENCY, Method for Developing Arrangements
for Response to a Nuclear or Radiological

Emergency, EPR-METHOD (2003), Updating
IAEA-TECDOC-953, IAEA, Vienna (2003).
[5.30] INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION, Principles forIntervention for Protection of the Public in a
Radiological
Emergency,
Publication
63,
Pergamon Press, Oxford and New York (1993).

95

6. URANIUM MINING AND ORE PROCESSING
6.1. SCOPE
This section reviews the environmental impactof uranium mining and ore processing in Ukraine.
Particular attention is given to the management ofmill tailings, releases from current and former
plants, and data available on contamination ofwater bodies within the Dnieper River basin.
Radiation exposure of the public via water-borne
pathways is discussed in Section 8 and uranium
facilities are assessed as radiological hot spots in
Section 9.

6.2. OVERVIEW OF URANIUM MINING
AND PROCESSING IN THE DNIEPER
RIVER BASIN
As noted in Section 3, the only uranium
mining and ore processing in the Dnieper Riverbasin is in Ukraine. Uranium exploration started in1944 and led to the discovery of the Pervomayskaya
deposit in 1945 and the Zheltorechenskoye deposit
in 1946. Other ore bodies were subsequently
discovered within the boundaries of the
Kirovograd, Dnipropetrovsk and Nikolaev regions.
Figure 6.1 shows the 21 uranium deposits
discovered in Ukraine [6.1]. The largest deposits are
Severinskoye, Michurinskoye and Vatutinskoye.
Uranium was first produced in Ukraine at the
Prydniprovsky chemical plant, which was part of alarge industrial complex on the shores of the
Dnieper River in Dniprodzerzhinsk. From 1948
until its closure in 1991, about 42 × 106 t of uranium
tailings and other radioactive waste was generated.
The Zhovti Vody hydrometallurgical plant has
processed ores from southern Ukraine since 1959. It
is located at a former iron ore production site near
the centre of Ukraine’s main uranium province andis operated by the Eastern Mining and Concentrating Mill (VostGOK). The design capacity of themill is 1 × 106 t of ore per year, but in recent years it
has been operating at about 50% capacity.
Currently, most of the production comes from theIngulsky mine developed on the Michurinskoye
deposit. There is also a small amount of production
from the Smolino mine developed on the Vatutinskoye deposit. Ore from the Ingulsky and Smolino

96

mines is hauled to the mill at Zhovti Vody bydedicated trains [6.2].
There are proposals to mine the Severinskoye
deposit, which has reserves of 64 000 t U at an
average grade of 0.1%. Doubling of the capacity ofthe Zhovti Vody plant to 2000 t U/a is also
envisaged [6.2].
Three ore bodies, Bratskoye, Devladovo andSafonovskoye, have been exploited by the in situ
leaching method. This involves injection ofsulphuric acid and a small amount of nitric acid into
the ore body and pumping the uranium bearing
solution to the surface, where it is recovered. Thisavoids the problems of solid waste management
but, with unfavourable conditions, can result incontamination of groundwater.
The following sections discuss the source
terms arising from the uranium mines and mills insouthern Ukraine.

Ore processing plant- Dniprodzerzhinsk- Kirovohrad- Zhovti Vody
Uranium deposit

FIG. 6.1. Uranium ore deposits and uranium processing
operations
inUkraine[6.1].
1: Vatutinskoye;
2: Severinskoye; 3: Michurinskoye; 4: Zheltorechenskoye;
5: Pervomayskoye; 6: Lozovatskoye; 7: Kalinovskoye;
8: Yuzhnoye; 9: Nikolokozelskoye; 10: Nikolayevskoye;
11: Berekskoye; 12: Krasnooskolskoye; 13: Adamovskoye;
14: Sadovokonstantinovskoye;
15:
Bratskoye;
16:
Safonovskoye;
17: Devladovo;
18: Novogurievskoye;
19: Surskoye; 20: Chervonoyarskoye; 21: Markovskoye.

6.3. SYSTEMS FOR MONITORINGPOLLUTION FROM THE URANIUM
INDUSTRYIn Ukraine monitoring of the environment
around uranium mines and mills is based onstandards developed in the 1970s. Measurements ofradioactive pollution arising from liquid discharges(e.g. mine, drainage and tailings pond water) to nonstagnant receiving waters are carried out twice
yearly in spring and autumn. The location of thesampling points depends on specific conditions, but
typically sampling is carried out at the following
locations:
(a)
(b)
(c)

Above the site of release of liquid waste;
At the site of runoff water release;
Two to four points downstream of the releasesite (at the sites of possible water use, in theregion of settlements, etc.).

Water samples are analysed for uranium,
Ra and total alpha activity. The concentrations ofother radionuclides (230Th, 210Po and 210Pb) aredetermined if the uranium and/or total alphaactivities are above the permissible levels.
Radiation–sanitary monitoring at closed anddecommissioned uranium facilities is carried out
every three years. Reoriented uranium facilities (i.e.
those that formerly processed uranium but now
have different functions) are monitored every five
years. Measurements are made of the radiochemicalcomposition of drainage water and of the water
bodies that receive the water.
After cessation of uranium processing, waste
storage/disposal facilities are the responsibility of
new enterprises that are controlled by a speciallyestablished commission that has the power toevaluate and control the condition of the waste
management facilities. The commission is composedof specialists, local authorities and representativesof regulatory bodies.
In accordance with the 1996 government
document Provisions of the State Monitoring of
Waters, monitoring of the quality of surface andunderground waters of the Dnipropetrovsk regionis performed by specified State and regional laboratories. These laboratories perform measurements ofthe content of artificial radionuclides in theenvironment, namely 90Sr and 137Cs, and of total
beta and total alpha activity in drinking water and in
the surface waters of the Dniprodzerzhinsk (lowerpart), Dnieper and Kakhovka (upper part)
226

reservoirs and the tributaries of the Dnieper–Samara, Orel and Ingulets Rivers. The sampling is
performed several times a month, and the reports
are sent monthly to the higher regional authorities.
The Sanitary and Epidemiological Station
No. 8 and the Laboratory for Radiation Control ofIndustrial Enterprises ‘barrier’ monitor the tailingsat the Prydniprovsky chemical plant site and within
the sanitary and protective zones. These laboratories mainly perform routine measurements; there
is no interpretation of the data. Since the actuallevels of contaminants in water do not exceed thesanitary norms permitting unrestricted water use,
no attention is paid to assessments of low levels ofcontamination [6.3–6.6].
The regional administration supports scientificand research work on the ecological and toxicological state of surface waters of the region where
ecological hazards are greatest. The administration
also develops recommendations on minimization of
any negative impacts (particularly from tailings at
the former Prydniprovsky chemical plant site —Dniprovske D and Sukhachevskoye C).
Following a government decision in 1999, afield programme was developed to improve theradiological condition of uranium facilities and theenvironment in which they are located. The aim of
the programme is to implement State policy onradioactive waste management in uranium
processing in the region. The main aspects of thisprogramme are:(i)

Closure, restoration and temporary shutdown
of uranium facilities, where appropriate;(ii) Development and optimization of regionalradiation monitoring;(iii) Reduction of the harmful impact of uranium
facilities on the environment and humanhealth.
The following tasks are envisaged within theframework of this programme:— Identification of the negative impact ofuranium facilities on the environment;— Assessment of the contamination of theground, water and air;— Calculation of the dose rate to people living inareas affected by uranium facilities;— Determination of the required expenditures
for closure, redirection and temporary
shutdown of uranium facilities;97

— Determination of the expenditure needed for
reduction of the harmful impact of uranium
facilities on the environment;— Determination of the expenditure needed for
performance of radiation monitoring andpublic awareness.
During the first phase of the field programme,
the tasks and priorities were defined, and theadministrative, legislative and financial requirements for their realization elaborated. However,this programme is mainly focused on the problem oftechnological reconstruction and cleanup of thecontaminated areas. Owing to a lack of funds,
implementation of the various tasks has been
postponed and instead efforts are being focused onmonitoring programmes and research related toenvironmental impact assessment of the former
uranium reprocessing plants, tailings and uranium
ore mining, as well as the scientific justification of
the future regional SAP.
All investigations on the effects of tailings andformer sites of underground leaching on the state ofsurface and underground waters in the regions of
their location are provided by the specified Stateand regional laboratories. At present, there is no
routine monitoring of water released from thedecommissioned Pervomayskaya deposit; as aresult, it has not been considered in estimates ofcurrent or potential radiation exposure of the local
population.
The above analysis shows that there is anadequately developed infrastructure for radiation
and radioecological monitoring within the zone ofinfluence of the uranium industry. At the same time,the envisaged programme has not been fully
implemented because of funding problems. Accordingly, the majority of available data is of an episodic,
non-systematic nature and does not facilitate anunderstanding of the temporal trends in environmental data or an assessment of the effects onaquatic ecosystems.

6.4. SOURCES OF POTENTIALCONTAMINATION AT THE
ZHOVTI VODY SITE

mining of iron ore at the Novaya mine is still inprogress.
Figure 6.2 shows the layout of the major
mining operations and the location of waste. The
main sources of radioactive contamination are thethree tailings sites:
(a)
(b)
(c)
6.4.1.

98

Tailings KBZh

Tailings KBZh are located 2 km from thenorthern boundary of the town (see Fig. 6.2) on thedividing plateau between the Zheltaya and
Zelenaya Rivers. The closest settlements are Zhovti
Vody, 2 km to the south, Zeleny Gai in the southwest and Veselo Ivanovka, 1.7 km to the east in thevalley of the Zheltaya River. The site is an old ironore quarry, consisting of a little pit with a depth of
10–15 m and large pit with a depth of 60–65 m. No
measures have been taken to minimize seepage
from the tailings area.
Tailings were deposited at this site from 1964
until 1982 by the method of hydropouring. At
present, most of the tailings surface is covered with
0.4 m of clay to prevent dispersion of tailings dust.
The remainder is a small pond that serves as
emergency storage for the mill. The area of tailings
is 54.8 ha and the total mass of 19 × 106 t of tailings
occupies a volume of 12.4 × 106 m3. The tailings
water has a pH of pH7.1, a 238U concentration of
0.43 Bq/L, a 226Ra concentration of 0.96 Bq/L and a
total dissolved solids content of 7680 mg/L. These
values can be compared with the action levels (238U+ 234U = 1 Bq/L, 226Ra = 1 Bq/L) and with thepermissible concentrations (PCingest) of 10 Bq/L for
238
U and 1 Bq/L for 226Ra in drinking water (as per
Ref. [6.4]).
Restoration of the KBZh site began in 1991
but is still incomplete because of financial problems.
The project plan envisages the following covering
layers: 0.4 m of loamy clay (which is already inplace), 0.4 m of rock, 3.5 m of packed loamy clay
and 0.4 m of black soil [6.8, 6.9, 6.11].
6.4.2.

The mining and processing of uranium ores at
Zhovti Vody has negatively affected theenvironment as well as the sanitary state of the town
since the start of operations in the 1950s [6.7–6.10].
The mining of uranium ores ceased in 1990, but

Tailings KBZh;
Tailings Sch;
Tailings R.

Tailings Sch

The tailings impoundment Sch is located
1.5 km to the south of the town within the limits of
the Scherbakovskaya gully. It consists of two
sections, old and new, separated by a dyke (seeFIG. 6.2. Diagram of Zhovti Vody showing mines and tailings sites [6.8].

99

Fig. 6.2). The old section, which is 1.6 km long and0.6 km wide (at the dyke), has an area of 98.4 ha anda useful volume of about 5.5 × 106 m3. This section
was operated from 1959 until 1980 and is now used
for reserve storage only. The new section of thetailings is located in the western lower part of thegully. It has an area of 152 ha and a total mass of
34 × 106 t of tailings, which occupies a volume of
25 × 106 m3. This area was commissioned in 1979
and is still operating. The radiochemical compositions of the liquid and solid phases are given in
Tables 6.1 and 6.2, respectively.
Table 6.2 shows depletion in 230Th comparedwith the equilibrium value at secular equilibrium(compare the specific activities of 230Th with 226Ra
and 210Pb). This can be explained as follows:
samples were taken from superficial layers of thesolid tailings ‘mud’, whereas 230Th is partiallyleached and tends to migrate to the deeper layers of
the tailings. To obtain more accurate estimates of
the total activity of the radionuclides, a more representative sampling programme needs to be implemented. The ‘beaches’ of tailings Sch produce dust,
which is a source of radioactive contamination of
the air in the southern part of the surrounding
settlements during summer.

6.4.3.

Tailings R

Tailings R are located on the left slope of thevalley of the Zheltaya River in the Razberi gully.
The closest settlements are Zhovti Vody andMarianovka, situated 1.5 km to the west and southwest, respectively, and Udachny and Zaporozhets,
situated 0.4 km to the east. The area of the tailings
pond is 230 ha. This was originally a storage pond
for iron ore milling sludge but was also used as asettling mine for uranium mine drainage waters.
The solids retention system was constructed without
seepage controls; however, the natural material that
forms the dyke is loamy and clayey earth.
Table 6.3 gives the chemical and radiochemical composition of the liquid phase, maximum
permissible concentrations (MPCs) for chemicals
and PCingest for radionuclides in drinking wateraccording to the Radiation Safety Standard of
Ukraine [6.4].
The contaminated water seeps into theZheltaya River. In some cases the seepage waters
exceed the maximum permissible levels forchlorides, sulphates and even for 210Po in drinking
water. There is a need to assess their long term
impact on the environment.

TABLE 6.1. RADIOCHEMICAL COMPOSITION OF THE LIQUIDS IN TAILINGS SCH [6.12]
Volumetric activity (Bq/L)
Uranium-238

Radium-226

Lead-210

Polonium-210

Dyke water

0.74

2.6

1.2

0.4

Tailings water

2.2

8.1

0.8

0.5

10.0

1.0

0.5

0.2

ingestPC

TABLE 6.2. RADIOCHEMICAL COMPOSITION OF THE SOLIDS IN TAILINGS SCH
Radionuclides and their activity (Bq/kg)
Year of deposition
Lead-210

Radium-226

Thorium-230

Thorium-232

Uranium-238

1992

5 760

7 010

4730

18

1980

2000

10 360

12 255

4860

32

1490

2001

5 910

7 840

3265

54

1045

2002

6 175

7 270

2400

35

1770

100

TABLE 6.3. COMPOSITION OF CONTAMINATED WATERS OF TAILINGS R
Radium- Polonium210
226(Bq/L)(Bq/L)pH

Cl–(mg/L)

SO2–
4(mg/L)

NO–3(mg/L)

NH4+(mg/L)

Fetotal(mg/L)

Utotal(mg/L)

New

9.3

360

943

1.0

3.8

0.6

0.13

0.33

0.24

Old

9.3

220

815

1.15

n.d.

0.1

0.1

0.10

0.02

Tailings water

9.25

320

944

0.75

0.45

0.18

0.4

0.02

0.11

Mine water

8.35

1130

457

0.65

n.d.

0.1

0.04

0.12

0.006

MPC and PCingest
according to Ref. [6.4]

—

350

500

10

—

—

0.8

1.0

0.2

Sampling place

Tailings

Release to Zheltaya River

n.d.: Not detected.

6.5. ASSESSMENT OF THE SOURCES OF
CONTAMINATION OF NATURALWATERS IN THE ZHOVTI VODY AREA
The water basin within the limits of Zhovti
Vody town is the Zheltaya River, which is a left
tributary of the Ingulets River. At present, its bed issilted, and only a small channel is cleared. The
treated mine waters from the Novaya mine aredischarged into it.
The length of the river is 61 km and the area of
the watershed is 490 km2. The average slope of theriver is 0.00175. The average annual drainage is
1.24 L·km–2·s–1. The average velocity of the current
is 0.1–0.2 m/s; during flooding it increases to 0.5 m/s.
Melting snow is the main contributor to flow and is
responsible for two thirds of the annual drainage;
rain and groundwaters are of secondary importance.
For most of the year, the river bed is dry, forming
chains of separated stretches, and, at somelocations, the river is parched for up to 10 months.
Downstream of the wastewater outlet from theuranium mill, the water has elevated levels of total
dissolved solids (TDS). Table 6.4 presents theresults of the chemical analysis of the river water at
the town of Zhovti Vody.
There are clean water bodies within the town:
in the north-eastern section there is a municipal
beach, in the south-eastern section there is a beachand pond used by children, and in the eastern part
there is a reservoir, Vodobud, used at present as areserve water body for the drinking water supply.
Table 6.5 gives the results of radiochemical analysis
of water samples of the Zheltaya River, startingfrom the source and finishing with the exit of theriver beyond the limits of the town.
The results confirm contamination of theZheltaya River with uranium from the milling
operation. In the area of Netesovka the concentration of uranium in the water exceeds the concentration at the source of the river by a factor of 80.
Even at a distance of more than 10 km, in the areaof Annovka, high activities of natural radionuclides
are apparent (Table 6.6), exceeding by ten times theactivity of these radionuclides in the Saksagan andIngulets Rivers.
Some dose estimates arising from water
consumption for the most conservative scenario ofwater use from the Zheltaya River have been
calculated for the residents of Annovka: see Section
8.4.2.
The results in Ref. [6.12] and the dose calculations presented in Section 8.4.2 show that theconservatively estimated annual doses fromconsumption of river water may exceed theconstraint value of 0.05 mSv established in Ref. [6.4]for water use in areas of uranium mining andmilling. These assessments draw attention to the
problem and indicate the need for more extensive
monitoring and remedial works to reduce releasesof radioactive substances into the river.

101

TABLE 6.4. CHEMICAL COMPOSITION OF THE WATER FROM THE ZHELTAYA RIVER ATZHOVTI VODY (1995)
April 1995

May 1995

June 1995

pH

7.65

8.2

8.2

Hardness (meq/L)

11.8

14

21.6

Ca + Mg (mg/L)

189

280

343

Na + K (mg/L)

104

264

360

CO3 (mg/L)

—

40

—

HCO3 (mg/L)

415

346

354

Chlorine (mg/L)

142

177

247

SO4 (mg/L)

256

650

432

NH4 (mg/L)

0.08

1

0.26

NO3 (mg/L)

n.d.

n.d.

0.17

NO2 (mg/L)

—

1.5

0.02

TDS (mg/L)

1106

1757

1380

n.d.: Not detected.

TABLE 6.5. CONCENTRATION OF NATURAL RADIONUCLIDES IN WATER FROM THEZHELTAYA RIVER (1999)
Sampling site

Total uranium (Bq/L)

Radium-226 (Bq/L)

Zheltaya River (source)

0.08

0.013

Veselo Ivanovka reservoir

0.08

0.015

Vodobud reservoir

0.07

0.047

Stream from Vodobud reservoir

0.04

0.011

Zheltaya River (Marianovka)

2.14

0.010

Zheltaya River (Netesovka)

5.9

0.013

PCingest [6.4]

10.0

1.0

TABLE 6.6. CONCENTRATION OF NATURAL RADIONUCLIDES IN THE INGULETS, SAKSAGAN
AND ZHELTAYA RIVERS (MAY–JUNE 2002)
Activity (mBq/L)
234

U/238U

Sampling place

Uranium238

Uranium234

Lead210Radium226

Polonium210

Zheltaya River in Annovka in May

1020 ± 100

1160 ± 115

<11

8±3

20 ± 3

1.13

Zheltaya River in Annovka in June

1400 ± 90

1600 ± 130

—

—

—

1.14

36 ± 558 ± 6<115±2

2.4 ± 0.5

1.61

Ingulets River in Aleksandria

35 ± 554 ± 6<11

16 ± 50.4 ± 0.1

1.54

Ingulets River (Iskra reservoir)

31 ± 548 ± 6<11

13 ± 30.5 ± 0.2

1.54

Saksagan River (Kress reservoir)

55 ± 677 ± 7<11

7±4

1.1 ± 0.5

1.40

PCingest [6.4]

10 000

10 000

500

1000

200

Drinking water in Zhovti Vody

102

6.6. EFFECT OF IN SITU LEACHING OF
URANIUM ON CONTAMINATION OF
NATURAL WATERS
6.6.1.

Devladovo site

One of the former in situ leaching sites,
Devladovo (see Fig. 6.1, position 17), is situated at
the interfluve of the Saksagan and Kamenka Rivers.
Exploitation of the deposit was completed by 1984
and the affected lands were recultivated andtransferred to general land tenure [6.7, 6.13].
During decommissioning, the underground waters
were found to be contaminated with naturally
occurring radionuclides. The legislation then inplace did not envisage restoration of theunderground waters to their initial state. Until 1990,
the mine water ponds remained on the Devladovosite.
The ore deposits were leached within the
Buchak water bearing horizon. This horizon
occupies a significant portion of the deposit; itsgroundwaters
discharge
tothe
Dnieper
Ternovskaya valley. At present, this horizon ofunderground waters is contaminated with residualacid solutions containing natural radionuclides. The
water-containing rocks are coal and carbon freesands up to 15 m thick. The underground water fluxof this horizon is pressurized; the water pressure is
28–40 m and flow is in the direction of east to west,
with slopes of the piezometric surface of
0.0015-0.0028. The valley of the Kamenka River
supplies the water horizon under natural conditions.
The release takes place into the Saksagan River.
The underground waters of the Buchak water
bearing horizon have naturally elevated concentrations of sulphates and high TDS and, for thatreason, were not used for drinking water prior to
the development of the ore body. Table 6.7 gives
data on the background concentrations of uranium
series members taken from the horizons beyond theboundary of the impact area.
The main source of contamination of theunderground waters was the leaching solutions,with typical concentrations of 10 g/L sulphuric acidand 2 g/L nitric acid. During the period of
operation, 200 000 t of sulphate ion (as sulphuricacid) and 18 600 t of nitrate (as nitric acid) werepumped into the horizon. The extent of theartificial contamination from leaching covers thewhole area of the former site in the direction ofunderground water movement from east to west in
the monitored area.

The major contributors to radioactive contamination are Utotal, 210Pb and 210Po. The measured
concentrations are within the following ranges:
Utotal from 2.5 to 885 Bq/L, 210Pb from 0.2 to 15 Bq/L
and 210Po from 0.02 to 0.7 Bq/L.
6.6.2.

Forecast of the long term potential
contamination of the Saksagan RiverIn 1997, with the assistance of COGEMA–
SGN (France) and under the TACIS programme,
modelling studies were undertaken to forecast the
future hydrological and radiological situation near
the Devladovo site [6.14]. The task was to forecast
the uranium concentrations for the next 1000 years,
assuming that the object of contamination would be
the Saksagan River, which is 13.5 km from the
Devladovo site and the main regional source ofwater supply.
Two sources of contamination wereconsidered:(a)(b)

Pond water on the surface, contaminating the
Quaternary water bearing horizon;
Residualsolutionsfromundergroundleaching, contaminating the Buchak water
bearing horizon [6.13].

Simulation of outflow of pollutants from thewaste storage pond for times in excess of 1000 years
showed that, with a high probability (80%), contamination would reach the Saksagan River withconcentrations exceeding the current sanitary
standards [6.3–6.6]. The predicted concentrations
1000 years from now are given in Table 6.8 [6.14].
These estimates, made on the basis ofmeasurements and simulation, show that there is no
problem with current contamination of the surface
water in the region. However, there is a highprobability that contamination above current
sanitary standards will occur from several hundred
to one thousand years in the future, when polluted
water containing uranium series nuclides reaches
the Saksagan River. Accordingly, the movement ofthese contaminated groundwaters should bemonitored within the framework of long term
environmental programmes.
One of the priority tasks is to create an
ongoing operating system for external radioecological monitoring of the environment (water,soil, vegetation, air, food products) in the regions of
the former and present uranium facilities to assessthe developing situation and to justify possible
103

TABLE 6.7. BACKGROUND CONCENTRATION IN UNDERGROUND WATERS OF THE BUCHAKHORIZON (FOR 1998) AT LOCATIONS BEYOND THE IMPACTED AREAS [6.13]
Concentration (Bq/L)
SO2–
4 (mg/L)TDS (mg/L)

1

619

2

350

3

Well No.

Uranium-238

Radium-226

Thorium-230

Lead-210

Polonium-210

2580

1.23

—

—

—

—

1542

0.65

—

—

—

—

440

1245

1.95

0.27

0.22

0.56

0.11

5

584

1836

0.59

0.02

0.02

0.37

0.04

6

498

2274

0.79

0.14

0.34

1.11

0.08

14

814

2199

0.79

—

—

—

—

33

526

2344

0.69

—

—

—

—

34

718

1836

0.79

0.15

0.06

0.22

0.04

98-2

4023

8062

0.59

—

—

—

—

B-58

3353

5513

0

0.10

0.09

1.37

0.15

B-59

297

598

0.84

0.28

0.02

0.59

0.07

B-61

661

2686

1.77

0.01

0.60

0.51

0.04

B-64

533

2818

0

—

—

—

—

B-69

638

2942

0.98

0.07

0.02

0.22

0.06

B-78

718

2242

1.28

0.10

0.09

1.07

0.09

B-97

627

2145

0.42

—

—

—

—

B-99

709

2428

0.59

0.24

0.07

0.67

0.07

MPC andPCingest

500

1000

10

1

0.7

0.5

0.2

TABLE 6.8. ESTIMATED RADIONUCLIDE CONCENTRATION (Bq/L) WITHIN THE GROUNDWATER OF THE QUATERNARY HORIZON PREDICTED FOR 1000 YEARS FROM NOW
Close zone of Devladovo site

Zone of observational control

Uranium-238

2.7

1.5

Radium-226

1.1

0.53

Thorium-230

0.33

0.13

Lead-210

0.86

0.53

Polonium-210

0.11

0.06

104

remedial measures. It is very important tocoordinate the work of the present system of radioecological monitoring by external agencies.

6.7. IMPACT OF THE FORMERPERVOMAYSKAYA URANIUMMINING OPERATION ON
RADIOACTIVE CONTAMINATION OF
NATURAL WATERS
The first uranium mining enterprise in the
Ukraine was the exploitation of the Pervomayskayauranium ore deposit located at Krivoy Rog [6.1,
6.15, 6.16]. In the late 1960s uranium mining was
stopped, but mining of iron ore at the Objedinyonnaya mine continued. In early 1998 iron ore
mining finally ceased and decommissioning was
begun. The total area of the mining enterprise to berehabilitated is 68.5 ha. Uranium mining contaminated the environment due to ore dispersal,
leaching of natural radionuclides from the ore,
uncontrolled waste use for other purposes and dust
contamination.

Within the area of the enterprise a stream
flows through the Gryadkovataya narrows, which
enters the Saksagan River. To estimate pollution in
the stream, samples were taken after rainfall. Oneof the samples was taken upstream of the industrial
site; the other was taken downstream. The results of
the analysis are given in Table 6.9. These results
confirm pollution of surface waters by naturalradionuclides.
At present, water from the former Pervomayskaya mine is pumped to the tailings pond of thejoint stock company SevGOK, located 7 km fromthe mine. Table 6.10 shows the concentration ofnatural radionuclides in mine water and tailings
water [6.17].
Both the mine water and the tailings water
exceed the natural background levels. The main
contributors to dose are 238U, 234U and 226Ra.
However, the current situation does not create asignificant risk to the residents of Krivoy Rog, sinceestimates of annual effective exposure, even for themost conservative scenarios of water consumption,
do not exceed 0.01–0.03 mSv/a. Nevertheless,despite the relatively low level of current
population exposure, the situation should be
regularly monitored at the local and regional level.

TABLE 6.9. RADIONUCLIDE CONCENTRATION IN WATER SAMPLES FROM THE STREAM
THROUGH THE GRYADKOVATAYA NARROWS AND THE SAKSAGAN RIVER
Radioactivity (Bq/L)
Site of water sampling
Total alphaUranium-238

Radium-226

Lead-210

Polonium-210

Upstream of industrial site

<0.4

0.033 ± 0.002

0.045 ± 0.011<0.0120.007 ± 0.0014

Downstream of industrial site

2.3 ± 1.0

1.2 ± 0.3

0.09 ± 0.018<0.0110.002 ± 0.0006

Saksagan River (background)

0.32 ± 0.025

0.03 ± 0.004

0.015 ± 0.003

0.004 ± 0.001

0.001 ± 0.0003

TABLE 6.10. AVERAGE CONCENTRATION (Bq/L) OF RADIONUCLIDES IN MINE WATER FROM
THE PERVOMAYSKAYA MINE AND WATER FROM THE SevGOK TAILINGS
Mine water from Pervomayskaya

SevGOK tailings

1998

Oct. 2001

Nov. 2001

Oct. 2001

Nov. 2001

Uranium-238

n.d.

0.05

0.14

0.04

0.12

Uranium-234

n.d.

0.15

0.25

0.34

0.19

Thorium-230

0.16<0.001<0.001<0.001<0.001Radium-226

0.27

0.028

0.029

0.018

1.32

Lead-210

0.34

<0.01

0.03

<0.01

<0.01

Polonium-210

0.14<0.001<0.001<0.001<0.001n.d.: Not detected.

105

6.8. RADIOACTIVE WASTE FROM FORMERURANIUM PROCESSING IN
DNIPRODZERZHINSK
According to the National Reports on theState of the Environment in Ukraine (1994–2001),
the Dnipropetrovsk region is one of the mostunfavourable in terms of contamination of air,adjacent catchment areas and water bodies. One of
the reasons for this situation is the large concentration of industrial enterprises, which include
chemical, coke and metallurgical plants. These
enterprises have severely affected the environmentand human health in the region.
One of the metallurgical facilities was theformer Prydniprovsky chemical plant, at whichuranium ores were processed from 1948 until 1991.
It is located on a large industrial site within the
territory of the city of Dniprodzerzhinsk in the
Dnipropetrovsk region. During operation of thePrydniprovsky chemical plant, nine tailings dumps

were created, containing about 42 × 106 t ofradioactive waste with a total activity of
3.2 × 1015 Bq (86 000 Ci). Some of the radioactive
waste is located within the territory of theindustrial zone of Dniprodzerzhinsk, while otherwaste is stored about 14 km to the south-east (seeFig. 6.3).
The city of Dniprodzerzhinsk is a large
industrial centre; the population at the beginning of2000 was 276 500 people. The residential area covers
41% of the municipal territory and the industrial
and communal areas cover 18%. The enterprises
located on the right bank area of the town aregrouped into industrial zones.
In addition to imported ores, the Prydniprovsky chemical plant processed uranium bearing
sludges obtained from cast iron smelting of ironores from the Krivoy Rog region. In the early 1990s
the Prydniprovsky chemical plant was split into
several separate enterprises, and processing of
uranium was stopped.

FIG. 6.3. Location of radioactive waste in the Dniprodzerzhinsk region [6.18] (see text for identification of numberedpositions).

106

Information on the main radioactive waste
storage areas is given in Table 6.11. Initially, tailings
were stored in nearby clay gullies and open pits,
which are unsuitable for the long term storage ofradioactive waste. Tailings were deposited on theindustrial site at Zapadnoye and Centralny Yar(which operated from the early 1950s). The tailings
D (Dniprovske) site, which operated from 1954 to
1968, was established on the floodlands of the
Dnieper River. In the period from 1968 to 1993,
radioactive waste was stored in the speciallyconstructed sections I and II of tailings C, which islocated to the south of Dniprodzerzhinsk city (seeFig. 6.3).
The deposited tailings and other radioactive
material are a source of current and future contamination of:
(a)
(b)

(c)

The atmosphere, via radioactive dust andaerosols, and radon and its progeny;
Watercourses, including the Dnieper Riveritself, through seepage and migration of radionuclides and chemical components of thewaste;
Watercourses and land, if erosion orcatastrophic failure of the radioactive waste
storage systems were to occur.

The sources of radioactive waste andradioactive contamination are briefly described in
the following sections.
6.8.1.

volume is about 350 000 m3 (0.77 × 106 t). The total
activity of the stored waste is 180 TBq [6.11, 6.16,
6.18].
The tailings are located on 6 ha of land in thesouth-western part of the industrial site within afenced area with earthen dykes in a spent clay open
pit (see position 1 in Fig. 6.3). In terms of geomorphology, the tailings are situated within theboundaries of the floodland terrace of the Dnieper
River. The general slope of the surface is from thesouth to the north. The hydrogeological conditions
are characterized by the development of an alluvial
water bearing horizon, with the depth of deposition
being 12–22 m. In the north-western section, thealluvial horizon reaches the bottom of the tailings.
The surface of the tailings is partially covered
with loess and loamy sands along with construction
and domestic waste with a thickness of up to 2.5 m.
The exposure rate of gamma radiation1 within thewaste is mostly within the range 100–2000 μR/h; on
the surface it is mostly 20–40 μR/h, but on theuncovered surface it is up to 100–2200 μR/h. The
thickness of contamination of the ground beneaththe foundation of the tailings varies from 0.2 to
5.4 m. For this zone, exposure rates of 30–100 μR/h
are typical.
The concentration of 226Ra in the waste varies
from 789 to 1.72 × 106 Bq/kg (the latter over a very
limited area), 238U from 952 to 3200 Bq/kg and 230Th
from 9800 to 32 000 Bq/kg [6.16]. The 222Rn flux
from the surface of the tailings impoundment,

Tailings Zapadnoye
1

The radioactive waste on this site wasdeposited by both hydropouring and piling methods
between 1949 and 1954. The radioactive waste

Exposure to gamma radiation is sometimes
measured in units of roentgen (R) or microroentgen(μR). The SI equivalent is the coulomb per kilogram. One
coulomb per kilogram is equivalent to 3881 R.

TABLE 6.11. CHARACTERISTICS OF THE MAIN STORAGE AREAS FOR RADIOACTIVE WASTE
FROM THE PRYDNIPROVSKY CHEMICAL PLANT (PRELIMINARY ASSESSMENT IN 2001)
Operational period

Area (ha)Radioactive waste
mass (106 t)

Radioactive waste
volume (106 m3)

Total activity(TBq)

Zapadnoye

1949–1954

6.0

0.77

0.35

180

Centralny Yar

1951–1954

2.4

0.22

0.10

104

Yugo-Vostochnoye

1956–1980

3.6

0.33

0.15

67

C, section I

1968–1983

90

19.0

8.6

710

C, section II

1983–1992

70

9.6

4.4

270

Base C

1960–1991

25

0.3

0.15

440

D

1954–1968

73

12.0

5.9

1400

107

where covered by a protective layer, is around 0.32
to 1.5 Bq·m–2·s–1, whereas radon exhalation
background levels are only around 9 to
18 mBq·m-2·s–1 [6.19]. Annual emission of radon to
the atmosphere is estimated to be 0.75 TBq.
6.8.2.

Tailings Centralny Yar

The radioactive waste on this site wasdeposited by both hydropouring and piling methods
between 1951 and 1954. In total, 100 000 m3 (0.22 ×
106 t) of radioactive waste with a total activity of 104
TBq was deposited.
The tailings are located on 2.4 ha of land in thesouth-central part of the former Prydniprovsky
chemical plant and within the recreation zone of thetown (see position 2 in Fig. 6.3). The site is situatedin a sandy gully running from the south to the northand within the floodland terraces of the Dnieper
River.
The hydrological conditions are characterized
by seasonal fluctuations of the alluvial water
bearing horizon. The surface of the tailings iscovered with loess and loamy sands fromconstruction waste (thickness is 1.5–6.5 m). The
exposure rate within the waste varies from 15 to
30 μR/h (in the southern part of the tailings) tomore than 10 000 μR/h. On the surface of thetailings the exposure rate varies from 20 to 1000 μR/
h. The radon flux from the surface of the tailings
varies from 0.24 to 2.57 Bq·m–2·s–1. The annual
emission of radon to air is 0.6 TBq.
There are no data on possible migration ofradionuclides via underground waters into thedrainage network.
6.8.3.

Tailings Yugo-Vostochnoye

The radioactive waste on this site was
emplaced by the piling method between 1956 and1980. The radioactive waste volume is about
150 000 m3 (330 000 t). The total activity of thestored waste is 67 TBq [6.11, 6.18, 6.19].
The site is located on 3.6 ha of land in thesouth-eastern part of the industrial site of theformer Prydniprovsky chemical plant within theboundaries of a large gully and on the floodland
terraces of the Dnieper River (see position 3 inFig. 6.3).
The site contains piled material comprisingheterogeneous industrial waste such as sludges,
metal, construction and domestic waste (concrete,stone, wood, gravel, etc.) and loamy sands with a108

total thickness of 0.5–3.0 m beyond the limits and up
to 19.2 m within the limits of the waste dump. Thus
the site is highly porous and subject to high rates of
seepage. The rocks beneath the tailings are overlain
by loess, loamy sands and clay sands ranging inthickness from 7.5 to 27.5 m, and alluvial sands 20 m
thick. The subsurface hydrological conditions are
similar to those at Centralny Yar.
The exposure rate within the waste varies
from 60 to more than 6000 μR/h; on the surface it
ranges from 30 to more than 3000 μR/h. The radon
flux from the surface of the tailings varies from 0.11
to 1 Bq·m–2·s–1. Annual emissions of radon are
estimated to be 0.9 TBq.
6.8.4.

Tailings Dniprovske (D)Tailings D is a much larger and moresignificant tailings dump than those discussed
above. It was deposited by hydropouring between
1954 and 1968. It contains about 5.8 × 106 m3(12 × 106 t) of radioactive waste. The total activity ofthe stored waste is about 1400 TBq (40 000 Ci).
The tailings are located on the right side of theDniprovske reservoir at a distance of 0.8 to 1.2 km
and on the floodplain of the river. The Konoplyanka
River flows near the south and west boundaries of
the tailings (Fig. 6.3, position 4, and Fig. 6.4). On
the north side there are settling ponds of theDniprodzerzhinsk coke chemical plant. Bulk wastefrom the Dniprodzerzhinsk metallurgical combine
is located on the eastern and northern boundaries,
between the tailings and the reservoir. The
geological section beneath the foundation of thetailings is composed of alluvial deposits with a total
thickness from 3.0 to 15.5 m, located on an unevensurface of crystalline rock. The alluvial layer

FIG. 6.4. Tailings D, showing the slope to the Konoplyanka
River (right) and waste from the coke chemical plant in the
distance.

consists of humus silty clay sands and loamy sandswith a thickness of 0.1–3.3 m distributed over muchof the natural surface, and sands 3.0–15.3 m thick.
The tailings impoundment was constructed bybuilding a closed contour of protective dam walls of
6–11.8 m in height. The length of the dam perimeteris 4 km. The absolute elevation of the dam crest
before 1959 was 57.5 m, but after further
construction it reached 61.3–64.2 m. It wasconstructed on alluvial sands and loamy sands. The
fencing dam is a regular embankment built by thedry method with compacting. There are no seepage
control features either in the dam walls or the floor.
The tailings consist mainly of sandy material(fine and dusty), seldom of loamy sands and clay
sands, and are covered with a layer of phosphogypsum (a waste product from the production ofphosphate fertilizers) with a thickness of 1–5 m near
the dam walls and up to 19 m in the central andeastern part of the bowl.
The exposure rate of gamma radiation within
the tailings is mainly within the range 200–600 μR/h;
in some places it reaches 1000–4500 μR/h [6.19]. The
exposure rate on the surface of the tailings is
10–40 μR/h; at the more contaminated areas in thenorth-western part of the bowl it is 40–74 μR/h. The
total volume of solid waste is 22 × 106 t (including
phosphogypsum). The concentration of 226Ra in thewaste varies from 4400 to 52 000 Bq/kg, 238U from
125 to 3500 Bq/kg, 230Th from 3000 to 62 000 Bq/kg
and 210Pb from 4100 to 50 000 Bq/kg. The radon flux
from the surface of the tailings covered by a thicklayer of phosphogypsum is 1–26 mBq·m-2·s–1. The
tailings deposits are partly saturated with water. The
maximum recorded elevation of the level of theartificial horizon of tailings waters is 61.0 m,

indicating a substantial increase since 1975, when
the level was recorded at 52.0–54.5 m. The main
reason for the high artificial horizon is percolationof water from the north-eastern settling ponds ofthe Dniprodzerzhinsk coke chemical plant.
The hydrological conditions are characterized
by the availability of the artificial horizon of tailings
within the dam and an alluvial water bearing
horizon underneath. As a result of persistent inflow
and hydrostatic pressure within the tailings, radionuclide migration into the environment is occurring.
The radionuclides move into the alluvial water
bearing horizon, rivers and eventually the Dnieper
River. Estimates of the average annual release ofradionuclides to the Dnieper River via groundwaterand surface flow via the Konoplyanka River are
given in Table 6.12. Future releases are difficult topredict based on present knowledge. Comprehensive geotechnical studies need to be undertaken
to determine the long term stability of the tailings
and to model the release of radionuclides to the
Konoplyanka and Dnieper Rivers.
During 2000–2001 releases from both plants(the Dniprodzerzhinsk coke chemical plant and theDniprodzerzhinsk metallurgical combine) weresuspended. Fifty monitoring wells have been drilled
and equipped within the tailings area and in thesanitary protection zone.
Tailings D are considered as a possible hot
spot because of the large amount of radioactivity,
the long half-life of the main radionuclides, theproximity to the Dniprovske reservoir, the evidenceof current seepage and the possibility ofcatastrophic failure of the impoundment. Section
9.4 provides more information on tailings D (seeespecially Fig. 9.32).

TABLE 6.12. AVERAGED ANNUAL RADIONUCLIDE RELEASE TO
THE DNIEPER RIVER FROM TAILINGS D
Annual release (GBq)
Surface flow via the
Konoplyanka RiverVia groundwater fluxes

Uranium-238

55

0.2

Thorium-230

5.5

0.03

Radium-226

19

0.03

Lead-21044

0.15

Polonium-210

8.8

0.01

109

6.8.5.

Base C

Base C is located 14 km to the south-east of
the Prydniprovsky chemical plant (see position 7 inFig. 6.3) and within a fenced area of 720 m × 470 m(an area of 33 ha); temporary storage of uranium
raw material took place here between 1960 and1991. The main facilities at the site were bunkers
and open areas for ore storage, and the railway
access to them. The storage area is 25 ha.
Base C is contaminated with radioactivity, themain source of contamination being earlier stored
uranium ore and some residual material (spillage
along the railway, radioactive scrap metal, ore
pieces, etc.), which is stored in bunkers. The bunkers
are reinforced open iron tanks banked with earthen
dykes to heights of 2.5–4.5 m.
The exposure rate of gamma radiation of theremaining ore is from 300 to more than 3000 μR/h.
The contained solid radioactive waste in base C has
a total activity of 440 TBq. The radioactive waste
volume is 150 000 m3 (0.3 × 106 t). The exposure rateon the surface of the storage area does not exceed
4700 μR/h. The radon flux from the surface istypically 1.25–7.26 Bq·m–2·s–1, with a maximum of
21 Bq·m–2·s–1. Annual radon emissions are 23 TBq.
The hydrological conditions are characterized
by the availability of a water bearing horizon in theloess deposits, which are located at depths of 16–
18 m (absolute elevations are 142.0–146.5 m above
sea level) and the water bearing horizon in Neogene
deposits at depths of more than 90 m. The
underground water flows to the west and south-west
in the direction of the gully where tailings C aresituated.
6.8.6.

Tailings C

The tailings C impoundment is located 14 km
to the south-east of the Prydniprovsky chemicalplant in the Rassolovataya gully, which empties into
the valley of the Sukhaya Suhra River. It consists of
two sections separated by a raised road. Tailings andother waste were pumped as a slurry to the site fromthe Prydniprovsky chemical plant by a pipeline. The
Dnieper River is about 4 km from the site.
The first (I) section of the tailings dam (seeposition 8 in Fig. 6.3) was operated from 1968 to
1983. It contains about 19 × 106 t of radioactive
waste that occupies a volume of 8.6 × 106 m3 and a
total area of about 90 ha. The area has about 14 haof dry beaches; the rest is covered with water. The
concentration of 226Ra in the waste varies from110

560 to 13 500 Bq/kg, 238U from 170 to 880 Bq/kg,
230
Th from 350 to 83 000 Bq/kg and 210Pb from 500 to
14 400 Bq/kg.
The total radioactivity in this section is about
710 TBq (19 000 Ci). The maximum exposure rate is1200 μR/h. The radon flux from the surface is 0.03–
1.48 Bq·m–2·s–1. Annual radon emissions from thetailings surface are 19 TBq. The site has yet to berehabilitated.
The second (II) section, covering the lower
part of the gully, is formed by a dam crossing thegully (see position 9 in Fig. 6.3). It was commissioned in 1983 and is still used for disposal of nonradioactive waste (e.g. phosphogypsum). It contains
9.6 × 106 t of radioactive waste occupying a volumeof about 5.5 × 106 m3. The total area is 70 ha, of
which about 50 ha is covered with water.
The total activity is about 270 TBq (7000 Ci).
The exposure rate at the surface is low due todeposition of non-radioactive material on top of theuranium tailings. The content of the natural radionuclides in the sludge waters are: uranium from 0.4
to 2 Bq/L; 226Ra from 0.05 to 0.24 Bq/L; 230Th from0.05 to 0.10 Bq/L; 210Pb from 0.35 to 5 Bq/L; and210
Po from 0.04 to 0.09 Bq/L. This section of tailings
C is fully engineered with clay and polyethylene
barriers to minimize seepage.

6.8.7.

Other contaminated areas
Other contaminated areas include [6.18]:

(a)

(b)

(c)

(d)

(e)

A lanthanide dump area near the tailings C
site (see position 5 in Fig. 6.3), which contains
0.86 TBq of radioactive waste.
A blast furnace waste storage area (seeposition 6 in Fig. 6.3) near the base C site,
containing 11 TBq of radioactive waste.
Contamination of industrial areas andequipment within former plants (Prydniprovsky chemical plant and Dneproazot) that
handled radioactive material.
The Lazo site within the city area (see position
10 in Fig. 6.3). The contamination originatedfrom the Dneproazot complex; further study isrequired to establish the extent of the contamination.
Some limited areas, including living areas,
within the city, with exposure rates from 100–
1000 μR/h. These resulted from the use ofbuilding materials (e.g. blast furnace slag) withelevated levels of radioactive elements.

6.9. ASSESSMENT OF THE IMPACT OF
WASTE FROM THE PRYDNIPROVSKYCHEMICAL PLANT
The main water body within the observation
zone of the Prydniprovsky chemical plant is theDnieper River. As noted previously, a small
tributary of the Dnieper, the Konoplyanka River,flows past sections of tailings D (see Fig 6.4). In theobservation zone of tailings C are several artificial
water bodies (ponds at Taromskoye, Ordzhonikidze
and Ptitsefabrika) and a temporary watercourse in
the Rassolovataya gully.
The Dnieper River is about 1 km from tailings
D, 2.6 km from tailings Zapadnoye and Centralny
Yar, 1.8 km from tailings Yugo-Vostochnoye and4.2–4.4 km from tailings C and base C.
Elevated levels of barium, titanium,
manganese, nickel, lanthanum, lithium, lead,strontium and zirconium are observed downstreamof the radioactive waste sites, reaching the MPCs fordrinking water in some cases (e.g. manganese andlanthanum). Moreover, periodically the levels ofsulphates, nitrates, ammonium, phenol, oil products
and TDS in the Dnieper River exceed the MPC for
drinking water.
The main reasons for chemical pollution of the
Dnieper River are the discharge of untreated waters
by the industrial enterprises (totalling 270 × 106 m3/a),surface discharge (rain and snow melting waters)from the territory of the industrial and residential
area (approximately 3 × 106 m3/a) and releases into
the Dnieper River of polluted underground waters.
The chemical composition of the river water ischaracterized by a variety of contaminating species(sulphate, nitrate and iron) with TDS of 1.0–1.3 g/L.
The concentrations of monitored radionuclides, 238U and 226Ra, in the Dnieper River are
significantly lower than the permissible concentrations established in Ref. [6.4] for drinking water;
however, there is a tendency for an increase inconcentration downstream of the Konoplyanka
River inlet (e.g. in Karnaukhovka).
The main sources of radionuclide input into
the Dnieper River are seepage of contaminatedgroundwaters (mainly under tailings D), surface
discharge from the contaminated areas of theindustrial site and the discharge of the Konoplyanka
River, where the highest concentrations of radionuclides are recorded (see Table 6.13).
It is noteworthy that, in 1995, the Chief State
Inspectorate of Gosatomnadzor of Ukraine
reported: “In a series of wells within the plant area,
high levels of contamination of the undergroundwaters with 226Ra were registered and, in somewells, high levels of dissolved uranium were found(up to 2.4 mg/L). The aureole of contamination of
the underground waters with natural radionuclides
spread beyond the limits of tailings D in the
direction of the Dniprovske reservoir. The content

TABLE 6.13. RADIONUCLIDE CONCENTRATION IN THE DNIEPER AND KONOPLYANKA
RIVERS BASED UPON THE RESULTS OF SAMPLING FROM 1992–1999
Concentration (Bq/L)
Radionuclide
Min.

Max.

Averaged

Dniprodzerzhinsk reservoir

UtotalRadium-226

0.017
0.006

0.098
0.030

0.046
0.014

Dniprovske reservoir upstream of the
Konoplyanka River inlet

UtotalRadium-226

0.017
0.004

0.116
0.041

0.055
0.015

Dniprovske reservoir, Karnaukhovka, Utotal
downstream of the Konoplyanka River Radium-226
inlet

0.017
0.003

0.261
0.063

0.060
0.014

Konoplyanka River

UtotalRadium-226

0.034
0.004

0.770
0.163

0.112
0.120

PCingest [6.4]

UtotalRadium-226

10.0
1.0

Dnieper River111

of 2001. The concentration of uranium in the
Dniprovske reservoir in its upper and lower sections
varied from 20 to 50 Bq/m3 during spring andautumn and from 120 to 200 Bq/m3 during summer.
Table 6.16 shows the radioactivity of naturally
occurring radionuclides in bottom sediments. Thisshows that the concentrations of radionuclides in
the Konoplyanka River are typically 1.5–100 times
those of similar sediments in the Dniprovske
reservoir. The highest concentrations are registeredin the silty sediments of the Konoplyanka River(samples 7 and 8), where their values exceed by two
to five times the concentrations in the sandy
deposits (sample 6).

900
800

Utot (Bq/m3)

700
600

Dnieper
Konoplyanka

500
400
300
200
100

Jul. 2002

May 2000
Jun. 2001

May 1999
Aug. 1999
Sep. 1999

May 1998
Jun. 1998

Jul. 1997
Aug. 1997

Oct. 1995
May 1996
Jun. 1996
Sep. 1996

Jul. 1994
Aug. 1994
Sep. 1994
May 1995
Jul. 1995
Aug. 1995

May 1994
Jun. 1994

Jul. 1993
Sep. 1993
Nov. 1993

0Jun. 1992
Sep. 1992

of 226Ra exceeded the background values in theregion by three to ten times. The maximum concentrations of this radionuclide were registered in wells
drilled in the bank of the reservoir.”
The Konoplyanka River flows from 50–100 m
to the south of tailings D and 0.6–1.0 km to thenorth of tailings Zapadnoye, Centralny Yar andYugo-Vostochnoye. Figure 6.5 shows that theconcentration of uranium in the Konoplyanka Riveris consistently higher than in the Dnieper River.
Periodically in the Konoplyanka River, MPCs indrinking water are exceeded for sulphates, nitrates,
iron, ammonium, hardness, TDS (up to 1.4 g/L), oil
products and a series of metal ions, viz. barium (to1.8 times), lead (to 22 times), titanium (to fourtimes), manganese (to 22 times), lanthanum (to fourtimes) and zinc (to two times).
The regional laboratories studied water
samples from the Konoplyanka and Dnieper Rivers
during different seasons. The sampling locations areshown in Fig. 6.3 and the results in Tables 6.14 and6.15. The results show that the activity of naturalradionuclides in the Konoplyanka River is typically
2–20 times those in the Dnieper River.
The recent monitoring study by the Dnipropetrovsk National University determined theuranium concentrations in four rivers in the
Dniprodzerzhinsk area during the spring to autumn

FIG. 6.5. Concentration of total uranium (238U + 234U) in
the Dnieper and Konoplyanka Rivers. Note irregularsampling intervals [6.19].

TABLE 6.14. RADIONUCLIDE CONCENTRATION IN WATER SAMPLES FROM THE KONOPLYANKA AND DNIEPER RIVERS (JUNE 2001)
Concentration of natural radionuclides (mBq/L)
SampleNo.

Total alphaactivity(mBq/L)

Total beta
activity(mBq/L)10 ± 324 ± 1697 ± 67

1.3 ± 0.3

140 ± 15 160 ± 15

240 ± 140

290 ± 170

4.5 ± 1.2

38 ± 444 ± 440 ± 20260 ± 120

13 ± 58.8 ± 2.2

23 ± 320 ± 3220 ± 110370 ± 180

12 ± 51.1 ± 0.558 ± 362 ± 3130 ± 70

<0.1

Sampling place

Radium226

Lead210

Polonium- Uranium- Uranium210
238
234

1

Dniprodzerzhinsk reservoir

7±2

11 ± 63.3 ± 1

3

Konoplyanka River mouth

5±2

16 ± 5

4

Dnieper River7±2

11 ± 6

5

Dnieper River3±2

6Konoplyanka River

29 ± 75±2

7Konoplyanka River

20 ± 618 ± 61.5 ± 0.6147 ± 15 163 ± 15

350 ± 180240 ± 150

8

Konoplyanka River (granite
open pit)

14 ± 519 ± 70.2 ± 0.1

201 ± 15 192 ± 15

450 ± 180

410 ± 200

9Konoplyanka River

14 ± 514 ± 53.3 ± 1

24

27

<180

<0.27

10

Dnieper River7±2

11 ± 63.3 ± 19±311 ± 3<80

260 ± 170

PCingest [6.4]

1000

500

200

10 000

100

1000

112

TABLE 6.15. CONCENTRATION OF RADIONUCLIDES IN WATER OF THE KONOPLYANKA AND
DNIEPER RIVERS (NOVEMBER 2001)
Concentration of natural radionuclides (mBq/L)
Polonium- Uranium- Uranium210
238
234

Total alphaactivity(mBq/L)

Total beta
activity(mBq/L)<110.2 ± 0.1

13 ± 217 ± 2350 ± 110320 ± 140

34 ± 7<110.5 ± 0.2

115 ± 15118 ± 5300 ± 110590 ± 230

Dnieper River

51 ± 12<11

1 ± 0.519 ± 217 ± 2450 ± 160

290 ± 140

5

Dnieper River

41 ± 10<110.8 ± 0.3

7±2

14 ± 2230 ± 110<300

6Konoplyanka River

28 ± 512 ± 544 ± 1149 ± 11250 ± 120<300

7Konoplyanka River

11 ± 5<11

3.8 ± 1110 ± 15130 ± 151600 ± 500

1070 ± 320

8Konoplyanka River (granite
open pit)

10 ± 5<11

3.4 ± 0.8

16 ± 821 ± 81290 ± 300

760 ± 280

9

Konoplyanka River

23 ± 511 ± 51.8 ± 0.64645750 ± 250

<300

10

Dnieper River

24 ± 7<11

1.7 ± 0.4

13 ± 211 ± 2710 ± 2502

<300

PCingest [6.4]

1000

500

200

10 000

10 000100

1000

SampleNo.a

Sampling place

Radium226

Lead2101

Dniprodzerzhinsk reservoir

35 ± 7

3

Konoplyanka River mouth

4a

5 ± 1.2

The same as shown in Table 6.14.

TABLE 6.16. CONCENTRATION OF RADIONUCLIDES IN BOTTOM SEDIMENTS (Bq/kg)a
Sampleb

Sampling place

Potassium40

Caesium137

Lead210Radium226

Thorium232

Uranium238

1 (sand)Dniprodzerzhinsk reservoir

38 ± 2

3.1 ± 0.2

3.4 ± 1.4

2.7 ± 0.2

3.7 ± 0.3

3.0 ± 1.2

3 (sand)

Konoplyanka River mouth

106 ± 51.7 ± 0.1

12 ± 25.2 ± 0.2

7.1 ± 0.3

4.9 ± 1.64 (sand)

Dnieper River

93 ± 41.9 ± 0.1

9.0 ± 1.5

3.6 ± 0.2

7.1 ± 0.4

4.3 ± 1.55 (sand)

Dnieper River

181 ± 86.2 ± 0.3

30 ± 511 ± 0.4

13 ± 0.6

7.9 ± 3.0

6 (sand)

Konoplyanka River

153 ± 827 ± 165 ± 849 ± 1.926 ± 243 ± 137 (silt)

Konoplyanka River

164 ± 129.0 ± 0.7

152 ± 15130 ± 435 ± 2116 ± 30

8 (silt)

Konoplyanka River (granite
open pit)

301 ± 1632 ± 2330 ± 26

109 ± 3114 ± 4134 ± 34

9 (sand)

Konoplyanka River

113 ± 514 ± 119 ± 2

12.3 ± 0.3

5.6 ± 0.3

5.2 ± 1.610 (sand)

Dnieper River

86 ± 45.5 ± 0.3

21 ± 36.8 ± 0.3

6.8 ± 0.4

4.3 ± 1.8abSame sample as in Table 6.15.
In the soils of Ukraine the average content of natural radionuclides is: Utotal = 30–45 Bq/kg, 226Ra = 14–25 Bq/kg.

According to data obtained in spring toautumn 2001, the concentrations of uranium in thebottom sediments of the Dniprovske reservoir were
within the range 0.8–5.3 mg/kg (20–134 Bq/kg). The
highest levels of uranium in the Dniprovske
reservoir occur in the silt–sandy sediments at thesite located below the discharges of the Petrovsky
metallurgical plant. The values are 5.3–11.5 mg/kg,
which is comparable with the levels observed in theclayey bottom sediments of the Konoplyanka River.
However, there is no increase in concentration of

uranium in the water at this site, suggesting thaturanium is present in an insoluble form.
The above results and assessments indicatethat drainage from tailings D is having an effect on
the aquatic ecosystem of the river tributaries to the
Dnieper reservoirs and, in particular, theKonoplyanka River. Unfortunately, there are few
reliable data on the accumulation of natural radionuclides in the aquatic species of the rivers andreservoirs of this region. Radioecologicalmonitoring of the accumulation of radionuclides in113the phytoplankton, benthic organisms and fish of
the rivers and reservoirs should be part of any
future radioecological studies in this region.

6.10. PLANS FOR FUTURE RESTORATIONOF RADIOACTIVE WASTE SITES
Currently, because of economic problems,
there are no restoration activities. However, under
the State Programme for Improving Radioactive
Safety of Nuclear Industry Facilities in Ukraine, thegovernment has set out a new programmecomprising several tasks [6.2], including:
(a)

(b)

(c)

(d)

(e)

The complete restoration of the tailings
impoundment KBZh at Zhovti Vody andrestoration of the waste dumps of the Ingulsky
and Smolino mines.
Carrying out restoration of the Prydniprovsky
chemical plant uranium site, including
tailings D and C section I.
The development of an environmental
monitoring system for the Zhovti Vody andPrydniprovsky chemical plant sites. The
planned system includes analysis of air, soil,
surface and groundwater, vegetation, etc.
The development of new regulations for theoperation and restoration of the uranium
tailings in accordance with existing international recommendations.
The development and support of a comprehensive research programme.

(c)

(d)

(e)

(f)

6.11. CONCLUSIONS AND
RECOMMENDATIONS(g)
The following conclusions and recommendations are made in respect of radioactive contamination arising from former and current uranium
processing operations in Ukraine:
(h)
(a)

(b)

114

Uranium mining and milling in Ukraine has
had a negative impact on the environment.
The most serious problem is caused by about
100 × 106 t of accumulated tailings and otherradioactive waste from past and current
operations.
Most of the tailings dumps have not been
properly rehabilitated and will pose a longterm problem unless they are properly(i)stabilized. Tailings D at Dniprodzerzhinsk is
considered to have the greatest potential forpollution of the environment because of its
proximity to the Dnieper River, the evidenceof current seepage and the possibility ofcatastrophic failure of the impoundment.
There is a paucity of data on the levels ofradionuclides in the vicinity of uranium mines
and mills and radioactive waste impoundments. Consequently, it is not possible toestimate the current or future dose rates fromthese sources with any degree of accuracy.
An ongoing system for radioecologicalmonitoring of the environment (water, soil,
vegetation, air and food products) in theaffected regions (Zhovti Vody, mining areas
and Dniprodzerzhinsk) needs to be established. This should involve provision of
appropriate equipment and coordination of
the efforts of the external monitoring organizations. It is advisable to involve the scientificinstitutes of the Academy of Science of
Ukraine in this activity.
The pollution resulting from past and present
operations in the Dniprodzerzhinsk industrial
complex needs to be considered holistically inorder to understand their respective contribution to pollution of the Dnieper River basin
and the effects of interactions between the
major waste storage areas. Essentially, there
needs to be an overall plan for the site, which
will include rehabilitation of sites along withpossible further industrial development.
Rehabilitation of the non-operationaluranium tailings impoundments at Zhovti
Vody and Dniprodzerzhinsk needs to becompleted in order to ensure that they provide
long term containment.
In any rehabilitation plan, particular attention
should be given to tailings D and the
Konoplyanka River, which is acting as aconduit for the transfer of pollutants from thetailings impoundment into the Dnieper River.
The situation in the region of tailings C andadjacent to it needs regular control, and thedecisions on further use should be taken withregard to IAEA recommendations and on thebasis of cost–benefit analysis.
Current and future operations need to be
carried out in accordance with an environmental plan that includes funding provisions
to ensure progressive rehabilitation of closed
mines, dumps and other facilities.

(j)It is necessary to urgently start thedevelopment of modern standards onprotection of the environment, radiation
safety and monitoring in the zone of influenceof the uranium sites, consistent with therequirements of Ukrainian laws, Ref. [6.4] andrecommendations by international organizations such as the IAEA.

REFERENCES TO SECTION 6[6.1] OECD NUCLEAR ENERGY AGENCY,
INTERNATIONALATOMICENERGYAGENCY, Uranium 1999: Resources, Production
and Demand, OECD, Paris (2000).
[6.2] OECD NUCLEAR ENERGY AGENCY,
INTERNATIONALATOMICENERGYAGENCY, Environmental Remediation at
Uranium Production Facilities, OECD, Paris(2002).
[6.3] INTERNATIONALATOMICENERGYAGENCY, Regulatory Control of Radioactive
Discharges to the Environment, IAEA Safety
Standards Series No. WS-G-2.3, IAEA, Vienna(2000).
[6.4] Radiation Safety Norms of Ukraine, Rep. NRSU97, Ministry of Health of Ukraine, Kiev (1998).
[6.5] Radiation Safety Norms of Ukraine, Supplement:
Radiation Protection from Potential Irradiation
Sources, Rep. NRSU-97/D-2000, Ministry of
Health of Ukraine, Kiev (2000).
[6.6] Radiation Safety Standards of Ukraine, Basic
Sanitary Rules, Schedules and Requirements
Concerning the Order of Application (NRSU/
OSPU), Ministry of Health of Ukraine, Kiev
(2002).
[6.7] MOLCHANOV, A., SOROKA, Y., ISAYEVA,
N., MORTBERG, E., “The state of environment
on former site of in-situ leaching uranium”,
ICEM’95: Radioactive Waste Management andEnvironmental Remediation (Proc. 5th Int. Conf.
Berlin, 1995), American Society of MechanicalEngineers, New York (1995) 1507–1010.
[6.8] OECD NUCLEAR ENERGY AGENCY,
INTERNATIONALATOMICENERGYAGENCY, Environmental Activities in Uranium
Mining and Milling, OECD, Paris (1999).
[6.9] RUDY, C., et al., “Technologies for environmental
restoration in Ukraine”, Planning for Environmental Restoration of Radioactively Contaminated Sites in Central and Eastern Europe, Vol. 3:
Technologies for, and the Implementation of,Environmental Restoration of ContaminatedSites, IAEA-TECDOC-865, IAEA, Vienna (1996)
243–279.
[6.10] SOROKA, Y., MOLCHANOV, A., ISAYEVA,
N., “Rehabilitation program for territory of town
Zhovty Vody after 40 years of uranium ores

[6.11][6.12][6.13][6.14][6.15][6.16][6.17][6.18][6.19]

output”, ICEM’97: Radioactive Waste Management and Environmental Remediation (Proc. 6th
Int. Conf. Singapore, 1997), American Society of
Mechanical Engineers, New York (1997) 773–776.
RUDY, C., “Environmental restoration in regionsof uranium mining and milling in Ukraine:
Progress, problems and perspectives”, Planningfor Environmental Restoration of Uranium
Mining and Milling Sites in Central and Eastern
Europe, IAEA-TECDOC-982, IAEA, Vienna(1996) 189–198.
Assessment of Urgent Measures to be Taken for
Remediation at Uranium Mining and Milling
Tailings in the CIS, Regional Project No. G 4.2/93,
NUCREG 9308, COGEMA, Paris (1999).
Evaluation of Environmental Impact of theUnderground Leaching Site “Devladovo”, Branch
Programme for the Improvement of Radiation
State of Uranium Objects of Industry and their
Regional Locations, UkrSRIPI, Zhovti Vody
(2001) (in Russian).
Evaluation of Urgent Measures for the Recovery
of Uranium Ore Extraction and Processing Sites
in the NIS. Stage III, Modeling: Investigation of
the “Devladovo” Underground Alkalizing Site
(Ukraine), Regional Project TACIS 64.2/93–
NUCREG 9308, COGEMA–SGN, Paris (1998)(in Russian).
SOROKA, Y., “Decision of rehabilitation
problem for territories of the first uranium mine in
Ukraine”, ICEM’99: Radioactive Waste Management and Environmental Remediation (Proc. 7th
Int. Conf. Nagoya, 1999), American Society of
Mechanical Engineers, New York (1999).
SOROKA, Y., “Identification and characterization of radioactively contaminated sites in
Ukraine and planning for environmental restoration activities”, Site Characterization Techniques
Used in Environmental Restoration Activities,
IAEA-TECDOC-1148, IAEA, Vienna (2000)
201–218.
Studying the Conformance of Mining Waters in
the Run-offs of “Pershotravneva-Drenazna” Mineto the Requirements of Normative Documents of
Ukraine for the Radiation Factor, Report of
SRIRP/CSC “Tetra”, Kiev, Zhovti Vody (2001) (inRussian).
KOROVIN, V., et al., “Problem of radioactive
pollution as a result of uranium ores processing”,
Proc. Conf. on Scientific and Technical Aspects ofInternational
CooperationinChernobyl,
UKRATOM Vydav, Slavutich (2001) 469–476.
SOROKA, Y., KOROVIN, V., MOLCHANOV,
A., “Radioactive wastes of processing of uraniumores on Pridniprovsky chemical plant — Theirinfluence and problems of stabilization”, DisTec
2000: Radioactive Waste Disposal (Proc. Int. Conf.
Berlin, 2000), Kontek Gesellschaft für technische
Kommunikation, Hamburg (2000) 383–388.

115

7. OTHER RADIOLOGICAL SOURCESWITHIN THE DNIEPER RIVER BASIN

Sections 4–6 give information on andassessments of radiological sources associated withChernobyl affected areas, nuclear power plants anduranium mining and processing. This section briefly
considers other sources, which include:
(a)
(b)
(c)
(d)

Research reactors and associated facilities;
Sources resulting from medical and industrial
uses of radioisotopes;
Contaminated waste of Chernobyl origin thathas been buried;Radioactive waste storage/disposal facilities.

Military sources are not considered because of
the absence of reliable information. Spent fuel andradioactive waste produced by nuclear power plants
are discussed in Section 5.7.

7.1. RESEARCH REACTORS
There are two research reactors in Ukraine,
the 10 MW(th) WWR-M reactor at the Kiev
Institute for Nuclear Research of NASU and the
200 kW(th) IR-100 reactor at the Sevastopol
Institute for Nuclear Power and Industry. The IR100 reactor, originally used for training nuclear
submarine operators, was shut down in 1995.
The WWR-M reactor went critical in 1960 and
was used for research into nuclear physics, radioisotope production and radiobiology in the former
USSR and then Ukraine. The reactor has
undergone a number of upgrades to improve
performance and safety, including the following:
(a)
(b)
(c)
(d)
(e)
(f)

116

Installation of a modern system for physicalprotection;
Installation of a new computer system foraccounting of nuclear material;
Installation of a new system for fire
protection;
Installation and connection of two diesel
engines for emergency power;
Improvements to the control and safetysystems;
Installation of a facility for processing liquidradioactive waste.

The reactor is temporarily shut down.
Belarus operated a 4 MW(th) research reactor(IRT-M Minsk) at the Sosny Institute nuclear
complex from 1962 to 1988. There are plans todecommission the reactor. The spent fuel from thereactor will be stored in the Ecores State facility(see Section 7.4.2).
There are no research reactors within the
Russian section of the Dnieper River basin.
The research reactors within the Dnieper
River basin do not have any impact on thesurrounding environment or the Dnieper Riversystem. The decommissioning of these reactors will
generate a significant quantity of radioactive waste.

7.2. MEDICAL AND INDUSTRIAL USES OF
RADIOISOTOPESRadioisotopes are widely used in medicine
and industry within Belarus, the Russian Federationand Ukraine.
In Ukraine all users of radioisotopes need tobe licensed by the competent authority (Ministry ofEnvironmental Protection and Safety) inaccordance with the Law on Nuclear Energy
Utilization and Radiation Safety. There are about
8000 users and 100 000 ionizing radiation sources in
Ukraine. An inventory of these sources is in preparation.
In Belarus about 600 firms and companies use
radioactive material and radioactive sources ofvarying intensity in medicine, industry and research;
they include 60 laboratories that use open
radioactive sources for research purposes. The total
number of officially registered shielded sealed
radiation sources located on the premises of users isabout 6500. The most significant sources are used inresearch, industry and radiotherapy irradiators,
which are located as follows: 29 in the Minsk region;
11 in the Brest region; five in the Gomel region;
three in the Vitebsk region; three in the Grodno
region; and five in the Mogilev region.
In the Russian part of the Dnieper River basinseveral hundred firms and companies (primarily
medical) use radioactive material and ionizing
radiation sources; none of these (except the Kursk

and Smolensk nuclear power plants) is included in
the official list of nuclear and radiation facilities ofincreased hazard established by Resolution No. 707
of the Government of the Russian Federation(2 October 2001).
Radioisotopes used in diagnostic medicine
generally have short half-lives and have no impact
on the general public or the environment. Radiation
sources used in industry or radiotherapy are often
highly radioactive and can pose a localized problem
if not properly handled or secured.
In Belarus, Promatomnadzor is responsible
for the issuing of permits and licences for all
activities involving ionizing radiation sources where
the total activity of sources being used exceeds 3.7 ×1010 Bq (1 Ci). Promatomnadzor inspects radiation
sources to ensure that they are used and storedsafely.
Disused radiation sources are a potential
source of exposure if not properly managed. They
are often very intense sources of radiation and, inthe past, poor management has resulted in highexposures of individuals in several countries.
Regulatory authorities need to maintain a registerof sources and ensure that they are properly
licensed and managed.

7.3. BURIED WASTE OF CHERNOBYLORIGIN
7.3.1.

Storage and disposal sites in Ukraine

Soon after the Chernobyl accident,
radioactive waste storage and disposal sites were
established within the 10 km exclusion zone. The
contaminated items dumped in these sites included
soil, wood, equipment, structures and other debris.
The burial operations were carried out to reduceradiation levels near the Chernobyl nuclear power
plant and to prevent dispersion by wind and water.
There were two types of site: interim radioactive
storage sites (IRSSs), which were regarded as
temporary holding areas, and radioactive disposalsites (RDSs), which were considered to bepermanent. The burial activities were not well
documented at the time, but beginning in 1990 a
programme was undertaken to estimate inventories[7.1]. The sites were classified into various sectors
depending on their location. Table 7.1 shows thesector area, inventory and dose rate in themonitored zone. Figure 7.1 shows the location ofthese sites in the near zone of the Chernobyl
nuclear power plant. Further information on thegeology and other characteristics of each site isgiven in Ref. [7.1].

TABLE 7.1. CHARACTERISTICS OF RADIOACTIVE WASTE BURIAL SITES WITHIN THE 10 km
CHERNOBYL EXCLUSION ZONE IN 1996 [7.1]
Sector area(ha)

Waste volume(m3)

Activity(Bq)

Dose rate(mGy/h)125

2.9 × 105

1.1 × 1015

10–30 000

Ryzhii Les IRSS

400

5.0 × 105

14

30–10 000

Yanov Station IRSS

128

3.0 × 104

3.7 × 1013

Pripyat IRSS

70

1.6 × 104

13

10–600

Neftebaza IRSS

42

2.2 × 104

6.2 × 1013

20–500Peschanoe Plato IRSS88

1.0 × 105

13

20–600Kopachi IRSS

125

1.1 × 105

3.3 × 1013

10–30012

2–500

Storage/disposal site
Stroybaza IRSS

4.8 × 10

2.6 × 10

3.7 × 1025–8000

Chistogalovka IRSS

6—

3.7 × 10

Buriakovka RDS

14—

2.4 × 1015

3–280

15

20–400
7–600

Podlesny RDS

6—

2.5 × 10

Kompleksny RDS

2—

1.3 × 1015

117

Semikhody inlet
Pripyat inlet
Lake Azbuchin
5

ip
Pr

4

tR
ya

ty

er
iv

Ci

of
P

rip

ya
t

Chernobyl
nuclear power
plant

3
1

Cooling pond

2
Industrial site

1
Ro

dv

ing

Legend:

1

St

rea
m

Radioactive waste dumpsites:
1-Stroybaza; 2-Red Forest;
3-Yanov; 4-Neftebaza;
5-Peschanoe Plato
Groundwater flow
direction
0

0.5

1

1.5 kmFIG. 7.1. Waste storage sites in the near zone of the Chernobyl nuclear power plant.

The most likely mechanism for release ofradioactivity from these burial sites is via leachingof radionuclides from the waste and theirsubsequent transport by groundwater into rivers
and streams (mainly the Pripyat River) and theninto the Dnieper River basin. The release of radionuclides from burial sites via leaching andgroundwater migration is discussed in Section 4.
118

7.3.2.

Waste from decommissioning of Chernobyl
nuclear facilities

The last operating Chernobyl reactor (unit 3)
was shut down on 15 December 2000. Ukrainian
Government Resolution No. 399 of 25 April 2001
established a special State enterprise, known as‘Chernobyl nuclear power plant’, with the task ofsafely decommissioning the reactor units, providing
a new safe confinement for unit 4 and providing
radioactive waste management facilities for the
resulting waste.
The radioactive waste produced as a result of
current activities is taken from the industrial siteand buried at the specially constructed Buriakovka
radioactive waste storage site (see Table 7.1).
Over 19 000 m3 of liquid radioactive waste has
been collected at the Chernobyl nuclear power
plant site. The liquid storage facilities are currently
about half full. New facilities are under construction
for the safe processing of liquid and solid waste,
including a special waste management plant,
VECTOR, for incineration and packaging of solidradioactive waste.
7.3.3.

Chernobyl contaminated waste in Belarus

After the Chernobyl accident about a quarterof the territory of Belarus was contaminated withradionuclides. In the first years after the Chernobyl
accident, decontamination activities generated alarge amount of radioactive waste within the Gomel
and Mogilev regions. The decontamination waste
included removed soil, roofing of buildings, planks,
waste from stockbreeding farms, etc. Waste wasbrought into interim storage sites arranged near theplaces of the decontamination operations.
The interim storage sites used during theinitial stages of decontamination were created
without appropriate control by administrative
bodies or scientific support. Hydrogeologicalconditions were not considered and waste was
frequently deposited in the water areas of bogs, on
the catchments of the Pripyat and Sozh Rivers, andalong natural watercourses that drain into theserivers.
In 1990 a special State programme wasundertaken to estimate the inventory and assess thesituation at the sites. The location of 92 decontamination waste disposal sites (DWDSs) was specified,
27 in the zone of the Pripyat fallout trace (near fieldzone) and 65 in the zone of the Sozh trace (far fieldzone). Figure 7.2 shows their location. The regional
breakdown was 85 in the Gomel region, four in the
Mogilev region and three in the Brest region.
Thirteen are in the exclusion zone and three of them
are within the Polessye State RadioecologicalReserve. Table 7.2 shows a breakdown of theconditions at the disposal sites and Table 7.3 gives
the waste characteristics. The total area of the nearsurface disposal sites is 6.5 × 105 m2 and theinventory at all sites is estimated as follows:
(a)
(b)
(c)

137

Cs: 2.4 × 1012 Bq.
90
Sr: 2.5 × 1011 Bq.
239,240
Pu: 3.4 × 109 Bq.

In order to study the possible contaminationof groundwater from leaching of radionuclides fromthe disposal sites, 11 of the largest DWDSs werestudied by the Institute of Radioecological
Problems and the Belarusian Hydrogeological
Expedition. The sites studied covered the spectrumof natural conditions and engineered environments.
For each chosen DWDS, soils, the subsurface
ground, surface waters and groundwaters weremonitored.
To estimate the possible influence of thedisposal sites on the environment, the conditions ofoperation of the 24 largest and least satisfactory
repositories were analysed: 16 sites located in a zoneof the Pripyat trace and eight sites in a zone of the
Sozh trace. The results are summarized in Table 7.4.
Measurements and modelling studies showed that137
Cs does not move significantly beyond theboundaries of the site. Strontium is more mobile,
but the zone of influence where the 90Sr concentration is above the national permissible level(NPL) for water of 370 Bq/m3 extends only 100–
300 m beyond the site.
Thus it is concluded that radioactive waste ofChernobyl origin in the Belarusian part of the
Dnieper River basin can only locally contribute toradioactive contamination of groundwater. There isno significant risk of surface water contamination
due to radionuclide runoff from the radioactive
waste depositories. Nevertheless, studies haveshown that a number of measures should beundertaken in the future to put the repositories inorder, to establish a groundwater monitoring system
around the repositories and to continue specification of the radioactive waste inventory, especiallyat those sites that are located at sites of potential
irrigation, ravines, gullies and other forms of relief
where surface drainage forms and undergrounddrainage takes place. Specifically, in the near future,
it will be necessary to:(i)Carry out a classification of sites depending on
the level of potential danger and to decide on
the control and monitoring of the mostdangerous repositories;

119

LEGENDRadioactive contamination with caesium-137
37

185 555 1480

kBq/m2

1

5

Ci/km21540

Decontamination waste disposal sites
in the territory of the Dnieper basin (Belarus)
Ecores State facility
SETTLEMENTS
City
Town
Chernobyl nuclear power plant

FIG. 7.2. Location of sites (circles — see legend) of buried Chernobyl radioactive waste in Belarus.

(ii)

Carry out inspections and inventory measurements on sites within the exclusion zone in
Belarus;(iii) Solve questions of water use and land use
around disposal sites.
7.3.4.

Disposal sites in the Russian Federation

After the Chernobyl accident several dozen
radioactive waste disposal sites were established in
the Russian part of the Dnieper River basin(Bryansk region). The main content of the sites is

120

contaminated earth and radioactive waste produced
as a result of decontamination activities. The waste
was disposed of in trenches or earth embankments
without engineered barriers. Caesium-137 is thedominant radionuclide in the buried waste. Both thespecific and total radioactivity of waste localized in
the Russian part of the Dnieper River basin are
significantly lower than those in the Ukrainian andBelarusian parts. The total volume, radioactivity
and distribution of waste within administrative
districts of the Bryansk region are given in
Table 7.5.

TABLE 7.2. CONDITION OF DECONTAMINATION WASTE DISPOSAL SITES IN
BELARUS: NUMBER OF SITES ACCORDING TO LOCATION [7.2]
Condition

Pripyat River basin

Sozh River basin

Number in each region
In the exclusion zone
In the resettled zone

27
13
14

65
—
65

Design conditions
With an artificial barrier of clay or concreteWith a natural barrier (i.e. with an unsaturated(vadose) zone beneath the repository base)

4
17

7
23

Site characteristics
In quarries
In foundation pits
In trenches
In holesIn gullies
Surface repositories of heap type

6
10
7
1
—
3

21
12
10
3
3
16

Adverse conditions of operation
Can be flooded by rising groundwater
Can be swamped by surface water

6
—

35
3

TABLE 7.3. CHARACTERISTICS OF WASTE IN WASTE DISPOSAL SITES IN BELARUS [7.2]
Pripyat River basin

Sozh River basin

Characteristic
Caesium-137

Strontium-90

Caesium-137

Strontium-90

Activity in DWDSs (kBq)
Maximum
Minimum

450 × 1060.18 × 106

150 × 106
0.012 × 106

200 × 106
11 × 103

2.9 × 106
1 × 103

Specific activity (kBq/kg)
Maximum
Minimum

244.2
0.3

42.0
0.02

111.0
0.5

1.5
0.001

Volume of waste in DWDSs (m3)
Maximum
Minimum
Contamination of the territory
around DWDSs (kBq/m2)
Maximum
Minimum

41 000
180

8440
210

7.4. STORAGE/DISPOSAL OF
RADIOACTIVE WASTE FROMNON-POWER APPLICATIONS
7.4.1.

UkraineIn Ukraine all activities related to radioactive
waste management from non-power applications are

18 400
71

634
4

3125
210

78
1.0

carried out by the RADON State enterprise, which
operates facilities at six regional locations: Kiev,
Donetsk, Odessa, Kharkiv, Dnipropetrovsk andLviv. The total activity of accumulated radioactive
waste in these storage sites is about 27 PBq (mainly
tritium, 241Am, 137Cs, 60Co, 192Ir, 239Pu and 226Ra). Just
two facilities, Kiev and Dnipropetrovsk, are locatedin the Dnieper River basin.
121

TABLE 7.4. CONDITIONS AND CONSERVATIVE ESTIMATES OF RADIONUCLIDE MIGRATIONFROM THE LARGEST AND LEAST SATISFACTORY DECONTAMINATION WASTE DISPOSALSITES IN BELARUS [7.2, 7.3]
Pripyat River basin

Sozh River basin

Characteristic
Caesium-137

Strontium-90

Caesium-137

Strontium-90

271
1.5

67
0.14

37
1.6

1.1
0.02

Activity in DWDSs (GBq)
Maximum
Minimum
Area occupied by decontamination waste (m 2)
Maximum
Minimum

59.8 × 103
0.6 × 103

2.5 × 1030.11 × 103

4.7
0

0
0

Average thickness of protective barrier (m)Maximum
Minimum
Maximum activity in groundwaters (Bq/m3)
Directly beneath repository
At a distance of 100 m from repository

0–1 × 105~0Zone of influence at which Cw ≤ Cw, NPL (m)Period of potential hazard of repositories (a)200–75 000 × 104
0–1 × 104
100–330
245–370

37–1300 × 105~0

480–7000 × 103
0.15–900

100–180
290–360

TABLE 7.5. CHARACTERISTICS OF CHERNOBYL ORIGIN WASTE INDISPOSAL SITES WITHIN THE BRYANSK REGION (DATA FROM THE
FRENCH–GERMAN INITIATIVE ON CHERNOBYL)
Total 137Cs activity (109 Bq)
3

3

Total waste volume (10 m )Range

Krasnogorsk

32.4

31.5

20–40

Novozybkov

18.9

111.5

50–130

Zlynka

2.3

29.1

10–30

Gordeevka

21.4

30.9

20–40

Klintsy

8.6

1.9

0.3–2

RADON is responsible for the collection,transport, storage and burial of low and intermediate level radioactive waste and spent sources fromall domestic enterprises, establishments and organizations, except for enterprises involved in power
production.
The majority of RADON repositories arelocated close to big cities, so there is potential forhuman intrusion. Moreover, many sources were
disposed of nearly 30 years ago under non-ideal
conditions, and there is some risk of mechanicaldamage to encapsulated sources.
122

Best estimate

At the Kiev RADON facility, solid and liquid
waste is stored in underground iron reinforced
concrete reservoirs. These tanks are located on theoutskirts of Kiev between the villages of Pyrogiv
and Chapayivka in the Vita River valley. The basesof the tanks are above the groundwater horizon;
nevertheless, infiltrating waters can transportleakage to the river.
Tritium waste was buried at the Kiev site in
the 1960s to 1980s as solids (such as lithium–aluminium hydride), liquids (tritiated water withactivities between 1.85–18.5 TBq/L) and gases.

Tritium has escaped from these tanks byevaporation and diffusion through the walls of theconcrete tanks. In the mid-1990s a high concentration of tritium (viz. 1.5–5 × 105 Bq/kg) was
detected in the vadose zone at the Kiev site. The
concentration in some wells has reached 6–7 ×
105 Bq/L. Contaminated underground waters fromthe site flow towards the Vita River. The concentration of tritium in the river during 1995–1997 was
found to be higher than the natural background, but
significantly lower than PCingest for drinking water(30 000 Bq/L) in the National Radiation Safety
Standard [7.4].
There is about 550 TBq of stored radioactive
waste (mainly tritium, 137Cs, 60Co, 90Sr, 239Pu and210Po) at the Dnipropetrovsk RADON site. There isno evidence of release of tritium or other radionuclides from this site or of radioactive contamination of any waterways in the region.
Another issue is management of spentionizing sources of high activity (greater than
37 TBq (1000 Ci)) containing 60Co or 90Sr. There areover 1000 such sources; however, they are strictly
controlled at the special waste storage sites of
RADON and do not pose a significant risk to the
Dnieper River basin.
At some RADON sites the quantity of waste
in storage is approaching the capacity of the facility
and new facilities will need to be constructed in thenear future.
Since independence, the regulatory authorityof Ukraine requires preparation of a SAR for
operation of a nuclear facility, including radioactive
storage/disposal facilities. SARs are underdevelopment for RADON facilities.

surface repositories of the Ecores State facility.
Originally this facility was built for the storage anddisposal of waste generated by the research reactor(at the Sosny Institute), but it was later opened up toother sources of radioactive waste.
The legislative basis for the operation of
Ecores are the Norms of Radiation Safety (NRB2000), the Sanitary Rules for Radioactive Waste
Management, 1985, and the Basic Sanitary Rules ofRadiation Safety (OSP-2002), which weredeveloped on the basis of the relevant laws ofBelarus.
The Ecores State facility contains two closed
trenches and two repositories being filled withradioactive waste. It is located in a wooded region
near Minsk (Sosny settlement, Minsk region). The
minimum distance to the Sloust River is 2 km, thenearest pond is at 1.6 km distance. Table 7.6 gives
the hydrogeological conditions at one of the Ecoresdisposal repositories.
An assessment of the conditions of solidradioactive waste storage at the Ecores repositories
shows [7.3, 7.5]:
(a)

(b)
(c)

(d)
(e)

7.4.2.

Belarus

In Belarus, low and intermediate level waste is
generated by small enterprises. This is placed in near

The content in the filled vaults is a conglomerate of different material (plastic, glass,metal, rags) contaminated with both short
lived and long lived radioisotopes;
A closed vault contains irradiated fuel (about
2 kg U) from the Sosny research reactor;
Radioactive waste including long lived alphaemitters such as 239Pu, 241Am and 226Ra isdisposed of in vaults with the rest of the waste;
Some of the solid radioactive waste iscombustible material;
Significant amounts of radioactive waste are
directly stored in concrete vaults without
containerization, which excludes a second
barrier to radionuclide migration beyond theboundaries of the vaults.

TABLE 7.6. HYDROGEOLOGICAL CONDITIONS OF ONE OF THE ECORES REPOSITORIES
Characteristic

ValuesThickness of vadose zone

28.0–42.0 m

Hydraulic gradient of the groundwater flow

~0.001 m/m

Thickness of aquifer~20 m

Annual amplitude of the groundwater table fluctuations

0.9–1.0 m

Host rocks of vadose zone and aquifer

In general, mid-sands; inserts, small and large sands

123An analysis of the operating conditions of theEcores repositories indicates that waste is being
stored in violation of international recommendations for the safe storage of radioactive waste.
Furthermore, an assessment of the potential hazard
from the repositories has shown that, within thesanitary protection zone, it is possible that thepermissible concentration in the groundwater could
be exceeded in the future for the following
radioisotopes [7.3]:
(a)

(b)

Carbon-14, 16Cl, 60Co, 90Sr, 239Pu, 226Ra and232
Th, as a result of migration of radioactive
waste from the closed trenches;
Tritium, 90Sr, 238U, 239Pu and 226Ra, as a resultof migration from radioactive waste in repositories that are in the process of being filled.

(c)

(d)

It should be noted that these concerns are forthe local population living in the immediate vicinityof the facility. However, the repository is remotefrom the Dnieper River and any environmental
impact in the future will be localized.
The reconstruction of the Ecores facility will
include the following:(a)Conservative modelling shows that, within thesanitary protection zone, the maximum permissible
individual dose (1 mSv/a) may be temporarily
exceeded by a factor of ten to 1000 due to supply of
drinking water contaminated with radionuclides.
Beyond the boundaries of the sanitary protection
zone this is possible within 2000 to 20 000 years
because of 239Pu, 226Ra and 232Th seepage from therepositories. Within a period of 20 to 1000 years themost hazardous radionuclides are 14C, 36Cl, 90Sr,
238
U and tritium, because they are weakly absorbedby the geological medium. Their high migration
ability can result in contamination of the lower
aquifer, used for municipal water supply. The radionuclides 239Pu, 241Am, 226Ra and 232Th are hazardous
for future generations as long lived radiotoxic
isotopes that can contaminate the aquifer withhazardous concentrations in the distant future.
The need to upgrade the Ecores facility wasrecognized immediately after a new regulatory
regime was established in Belarus. In 1997 the joint
efforts of several ministries were responsible forlaunching a national project for the reconstructionof Ecores.
The following factors were important in thedecision to reconstruct the facility:
(a)

(b)

124

The Ecores repositories had been operated inviolation of the international safety requirements for a radioactive waste facility;
The present repositories of the Ecores facility
are almost completely full, threatening thenormal functioning of institutions andenterprises where radioactive sources arebeing used;

Safety assessment studies have shown that
there is a real threat of radioactive contamination of aquifers used for drinking water,
due to leakage of radionuclides from thewaste;The population of the nearest settlements wasconcerned about possible negative healthimpacts in the future.

(b)

(c)

(d)

Construction of an additional repository witha capacity of 3000 m3 that allows material fromthe old repositories to be relocated in the newfacility.
Design for long term storage rather thandisposal. This means that waste must be
retrievable
andproperly
conditioned,
packaged and labelled.
New plant and equipment for treatment andpackaging of waste, including compaction andcementation of waste.
Improvements in bore hole design for spentsealed radioactive sources.

In reconstructing the Ecores facility, a number
of issues have still to be resolved. These include[7.5]:
(a)
(b)
(c)
(d)

Technical procedures for the safe retrieval andsorting of waste from the existing repositories;
Long term safety considerations;Public acceptance of relatively high levels ofalpha emitters in a near surface facility;
Ensuring the safety of existing RADON wells.

Reconstruction of Ecores is in progress. The
rate of progress will be dependent on the availability of funding.

7.5. CONCLUSIONS(a)

There are no operating nuclear research
reactors within the Dnieper River basin. The
decommissioning of three non-operating

(b)

(c)

(d)

(e)

reactors will generate significant amounts ofradioactive waste.
Medical and industrial uses of radioisotopes
do not pose significant risks to the populationof the Dnieper River basin. Radioactive
sources with high radioactivity could be asource of local exposure. Regulatory
authorities should ensure that these sources
are properly licensed and managed.
There are many disposal or temporary storagesites for Chernobyl waste in Belarus, theRussian Federation and Ukraine. There is aneed to continue to monitor and characterize
the most hazardous of these sites; however,their impact appears to be quite localized andthey do not represent a major source ofcontamination of surface waters.
There are two RADON type waste storage
facilities at Kiev and Dnipropetrovsk in the
Ukrainian section of the Dnieper River basin.
Further safety assessments need to beundertaken to assess their environmental
impact.
The Ecores State facility near Minsk does notcomply with international standards for the
storage or disposal of radioactive waste. Thisfacility is a potential source of radioactive
contamination of the local population, but not

the Dnieper River basin as a whole. There areplans to reconstruct this facility to modern
standards, although this is dependent on theavailability of funds.

REFERENCES TO SECTION 7
[7.1]

[7.2]

[7.3]

[7.4]
[7.5]

KUKHAR, V., POYARKOV, V., KHOLOSHA,
V., “Radioactive waste”, The Chernobyl Accident:
A Comprehensive Risk Assessment (VARGO,
G.J., Ed.), Battelle Press, Columbus, OH (2000).
SHIRYAEVA, N., et al., “Status of the low level
waste repositories and use of their safety assessment for decision making processes in Belarus”,
paper presented at the Regional Workshop on
Upgrading and Safety Assessment for Near
Surface Waste Disposal Facilities, Budapest, 2002.
SHIRYAEVA, N., et al., “The state and safetyassessment of the low level waste repositories inthe territory of Belarus”, Waste Management 2000
(Proc. Conf. Tucson, AZ, 2000), Waste Management Symposia, Tucson, AZ (2000) CD-ROM.
Radiation Safety Norms of Ukraine, Rep. NRSU97, Ministry of Health of Ukraine, Kiev (1998).
BARIEV, E.R., NOVIKOV, G.F., ROZDYALOUSKAYA, L.F., “Achieving safety of RADONtype waste disposal facilities: Belarus experience”,
Issues and Trends in Radioactive Waste Management (Proc. Int. Conf. Vienna, 2002), IAEA,
Vienna (2003) 249–253.

125

8. ASSESSMENT OF HUMAN EXPOSURE TO RADIATIONWITHIN THE DNIEPER RIVER BASIN

Radioactivity in the environment or released
during an accident can result in human exposure.
This section is an assessment of the levels andeffects of human exposure to radiation from sources
within the Dnieper River basin.

8.1. OVERVIEW OF RADIATION DOSESAND ASSOCIATED HEALTH EFFECTS
This section gives a brief overview of theprinciples of radiation protection. It is based on thereports of the ICRP, the United Nations ScientificCommittee on the Effects of Atomic Radiation(UNSCEAR), the Basic Safety Standards [8.1] andan overview of radiation protection principles [8.2].
8.1.1.

Living organisms are continually exposed toionizing radiation from natural sources, which
include cosmic rays and terrestrial radionuclides(such as 40K, 238U, 232Th and their progeny, including222
Rn (radon)). Table 8.1 shows the average annual
dose and typical range worldwide from natural
sources. Data on the mean annual backgroundexposure in Ukraine, which is fairly typical of the
Dnieper River basin, are given in Section 8.4.
In addition to natural sources, radiation
exposure occurs as a result of human activities.
Table 8.2 shows the annual individual effective
doses in 2000 on a worldwide basis. Diagnostic
medical exposure is the largest non-natural sourceof radiation. The residual global effects of theChernobyl accident are now very small but, ofcourse, are higher in the Dnieper River basin.

Doses of ionizing radiation
8.1.2.

Alpha, beta and gamma radiation interact
with matter by causing ionization (i.e. removal ofelectrons from atoms or molecules). In living
matter, the process of ionization may damage
human cells, causing death to some and modifying
others. Exposure to ionizing radiation is measured
in terms of absorbed dose. The unit of absorbed
dose is the gray (Gy), which is a joule per kilogram(J/kg).
The biological effects of radiation to aparticular organ depend on the absorbed dose andthe type of radiation. The term ‘equivalent’ dose isused as a measure of biological damage to aparticular organ. Another term, the ‘effective dose’,is used to take account of the overall health risk due
to any combination of radiations affecting any
organ of the body. The unit of both equivalent doseand effective dose is the sievert. One sievert is arather large dose and so the millisievert (mSv) is
commonly used to describe normal exposures.
To evaluate the effects of exposing a defined
population group, the sum of all doses received by
the members of that group may be calculated. Thisis termed the ‘collective dose’ (in units of man-Sv).
It is sometimes used as a basis for decision making
when comparing the cost effectiveness of options(countermeasures) to reduce radiation exposure ofa population.
126

Radiobiological effects and health risks

When ionizing radiation passes through living
tissue it may interact with critical areas of the cell(such as the DNA), causing direct damage. Morefrequently, ionization will result in the formation offree radicals, which may then react with othermolecules within the cell. This may result in deactivation of chemical mechanisms or lead tointeraction with genetic material [8.4]. In most cases
the organism can repair cellular damage. At highTABLE 8.1.
RADIATION DOSES FROM
NATURAL SOURCES [8.3]Worldwide averageannual effective
dose (mSv)

Typical
range
(mSv)

0.4
0.5

0.3–1.0
0.3–0.6

Inhalation(mainly radon)

1.2

0.2–10Ingestion

0.3

0.2–0.8

Total

2.4

1–10

External exposure
Cosmic rays
Terrestrial gamma rays
Internal exposure

TABLE 8.2. EFFECTIVE DOSE IN 2000 FROM NATURAL AND HUMAN SOURCES [8.3]Worldwide average annual per
caput effective dose (mSv)

Range or trend in exposure

Natural background

2.4

Typically ranges from 1 to 10 mSv

Diagnostic medical
examinations

0.4

Ranges from 0.04 to 1 mSv at the lowest and highest levels of
health care

Atmospheric nuclear
testing

0.005

Decreased from a maximum of 0.15 mSv in 1963; higher in thenorthern hemisphere

Chernobyl accident

0.002

Decreased from a maximum of 0.04 mSv in 1986 (in the northernhemisphere); higher at locations nearer the accident site

Nuclear power
production

0.0002

Increased with expansion of nuclear programmes, but decreased
with improved practicedose rates, cells have less time to recover and theprobability of repair is lower.
The biological effects of radiation areclassified as either deterministic or stochastic.
Deterministic effects are those that are found tooccur only above some threshold of dose (typically
about 1 Sv or more), when large numbers of cells
are killed. Stochastic effects occur when a cell is
modified rather than killed. In such cases, the cell
resulting from the reproduction of a modified, but
viable, somatic cell may result in cancer after alatency period of from a few years to several
decades.
Knowledge of the effects of radiation
exposure on human health comes from epidemiological1 studies of the survivors of the atomic bombs
dropped on Hiroshima and Nagasaki, fromradiation accidents, from groups exposed torelatively high doses in radiotherapy, from occupational exposures and from experiments withanimals. Molecular radiobiology is now contributing
to an understanding of the mechanisms of radiation
damage.
It is known that radiation doses above about
100 mSv received in a short period lead to anincreased risk of cancer later in life. The risk factor
for fatal cancer averaged over all ages and cancer
types is about 1% for every 100 mSv of dose.
For radiation doses below 100 mSv theevidence of harm is not clear cut. At the levels ofdose typically received by the public, there is little
or no direct evidence of adverse health effects.
However, no threshold dose for stochastic effects
has been demonstrated. Given the scientific uncertainty, radiation authorities have considered it
1

Epidemiological data are now being gathered andassessed from the Chernobyl accident.

prudent to assume no threshold. This is termed the‘linear, no threshold hypothesis’.
The evidence for the relationship between
fatal cancer and dose is derived mostly from
relatively high doses and dose rates. Owing to thetime dependence of cellular repair mechanisms, theobserved figures need to be reduced for application
to low doses and low dose rates. Although theprecise figure is uncertain, the ICRP recommends,
on the basis of available evidence, that the risk
factor should be reduced by a factor of two. On thisbasis, the risk factor for a fatal cancer averaged over
all ages is 5%/Sv of dose.
The risk factors for radiation exposure aresubject to continuous review as more evidence
becomes available. In its latest publication [8.3],
UNSCEAR estimates the lifetime risk for solidcancer mortality from an acute exposure of 1 Sv tobe 9% for men and 13% for women. It recommends
that these estimates be reduced by 50% for chronic
exposures, with an uncertainty factor of two, higher
or lower. For leukaemia, the lifetime risk isestimated to be 1% for an acute dose of 1 Sv. The
available data suggest a non-linear response, so thatthe risk is reduced by 20-fold for a tenfold reductionin acute exposure (to 100 mSv).
Although deterministic effects did occur in theinitial phase of the Chernobyl accident, any current
and future exposures of the population of the
Dnieper River basin are likely to be chronic, lowdose rate exposures. On this basis, the risk
coefficient is taken as 5%/Sv of dose, as
recommended by the ICRP.
Hereditary effects in human populations due
to radiation have not been demonstrated, even in
the children of the survivors of the atomic bombingsin Japan [8.3]. However, radiation has been shownto cause hereditary defects in plants and animals,
127

and it can be assumed that humans are unlikely to
be exceptions to the rule. UNSCEAR has
concluded that the hereditary risk is 0.3–0.5%/Gy to
the first generation following exposure [8.3]. This isabout one tenth of the risk to the direct recipient of
the radiation of a fatal cancer.
8.1.3.

TABLE 8.3.
LIMITS [8.5]

ICRP RECOMMENDED DOSE

Dose limit
Application
Occupational
Effective doseInternational system of radiation
protection

Public20 mSv/a, averaged 1 mSv/aover five years

Annual equivalent dose to

Having regard for the detrimental effects ofradiation, the ICRP has recommended a system ofradiation protection for ‘practices’ (human activities
that give rise to additional controlled exposures)
based on three principles [8.2]:

The lens of the eye(a)interventions, the circumstances giving rise toexposure and the likelihood of exposure alreadyexist and so dose reduction can only be achieved bymeans of remedial actions (countermeasures). In
the context of this assessment, situations that may
require intervention include the state of theChernobyl shelter, cooling pond and Pripyat
floodplain or the uranium tailings from past
operations (as at Dniprodzerzhinsk). On the other
hand, controlled practices would include theoperation of nuclear reactors and uranium
processing plants.
The ICRP has recently provided guidance on
generic reference levels for intervention insituations involving prolonged radiation exposure[8.5]. In doing so, the ICRP has introduced theconcept of existing annual dose as that caused by all
persisting sources involving prolonged exposure.
The ICRP recommends that:

(b)

(c)

Justification of exposure. A practice thatinvolves exposures or potential exposures
should only be adopted if it is likely to
produce sufficient benefit to the individual or
society to outweigh the detriment or harm tohealth it may cause.
Optimization of protection. The magnitude ofindividual exposures, the number of people
exposed and the likelihood of exposures
should be kept as low as reasonably
achievable, economic and social factors being
taken into account (the ALARA principle).
Limitation of individual dose. The exposure ofindividuals should be subject to dose limits.
Table 8.3 gives the dose limits recommended
by the ICRP. These limits are designed toensure that deterministic effects are avoided
and that the risk of stochastic effects is
acceptably low.

The Statute of the IAEA gives it a responsibility to develop international standards for safety
in radiation protection. The IAEA has adopted the
ICRP recommendation in preparing the Basic
Safety Standards [8.1]. In turn, many countries(including Belarus, the Russian Federation andUkraine) have adopted these limits for regulatory
control purposes. The BSS gives numerical tables
for converting intake of radionuclides to dose, inorder that doses may be assessed and comparedwith dose limits, and so that radiation protection canbe optimized.
The dose limits in Table 8.3 apply to controlled
practices. Human activities that seek to reduce
existing radiation exposures or the likelihood of
exposure, and which are not part of a controlled
practice, are termed ‘interventions’. In the case of
128

150 mSv

15 mSv

The skin

500 mSv

50 mSv

The hands and feet

500 mSv—(i)

An existing annual dose of about 10 mSv may
be used as a generic reference level below
which intervention is not likely to bejustifiable for prolonged exposure situations.
(ii) Below a dose of 10 mSv/a, protective actions
to reduce a dominant component of theexisting annual dose are still optional andmight be justified. In such cases, specific actionlevels can be established for particularcomponents of the generic reference level.
(iii) Above a dose of 10 mSv/a, intervention may
possibly be necessary and its justification
should be considered on a case by case basis.
(iv) Situations in which the annual equivalent dosethresholds for deterministic effects in relevantorganscould
beexceededrequireintervention.

(v)An existing annual dose rising towards
100 mSv will almost always justify intervention.

Radiation exposures can also be classified as‘normal’ exposures, where the magnitude of the
exposure is fairly predictable, and ‘potential’
exposures, where exposure is feasible but notcertain. In the case of a potential exposure, it may
be possible to estimate the probability ofoccurrence and the resulting radiation exposure if itwere to occur.
In assessing radiation exposures, healthphysicists need to consider all possible exposure
routes and differences in human lifestyle and habitsthat can lead to higher than normal exposures. In agiven situation, one combination of exposure routes
and lifestyles will give the highest dose, often to
only a small group of people. The group thatreceives the highest exposure is known as thecritical group. The importance of the critical groupis that radiation protection measures are generally
applied to limit exposure to that group.
8.1.4.

Radionuclides in the Dnieper River basin

The main radionuclides currently at elevatedlevels in the Dnieper River basin are 137Cs, 90Sr and,to a much lesser extent, long lived isotopes of
plutonium from the Chernobyl accident and 238U
and its radioactive progeny from uranium mining
and ore processing in Ukraine. A brief summary of
the properties of these radionuclides is given below.
Caesium-137 is a beta emitter with a half-lifeof 30 years. It decays to a short lived daughter(137mBa), which is a gamma emitter. Consequently,
137
Cs can be a source of both internal and external
exposure. Being chemically similar to potassium,
caesium is taken up by plants and becomes part of
the food chain. It is soluble in body fluids and, uponingestion, is absorbed rapidly and distributed
almost uniformly throughout the body. It iseliminated by the kidneys with a biological half-life
in adults of 70–110 days [8.4]. Its biological half-lifein children is much shorter.
Strontium-90 is a beta emitter with a highfission product yield. It has a half-life of 29 years
and decays to 90Y, which is a stronger beta emitter.
Neither 90Sr nor 90Y emit gamma radiation, andmost of the dose from 90Sr is due to internal

exposure. Strontium is a member of the alkaline
earth group, which includes calcium, barium andradium. Like calcium, it is a bone seeker. About
25% of ingested 90Sr is absorbed into extracellular
fluid and about half this amount is deposited inbone, where it irradiates both calcified bone andadjacent bone marrow [8.4]. The effective half-lifeof 90Sr taken up in the body is about 15 years.
Plutonium has a number of isotopes, of which
239
Pu (half-life 24 000 years), 240Pu (half-life
6600 years) and 238Pu (half-life 88 years) are themost important in terms of potential long term
impact. Another isotope of plutonium, 241Pu, has a
half-life of 14.4 years and decays by beta emission to241
Am, which is an alpha emitter with a half-life of
432 years. Most isotopes of plutonium, americium
and other transuranic elements are alpha emitters,
which have a range of about 24 μm in bone and40 μm in soft tissue [8.4].
Owing to the short range of alpha particles,
plutonium only represents a biological hazard when
it is inside the body. Inhalation is the route of mostconcern for internal exposure. Deposition patterns
and retention of plutonium in the lungs depend on
physical and chemical properties, including its
solubility and particle size. The retention half-life in
the lungs is between 150 and 1000 days. If ingested
in soluble form, plutonium is concentrated in theskeleton and liver and has a biological half-life ofabout 200 years [8.4]. Plutonium is fairly immobile
in the environment and is strongly adsorbed on tosoils.
Uranium-238 has a very long half-life(4.5 × 109 years). It is the first member of a naturally
occurring decay chain that includes 14 radionuclides(eight alpha emitters and six beta emitters).
Important members of the decay chain are 230Th(half-life 80 000 years), 226Ra (half-life 1600 years)
and 222Rn (half-life 3.8 days). Thorium-230 is amajor inhalation hazard. Radium-226 is an alpha–gamma emitting bone seeker and a continual sourceof 222Rn. Although not a major radiation hazard in
its own right, radon, being a gas, is mobile in theenvironment and acts as a vehicle for dispersal of its
short lived, alpha emitting daughters, which depositin the lungs. Radon is the most significant isotope interms of occupational exposure in uranium mines
and is continually generated within uranium tailings
dumps. It is also a major contributor to the naturalradiation environment (see Table 8.1).

129

and leakage from tailings into Dnieper tributaries
and ultimately into the Dnieper River itself.
If river water is used for drinking and/or
irrigation, elevated levels of uranium compounds
and its daughter radionuclides may enter the humanbody. Ingestion is the major pathway of human
exposure, due to past and present operations of theuranium industry. However, in the immediate
vicinity of uranium tailings, a person could be
subjected to external exposure from gamma
radiation and to internal exposure via inhalation ofradon and its daughter products, and possibly
tailings dust.
Whereas natural radiation has accompanied
the whole of human history, significant environmental contamination with human-made radionuclides occurred during two time periods. The first
period of exposure started in the 1950s, andincreased in the 1960s, as the result of global stratospheric fallout from worldwide nuclear weapon
testing. The second period was in 1986, when a large
radioactive release occurred during the Chernobyl
accident. The largest population doses occurred in
the Dnieper River basin, and residual radionuclides
remain a source of radiation exposure.

8.2. MAJOR SOURCES AND PATHWAYS OFHUMAN EXPOSURE IN THE DNIEPER
RIVER BASIN
Radiation exposure of the population of the
Dnieper River basin is caused both by naturally
occurring radionuclides (40K, radionuclides of 238U,
235
U and 232Th decay chains, etc.) and human-maderadionuclides, mainly fission products (especially137
Cs and 90Sr). The pathways of human exposure
include external exposure from deposited gamma
emitting radionuclides and internal exposure via
ingestion of contaminated food and drinking water
as well as inhalation of airborne radionuclides. The
major pathways of human exposure from environmental radioactivity are schematically presented inFig. 8.1.
The concentrations of natural radionuclides inthe Dnieper River basin, and associated human
exposure levels, are generally close to averageworldwide levels. However, in uranium mining andmilling areas in the Dnipropetrovsk region of
Ukraine, concentrations of uranium and its
daughter radionuclides are significantly elevated inriver water due to releases to the Zheltaya River

Airborne effluent
discharge

Desposition
Original cloud ofcontaminated air

Direct irradiation

SourceSurface deposits
Liquid effluent
discharge

Exte
rnal

Run-off

Water bodies

Resuspension

Inhalation
External
irradiation
Deposition

irrad
iatio
n

External irradiation
Plants and crops

Sedimentation

UptakeExternal
irradiation

Resuspension
rain-splash

Sand and sedimentRoot
uptakeWater
purification

Uptakec Organisms

Aquatic plants
UptakeFood
preparation
Aquatic animalsnatio

External irradiation
Food
preparation

Irrig

UptakeDecomposition

Topsoil
Subsoil

UptakeB e nthiD e c o m p o s i ti o n

Ingestion

n

tio

Food
preparation
Food and drink

iga

Irr

Animalsg

Drinkin

FIG. 8.1. Main environmental pathways of human radiation exposure [8.7].

130

Deposition

Deposition
on skin/clothingCompared with the Chernobyl related
environmental contamination of the Dnieper Riverbasin with 137Cs and 90Sr, the historical global falloutof the same radionuclides, which happened 20–
30 years earlier, can be neglected in the present
dose calculations (see Ref. [8.6] for maps of the
distribution of fallout from global weapons testing
and the Chernobyl accident).
For completeness of public environmental
dose assessment, the levels of dose caused byregular discharges of Ukrainian nuclear power
plants should be considered. Reference [8.8] used
the PC CREAM computer code [8.9] to calculatedose rates for conditions of actual radioactive
discharges in 1988–1998 from four Ukrainian
nuclear power plants located in the Dnieper Riverbasin (Chernobyl, Khmelnitski, Rovno andZaporozhe). For these calculations, the minimum
distance between operating units and settlements
was taken to be 2 km. The results show that theappropriate annual doses range from 0.07 μSv forthe Khmelnitski nuclear power plant to 0.4 μSv for
the Zaporozhe nuclear power plant; these doses
rapidly decrease with increasing distance between
the source (the nuclear power plant) and the target(the settlement). The radionuclides that contributemost to the dose are 14C (long term exposure), 131I,
inert radioactive gases and tritium.
In the Russian Federation, gas–aerosol
releases of radionuclides to the environment fromRBMK reactors (the Kursk and Smolensk nuclear
power plants) are higher than those from WWER
units. Nevertheless, the population radiation doses
resulting from releases in the areas around theseplants are much lower than the site specific dose
constraints. Over the first 16 years of operation of
the Kursk nuclear power plant, the radiation dose to
the critical group was 40 μSv or, on average, 2.5 μSv/
a [8.10]. The main contributor to this dose (about95%) was exposure due to radionuclides in airborne
plumes.
From comparison of the above exposure levels
from nuclear power plants with the backgroundexposure (see Section 8.1), it is obvious that they
are negligible and therefore are not consideredfurther. The only radiological issue of concern withregard to nuclear power plants arises from possible
exposure following a nuclear accident. The
Chernobyl accident in 1986 was an example of amost severe nuclear power plant accident. Possiblelevels of human exposure in the event of an accident
at a Ukrainian nuclear power plant on the Dnieper
River are considered in Section 9.

8.3. MODELS OF EXTERNAL AND
INTERNAL EXPOSURE
8.3.1.

Model for external exposure

In this analysis we consider quasi-stationary
conditions when the dose rate both in the open air
and in buildings changes slowly during the year,
mainly because of the presence or absence of snow
cover. In the Dnieper River basin, such conditions
are applicable to long lived, naturally occurring
radioactive material (NORM) and fission products,from both global fallout and the Chernobyl
accident. In the case of the Chernobyl accident, thedominant radionuclide for external dose calculations is 137Cs, which has a half-life of 30 years and ahalf-life for dose reduction due to soil redistribution
processes of about 50 years [8.3, 8.11]. The effective
half-life of 137Cs/137mBa gamma radiation dose rate
reduction in open air due to both mechanisms isabout 20 years.
In order to assess external doses to humanscaused by natural radiation in temperate climate
conditions, Ref. [8.3] used a simple model ofhumans spending 80% of their time indoors and
20% outdoors. This model can be applied to areasslightly contaminated with Chernobyl fallout. For
the most significantly Chernobyl affected areas,
more precise models have been developed to justify
countermeasures in the early period, and to support
remediation and epidemiological studies in the later
period.
Deterministic models of exposure of different
age and social groups of the population residing in
the Dnieper River basin have been developed for
the Chernobyl accident on the basis of numerous
experimental investigations [8.12, 8.13]. Thesestudies included measurements of the dose rate indifferent periods after the accident above virgin soil
and in typical plots of settlements (including
residential, industrial and recreational buildings),
inhabitants’ surveys about their mode of behaviour
during different seasons, radionuclide analyses in
profiles of virgin soil and over 10 000 measurements
of individual doses using the thermoluminescencemethod [8.11–8.13].
According to the deterministic model
presented in Fig. 8.2, the average annual effective
dose Ek in the kth group of a settlement’s
inhabitants depends on: the absorbed dose rate in·air, D(t), at a height of 1 m above an open plot ofvirgin soil in this settlement and its vicinity; thelocation factor, LFi, which is equal to the ratio of131

Dose rateover soil

LocationfactorD(t)LFi

External dose to a human Ek
Ek = ∫ D(t) dt ∑ LFi OFik CFik
i

CFik

OFik

Dose conversion
factor

Occupancy
factor

FIG. 8.2. Model of external exposure of the kth occupational group of the population (i: location index).

dose rate at the ith typical plot in the settlement to·D(t); the occupancy factor, OFik, which is equal to
the fraction of time spent during a year at the ith
plot; and a conversion factor, CFik, which converts
the absorbed dose rate in the air to the effective
dose. Numerical values of the model parametersboth for the Russian Federation and Ukraine can befound in Refs [8.11-8.13].
Table 8.4 presents the generic dose conversion
parameters needed in order to reconstruct the past,assess the present and forecast the future average
effective external doses to the adult population of asettlement located in the intermediate (100 km < D< 1000 km) zone of Chernobyl contamination basedon experimental data and models developed in the
Russian Federation and Ukraine [8.12, 8.13]. The
values for indicated time periods for the populationof a settlement are given separately for the urban
and rural populations as the ratios of the mean
external dose (E) to the mean 137Cs soil deposition
in a settlement, as of 1986 (σ137) (μSv·kBq–1·m–2).
From Table 8.4, one can conclude that the urban
population has been exposed to a lower dose by afactor of 1.5 to 2 compared with the dose to therural population living in areas with similar levels ofradioactive contamination. This arises because of
the better shielding features of urban buildings anddifferent occupational habits.
The parameters obtained from independent
sets of Russian and Ukrainian data are in
reasonable agreement. Some differences can be
explained as being due to the different compositionsof radionuclide deposition that occurred in different
parts of the Chernobyl affected areas and to various
human habits. Multiplication of the parameterspresented in Table 8.4 by the mean 137Cs soil
deposition (as of 1986) gives an estimate of theexternal dose caused by gamma radiation from all
the deposited radionuclides.
Depending on occupation and type ofdwelling, the average doses to different social andage groups of people living in the same Russian
settlement differ by a factor of 1.7 from the meanvalue for a settlement [8.14] — Table 8.5.
8.3.2.

Model for internal exposure

The structure of a simple, Chernobyl related
model of internal exposure of a person located in anarea contaminated with radionuclides is presented
in Fig. 8.3. The main pathways of radionuclide
intake into the body of a person of kth age and

TABLE 8.4. RECONSTRUCTION AND PROGNOSIS OF THE AVERAGE EFFECTIVE EXTERNALDOSE TO THE ADULT POPULATION IN THE INTERMEDIATE (100 km < D < 1000 km) ZONE OF
CHERNOBYL CONTAMINATION
E/σ137 (μSv·kBq–1·m–2 of 137Cs)aPopulation
1986

1987–1995

1996–2005

2006–2056

1986–2056

Russian Federation [8.11, 8.12] Rural

14

25

10

19

68

Urban

9

14

5

9

37

Rural

24

36

13

14

88

Urban

17

25

9

10

61

Ukraine [8.13]aσ137 is given as for 1986.

132

TABLE 8.5. RATIO OF THE AVERAGE EXTERNAL EFFECTIVE DOSES IN SOME POPULATIONGROUPS TO THE MEAN DOSE IN A SETTLEMENT [8.14]
Type of dwelling

Indoor workers

Outdoor workers

Herders, foresters

Schoolchildren

Wooden

0.8

1.2

1.7

0.8

One to two storey, brick

0.7

1.0

1.5

0.9

Multistorey

0.6

0.8

1.3

0.7

gender group are considered: viz. inhalation withaverage inhalation rate IRk (m3/d) of air with timedependent concentration of rth radionuclide ACr(Bq/m3) and ingestion of the set of fth foodproducts,
includingdrinking
water,
withconsumption rate CRfk (kg/d) with time dependent
specific activity SAfr (Bq/kg). The model is also
applicable to the intake of NORMs.
Data on the radionuclide content in the air,drinking water and agricultural and natural foodproducts are obtained from current radiation
monitoring and radioecological studies. The rates of
air inhalation by persons of different ages andgenders for different activities are well known fromphysiological studies [8.15]. The consumption rateof different food products varies significantly,
depending both on age and gender and on local
technologies of agricultural production, collectionof natural food, dietary habits, etc. For internal dose
estimation after the Chernobyl accident, these data
were obtained by population surveys [8.16] andanalysis of statistical data. Age dependent dosecoefficients for inhalation and ingestion of differentAirconcentration

Inhalation
rate

Inhalation dosecoefficient

AC r ( t)

IR k

DCrk

Inhalation
E k = IR k

∑ DC ∫ AC ( t) dt
rk

r

r

Ingestion
E k = ∑ CD rkr∑ CR ∫ SA ( t) dt
fk

fr

f

SAfr ( t)

CR fk

CD rk

Food specificactivityFoodconsumption rate

Ingestion dosecoefficient

FIG. 8.3. Model of internal exposure of the kth age andgender group of the population. r: radionuclide index; f:food product index.

types of radioactive material are usually taken from
ICRP publications [8.15, 8.17, 8.18].
Table 8.6 presents the generic dose conversion
parameters needed in order to broadly reconstruct
the past, assess the present and forecast the future
average effective internal dose of the adult rural
population of a settlement located in the intermediate (100 km < D < 1000 km) zone of Chernobyl
contamination based on experimental data andmodels developed in the Russian Federation andUkraine [8.16]. The values for each indicated time
period for the population of a settlement are given
separately for various soil types as the ratios of themean internal dose (E) to the mean 137Cs soil
deposition in a settlement as of 1986 (σ137)(μSv·kBq-1·m-2). From Table 8.6 one can conclude
that people living in areas with a higher clay content(e.g. black soil) obtained a lower internal dose
because of slower radionuclide transfer from soil toplants.
The urban population of the affected areas has
been exposed to lower internal doses comparedwith the doses to the rural population living in areas
with similar levels of radioactive contamination,
because of consumption of foodstuffs from noncontaminated areas and different dietary habits.
The parameters obtained from independent sets ofRussian and Ukrainian data significantly differ forsome soil types and time periods (see Table 8.6).
Some of these discrepancies can be explained by thedifferent meteorological conditions (mainly dry in
Ukraine and wet in the Russian Federation) ofradionuclide deposition that occurred in different
parts of the Chernobyl affected areas and different
food consumption habits.
Multiplication of the parameters presented inTable 8.6 by the mean 137Cs soil deposition (as of1986) gives an estimate of the internal effective
dose caused by radiation from 137Cs and 134Cs (forthe Russian Federation, also from 90Sr and 89Sr).
Dose estimates are given for conditions whencountermeasures against internal exposure were
not applied. Thyroid doses caused by intake ofiodine radionuclides in the immediate aftermath of133

TABLE 8.6. RECONSTRUCTION AND PROGNOSIS OF THE AVERAGE EFFECTIVE INTERNALDOSE TO THE ADULT RURAL POPULATION IN THE INTERMEDIATE (100 km < D < 1000 km)
ZONE OF CHERNOBYL CONTAMINATION
E/σ137 (μSv·kBq–1·m–2 of 137Cs)aSoil type1986

1987–1995

1996–2005

2006–2056

1986–2056

90

60

12

16

180

Black

10

5

1

1

17

Peat bog

19

167

32

31

249

Sandy

19

28

5

5

57

Clay

19

17

3

3

42

Black

19

6

1

1

27

Russian Federation [8.14] Soddy–podzolic sandy

Ukraine [8.19]aσ137 is given as for 1986.

the Chernobyl accident are considered elsewhere[8.3].
For specific assessment of doses to the
population of riparian settlements caused byreleases of natural radionuclides from operating
uranium plants or from uranium tailings into riverwater, a simplified procedure was used in theabsence of data on concentrations in foodstuffs. In
this case, only the dose resulting from consuming
river water for drinking and food preparation isconsidered. Table 8.7 gives the dose coefficients for
those radionuclides belonging to the 238U decay
chain that contribute most to internal human
exposure from drinking water. These coefficientsare used in Section 8.4.2 to estimate the annual dose
to affected members of the general public.

8.4. DOSE FROM NATURAL
RADIONUCLIDESIn this section, radiation exposures arereviewed for the general public and for inhabitantsof some Ukrainian riparian settlements located in
the Dnipropetrovsk region, where releases ofuranium series radionuclides occur.
8.4.1.

General public

To assess mean levels of exposure of the
Ukrainian population from natural sources, we usedmostly nationwide and region specific data from
Ref. [8.8]. These data are largely based on Ref. [8.3],
with adjustments to account for the geographical

TABLE 8.7. PARAMETERS USED FOR ESTIMATION OF AGE DEPENDENT INTERNAL DOSEFROM INTAKE OF URANIUM-238 CHAIN RADIOISOTOPES WITH DRINKING WATER [8.1, 8.17,
8.18, 8.20]
Age group (years)
Radionuclide
Dose
coefficientfor ingestion(Sv/Bq)

<1

1–2

2–7

7–12

12–17

>17

Uranium-238

3.4 × 10–7

1.2 × 10–7

8.0 × 10–8

6.8 × 10–8

6.7 × 10–8

4.5 × 10–8

Uranium-234

3.7 × 10–7

1.3 × 10–7

8.8 × 10–8

7.4 × 10–8

7.4 × 10–8

4.9 × 10–8

Thorium-230

4.1 × 10

–6

–7

–7

–7

–7

2.2 × 10

2.1 × 10–7

Radium-226

4.7 × 10–6

9.6 × 10–7

6.2 × 10–7

8.0 × 10–7

1.5 × 10–6

2.8 × 10–7

Lead-210

8.4 × 10–6

3.6 × 10–6

2.2 × 10–6

1.9 × 10–6

1.9 × 10–6

6.9 × 10–7

Polonium-210

2.6 × 10–5

8.8 × 10–6

4.4 × 10–6

2.6 × 10–6

1.6 × 10–6

1.2 × 10–6

180

180

400

580

760

800

Annual consumption ofdrinking watera (L)a4.1 × 10

3.1 × 10

2.4 × 10Equal to total consumption of water from all sources, excluding milk, mother’s milk (for infants) and water originatingfrom oxidation of organic food components [8.17, 8.18, 8.20].

134

TABLE 8.8. AVERAGE ANNUAL EFFECTIVE DOSES TO THE UKRAINIAN POPULATION FROM
NATURAL SOURCES
Mean annual effective dose (mSv)
External

Internal

Total

Cosmic radiation

0.3

—

0.3

Cosmogenic radionuclides

—

0.02

0.02

Potassium-40

0.1

0.2

0.3

Uranium-238 chain (without 222Rn and its daughters)

0.1

0.2

0.3

0.2

0.02

0.2

Radon-222 and its daughters

—

1.3

1.3

Radon-220 (thoron) and its daughters

—

0.1

0.1

Total

0.7

1.8

2.5

Primordial radionuclides

Thorium-232 chain (without

220

Rn and its daughters)

conditions and dominating soil types within
Ukraine.
With regard to radon concentration in
dwellings located in different regions of Ukraine,
Ref. [8.8] provides maps with appropriate averagevalues derived from a special measurement
programme [8.21, 8.22]. To convert the radon
concentrations to effective dose, we used the modelin Ref. [8.23], which is used in the Basic Safety
Standards [8.1], with the accepted equilibrium
factor between radon and its daughters of 0.4 rather
than the value of 1.0 used in Ref. [8.8]. The resulting
calculations are shown in Table 8.8.
Comparison of Tables 8.1 and 8.8 shows thatthe average annual effective doses to the Ukrainian
population from natural sources are not significantly different from the world average value of
2.4 mSv/a. Taking into account the similarity ofnatural conditions in the neighbouring regions ofBelarus, Ukraine and the European part of theRussian Federation, it is concluded that theestimates of public exposure given in Table 8.8 arereasonable averages for the Dnieper River basin asa whole.
8.4.2.

Population of the Ukrainian uranium
mining and milling areas

As discussed in Section 6, there are two areasof uranium mining and milling activity (both pastand present) in the Ukrainian part of the Dnieper
River basin: Zhovti Vody and Dniprodzerzhinsk
and their vicinities (see Fig. 3.1). Table 8.9 gives
typical concentrations of radionuclides in rivers inthese areas based on monitoring data presented in
Section 5. The locations considered for this analysis
are: (a) on the Zheltaya River downstream of themining–milling close to the mining area; (b) on the

TABLE 8.9. ASSESSED CONCENTRATIONS OF THE MOST RADIOLOGICALLY IMPORTANT
URANIUM-238 CHAIN RADIONUCLIDES IN RIVER WATER BASED ON MONITORING DATA
Activity concentration (Bq/L)
Uranium238

Uranium234

Radium226

Lead210

Polonium210

Zheltaya River, Annovka village, 2002

1

1

0.01

<0.01

0.02

Ingulets River, Alexandria town, 2002

0.04

0.05

0.02

<0.01

0.001

Saksagan River, Kress reservoir, 2002

0.06

0.08

0.007

<0.01

0.005

Konoplyanka River, 1992–2001

0.1

0.1

0.03

0.01

0.002

Dnieper River, Dniprodzerzhinsk reservoir, 1992–2001

0.02

0.02

0.02

<0.01

0.003

135

TABLE 8.10. ASSESSED ANNUAL INTERNAL DOSESa (mSv) FROM CONSUMPTION OF RIVER
WATER FOR DRINKING AND FOOD PREPARATION IN URANIUM MINING AND MILLING
AREAS
Age group (years)

Zheltaya River, Annovka village, 2002

<1

1–2

2–7

7–12

12–17

>17

0.28

0.10

0.13

0.14

0.17

0.12

Ingulets River, Alexandria town, 2002

0.04

0.01

0.02

0.02

0.04

0.01

Saksagan River, Kress reservoir, 2002

0.06

0.02

0.02

0.03

0.03

0.02

Konoplyanka River, 1992–2001

0.08

0.03

0.03

0.05

0.08

0.03

Dnieper River, Dniprodzerzhinsk reservoir, 1992–2001

0.05

0.01

0.02

0.03

0.04

0.01

a

Doses calculated from assessed monitoring data (Table 8.9) are included as well as estimated contributions from 230Th andradionuclides of the 235U chain; in total, these increase the dose by about 20%.

banks of the Ingulets River receiving water from thehighly contaminated Zheltaya tributary and
Saksagan River located in the same area; (c) near
the mouth of the Konoplyanka River (at present an
uninhabited area); and (d) on the shores of the
Dnieper River downstream of the Prydniprovsky
chemical plant located within the industrial
complexes at Dniprodzerzhinsk.
The data in Table 8.9 were then used alongwith the dose rate coefficients and the age related
drinking water consumption data (see Table 8.7) todetermine the annual internal doses, which are
shown in Table 8.10.
Based on the available water monitoring data,
the highest levels of human exposure are received
by inhabitants of settlements located on the banksof the Zheltaya and Konoplyanka Rivers. The
annual dose estimates are about at the level (0.1
mSv/a) recommended by the World Health Organization (WHO) [8.24] as the maximum for drinking
water2. However, it should be noted that both ofthese streams are relatively small and known to behighly polluted with various contaminants; it istherefore difficult to imagine conditions in which2

For uranium, the chemical toxicity also needs tobe considered. In the addendum to the WHO guidelines,
published in 1998, a health based guideline concentrationof 0.002 mg U/L was established, which is well below thelimit based on radiological considerations. It has been
noted by the WHO that several human studies are under
way that may provide helpful additional data. At themeeting to plan the revision of the guidelines held in
Berlin in June 2000 it was concluded that uranium would
be a candidate for future revision when new studies arecompleted.

136

the local population would use this water for
drinking, food preparation or other domestic needs.
In contrast, water from the bigger rivers, theIngulets, Saksagan and especially the Dnieper, isregularly used for domestic needs, including
drinking and food preparation. However, according
to available monitoring data, consumption of waterfrom these rivers does not lead to human exposurelevels that exceed any international safety standard
for uranium chain radionuclides.
On the one hand, the dose estimations
presented in Table 8.10 were made using the very
conservative assumption that inhabitants of affectedareas receive all their drinking water from contaminated streams. On the other hand, data on radionuclide concentrations in fish and crayfish areunavailable, and therefore this pathway could not
be analysed. Thus our estimates should beconsidered as preliminary and with substantial
uncertainties. In order to calculate dose rates fromall the major human exposure pathways, additional
monitoring data are required, especially those
relevant to contamination levels and theconsumption rate of river fish and other aquatic
species.
A simple estimate of the collective dose to the
population of riparian settlements caused by theannual releases of uranium chain radionuclides tothe Konoplyanka–Dnieper River water can bemade for the Dniprodzerzhinsk area. Appropriate
simplified screening models developed by
UNSCEAR [8.25] and the IAEA [8.3] have been
applied to the release conditions at tailings D of thePrydniprovsky chemical plant (refer to Sections 5
and 9 for further information on the condition ofthese tailings). The annual release was estimated bymultiplying the assessed radionuclide concentration

in the Konoplyanka River water (see Table 8.9) by
the average annual water discharge (about
1 ¥ 106 m3/a). Once per hundred years the discharge
is three times as high (i.e. about 3 ¥ 106 m3/a). The
collective effective dose commitments per unit
activity discharged into freshwater bodies (forscreening purposes) are presented in Refs [8.3,8.25]. Application of both models gives a crude
mean estimate of the collective dose of about
0.03 man Sv and, once per hundred years, about
0.1 man Sv. Both of these values are insignificant
from a radiation protection perspective.
The potential for failure of tailings dams thathave not been stabilized against erosion orcatastrophic failure is discussed in Section 6. Any
failure and subsequent dispersal of tailings intoriver systems could result in significant individualand collective dose rates; however, an analysis ofthese dose rates would require a probabilistic based
assessment for each tailings impoundment and isbeyond the scope of this study.

8.5. PRESENT AND FUTURE HUMANEXPOSURE LEVELS CAUSED BY
CHERNOBYL FALLOUTThis section is concerned with current andfuture exposures resulting from contamination of
the Dnieper River basin with radionuclides ofChernobyl origin. For completeness, some of thetables contain estimates of past effective doses.
Inhabitants of areas contaminated with radionuclides in 1986 are still being subjected both toexternal exposure from 137Cs gamma radiation andto internal exposure due to consumption of local
foodstuffs containing 137Cs and, to a lesser extent,
90
Sr. According to model estimates and direct
human measurements [8.26], inhalation of
plutonium radionuclides and 241Am does not significantly contribute to human doses. Thyroid doses
caused by intake of iodine radionuclides weresignificant only during the initial period after theaccident and are considered elsewhere [8.3].
Most of the dosimetric parameters needed toestimate mean Chernobyl caused external andinternal doses to inhabitants of a particular
settlement for a particular time period arepresented in Tables 8.4 and 8.6. In broad terms, themost important factors controlling the mean
external dose are the settlement type (rural or

urban) and 137Cs soil deposition; whereas theimportant controlling factors for internal dose to
the rural population are the dominant soil type and137
Cs soil deposition.
In accordance with the environmental
behaviour of 137Cs and 90Sr, external exposure
prevails in areas with dominantly black soils, andthe contribution of internal exposure to the total(external and internal) dose does not exceed 10%.
In contrast, in areas with light sandy soils, thecontributions from internal and external exposure
are comparable, and in areas with peaty soils
internal exposure dominates. At present, along with
consumption of local vegetable and animal (milkand meat) food products, consumption of natural
foods (lake fish, forest mushrooms and berries,
game, etc.), which is typical for the Dnieper Riverbasin population, significantly contributes (up to
50–70%) to 137Cs intake in the human body and theassociated internal dose. According to numerous
studies, the contribution of 90Sr to the internal doseregardless of natural conditions is usually below
5%.
In towns and cities the internal dose ispartially determined by radioactive contaminationof foodstuffs produced in the surrounding districts.
However, importation of foodstuffs from noncontaminated areas has significantly reduced intakeof radionuclides, and the corresponding internal
doses received by the urban population are typicallya factor of two to three less than in rural settlementswith an equal level of radioactive contamination.
Deviation of the dose to critical groups
compared with the settlement average values varies
by a factor of 1.5–2 for external exposure (see Table
8.5) and about three for internal exposure; thus
about a factor two to three for total (external andinternal) exposure. The group most subjected toexternal exposure is adults working outdoors(foresters, herders, field workers, etc.) and thoseliving in dwellings with low shielding properties (e.g.
one storey wooden houses). The group mostsubjected to internal exposure from 137Cs is adults
consuming both locally produced agricultural
animal foods (milk, dairy products, etc.) and natural
foods (mushrooms, lake fish, berries, etc.) inamounts exceeding average consumption rates. The
critical population groups residing in particular
localities are groups of people belonging to bothgroups of the most exposed people (i.e. subjected toelevated external and internal exposure).

137

TABLE 8.11.
PAST (1986–2000), PRESENT (2001) AND FUTURE (2002–2056) AVERAGECHERNOBYL RELATED EFFECTIVE DOSES (mSv) OF ADULT RESIDENTS OF AREAS WITH
CAESIUM-137 SOIL DEPOSITION OF ABOUT 0.04 MBq/m2 (1 Ci/km2) IN 1986
Time period
1986–2000

2001

2002–2056

Lifetime (1986–2056)

Rural

3–13

0.05–0.15

1–3

4–16

Urban

2–8

0.03–0.1

1–2

3–10

8.5.1.

General public

In the countries most affected by the
Chernobyl accident (Belarus, the RussianFederation and Ukraine), areas with average 137Cs
soil deposition below 37 kBq/m2 (1 Ci/km2) are notofficially considered to be affected or contaminated;
human exposure levels in these areas have notrequired substantial protective or remediation
actions since 1986. Thus for the purposes of thisreport those areas where no remediation actions arenecessary at present are considered separately fromcontaminated areas and hot spots.
Depending on the level of 137Cs soil
deposition, people living beyond the contaminatedareas (i.e. more than 80% of the Dnieper Riverbasin area) have been subjected to Chernobyl
related external exposure during the first 15 years(1986–2001) from gamma radiation of all thedeposited radionuclides in the range fromalmost zero in low contaminated areas up to
2.5 mSv in rural settlements and up to 1.7 mSv intowns and cities with 37 kBq/m2 of 137Cs in soil.
At present, they are receiving up to 0.05 mSv/a
in rural settlements and up to 0.03 mSv/a in towns
and cities. In the period from 2002 to 2056
(70 years after the accident), they will receive up to
0.7 mSv in villages and up to 0.5 mSv in towns andcities.
The effective internal doses (excluding short
lived 131I) received by the rural population strongly
depend on the dominating soil type in the village
and its vicinity. Thus in black soil areas people
received during the first 15 years after the accident
exposures ranging from almost zero in low contaminated areas up to 1 mSv (most of it in 1986) in rural
settlements with 37 kBq/m2 of 137Cs in the soil. In
areas with sandy, soddy–podzolic soils, the dose was
two to three times as much; in areas withdominating peaty soils, the internal dose wastypically an order of magnitude larger than in blacksoil areas.
138

At present, the inhabitants of low contaminated areas are receiving from ingestion of local
food up to 0.004 mSv/a in black soil areas, up to
0.04 mSv/a in sandy soil areas and about 0.1 mSv/ain villages located in peaty soil areas. In the period
2002–2056 they will receive, additionally, an internal
dose of less than 0.1 mSv in black soil areas, up to
0.7 mSv in sandy soil areas and about 1–2 mSv invillages located in peaty soil areas.
Table 8.11 summarizes the total exposures(external and internal) in areas of low contamination. From 1986–2000, rural inhabitants living inblack soil areas received up to 3 mSv, in sandy soil
areas up to 6 mSv and in peaty areas up to 13 mSv.
Bearing in mind that during the same period theyreceived about 30–40 mSv of natural backgroundradiation, non-intervention in these areas appears
to have been sound policy. This conclusion is also
relevant to current and future human exposures inlow contaminated areas.
8.5.2.

Inhabitants of contaminated areas

The total area of the Dnieper River basin
where the 137Cs contamination of soil, as of 1993–
1995, was ≥0.04 MBq/m2 is about 85 000 km2 (seeTable 4.2). Within this area, there were inhabitedregions with an average 137Cs soil deposition of up
to 3 MBq/m2 (80 Ci/km2 in 1993–1995, 100 Ci/km2 in1986) where the application of protective actions in
the early period and remediation actions in the longterm have been important measures to protect
human health. Owing to the substantial social
importance and costs of these actions, there havebeen more monitoring and dose assessment studies
in these areas than in ‘non-affected’ areas.
The assessment of public doses given below isbased on numerous measurements of the content of
137
Cs, 90Sr and plutonium radionuclides in soil inmany thousands of localities, 137Cs and to a lesser
extent 90Sr concentrations in foodstuffs, in vivo
whole body measurements of 134Cs and 137Cs ininhabitants in many hundreds of localities, postmortem measurements of 90Sr and plutonium radionuclides in tissues, as well as individual external
dose measurements in about 100 localities. Models
of human exposure have been developed (seeSection 8.3) based on some of these measurements
and verified in other studies.
In order to avoid presentation of dosimetricdata on a site by site basis, mean effective doses toadult residents of rural and urban localities havebeen determined as a function of soil 137Cs concentration and predominant soil type. The 137Cs soil
concentration is subdivided into two grades: 0.04–
0.6 MBq/m2 (1–15 Ci/km2) and above 0.6 MBq/m2(i.e. actually 0.6–4 MBq/m2 (15–100 Ci/km2) as of1986). The level of 0.04 MBq/m2 is considered as aconventional border between ‘non-contaminated’and ‘contaminated’ areas. In areas contaminatedwith 137Cs above 0.6 MBq/m2, application of active
countermeasures (i.e. agricultural restrictions),
decontamination measures and recommendations
to restrict consumption of locally gathered natural
foods (forest mushrooms and berries, lake fish, etc.)
have been mandatory.
8.5.2.1. External exposure
For the period 1986–2000 the mean external
doses to residents of rural settlements with 137Cs soil
deposition of 0.04–0.6 MBq/m2 were in the range 2–
30 mSv, whereas in settlements with soil depositionof 0.6–4 MBq/m2 the dose ranged from 30 to
200 mSv, taking into account decontamination of
the most contaminated settlements carried out in
1986–1989. At present, the mean annual external
doses to the residents of the same two groups ofrural settlements are 0.05–0.7 mSv and 0.7–2.4 mSv,
respectively. Naturally, the inhabitants ofsettlements with the highest levels of radioactive
soil contamination receive the most elevated doses;
in some of the settlements the annual external doses
are above the national action level of 1 mSv.
Calculations based on the dosimetric models
presented in Section 8.3 show that, by 2001, theresidents had already received about 70% of the
lifetime external dose caused by the Chernobyl
fallout. During the coming years (2001–2056) they
will receive the remaining 30%, i.e. 1–13 mSv and
13–80 mSv, respectively, in the two groups ofsettlements described above.
The external doses to urban residents havebeen estimated to be a factor of 1.5–2 lower than invillages with equal 137Cs soil deposition.

8.5.2.2. Internal exposure
The mean internal doses to residents of rural
settlements strongly depend on the soil properties.
For assessment purposes, soils are classified into
three major soil types: (a) black or chernozem soil;(b) podzol soil (including both podzol sandy andpodzol loamy soils); and (c) peat–bog or peat soil.
In the settlements with 137Cs soil deposition of 0.04–
0.6 MBq/m2, the mean internal effective doses
accumulated from 1986 to 2000 are in the range ofabout 1–12 mSv for black soil, 3–30 mSv for podzol
soil and 8–120 mSv for peat soil. In the settlementswith higher 137Cs soil deposition, located predominantly in podzol soil areas, the accumulated doses
reached about 100 mSv even after account is takenof countermeasures.
At present, the mean annual internal doses
received by residents of rural settlements are lessthan 0.1 mSv (black soil), 0.03–0.4 mSv (podzol
soil), 0.1–2 mSv (peat soil) and 0.4–2 mSv (podzol
soil above 0.6 MBq/m2). The most elevated internal
doses in some of the settlements are above thenational action level of 1 mSv; these are now being
received by the inhabitants of settlements with thehighest levels of radioactive soil contamination orby these living in peaty areas with modest 137Cs soil
deposition.
The dosimetric models presented in
Section 8.3 predict that by 2001 the residents had
already received at least 75% of their lifetime
internal dose due to 137Cs, 134Cs, 90Sr and 89Sr in the
Chernobyl fallout. During the coming years (2001–2056) they will receive the remaining 25% (i.e. lessthan 1 mSv for black soil, 0.5–7 mSv for podzol soil
and 2 to about 30 mSv for peat soil). In the mostcontaminated podzol soil areas, an effective dose of
7–50 mSv can still be expected.
The internal doses to urban residents havebeen estimated to be a factor of 1.5–2 lower than invillages with equal 137Cs soil deposition.
For critical groups in contaminated areas, wild
foods (forest mushrooms, game, forest berries, fish)
can make an important contribution to dose [8.14,
8.16, 8.27, 8.28]. Reference [8.29] studied 137Cs
intake of the rural population in the Bryansk regionof the Russian Federation and found that natural
foods contributed about 20% of the total uptake in1987 but up to 80% in 1994–1999. The relative
contribution of wild foods to the internal dose hasrisen gradually because of the substantial reductionof the radionuclide content in both vegetable andanimal agricultural foods, while the contamination
139

TABLE 8.12. PAST (1986–2000) AND FUTURE (2001–2056) MEAN CHERNOBYL RELATEDEFFECTIVE DOSES (mSv) TO ADULT RESIDENTS OF AREAS WITH CAESIUM-137 SOIL DEPOSITION ABOVE 0.04 MBq/m2 (1 Ci/km2) IN 1986
Caesium-137
in soil(MBq/m2)
Rural

Soil typeBlack
2001–2056

1986–2000

2001–2056

1986–2000

2001–2056

3–40

1–14

5–60

1–20

10–150

3–40

60–300

20–1004–40

1–13

0.04–0.6—

0.04–0.6

2–30

1–9

TABLE 8.13.
ANNUAL (2001) MEAN
CHERNOBYL RELATED EFFECTIVE DOSES(mSv) TO ADULT RESIDENTS OF AREAS
WITH CAESIUM-137 SOIL DEPOSITIONABOVE 0.04 MBq/m2 (1 Ci/km2) IN 1986

Rural

Peat

1986–2000

0.6–4
Urban

PodzolSoil type

Caesium-137
in soil (MBq/m2)

Black

PodzolPeat

0.04–0.6

0.05–0.8

0.1–1

0.2–2

0.6–4

—

1–5

—

—
8–100

2–20

lake fish. Reference [8.29] found similar trends in astudy in 1996 of residents of Kozhany (Bryansk
region), located on the coast of a highly contaminated lake, where natural foods contributed anaverage of 50–80% of 137Cs intake. Men were more
likely to eat natural foods than women and there
was a positive correlation between consumption ofmushrooms and fish. The average annual internal
dose due to 137Cs was estimated to be 1.2 mSv formen and 0.7 mSv for women in 1996.
8.5.2.3. Total dose

Urban

0.04–0.6

0.03–0.4 0.05–0.6 0.1–1

of wild foods has decreased much more slowly. In
the latter period, the highest contributions to 137Cs
intake (and, by inference, internal dose) were forest
mushrooms, followed by forest berries, game andTable 8.12 summarizes the mean total(external and internal) effective doses accumulated
during 1986–2000 and forecast for 2001–2056.
Table 8.13 gives the annual dose in 2001.
Figure 8.4 shows the geographical pattern of
cumulated effective doses to the population of the

TABLE 8.14. EFFECTIVE DOSES TO THE POPULATION IN SOME CONTAMINATED DISTRICTS
OF THE BELARUSIAN PART OF THE DNIEPER RIVER BASIN
Effective dosea for the time period (mSv)

District

Caesium-137
soil depositiona(MBq/m2)

1986–2000

2001–2015

1986–2015

Gomel

Bragin

0.8

50

13

63

Gomel

Narovlya

0.8

48

12

60

Gomel

Vetka

0.75

42

8

50

Gomel

Korma

0.5

37

9

46

Mogilev

Krasnopolye

0.7

37

4

41

Mogilev

Slavgorod

0.4

30

7

37

Mogilev

Bykhov

0.2

13

4

17

Brest

Stolin

0.1

10

2

12

Regiona

Mean values for the district.

140

mSv

Chernobyl
nuclear power plant

FIG. 8.4. Geographical pattern of effective dose from external and internal exposure among the population of the Dnieper
River basin for 1986–2000.

mSv

Chernobyl
nuclear power plant

FIG. 8.5. Prognoses of expected effective doses to the population of the Dnieper River basin within Belarus for 2001–2015.

141

(a)

Differences in agricultural and radioecologicalconditions of contaminated regions, leading toconsiderably different values for the transfer
factor of 137Cs from soil to agricultural
products;
Differences in implementation of countermeasures between high and low contaminatedterritories.

(b)

Effective dose (PSv per kBq/m2)

Figures 8.6 and 8.7 illustrate the timedependent contributions of the exposure pathways
to the mean dose received by inhabitants of twoareas in the Belarusian part of the Dnieper Riverbasin: the Gomel–Mogilev caesium spot (predominantly with podzol soils and agricultural countermeasures applied) and the Belarusian section of the
Brest region (with podzol and peaty soils and a high137
Cs soil to plant transfer factor).
For the Gomel–Mogilev region, external
exposure dominates, whereas in the Brest region
internal exposure contributes about 70% of thetotal dose because of the high 137Cs soil to planttransfer factor. For settlements with normal transfer
factors such contribution is in the range from 15%
to 35% [8.30].
In order to assess the contributions ofdifferent pathways and their components to theeffective dose, the dosimetric models given inRefs [8.30–8.32] were applied to the conditions of a

Effective dose (PSv per kBq/m2)

Belarusian part of the Dnieper River basin for
1986–2000 and Fig. 8.5 shows prognoses for
2001-2015. The average effective doses to the
population of selected contaminated districts are
given in Table 8.14 [8.30].
The relative contributions of external andinternal exposure pathways vary in different regions
because of the following factors:

70
60
External exposure

50

Internal exposure
Total

40
30
20
10
0
1986

1988

1990

1992

1994

1996

1998

2000

Year

FIG. 8.7. Dynamics of the contributions of internal andexternal exposures to the total dose in the Belarusiansection of the Brest region.

carefully studied Belarusian village, Svetilovichi,
located in the podzol soil area. Figure 8.8 shows thecontributions of the various pathways.
External exposure from soil is the largest
contributor to dose; however, ingestion of local
food is also important. Other pathways (drinking
water, eating of fish, swimming, exposure from theshore) are insignificant for the average person.
According to the data presented in Table 8.13,
the mean annual effective dose in the most contaminated settlements and moderately contaminatedsettlements located in peaty soil areas reached 2–
5 mSv. Correspondingly, the dose received by
critical population groups in these settlements is
estimated to be in the range 4–10 mSv. In somecases, after taking account of the natural
background (2 mSv), the existing annual dose (seeSection 8.1.3) could exceed the ICRP recommendation of 10 mSv at which intervention should beconsidered [8.5].
From Table 8.12 it can be concluded that the
lifetime dose (1986–2056, or 70 years after theaccident) in the most contaminated settlements

30
25

External exposure
Internal exposure
Sum

20

External from
soil
66.5%

External from
shore
0.8%

15

Internal fromfood ingestion
30.5%

10
5
0
1986

1988

1990

1992

1994

1996

1998

2000

Year

FIG. 8.6. Dynamics of the contributions of internal andexternal exposures to the total dose in the Gomel–Mogilev
caesium spot.

142

External fromswimming
0.002%

Internal fromdrinking water
0.1%

Internal from fish
ingestion
2.1%

FIG. 8.8. Contributions of different pathways to theeffective dose received by the general population of Svetilovichi, Gomel region, Belarus, in 1998–1999.

where countermeasures were undertaken will be
about 0.4 Sv, and without countermeasures would
exceed 0.5 Sv. Correspondingly, the lifetime dose tocritical population groups in these settlements
would exceed 1 Sv, which is the intervention level
for resettlement established in the Basic Safety
Standards [8.1]. Thus resettlement of people fromthe settlements with an initial 137Cs soil depositionof 3 MBq/m2 and more should be retrospectively
assessed as having been justified at that time.
Currently, since people have already received morethan 70% of their lifetime dose and for the next
50 years the mean committed dose hardly exceeds
100 mSv (≈200 mSv in the critical group),
resettlement is no longer justified.
In reality, most of the inhabitants ofsettlements with such a high level of radioactive
contamination, and many others exposed to lower
levels of contamination (by factors of three to five),
were resettled to non-contaminated areas mainly inthe spring and summer of 1986 and later, up to
1990. In the most contaminated settlements, only a
few hundred people remained, predominantly
elderly people who had refused to relocate to otherareas.
The inhabitants of the settlements of theGomel and Mogilev regions in Belarus and theBryansk region of the Russian Federation, where137
Cs soil contamination exceeds 1 MBq/m2, aresubjected to the highest exposure. In many tens of
the settlements, the average annual exposure level
still exceeds the national action level of 1 mSv.
According to the methodology of this report, thesettlements located in the Chernobyl accident areas,
where average total annual doses to inhabitantscaused by environmental 137Cs and 90Sr range from
1 to about 5 mSv, should be considered as local hot
spots where remediation actions are still needed inorder to reduce human exposure levels. These hot
spots are considered further in Section 9.

8.6. CONTRIBUTION OF AQUATIC
PATHWAYS
The model for internal exposure described in
Section 8.3.2 is applicable to both terrestrial andaquatic pathways. The discussion in Section 8.5 wasconcerned mainly with terrestrial pathways. Thissection discusses the contribution of aquatic
pathways, including drinking water, ingestion of fish
and other aquatic species, and irrigation of crops
with river water.

8.6.1.

General public

The contribution of freshwater pathways tothe public exposure is dependent on the direct
consumption of water and fish containing radionuclides as well as the flooding of land used forlivestock grazing and haymaking, and utilization ofriver water for irrigation of agricultural land, whichleads to subsequent human exposure via terrestrial
pathways. In the lower Dnieper River reaches, notsubjected to direct radionuclide contamination in
1986, almost all the Chernobyl exposures are
attributed to water pathways; however, the dose
itself is very low. In most of the directly Chernobyl
contaminated areas the human dose is much higher(see Section 8.5), but it is mostly attributable toterrestrial pathways.
Although individual doses are not of concern
to the general public living in areas of low contamination, water pathways along the Dnieper cascadein Ukraine require further analysis because of thelarge number of people who are exposed. Three
pathways need to be considered, as discussed in
Sections 8.6.1.1–8.6.1.3.
8.6.1.1. Consumption of drinking water from theDnieper reservoirs
The Dnieper cascade is a source of drinking
water for more than eight million people. The main
consumers of drinking water from the Dnieper
River live in the Dnipropetrovsk and Donetsk
regions. In Kiev, Dnieper River water is used bymore than 750 000 people.
8.6.1.2. Consumption of fish taken from theDnieper reservoirs
The Dnieper reservoirs are used intensively
for commercial fishing. The annual catch is morethan 25 000 t. There was no increase or decrease infishing after the Chernobyl accident.
8.6.1.3. Consumption of agricultural products
grown on lands irrigated using water fromthe Dnieper reservoirs
In the Dnieper River basin within Ukraine
there are more than 1.8 ¥ 106 ha of irrigated agricultural land. Almost 72% of this territory is irrigatedwith water from the Kakhovka reservoir. About
50% of the irrigated area is used for forage planting.
Vegetables occupy less than 10% of the planted
143

35
30

60

25
20

40

15
10

20

5
0

0
1

4

7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70

Fish

Drinking water

Annual collective dose

50
45
40
35
30
25
20
15
10
5
0

80
60
40
20
0
1

4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70

Irrigation

Annual collective dose

Drinking water

FIG. 8.9. Collective effective dose and percentage
breakdown according to water use pathway for the Kiev
region population as a function of time from 1986.

FIG. 8.11. Collective effective dose and percentage
breakdown according to water use pathway for the
Crimea population as a function of time from 1986.

Annual collective dose (man-Sv)

Irrigation

100

Annual collective dose (man-Sv)

40

Collective dose (%)

Collective dose (%)

45
80

Annual collective dose (man-Sv)

50

100

collective dose and the breakdown according to thepathway for three regions: Kiev, Poltava (water
drawn from the Kremenchug reservoir) and Crimea(water drawn from the Kakhovka reservoir). These
calculations assume that no further protective
measures are undertaken.
Figures 8.9 and 8.10 show that the annual
collective dose decreased rapidly in the first five
years after the accident and more slowly thereafter.
This is not true of the Crimea region, due to thebuffering effects of distance from the source.
Currently, the annual collective dose is about
8 man Sv for the Kiev region, 4 man Sv for the
Poltava region and 5 man Sv for the Crimea region.
Tables 8.15–8.17 show estimates of collective
dose from these three pathways for 1999, a year ofintense spring flooding that washed out radionuclides (especially 90Sr) from the Pripyat
floodplain (see discussion in Section 4). For thiscase, the dose from 90Sr dominates and irrigation is
the main pathway. Note that these data differ
somewhat from those in Figs 8.9–8.11, because theformer study was carried out before 1999 and theextreme flooding in that year could not have been
anticipated.

50
45
40
35
30

Collective dose (%)

100
80
60

25
20
15
10
5
0

40
20
0
1

4

7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70

Irrigation

Fish

Drinking water

Annual collective dose

FIG. 8.10. Collective effective dose and percentage
breakdown according to water use pathway for the
Poltava region population as a function of time from1986.

area. Milk production from irrigated areas also
needs to be considered.
In the early 1990s estimates were made of thecollective dose to people from these three pathways
for a period of 70 years after the accident (i.e. from1986 to 2056) [8.33, 8.34]. A long term hydrologicalscenario was analysed using the computer model
WATOX [8.35]. Historical data were used toaccount for the natural variability in river flow.
Dose assessment studies were carried out toestimate the collective dose from the threepathways [8.36]. Figures 8.9–8.11 show theTABLE 8.15. COLLECTIVE DOSE ESTIMATES DUE TO TAP WATER INGESTION BY THE
POPULATION ALONG THE DNIEPER RIVER CASCADE DURING 1999
Collective dose (man-Sv)
Reservoir
Kiev

Population
500 000

Strontium-90

Caesium-137

Total

0.57

0.09

0.66

Kanev

250 000

0.15

0.02

0.17

Kremenchug

900 000

0.46

0.03

0.48

Zaporozhe

2 000 000

1.05

0.04

1.09

Kakhovka

4 000 000

2.05

0.03

2.09

Total

8 250 000

4.3

0.2

4.5

144

TABLE 8.16. ESTIMATED COLLECTIVE DOSE DUE TO FISH INGESTION BY THE POPULATIONALONG THE DNIEPER RIVER CASCADE DURING 1999
Collective dose (man-Sv)
Reservoir

Fish catch (t)Strontium-90

Caesium-137

Total

Kiev

1 520

0.08

0.15

0.22

Kanev

760

0.02

0.04

0.06

Kremenchug

2 730

0.07

0.04

0.11

Zaporozhe

6 060

0.15

0.07

0.22

Kakhovka

13 900

0.29

0.05

0.34

Total

24 970

0.60

0.35

0.95

TABLE 8.17. ESTIMATED COLLECTIVE DOSE DUE TO CROP AND MILK PRODUCTION ALONG
THE DNIEPER RIVER CASCADE DURING 1999
Collective dose (man-Sv)
Reservoir
Strontium-90

Caesium-137

Total

Kiev

1.03

0.03

1.06

Kanev

0.57

0.01

0.58

Kremenchug

1.89

0.01

1.90

Zaporozhe

0.99

0.003

0.99

Kakhovka

17.33

0.27

17.4

Total

21.8

0.32

21.9

8.6.2.

Hot spots: closed lakes

In Section 4 the concentrations of radionuclides in river water and some aquatic species
were reported. It was shown that the concentrationsof radionuclides in flowing rivers are now quite low
and do not present a significant radiation exposure
problem. The exception is a number of ‘closed’ lakes(without regular outflow) located in peaty areas,
where the concentrations of 137Cs (and to a lesser
extent 90Sr) in both water and fish are much higher
than in the nearest rivers. These concentrations do
not significantly decrease with time, and in manylakes still exceed the permissible levels for drinking
water and especially for fish (see Section 4).
The contribution of aquatic pathways to the
dietary intake of 137Cs and 90Sr is usually quite small.
However, the 137Cs concentration in the muscle ofpredatory fish such as perch or pike may be quite
high in lakes with long water retention times, as
found in Scandinavia and the Russian Federation[8.29, 8.37–8.39]; for example, the concentration of137
Cs in the water of Lakes Kozhanovskoe andSvyatoe, located in the severely contaminated partof the Bryansk region of the Russian Federation,
was still high in 1996: concentrations were 10–20 Bq
137
Cs/L and 0.6–1.5 Bq 90Sr/L [8.38]. The concentrations of 137Cs in the muscles of crucian (Carassius
auratus gibeio) sampled in Lake Kozhanovskoe
were within the range 5–15 kBq/kg and in pike
(Esox lucius) within the range 20–90 kBq/kg [8.29,
8.38]. The activity of 137Cs in inhabitants of Kozhany
village, located along the coast of Lake Kozhany, as
measured by whole body counters in the summer of
1996, was 7.4 ± 1.2 kBq in 38 adults who did notconsume lake fish (according to interviews
performed before the measurements) but was 49 ±8 kBq in 30 people who often consumed lake fish
[8.3]. Taking into account seasonal changes in 137Cs
whole body activity, the average annual internal
doses were estimated to be 0.3 mSv and 1.8 mSv inthese two groups, respectively.
145

Closed lakes are assessed to be local hot spots
and are considered further in Section 9.

(f)8.7. CONCLUSIONS
(a)

(b)

(c)

(d)

(e)

146

The average dose rate to Ukrainian citizens
from natural radiation sources is about
2.5 mSv/a, which is close to the global average.
This value is also considered to be areasonable estimate of the average dose rate
to the population of the Dnieper River basin
as a whole.
The inhabitants of areas contaminated withradionuclides from the Chernobyl accident in1986 are still being subjected both to external
exposure from 137Cs gamma radiation and tointernal exposure due to consumption of local
foodstuffs containing 137Cs and, to a lesser
extent, 90Sr. The most important factors
controlling the mean external dose are thesettlement type (rural or urban) and the levelof 137Cs soil deposition (in kBq/m2). Forinternal exposures, the most important factors
are the soil type and the level of 137Cs soil
deposition. On average, effective doses to the
inhabitants of rural settlements are higher
than those to urban dwellers.
From 1986 until 2000 rural inhabitants in‘unaffected’ areas (137Cs fallout < 0.04 MBq/m2) living in black soil areas received effective
radiation doses of up to 3 mSv, in sandy soil
areas up to 6 mSv and in peaty soil areas up to
13 mSv. Bearing in mind that during the same
period they received about 30–40 mSv ofnatural background radiation, the policy of
non-intervention in these areas can be retrospectively assessed as justified.
Currently, the inhabitants of areas of low
contamination from Chernobyl fallout arereceiving from ingestion of local foods up
to 0.004 mSv/a in black soil areas, up to
0.04 mSv/a in sandy soil areas and about
0.1 mSv/a in villages located in peaty soil areas.
External doses rates are up to 0.05 mSv/a inrural settlements and up to 0.03 mSv/a in towns
and cities.
In ‘affected’ areas, the current mean annual
external doses received by residents of rural
settlements are 0.05–0.7 mSv in regions where
the 137Cs soil deposition ranges from 0.04 to
0.6 MBq/m2 and 0.7–2.4 mSv where the soil

(g)

(h)

(i)

(j)

deposition is from 0.6 to 4 MBq/m2. The
external doses to urban residents have been
estimated to be a factor of 1.5–2 lower than invillages with equal 137Cs soil deposition.
In ‘affected’ areas, the current mean annualinternal doses to residents of rural settlements
are less than 0.1 mSv (black soil), 0.03–0.4 mSv(podzol soil), 0.1–2 mSv (peat soil) and 0.4–
2 mSv (podzol soil above 0.6 MBq/m2). The
most elevated internal doses in some of thesettlements are above the national action levelof 1 mSv; these are now being received by the
inhabitants of settlements with the highest
levels of radioactive soil contamination or bythese living in peaty soil areas with modest
137
Cs soil deposition.
Dosimetric models have been developed andtested to estimate past, present and futureradiation exposures from all Chernobyl
related pathways. The models predict that, by
2001, people in affected areas had alreadyreceived at least 75% of their lifetime internal
dose due to 137Cs, 134Cs, 90Sr and 89Sr in
Chernobyl fallout. Dose rates will decrease
slowly with time over the next 50 years as
deposited 137Cs (half-life 30 years) decays andis made less available by soil redistribution
processes.
For critical groups in Chernobyl contaminatedareas, wild foods (e.g. forest mushrooms,
game, forest berries and fish) can make animportant contribution to dose; for example,
in one study in the Bryansk region of theRussianFederation,‘natural’foods
contributed from 50% to 80% of 137Cs intake.
The average annual internal dose due to 137Cs
was estimated to be 1.2 mSv for men and 0.7
mSv for women.
In most cases, aquatic pathways (drinking
water, fish consumption and irrigation) makeonly a small contribution to the total dosefrom Chernobyl sources. At times of floodingof the Pripyat floodplain, dose rates increase
somewhat due to washout of 90Sr.
Furthermore, in some closed lakes the concentration of 137Cs remains high and high levels ofcontamination are found in fish. People who
illegally catch and eat contaminated fish may
receive internal doses in excess of 1 mSv/afrom this source.
Routine releases of radionuclides fromoperating nuclear reactors in the Dnieper
River basin do not contribute significantly to

(k)

(l)

radiation exposure of communities living intheir vicinity.
More data are required in order to makereliable estimates of exposures of people
living in uranium affected areas. Estimates of
exposure from the drinking water pathway
suggest low dose rates, except in small areasthat are unlikely sources of drinking water.
Further work is needed to assess the potential
short term and long term doses that might bereceived if tailings impoundments adjacent towaterways in Ukraine were to fail and releasetailings and/or contaminated water into
adjacent rivers.

REFERENCES TO SECTION 8[8.1] FOODAND
AGRICULTURE
ORGANIZATIONOF
THE
UNITEDNATIONS,INTERNATIONALATOMICENERGYAGENCY,INTERNATIONALLABOURORGANISATION,OECD
NUCLEAR
ENERGYAGENCY,PANAMERICAN HEALTH ORGANIZATION,WORLDHEALTHORGANIZATION,
International Basic Safety Standards forProtection against Ionizing Radiation and for the
Safety of Radiation Sources, Safety Series No. 115,
IAEA, Vienna (1996).
[8.2] INTERNATIONAL
COMMISSIONON
RADIOLOGICALPROTECTION,
1990
RecommendationsoftheInternational
Commission
onRadiologicalProtection,
Publication 60, Pergamon Press, Oxford and New
York (1991).
[8.3] UNITED NATIONS, Sources and Effects of
Ionizing Radiation (Report to the General
Assembly), Annex J: Exposures and Effects of theChernobyl Accident, United Nations ScientificCommittee on the Effects of Atomic Radiation(UNSCEAR), UN, New York (2000).
[8.4] INTERNATIONALATOMICENERGYAGENCY, The Radiological Situation at theAtolls of Mururoa and Fangataufa: Main Report,
Radiological Assessment Reports Series, IAEA,
Vienna (1998).
[8.5] INTERNATIONAL
COMMISSIONON
RADIOLOGICAL PROTECTION, Protectionof the Public in Situations of Prolonged Radiation
Exposure, Publication 82, Pergamon Press, Oxford
and New York (2000).
[8.6] DE CORT, M., Atlas of Caesium Deposition on
Europe after the Chernobyl Accident, Rep. 16733,
Office for Official Publications of the European
Communities, Luxembourg (1998).

[8.7] INTERNATIONALATOMICENERGYAGENCY, The International Chernobyl Project:
Technical Report, IAEA, Vienna (1991).
[8.8] KOVALENKO, G., RUDJA, K., Radioecology of
Ukraine, Kiev University, Kiev (2001) (inRussian).
[8.9] SIMMONDS, J.R., LAWSON, G., MAYALL, A.,
Methodology for Assessing the RadiologicalConsequencesof
RoutineReleasesofRadionuclides to the Environment, Rep. DOC XI5026/94,
CommissionoftheEuropeanCommunities, Luxembourg (1994).
[8.10] GUSAROV, V.I., et al., “The Kursk NPP as asource of radioactive releases to theenvironment”, Ecology of the Regions of Nuclear
Power Plants, Atomenergoproekt, No. 5 M (1996)
6–30 (in Russian).
[8.11] GOLIKOV, V.Y., BALONOV, M.I., JACOB, P.,
External exposure of the population living in areasof Russia contaminated due to the Chernobyl
accident, Radiat. Environ. Biophys. 41 10 (2002)
185–193.
[8.12] GOLIKOV, V., BALONOV, M., ERKIN, V.,
JACOB, P., Model validation for external doses
due to environmental contaminations by the
Chernobyl accident, Health Phys. 77 (1999) 654–
661.
[8.13] LIKHTAREV, I., KOVGAN, L., JACOB, P.,
ANSPAUGH,
L.,
Chernobyl
accident:
Retrospective and prospective estimates ofexternal dose of the population of Ukraine, HealthPhys. 82 (2002) 290–303.
[8.14] BALONOV, M.I., “Chernobyl dose forpopulation of areas radiocontaminated after the
Chernobyl accident”, Environmental DoseReconstruction and Risk Implications (Proc. Ann.
Mtg of the National Council on Radiation
Protection and Measurements, Arlington, VA,
1995) (TILL, J., Ed.), National Council on
Radiation
Protection
andMeasurements,
Bethesda, MD (1996) 207–243.
[8.15] INTERNATIONAL
COMMISSIONON
RADIOLOGICALPROTECTION,
Agedependent Doses to Members of the Public fromIntake of Radionuclides: Part 4, Inhalation Dose
Coefficients, Publication 71, Pergamon Press,
Oxford and New York (1995).
[8.16] JACOB, P., et al., Pathway Analysis and DoseDistributions, Rep. EUR 16541 EN, European
Commission, Brussels (1996).
[8.17] INTERNATIONAL
COMMISSIONON
RADIOLOGICALPROTECTION,
Agedependent Doses to Members of the Public fromIntake of Radionuclides: Part 1, Publication 56,
Pergamon Press, Oxford and New York (1989).
[8.18] INTERNATIONAL
COMMISSIONON
RADIOLOGICALPROTECTION,
Agedependent Doses to Members of the Public fromIntake of Radionuclides: Part 2, Ingestion Dose147

[8.19][8.20][8.21][8.22][8.23][8.24][8.25][8.26][8.27][8.28][8.29]

148

Coefficients, Publication 67, Pergamon Press,
Oxford and New York (1994).
LIKHTAREV, I., et al., Internal exposure fromthe ingestion of foods contaminated by 137Cs after
the Chernobyl accident—Report 2: Ingestion
doses of the rural population of Ukraine up to 12 yafter the accident, Health Phys. 79 (2000) 341–357.
INTERNATIONAL
COMMISSIONON
RADIOLOGICAL PROTECTION, Reference
Man: Anatomical, Physiological and Metabolic
Characteristics, Publication 23, Pergamon Press,
Oxford and New York (1973).
LOS, I., BUZINNY, M., PAVLENKO, T., Radonstudies in Ukraine: Results and plans for future
research, Ann. Assoc. Belg. Radioprot. 21 (1995)
131–143.
PAVLENKO, T., LOS, I., AKSENOV, N., Indoor
222
Rn and irradiation doses on the territory of
Ukraine, Radiat. Meas. 26 (1996) 585–591.
INTERNATIONAL
COMMISSIONON
RADIOLOGICAL PROTECTION, Protection
against Radon-222 at Home and at Work,
Publication 65, Pergamon Press, Oxford and New
York (1994).
WORLD HEALTH ORGANIZATION, Draft
Third Edition of the WHO Guidelines for
Drinking-water Quality, WHO, Geneva (2003),
http://www.who.int
INTERNATIONALATOMICENERGYAGENCY, Generic Models for Use in Assessing
the Impact of Discharges of Radioactive
Substances to the Environment, Safety Reports
Series No. 19, IAEA, Vienna (2001).
IVANOVA, N.P., SHVYDKO, N.S., ERSHOV,
E.B., BALONOV, M.I., Population doses in
Russia from plutonium fallout following theChernobyl accident, Radiat. Prot. Dosim. 58(1995) 255–260.
BRUK, G.Y., et al., “The role of the forest
products in the formation of internal exposure
doses to the population of Russia after the
Chernobyl accident”, Contaminated Forests(LINKOV, I., SHELL, W.R., Eds), NATO Science
Series, Vol. 58 (1999) 343–352.
SHUTOV, V.N., et al., The role of mushrooms andberries in the formation of internal exposure doses
to the population of Russia after the Chernobyl
accident, Radiat. Prot. Dosim. 67 (1996) 55–64.
TRAVNIKOVA, I.G., et al., Lake fish as the main
contributor of internal dose to lakeshore residents
in the Chernobyl contaminated area, J. Environ.
Radioact. 77 (2004) 63–75.

[8.30] DROZDOVITCH, V.V., MINENKO, V.F.,KUKHTA,T.S.,
ULANOVSKY,
A.V.,
BOUVILLE, A., Personal communication (2003).
[8.31] ECKERMAN, K.F., RYMAN, J.C., External
Exposures to Radionuclides in Air, Water, andSoil, Federal Guidance Rep. No. 12, EPA 402-R93-081, Environmental Protection Agency,
Washington, DC (1993).
[8.32] MINENKO, V.F., DROZDOVITCH, V.V.,
TRETYAKEVITCH,
S.S.,
Methodologicalapproaches to calculation of annual effective dose
for the population of Belarus, Radiat. Risk 7(1996) 246–252.
[8.33] ZHELEZNYAK, M., et al., “Modelling ofradionuclides transport in the set of riverreservoirs”, Computational Methods in Water
Resources X (PETERS, A., et al., Eds), Vol. 2,
Kluwer, Dordrecht (1994) 1189–1196.
[8.34] BERKOVSKI, V., VOITSEKHOVITCH, O.,
NASVIT, O., ZHELEZNYAK, M., SANSONE,
U., “Exposures from aquatic pathways”, The
Radiological Consequences of the Chernobyl
Accident (Proc. Int. Conf. Minsk, 1996)(KARAOGLOU, A., DESMET, G., KELLY,
G.N., MENZEL, H.G., Eds), Commission of theEuropean Communities, Luxembourg (1996) 283–
294.
[8.35] ZHELEZNYAK, M.K., et al., Mathematicalmodeling of radionuclide dispersion in the
Pripyat–Dnieper aquatic system after the
Chernobyl accident, Sci. Total Environ. 112 (1992)
89–114.
[8.36] BERKOVSKI, V., RATIA, G., NASVIT, O.,
Internal doses to Ukrainian populations using
Dnieper River water, Health Phys. 71 (1996) 37–
44.
[8.37] HAKANSON, L., “Radioactive caesium in fish in
Swedish lakes after Chernobyl — Geographicaldistributions, trends, models, and remedial
measures”, The Chernobyl Fallout in Sweden —Results from a Research Programme on
Environmental Radiology (MOBERG, L., Ed.),
SwedishRadiation
Protection
Institute,
Stockholm (1991) 239–281.
[8.38] KONOPLEV, A.V., et al., Study of 137Cs and 90Sr
behavior in Lakes Svyatoe and Kozhanovskoe,
Bryansk region, Meteorologiyai Gidrologiya 11(1998) 45–53 (in Russian).
[8.39] RYABOV, I., et al., “Radiological phenomena of
the Kojanovskoe Lake”, The RadiologicalConsequences of the Chernobyl Accident (Proc.
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DESMET, G., KELLY, G.N., MENZEL, H.G.,
Eds), European Commission, Luxembourg (1996)
213–216.

9. RADIOLOGICAL HOT SPOTSIN THE DNIEPER RIVER BASIN

9.1. CONCEPT OF RADIOLOGICALHOT SPOTS
The UNDP–GEF Dnieper Basin Environmental Programme utilizes the water assessment
methodology known as global international waters
assessment (GIWA) [9.1]. As part of a detailed
assessment of pollutant sources, the GIWA
methodology requires identification of thegeographical location of hot spots and assessment of
their impact. According to the extent of its impact, a
hot spot can be further classified as either a transboundary hot spot, a national hot spot or a local hot
spot.
For non-radioactive contaminants, theUNDP–GEF project defines a hot spot as a location
where the maximum permissible concentrations ofcontaminants in water are currently exceeded. The
IAEA team considers that, for radioactive contaminants, a somewhat modified definition should be
used having regard for international principles ofradiation protection and radioactive waste
management.
The IAEA has proposed nine principles forthe management of radioactive waste: (1)protection of human health; (2) protection of theenvironment; (3) protection beyond national
borders; (4) protection of future generations; (5)burden on future generations; (6) national legal
framework; (7) control of radioactive waste
generation; (8) radioactive waste management
independences; and (9) safety of radioactive waste
management facilities [9.2]. These principles need
to be applied in determining and assessing radiological hot spots.
As discussed in Section 8, limits on exposureof workers and the general public to radiation havebeen recommended by the ICRP [9.3]. These
recommendations were adopted by the IAEA andincorporated in the Basic Safety Standards [9.4].
Based on these exposure limits, advisory andregulatory bodies may apply generic or site specificmodels to derive radiological criteria, reference
levels or maximum permissible levels for radioactivity in air, water, soil or biota.
One of the cornerstones of radiation
protection is the ALARA principle, which statesthat exposures should be as low as reasonably
achievable, economic and social factors being taken
into account (see Section 8.1.3). This poses anadditional criterion to be met when considering
appropriate countermeasures to reduce radiation
doses to workers and the general public.
Fruitful discussions on the definition of a hot
spot, especially in the context of radiologicalhazards, took place at a UNDP–GEF organizedworkshop in Kiev in September 2002 and at a
project meeting at the IAEA in Vienna in October
2002.
Following discussions at the Kiev workshop,
the following definitions were adopted for thisstudy:
(a)

(b)

(c)

(d)

Hot spot. A technical facility, object or local
natural site that is contaminated with radionuclides or, in the future, could become asource of environmental radioactive contamination above reference levels or could resultin human or biota exposure above radiologicalcriteria.
Transboundary hot spot. A hot spot that is, orin the future could become, a source ofenvironmental radioactive contamination
above reference levels or could result inhuman or biota exposure above radiologicalcriteria on the territory of another country.
National hot spot. A hot spot that occupies, orin the future could occupy, a substantial
national territory and that has no significant
transboundary impacts.
Local hot spot. A hot spot that occupies a
local area.

In this analysis a distinction is also madebetween actual (i.e. current) and potential (i.e.
possible future) hot spots. Potential hot spots
are facilities, objects or sites that are not currently
a major problem but could be in the future
if appropriate countermeasures are not undertaken.
In addition to these actual and potential hot
spots, an accident at a nuclear power plant is
considered in this section because of its potential for
considerable transboundary impacts.
149

9.2. LIST OF THE CANDIDATERADIOACTIVE HOT SPOTS
On the basis of the information discussed in
Sections 4–7, the following list of candidate hot
spots was selected by the IAEA expert group as
requiring further assessment before possible classification (as actual or potential hot spots, and astransboundary, national or local hot spots):
(a)
(b)
(c)
(d)
(e)

(f)
(g)
(h)

The Pripyat River floodplain within the CEZ;
The Chernobyl cooling pond;
The Chernobyl shelter in the event of its
collapse;
The CEZ (both in Belarus and Ukraine);
Highly contaminated areas outside the CEZ,
especially closed lakes and ponds in Belarus,
the Russian Federation and Ukraine;
Contaminated sediments in the Kiev
reservoir;
Sites in Ukraine where uranium ores were, orare being, processed;
Radioactive waste storage/disposal facilities.

Possible nuclear accident sites include all the
nuclear power plants in the Dnieper River basin or
immediately adjacent to it, viz.:(i) Kursk nuclear power plant;(ii) Smolensk nuclear power plant;(iii) Rovno nuclear power plant;(iv) Khmelnitski nuclear power plant;(v) Zaporozhe nuclear power plant;(vi) South Ukraine nuclear power plant;(vii) Ignalina nuclear power plant.
All sites from this candidate list were assessed,
having regard for the above criteria, on the basis ofexisting monitoring data and/or simulations ofpossible releases.

9.3. ASSESSMENT OF THE HOT SPOTS IN
THE CHERNOBYL AFFECTED AREAS
9.3.1.

Pripyat River floodplain upstream of theChernobyl nuclear power plant

The hottest spot in the Chernobyl affectedarea along the Pripyat River is the heavily contaminated floodplain upstream of the Chernobyl nuclear
power plant (within a distance of 10 km upstream of150

the Yanov bridge) near the city of Pripyat (seeFig. 9.1).
The floodplain can be inundated by a flood of
25% probability (on average once per four years),
where the maximum discharge exceeds 2000 m3/s.
The first assessments of the consequences offlooding based on mathematical models were
performed in 1989–1990 [9.5, 9.6]. The modellingconsidered the Pripyat River and all downstream
reservoirs on the Dnieper River system. Using the
2-D COASTOX model it was shown that, for the
25% probability case (the lowest flood inundating
this territory), the concentration of 90Sr in water at
the Yanov bridge would increase to about
10 000 Bq/m3. The Ukrainian national maximum
permissible level for 90Sr concentration at that timewas 3700 Bq/m3; currently it is 2000 Bq/m3.
The fluxes of radionuclides from the Dnieper
reservoirs into the Black Sea through the Dnieper–Bug estuary were evaluated using the 3-D model
THREETOX [9.7], with special emphasis on therole of the estuary as a river–sea interface for radionuclide transport. Figures 9.2 and 9.3 show thesimulation of the vertical profile of 137Cs and 90Sr forthe month of July 1987. As explained in Section 4,
137
Cs tends to become fixed to the clay sedimentsthat are deposited in the deeper parts of thereservoirs, and, consequently, very little flows
through the cascades to the Dnieper–Bug estuary.
However, although the 90Sr concentration decreases
with distance from the source (mainly due todilution), about 40–60% passes through the cascade
and reaches the Black Sea, where it is diluted withsaline water. The outflow of 137Cs from theDnieper–Bug estuary in the two year period
May 1986–April 1988 was 0.7 TBq, which
represents about a half of the total input to the
Dnieper system (1.4 TBq). However, the outflow of90
Sr was 15.5 TBq, representing 92% of the total
input of 16.8 TBq. The analysis showed that, due tothe low rate of deposition of 90Sr in the reservoirs
and in the estuary, most of the 90Sr that was washedout from the Pripyat floodplain was transported to
the Black Sea via the river–reservoir–estuarysystem. This situation remains the same today,
although the levels of radionuclides are lower.
The construction of a dyke to prevent theflooding of the left side of the contaminatedfloodplain was recommended in 1989–1990 as themost effective urgent water protection countermeasure. Before the dyke was constructed, the firstlarge scale inundation of this floodplain took place
on 21 January 1991, due to an ice jam in the channel

44
88

9
9

11
11
10
10
11

55
33
22

12
12

66

77

m

FIG. 9.1. Aerial photograph taken in 2000 showing the reclamation work along the Pripyat River in the Chernobyl near zone.
The dashed line near location 6 is the position of the geological section through the Chernobyl nuclear power plant. 1: Pripyat
River; 2, 3, 5, 8: former channels closed off from the river in 1986; 4: Lake Gloubokoe; 6: Lake Azbuchin (covered with sand);
7: cooling pond; 9: reclaimed area with the pumping station; 10: water flow control gate; 11: water protection dyke on the leftbank (built in 1992); 12: water protection dyke on the right bank (built in 1999).

km

FIG. 9.2. Simulated distribution of dissolved 137Cs (Bq/m3) in a vertical cross-section of the Dnieper–Bug estuary in July 1987.

151

m

km

FIG. 9.3. Simulated distribution of dissolved 90Sr (Bq/m3) in a vertical cross-section of the Dnieper–Bug estuary in July 1987.

of the Pripyat River at the Chernobyl nuclear power
plant. The measured data confirmed the modelling
prediction; 90Sr concentrations of 11 000 Bq/m3 were
measured at the Yanov bridge. The washout fromthe floodplain in January 1991 produced peaks in
90
Sr and 137Cs concentrations in the Pripyat River(see Section 4, Fig. 4.13). The propagation of this‘signal’ from the vicinity of the Chernobyl nuclear
power plant was measured along the 900 km
pathway from the Pripyat River alongside theChernobyl nuclear power plant to the Dnieper–Bug
estuary via the Dnieper reservoirs.
During 1991–1992 a protective dyke wasconstructed to prevent the flooding of the mostcontaminated areas on the left bank floodplain (seeFig. 9.1). The cost effectiveness of this countermeasure has been estimated by calculating the
averted collective dose as a result of the remedialactions [9.8, 9.9]. The direct cost of the remedial
work on the left bank was about $15 million. It wasestimated that this countermeasure would result inan averted collective dose of 600–700 man Sv over a
period of 75 years. Ignoring ongoing maintenancecosts, this countermeasure was justified based on amonetary value of about $40 000 per averted manSv.
The effectiveness of the engineering works
was demonstrated during the high summer rain
flood in 1993, the winter ice jam inundation in 1994
and the historic flood of 1999. This countermeasure
also had a positive social impact due to the wide152

publicity in the media about the success of thisaquatic protection measure in the Chernobyl area.
The construction of this dyke has reduced theradionuclide fluxes to the Pripyat River; however,as was described in Section 4, during eachsignificant spring flood in the 1990s there was ameasurable increase in the concentration of 90Sr in
the Dnieper reservoirs, caused by radionuclide
wash-off from the contaminated and still
unprotected Pripyat floodplain areas. The highest
flood since the Chernobyl accident took place in thespring of 1999, when the maximum discharge of3000 m3/s from the Pripyat River was the highest
since the historically high flood of 1979 (4500 m3/s).
The construction of the right bank dyke was notcompleted at that time and part of the right bankfloodplain was flooded for two weeks (see Section 4,
Fig. 4.17), primarily due to the dyke overflow. As aresult of these wash-off processes, the maximum
measured concentration of 90Sr at the city ofChernobyl (10 km downstream of the Yanov
bridge) was 2000 Bq/m3, and the ten day averaged
concentration had a maximum of 1500 Bq/m3, which
is close to the maximum permissible concentrationof 90Sr in the Ukrainian drinking water standard of2000 Bq/m3.
The above mentioned maximum concentration of 90Sr (2000 Bq/m3) at the outlet of thecontaminated floodplain during the 1999 flood(maximum discharge: 3000 m3/s) is in agreementwith an earlier prediction [9.10] made as part of anTABLE 9.1.
SIMULATED AVERAGED CONCENTRATIONS OFSTRONTIUM-90 IN THE PRIPYAT RIVER AT THE OUTLET OF THE
CONTAMINATED FLOODPLAIN FOR THE EXISTING LEFT BANK DYKE
AND AFTER CONSTRUCTION OF THE RIGHT BANK DYKE [9.10]
Strontium-90 (Bq/m3),
only left bank dyke

Strontium-90 (Bq/m3),
left bank and right bank dykes

2000

2148

1259

2500

2926

1222

3100

2000

1074

4300

1444

926

6000

1296

926

Q (m3/s)

1000
900
800
700
3
C (Bq/m)

600
500
400
300
200
100
0
12/31/98 02/19/99 04/10/99 05/30/99 07/19/99 09/07/99 10/27/99 12/16/99

(a)
600

400

3

C (Bq/m)

500

300
200
100
0
12/31/98

02/19/99

04/10/99

05/30/99

07/19/99

09/07/99

10/27/99

12/16/99

(b)
600

3

C (Bq/m)500

assessment of the effectiveness of the constructionof the dykes (see Table 9.1).
The propagation of the 90Sr peak through the
Dnieper reservoir cascade was simulated by the 1-D
model RIVTOX. Figure 9.4 shows good agreement
between the 1-D model and measured concentrations. The peak concentrations of 90Sr generated
from wash-off of the small floodplain area at the
Chernobyl nuclear power plant were measured at
the Kiev hydropower plant on 10 April 1999, at
Zaporozhe (Dnieper hydropower plant) at the endof June, and in November near the Kakhovkahydropower plant. The long travel time to the
Kakhovka hydropower plant is explained by thesize of the Kakhovka reservoir, which has a lengthof 250 km and a volume of 16 km3.
Estimates of the collective dose from thefloods of 1999 are reported in Section 8.6.1. Theseshow the continuing importance of 90Sr wash-off
during periods when the Pripyat floodplain is
inundated.
A long term assessment of 90Sr dynamics inthe Kiev reservoir, assuming no further remedial
works, is presented in Fig. 9.5. The scenario of theworst radiological conditions was based on a

400
300

1000

200
800

Worst scenario

0
12/31/98 02/19/99 04/10/99 05/30/99 07/19/99 09/07/99 10/27/99 12/16/99(c)FIG. 9.4. Ten day averaged concentrations of 90Sr at thedams of the hydropower plants of (a) Kiev reservoir, (b)Zaporozhe reservoir, (c) Kakhovka reservoir incomparison with simulation results (triangles) of the 1-D
model. C: 90Sr activity concentration in water.

Bq/m3

100
Best scenario

600
400
200
0
1996

2004

2012

2020

2028

2036

2044

2052

Year

FIG. 9.5. Simulation of the long term fate of 90Sr in the Kiev
reservoir [9.10].

1539.3.2.

Chernobyl cooling pond

As noted in Section 2, the Chernobyl coolingpond covers an area of approximately 23 km2 andcontains approximately 149 × 106 m3 of water. It is
located between the Chernobyl nuclear power plant
and the Pripyat River (see position 7 in Fig. 9.1).
The total inventory of radionuclides in the pond isestimated to be in excess of 200 TBq (about 80%
137
Cs, 10% 90Sr, 10% 241Pu and less than 0.5% eachof 238Pu, 239Pu, 240Pu and 241Am), with the deep
sediments containing most of this activity. The 90Sr
annual flux to the Pripyat River from the coolingpond via groundwater was estimated in a recent
study [9.12] as 0.37 TBq (i.e. a factor of 10–30 lessthan the annual 90Sr fluxes via the Pripyat Riverduring recent years). Accordingly, the cooling pondcannot be considered as an actual hot spot.
Currently, the water level is kept artificiallyhigh: 6 m above the average water level in the
Pripyat River. However, this will change when thecooling systems at the Chernobyl nuclear power
plant are finally shut down and pumping of water
into the pond is terminated. As the pond dries out,
the sediments will be partly exposed and subject todispersal.
Another potential problem that needs to beconsidered is a breach in the cooling pond (as aresult of erosion, a terrorist attack or any otherreason), after which a large amount of contaminated water and sediment would be released into154

the Pripyat River. The assessment of the coolingpond as a potential hot spot was provided within theframework of a recent project [9.12]. It was shownin this study that the resuspension of the dried
sediments would produce only local effects andwould not significantly influence the contaminationof the Dnieper River system.
An analysis of the consequences of a coolingpond dam break was undertaken in a specialized
modelling study. The 2-D lateral–longitudinal radionuclide transport model COASTOX was used tosimulate overland flow, suspended sedimenttransport and radionuclide transport both in thecooling pond and on the neighbouring floodplain
after a dam break. The model was tested withinvarious studies of radionuclide transport in the
Chernobyl zone [9.6, 9.10, 9.13] and was included in
the Hydrological Dispersion Module of theEuropean Union decision support system RODOS[9.14]. The model has been recently applied tosimulate radionuclide wash-off from small
watersheds [9.15, 9.16]. It consists of separate
modules describing overland flow, sedimenttransport, erosion/deposition processes, radionuclide transport in solution and on suspended
sediments by overland flow, and contamination of
the upper soil layer. The objectives of thesimulations were to evaluate discharge of 137Cs and90
Sr to the Pripyat River following a partial breachin the cooling pond. The initial total radionuclide
concentrations of 137Cs were set to 0.089 Bq/L in the
Pripyat River and 2.6 Bq/L in the cooling pond. The
corresponding values for 90Sr were 0.3 Bq/L and
1.9 Bq/L, respectively.
Figures 9.6–9.8 illustrate the dynamics ofinundation of the surrounding territory after ahypothetical dam failure involving a 150 m long
breach. The 90Sr concentration averaged over theriver cross-section downstream of the cooling pondin solution and on sediments is shown in Figs 9.9 and
9.10.
8000

Distance (m)sequence of high water years in the next decade.
The modelling results demonstrate that the large
southern Kakhovka reservoir, while dampening theseasonal oscillations, will, after some years, havepractically the same 90Sr concentration as the Kiev
reservoir.
Modelling studies of the effect of completing
the right bank dyke construction show a significant
reduction in 90Sr concentrations during periods offlooding (see Table 9.1) and a corresponding
reduction in dose to the downstream population.
The estimated reduction in collective dose over the
next 70 years is 150–300 man Sv [9.11].
The results presented in this section show that
the Pripyat River floodplain upstream of theChernobyl nuclear power plant continues to be a
hot spot that generates fluxes of 90Sr through the
Dnieper cascade and into the Black Sea during eachhigh flood. The intensity of this hot spot would bediminished by completion of the construction of theright bank protection dyke in the CEZ.

6000

4000

Breach

2000

0
0

2000

4000

6000

8000

10 000

12 000 14 000

16 000 18 000

20 000Distance (m)FIG. 9.6. Inundated territory 30 s after a dam failure
involving a 150 m breach.

12
5000

10
8

Bq/L

Distance (m)

14

0

0

5000

10 000

15 000620 000Distance (m)4FIG. 9.7. Inundated territory 500 min after a dam failure
involving a 150 m breach.

2
0
0.0

0.5

1.0

1.5

Distance (m)DaysFIG. 9.10. Concentration of 90Sr on suspended sediments in
the Pripyat River downstream of the cooling pond.

5000

0

5000

10 000

15 000

20 000Distance (m)FIG. 9.8. Inundated territory 30 h after a dam failure
involving a 150 m breach.
2.0

Strontium-90 in solution (Bq/L)

0.5
0

Bq/L

1.5

Kiev
Kanev

0.4

Dnieper
Kakhovka

0.3
0.2
0.1
0
1 31 1 31 30 30 29 29 28 27 27 26 26
Jan. Jan. Mar. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.

FIG. 9.11. Dynamics of 90Sr in solution along the cascade of
the Dnieper reservoirs after a 150 m breach in the coolingpond dam.

1.0

0.0
0.0

0.5

1.0

1.5

Days

FIG. 9.9. Concentration of 90Sr in the Pripyat River insolution downstream of the cooling pond.

The radionuclide discharge of soluble 90Sr tothe Pripyat River increases approximately 10 and 20
times for a dam failure with a 60 m and 150 m
breach, respectively. Similarly, the discharge of 137Cs
in soluble form to the Pripyat River increases
approximately 30 and 60 times. The output of the2-D modelling integrated over the cross-section
downstream of the cooling pond has been used as
input data to the 1-D model of the transport of theradionuclides through the whole Dnieper reservoir
cascade. The data for 90Sr are shown in Figs 9.11 and
9.12.

Strontium-90 in suspended sediments (Bq/L)

0.5
0.010
Kiev
Kanev

0.008

Dnieper
Kakhovka

0.006

0.004

0.002

0.000

1 31 131 30 30 29 29 28 27 27 26 26
Jan. Jan. Mar. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.

FIG. 9.12. Dynamics of 90Sr in suspension along thecascade of the Dnieper reservoirs after a 150 m breach in thecooling pond dam.

The results of the simulation of a dam break
can be compared with the results for the last large
flood in 1999 (Fig. 9.4). From this comparison it isclear that, for the dam break scenario, the maximum
155

90

Sr concentration in the Kiev reservoir is a factor of
two less than that during the flood in 1999. The
comparison of annual fluxes of 90Sr shows that theannual flux after a dam break is about 75% of theannual flux for the high spring flood. In contrast, themaximum concentration of 137Cs is low (0.06 Bq/L
in the Kiev reservoir) and therefore could not havea significant influence on individual doses via
aquatic pathways.
The general conclusion from the above
analysis is that the Chernobyl cooling pond can beconsidered as a potential local hot spot in the eventof a dam break, but that the impact would be lower
than that due to periodic flooding of the right bank(see Section 9.3.1).
After the cooling pond is decommissioned, theheavily contaminated sediments will become
exposed. This could lead to dispersal by wind andwater as well as exposure via human intrusion. At
that time (after 2007) it will be necessary to carryout remedial work involving removal of the mostcontaminated sediments and covering/revegetationof the bottom of the pond.
9.3.3.

Chernobyl shelter

As noted in Section 3, the Chernobyl shelter
was constructed hastily in 1986 in order to prevent
further escape of radioactivity into the environment
and to protect personnel working on the site.
Figures 3.2 and 3.3 show the damaged reactor
before and during construction of the shelter. The
accident entirely destroyed the core and severely

damaged the reactor building, turbine hall andnearby structures.
The shelter contains between 173 and 200 t of
nuclear fuel (from a total core load of 215 t), with anestimated activity of up to 750 PBq (20 × 106 Ci) of
238
U and 235U and their daughter products as well as
long lived fission and neutron activation products,
including 137Cs, 90Sr, plutonium radionuclides and241
Am [9.17, 9.18]. Most of the fuel is now containedin a lava-like matrix containing many inclusions ofvarious uranium compounds, finely dispersed fueldust and aerosols.
The current shelter is not acceptable as apermanent solution to the problem of containmentof the residual fuel. Already there are holes anddefects in the structure and the possibility ofcollapse cannot be excluded. Construction of a newsafe confinement (NSC) at an estimated cost of$768 million is expected to be complete by 2008.
The project is being funded by 20 western governments, the European Union and Ukraine. The
structure is envisaged to be a moveable steel arch
120 m long, 100 m high and spanning 260 m. It will
be slid into place along a set of steel rails. The
structure will be designed to last at least 100 years.
Currently, contamination of the environment
by radioactive substances from the shelter may
occur in two principal ways: (1) release of fuel dust
into the atmosphere through openings in the shelter
if there is a collapse of internal structures; and (2)migration of radionuclides through the subsurface
together with water that is inside the shelter (seeFig. 9.13).

South

North

Turbo-generator hallCascade wall
29.35 m16.7 m
8.4 m

5.75 m-5.5 m
23 m

23 m
A

28 m

13 m
B

6m

V G

0.0 m

Water
24 m

12 m 12 m
I

L

N

24 m

1.7 m
T U

FIG. 9.13. Chernobyl unit 4 shelter, showing water pathways [9.17].

156

Room 001/3
48.25 m

Yu

(a)

9000

Bq/m2
8000
15 000 000
7000
7 500 000

700 000
5000

500 000
100 000

4000
50 000
10 000

3000

5000
2000

1000
500

1000

0
-7000

-6000

-5000

-4000

-3000

-2000

-1000

0

1000

2000

3000

Distance (m)FIG. 9.15. Strontium-90 density due to the Chernobyl
accident, upstream of the Yanov bridge.

Atmospheric dispersion from a collapse
followed by fallout and surface watertransport;
Radionuclide transport from the shelter to the
Pripyat River via groundwater.

(b)

3 000 000

6000

Distance (m)An environmental impact assessment for the
NSC is being prepared. It considers the environmental pathways in the event of a collapse of theexisting shelter, both before and after the NSC isconstructed [9.19, 9.20].
If the existing shelter collapses before the
NSC is constructed, it has been estimated that there
will be atmospheric dispersion and subsequent
fallout of 10.4 TBq of 137Cs, 5.04 TBq of 90Sr and0.18 TBq of 239,240Pu [9.19]. Depending on theatmospheric conditions at the time, there may betransboundary impacts.
The airborne pathway is considered elsewhere[9.19]; the following analysis focuses on waterborne
pathways. Two mechanisms are considered:

9000

Bq/m2
8000

15 000 000

7000

7 500 000

The atmospheric fallout from a collapse of the
shelter will be partly deposited in the floodplain
and, to a lesser extent, directly into the Pripyat
River. Figures 9.14–9.17 compare the densities ofcontamination of 90Sr and 137Cs for the worst casescenario for the water pathway with the actual
deposition densities from the Chernobyl accident.
Table 9.2 gives estimates of the radioactivity
deposited in the watershed area or directly into
water. Two scenarios have been considered:

Distance (m)9.3.3.1. Assessment of Dnieper River basin
contamination due to surface water transport

6000

3 000 000
700 000

5000
500 000
100 000

4000

50 0003000

10 000
5000

2000
1000
500

1000

0
-7000.00 -6000.00 -5000.00 -4000.00 -3000.00 -2000.00 -1000.00

0.00

1000.00 2000.00 3000.00

Distance (m)FIG. 9.16. Caesium-137 density for the worst case hydrological scenario.

9000
9000

Bq/m2

8000

Bq/m2
8000

15 000 000

7000

15 000 000
7000

7 500 000
7 500 000

6000

5000

500 000
100 000

Distance (m)700 000

Distance (m)3 000 000

3 000 0006000

700 000
5000
500 000
100 000

4000

4000

50 00050 0003000

10 000

10 000

3000

5000
2000

5000
2000
1000

1000
500

500

1000

1000

0
-7000

0
-7000
-6000

-5000

-4000

-3000

-2000

-1000

0

1000

2000

3000

-6000

-5000

-4000

-3000

-2000

-1000

0

1000

2000

3000

Distance (m)Distance (m)FIG. 9.14. Strontium-90 density for the worst case hydrological scenario.

FIG. 9.17. Caesium-137 density due to the Chernobyl
accident, upstream of Yanov bridge.

157

TABLE 9.2. TOTAL AMOUNT OF RADIONUCLIDES DEPOSITED ON WATER AND ON THE
NEAR-PRIPYAT TERRITORY FOR TWO SCENARIOS INVOLVING THE COLLAPSE OF THE
EXISTING SHELTER [9.19]
Total activity (TBq)
Area of contamination

No NSC

Under NSC

Strontium-90

Caesium-137

Strontium-90

Caesium-137

1. All areas presented in Figs 9.14–9.17
outside the floodplain protection dyke

3.7

8.0

0.26

0.53

2. Part of 1 covered by water

0.8

1.7

0.05

0.11

3. Part of 1 on land

2.9

6.3

0.21

0.42

The upper estimate of the coefficient for 90Sr
washing out from the Chernobyl watersheds due torain is 2 × 10–4 mm–1; this means that 1% of the total
amount of 90Sr will be washed out into the riverduring the assumed 50 mm rainfall. The wash-off
coefficients of 137Cs have lower values; however, wehave used the same 1% as a conservative upper
estimate. The total amount of the radionuclides
washed out by the flooding (10%) and by therainfall (1%) was assumed to be distributed in thefollowing way: 60% during 11 h of the first day, 30%
during the second day and 10% during the third day.
The 90Sr and 137Cs releases to the Pripyat River over
the three days are presented in Table 9.3.
For transuranic elements, the same
assumptions give total releases to the Pripyat Riverfor the no NSC case as follows: 239,240Pu = 0.04 TBq,
241
Am = 0.015 TBq.
The 1-D model RIVTOX was used in thisassessment. It was developed at the Institute ofcollapse with no NSC and collapse under the NSC.
Contamination within the area of the left bankprotection dyke (beyond position 11 in Fig. 9.1) has
not been considered because it could not be washed
out into the Pripyat River.
In the modelling exercise it was assumed thatany fallout that deposited directly on to water(row 2 in Table 9.2) would be diluted in the Pripyat
River within one hour. It was also assumed thatheavy rain was falling and 50 mm of precipitation
occurred over the next two days. (This amountcorresponds to the monthly average for this area.)
For the radionuclides deposited on land it was
assumed that 10% was removed from the floodplainby the inundating flood flow and washed into theriver during the next 11 h and over the following
two days. This percentage was determined to be aconservative upper estimate based on modellingstudies of the radionuclide transport from thisfloodplain [9.6, 9.10].

TABLE 9.3. PREDICTED RELEASE OF RADIOACTIVITY INTO THE PRIPYAT RIVER FOR TWOSCENARIOS OF A SHELTER COLLAPSE
Activity (TBq)
PeriodNo NSC
Strontium-90

Under NSC

Caesium-137

Strontium-90

Caesium-137

First hour

0.78

1.74

0.053

0.115

Eleven hours of the first day

0.19

0.41

0.013

0.027

Second day

0.10

0.21

0.007

0.014

Third day

0.03

0.07

0.002

0.005

Total

1.10

2.43

0.075

0.160

158

Mathematical Machines and Systems Problems
Cybernetics Centre in Kiev to solve water contamination and use problems of Ukrainian rivers after
the Chernobyl accident [9.6, 9.21, 9.22]. The radionuclide transport part of the model is based on theapproaches of the TODAM model [9.23]; however,adsorption–desorption processes have beenaccounted for and simplifications have been madein regard to the particle size of sediments. RIVTOX
was validated for the Clinch River (Tennessee)
within the framework of the IAEA VAMP
programme [9.24] and for the Dudvah River–Vah
River system; the latter is a Danube tributary [9.25].
The model includes a submodel of radionuclidetransport and two submodels for the driving forces(hydraulics and sediment transport).
The results of the simulation of 137Cs and 90Sr
concentrations in the Dnieper reservoir cascade forthe no NSC scenario are presented in Fig. 9.18. In
these graphs ‘normal conditions’ (i.e. no sheltercollapse) are shown as a thin line. The concentrations are plotted as cross-sectional averages at thehydropower plants. The peak 90Sr concentrations
are 700 Bq/m3 at the Kiev hydropower plant and390 Bq/m3 at the Kanev hydropower plant. After
dilution in the large Kremenchug reservoir, theconcentration diminishes to 225 Bq/m3; the peakarrives at the Kremenchug hydropower plant morethan 150 days after passing through the Kiev
reservoir. The peak arrives at the Kakhovkahydropower plant 330 days after passing throughthe Kiev reservoir and has a value of 178 Bq/m3,
which is only 45 Bq/m3 greater than for ‘normal
conditions’. The Ukrainian drinking water limit for90
Sr is 2000 Bq/m3, so even at the Kiev hydropower
plant the peak concentration for a shelter collapse
would be only 35% of the drinking water limit.
A collapse of the shelter would increase theannually averaged 90Sr concentration at the Kiev
hydropower plant by 24 Bq/m3 (or 12.5%) in thefirst year and by 17–20 Bq/m3 (or 12–14%) at the
Dnieper and Kakhovka hydropower plants in thesecond year.
The 137Cs peak concentrations caused by acollapse of the shelter have significant values only in
the Kiev reservoir (455 Bq/m3 in solute and 175 Bq/
m3 on suspended sediments) and in the Kanev
reservoir (137 Bq/m3 in solute and 74 Bq/m3 on
suspended sediments). Further downstream, at the
Kremenchug reservoir, the peak concentration is
only 5 Bq/m3 above the level of ‘normal conditions’(Fig. 9.19).

(b)

600

400

3

500

Bq/m

Bq/m

3

(a)
800

400
200

300
200
100
0

0
1

91

181

271

361

451

541

631

1

721

91

181

271

361

451

541

631

721

541

631

721

Time (days)

Time (days)

(c)

(d)
250

200

200

150

150

3

Bq/m

Bq/m

3

250

100
50
0

100
50
0

1

91

181

271

361

451

Time (days)

541

631

721

1

91

181

271

361

451

Time (days)

FIG. 9.18. Simulated 90Sr concentrations in the Dnieper reservoirs after a hypothetical shelter collapse for the ‘no NSC’ case(bold line) and under normal conditions (thin line). (a) Strontium-90, Kiev reservoir; (b) 90Sr, Kanev reservoir; (c) 90Sr,
Kremenchug reservoir; (d) 90Sr, Kakhovka reservoir.

159

Kiev

Kanev

Kremenchug

event of a shelter collapse, due to a reduction in thearea subject to flooding.

Caesium-137 solute (Bq/m3)

500

9.3.3.2. Radionuclide flux from the shelter to the
Pripyat River via groundwater

400

300

200

100

0
1
31
1
31 30 30 29 29
Jan. Jan. Mar. Mar. Apr. May Jun. Jul.

28 27 27 26 26
Aug. Sep. Oct. Nov. Dec.

FIG. 9.19. Propagation of 137Cs in solute through the
Dnieper reservoirs after the ‘shelter collapse, no NSC’scenario.

At the Kiev reservoir, the annual averaged
Cs concentration is 19.6 Bq/m3 (87% greater thanthe ‘normal conditions’) in the first simulation year,
while at the Kanev reservoir the annual concentration exceeds 7.3 Bq/m3 (45% above the ‘normal
conditions’). In the second simulation year, due toradionuclide exchange processes (adsorption anddesorption) with the contaminated bottom
sediments, the annual averaged 137Cs concentrationis still 50–60% greater in the Kiev and Kanev
reservoirs than under ‘normal conditions’.
For 238Pu, 239,240Pu and 241Am, the simulated
concentrations at the Kiev hydropower plant areless than 1 Bq/m3 and much less than the maximum
permissible levels for these radionuclides.
Therefore, for these radionuclides, fallout from thecollapsed shelter has no significant dose impact on
the Dnieper River system.
The results of this modelling assessment
demonstrate that fallout on the Pripyat floodplain
after a potential collapse of the shelter can produce
a supplementary release of 90Sr and 137Cs from the
CEZ via the Pripyat River to the Dnieper
reservoirs. The peak concentrations in the upper
reservoirs of 90Sr could approach those predicted
during high spring floods; however, they would not
result in a significant impact on the annual doses via
aquatic pathways. After construction of the NSC,
the consequences of a shelter collapse would besignificantly diminished. Completion of theconstruction of the right bank protective dyke also
will decrease the Pripyat River contamination in the
137

160

As noted earlier, water is currently able toenter the existing shelter through a number ofbreaks in the containment. This problem has been
investigated in a recent report [9.26], whichconcludes that the actual volume of water ingress is
no more than 2000 m3/a.
The investigation used tracers that were
injected both via the dust suppression system andlocally into the bubbling pond area. It was demonstrated that the water, which flows from thenorthern and central parts of unit B and the Nuclear
Island auxiliary system, accumulates in room 001/3(see Fig. 9.13). The water then flows through thedividing wall into the unit 3 drainage watercollection system. The experimentally determinedwater egress rate was 1300 m3/a. Visual observations
indicate a leakage value of 840 m3/a. Therefore theegress rate from room 001/3 was estimated to range
from 840 to 1300 m3/a.
Water from the eastern part of unit B
ingresses to room 018/2, where there are sumps forthe drainage water collection system. It is highly
likely, therefore, that water from the eastern part ofunit B also flows into unit 3. The volumes were
estimated to be within the range 390–850 m3/a.
Therefore, the combined egress rate from rooms
001/3 and 018/2 is no more than about 2000 m3/a.
Essentially the same conclusions about thewater fluxes in the shelter were reached in a more
recent report [9.17]. The existing information [9.17,
9.26] demonstrates the importance of room 001/3, in
which water accumulates. Infiltration of the heavily
contaminated water from this pool through thefloor is the main source of the contamination of thevadose zone and groundwater beneath the shelter.
The water in the shelter is a source of theradionuclide fluxes via the vadose zone beneath the
shelter and then via groundwater to the Pripyat
River. The modelling assessment of these radionuclide fluxes before construction of the NSC andunder the impact of the NSC were considered in the
NSC environmental impact assessment studies[9.19, 9.20], which are summarized below.
The data of contamination of the water in the
shelter, based on Ref. [9.26], have recently been
updated [9.17]. In the latest report it is estimatedthat the activities of radionuclides in water in room

kg and plutonium = 30 L/kg. The exchange rate
coefficients, hydraulic conductivities and dispersivity values used for different soils are presented
with model descriptions in Ref. [9.19].
9.3.3.3. Scenario 1: Shelter without the newsafe confinement
Scenario 1 considers the radionuclide contamination of the subsurface environment due to water
infiltration from room 001/3 under the current
hydrological conditions. The water in room 001/3
was fixed at a depth of 1.4 m, or 112.8 m above sea
level. The water levels in the incoming channel and
the Pripyat River were assigned at 109.82 m and104.2 m, respectively. The hydrological conditions
were not changed during the simulation.
Figure 9.21 shows the predicted 90Sr concentrations after 100 years [9.19]. A 90Sr concentrationof 4 × 109 Bq/m3 is located less than 100 m from the
shelter. (Note that the shelter is located at 1000 m inthis simulation.) Even the 100 Bq/m3 concentrationlevel is reached only 600 m from the shelter,compared with the distance of 2.5 km from the
shelter to the Pripyat River.
It would take approximately 800 years for 90Sr
to reach the Pripyat River, as shown in Fig. 9.22.
Bq/m3
800

Elevation (m)001/3 are as follows: 5.2 × 109 Bq/m3 for 137Cs, 1.0 ×
109 Bq/m3 for 90Sr and 360 Bq/m3 for 239Pu.
The 2-D vertical model SUSTOX was used todescribe radionuclide transport in the vadose zone
and in groundwater to the Pripyat River, which is 2.5
km from the shelter in the direction of thegroundwater flow [9.27]. The use of a 2-D model isconservative (i.e. predicts a greater radionuclide
concentrations in the subsurface water because it
does not account for the lateral dispersion anddilution that occurs under more realistic conditions).
SUSTOX has been validated and used inprevious studies of radionuclide transport in thesubsurface environment of the shelter [9.27, 9.28].
In SUSTOX, adsorption and desorption between
exchangeable sorbed solid and fixed solid phases
are considered as non-equilibrium exchangeable
processes that are described by first order kinetic
equations. In cases where the influence of thermal
gradients on flow fields and transport through thegas phase is negligible, SUSTOX produces results
similar to the MSTS code developed at the PacificNorthwest National Laboratory [9.29, 9.30].
SUSTOX uses a more detailed description of theradionuclide exchanges between the solid and liquid
phases of porous media than MSTS.
Figure 9.20 shows the vertical profile used forthe modelling calculations [9.19]. It includes thedrainage system, the incoming channel, a crosssection of the shelter and the Pripyat River.
Two scenarios were simulated, the current
condition (without the NSC) and after NSC
construction. The radionuclide migration from the
shelter to the Pripyat River through the subsurface
flow was simulated for 90Sr, 137Cs and 239Pu for bothscenarios 1 and 2. As a part of the assessment, asensitivity analysis was also performed to evaluate
the dispersivity values.
The values of the distribution coefficient Kd
used in the study were: 90Sr = 1.0 L/kg, 137Cs = 2.0 L/

900

1000

1100

110

1000

1500

2000

2500

3000

3500
110

Shelter
Incoming channel

100

Pripyat River

100

Sand
90

90
Marls of the Kiev eocene

80
0

500

1000

1500

2000

2500

3000

80
3500

Distance (m)

1500

1600

1700

100

90

90

80

80

4.0E+009
1.0E+009
1.0E+008
1.0E+007
1.0E+006
1.0E+005

900

1000

1100

1200

1300

1400

1500

1600

1700

1.0E+004
1.0E+003
1.0E+002

Distance (m)FIG. 9.21. Predicted 90Sr concentrations in the aqueous
phase without the NSC after 100 years.

Dispersivity = 0.2 m
Dispersivity = 1.2 m
Dispersivity = 2.0 m

0.0004

Dispersivity = 5.0 m
Dispersivity = 10.0 m

0.00030.00020.00010.00000

FIG. 9.20. Geological section from the shelter to the Pripyat
River in the north-north-west direction. The position of thesection is shown in Fig. 9.1.

1400

100

800

Strontium-90 discharge (Bq/s)

Elevation (m)

500

1300

110

0.0005

0

1200

110

100

200

300

400

500

600

700

800

900

1000

Time (years)

FIG. 9.22. Sensitivity of 90Sr seepage into the Pripyat River
from the shelter on the longitudinal hydraulic dispersivity.

161

Bq/m3

Elevation (m)

800

850

900

950

1000

1050

1100

1150

4.0E+009

1200

1.0E+009
110

110

100

100

1.0E+008
1.0E+007
1.0E+006
1.0E+005
1.0E+004

90
800

850

900

950

1000

1050

1100

1150

90
1200

Distance (m)1.0E+003
1.0E+002

Plutonium-239 discharge (Bq/s)

FIG. 9.23. Predicted 137Cs concentrations in the aqueous
phase without the NSC after 100 years.

2.0

1.6

1.2

0.8

0.4

0.0
0

10 000

20 00030 00040 000Time (years)

FIG. 9.24. Predicted 239Pu seepage discharge to the Pripyat
River from the shelter (Kd = 30 mL/g).

Bq/m3
800

Elevation (m)With its half-life of 29.1 years, 90Sr would be reduced
to 5.7 × 10–9 of its original concentration due toradionuclide decay. This is reflected in the trivial
90
Sr influx (approximately 0.0004 Bq/s) to the riverat that time. When this 90Sr influx is fully mixed withthe average Pripyat River discharge of 404 m3/s, theresulting 90Sr concentration in the river would be
only 1 × 10–6 Bq/m3, as compared with the current
90
Sr level of 100 Bq/m3. Note that the Ukrainian
drinking water limit is 2000 Bq/m3. Thus infiltrationof 90Sr from the shelter will not cause any harmful
impacts on the Pripyat River.
Predicted 137Cs concentrations after 100 years
are shown in Fig. 9.23 [9.19]. Compared with 90Sr,
137
Cs moves much more slowly, and even after
2000 years its plume is still only 200 m from the
shelter. The radionuclide decay over 2000 years
would reduce the 137Cs concentration by a factor of
1 × 10–20. Thus 137Cs would not cause any harmful
impacts on the Pripyat River and on humans
through the aquatic pathway.
Owing to its high adsorption to the soil matrix,
239
Pu migrates at a much slower rate than 90Sr or
137
Cs; however, its half-life is much longer(24 000 years). The predicted flux is shown in Fig.
9.24 [9.19]. The maximum groundwater 239Pu influxfrom the shelter into the Pripyat River is 2 Bq/s.
When this influx is fully mixed with the average
Pripyat River discharge of 404 m3/s, the resulting
239
Pu concentration in the river would be only 0.005
Bq/m3, as compared with the current 239Pu level of
0.25 Bq/m3. As stated above, the Ukraine regulatory
limit of 239Pu is 1000 Bq/m3. Thus infiltration of239
Pu from the shelter even without the NSC will notcause any harmful impacts on the Pripyat River.

900

1000

1100

1200

1300

1400

1500

4.0E+009
1.0E+009

110

110

100

100

90

90

80

80

1.0E+003

1500

1.0E+002

1.0E+008
1.0E+007
1.0E+006
1.0E+005
1.0E+004

800

900

1000

1100

1200

1300

1400

Distance (m)9.3.3.4. Scenario 2: Shelter with the newsafe confinement

FIG. 9.25. Predicted 90Sr concentrations in the aqueous
phase with the NSC after 100 years.

Scenario 2 assumes no water influx to room
001/3. Thus the water level in room 001/3 decreases
to zero over 1.5 years after NSC construction, due
to water leakage through the concrete floor andwalls of the room, and water evaporation. The
impact of NSC construction was simulated by also
imposing a more permeable barrier and the NSC
piles [9.19]. It was assumed that the NSC would last
100 years and that after that time all radionuclides
in the shelter would be removed. All otherassumptions are the same in scenarios 1 and 2.
Comparison between Fig. 9.21 (without theNSC) and Fig. 9.25 (with the NSC) reveals that the
NSC would make the 90Sr concentrations smaller

than those without the NSC because of less 90Sr
infiltration through the shelter’s concrete floor, withless or no driving force of water in room 001/3. This
would further reduce the 90Sr concentrations andinflux to the Pripyat River.
Modelling studies have also been carried out
for migration of 137Cs and 239Pu with the NSC in
place [9.19]. In both cases the flux to the Pripyat
River is negligible.
This assessment concludes that, with orwithout the NSC, there would be no adverse
impacts on the Pripyat River from infiltration of90
Sr, 137Cs and 239Pu in the shelter. Although the162shelter is considered a hot spot because of its
potential for human exposure via various othermechanisms, the Pripyat–Dnieper river pathway
does not lead to any significant exposures of current
or future generations.
9.3.4.

Chernobyl exclusion zone (Ukrainian andBelarusian parts)

This section considers contaminated areas of
the CEZ other than the floodplain, the shelter andthe cooling pond, which are discussed above.
As was described in Section 4, the secondary
contamination of water bodies by 137Cs in the CEZ
has decreased significantly during the 17 years after
the accident, and now the concentrations of 137Cs in
the rivers are significantly lower than the maximum
permissible levels. However, the secondary postaccident source of 90Sr fluxes into the surface waters
is still significant.
The water in small rivers, creeks and small
floodplain lakes in the area close to theChernobyl nuclear power plant even today has 90Sr
concentrations, during the spring floods, of 1–100
Bq/L (i.e. higher than the Ukrainian and Belarusianmaximum permissible levels). The most contaminated water bodies are Lake Glubokoe (100–300
Bq/L), Pripyat Zaton (80–100 Bq/L), Semikhody
Zaton (30–40 Bq/L) and Glinitsa creek (10 Bq/L).
Although the concentrations exceed the maximum
permissible levels, the total input of these sources
into the flux from the Chernobyl zone via the
Pripyat River is relatively small.
The total 90Sr flux from the Pripyat River into
the Kiev reservoir has varied over the past ten years
from 3 to 10 TBq/a, increasing in the years of highfloods. Analysis of the contribution of the different
sources to the total 90Sr flux from the Pripyat Riverto the Kiev reservoir (see Section 4, Table 4.15)
shows that 64–74% of the flux in different years is
generated in the CEZ. In the last year of high flood(1999), 50% of this flux was generated by thecontaminated floodplain.
During periods of high water, the temporarystorage locations for radioactive waste in thevicinity of the Pripyat River are inundated. During
inundation the activity of 90Sr in the river water at
the local areas around these waste dumps wasobserved to be in the range 10–100 Bq/L. However,the 90Sr flux from all disposal sites into the Pripyat
River at present does not exceed 0.035–0.07 TBq/a.
The total contribution of Pripyat Rivertributaries (Uzh, Braginka, Sakhan) to thewaterborne transport of radionuclides from the
CEZ over the past five years does not exceed 9–13%, and considering all the sources does notexceed 5–6%.
After the Chernobyl accident the Polessye
State Radioecological Reserve was establishedwithin the territory of Belarus by decision No. 59-5of the BSSR Council of Ministers on 24 February
1988. It includes an area within the 30 km exclusionzone. The total area is 1700 km2 and includes
polluted soils of the Khoiniki, Bragin and Narovlya
districts of the Gomel region.
The Polessye State Radioecological Reserve islocated in the Pripyat River catchment, with the
Pripyat River and a group of small rivers andchannels, the largest of which are the SlovechnoRiver, Pogonyanskj channel, Nizhnya Braginka
River and Nesvich River. In these small rivers, a
reduction in runoff of 137Cs has been observed forseveral years; however, the concentrations of 90Sr
still exceed the national maximum permissible level
during flood periods.
It can be concluded that the CEZ as a wholeshould be considered as a hot spot. The radionuclide concentration in some water bodies within the
CEZ exceeds the maximum permissible levels. The
most dynamic source term component of the CEZ,
which provides the major part of the flux from the
CEZ to the Dnieper reservoirs in the years of highfloods, is the Pripyat River floodplain upstream of
the Chernobyl nuclear power plant.
9.3.5.

Affected areas outside the Chernobyl
exclusion zone: closed lakes

As described in Section 4, since the Chernobyl
accident the 137Cs concentration in the rivers, lakes
and ponds with running water has decreased
approximately by one half every two years [9.31].
As a consequence, the concentration of this radionuclide in river water and fish, even in the mostcontaminated areas, is currently well below theintervention level. However, the water 137Cs
contamination in lakes with standing water and slow
water running systems has decreased at a muchslower rate and remains quite high even today [9.32,
9.33].
Some of the most contaminated lakes are near
the Besed River. These include the Belarusian lakes
Revuchee, Svyatskoe and Svyatoe and the Russian
lakes Kozhanovskoe and Svyatoe (see Fig. 9.26).
(Note that there are two lakes named Svyatoe. Lake
Svyatoe in the Russian Federation is near the village
163

FIG. 9.26. Location of some contaminated lakes along the Besed River in the Dnieper River basin.

9.3.5.1. Russian Federation
Figure 9.27 shows the 137Cs concentrations in
Lake Kozhanovskoe and Lake Svyatoe near the
Besed River as a function of time. The decline inconcentrations with time has been very slow. In thefirst lake, the 137Cs concentration is still at the intervention level (11 Bq/L), and in the second it is about
50% of the limit.
Table 9.4 illustrates the high levels of 137Cs infish living in Lakes Kozhanovskoe [9.33] andSvyatoe [9.32]. The table also shows the164

consumption limit to reach the annual dose of
1 mSv. This assumes that fish are the only source of137
Cs intake and so would need to be adjusted
downwards having regard for other intakes (such as

40

Caesium-137 (Bq/L)of Zaborje, Bryansk region. This lake has a surface
area of 100 000 m2 and an average depth of 3 m.
Lake Svyatoe in Belarus is near the village ofMokroe, Mogilev region. It has a surface area of 260
000 m2 and an average depth of 2.8 m.)
Contaminated lakes exist in all three
countries. Specific information is provided in thefollowing sections.

Svyatoe
30

Kozhanovskoe
Intervention level

20

10

0
1992

1994

1996

1998

2000

2002

Year

FIG. 9.27. Dynamics of 137Cs concentration in the waters ofLakes Svyatoe and Kozhanovskoe [9.32, 9.34]. Note: Theintervention level is a Russian national standard establishedby the Russian Standards of Radiation Safety, 1999 (11 Bq
137
Cs/L).

TABLE 9.4. CAESIUM-137 CONCENTRATION IN FISH TISSUE IN LAKES KOZHANOVSKOE AND
SVYATOE
Fish

PeriodCaesium-137(kBq/kg)

Consumption limit(kg/a)

Kozhanovskoe

Carassius carassius

1998–1999

5–10

10.3

Kozhanovskoe

Esox lucius

1998–1999

6–12

8.6

Kozhanovskoe

Rutilus rutilus

1998–1999

2–6

19.3

Svyatoe

Carassius carassius

1998–2001

6–12

8.6

mushrooms, milk and meat). It has been demonstrated that consumption of such fish can lead to
substantial radiation doses to members of the public(see Section 8.6.2).
9.3.5.2. Belarus
A systematic study has been conducted on
three lakes in Belarus — Svyatskoe, Rislavskoe andRevuchee. These are typical of the polluted regionof the Gomel region, but differ in their trophic,hydrological and physicochemical characteristics.
Lakes Svyatskoe and Rislavskoe are dynamic, withsharply expressed stratification of the water.
However, the temperature stratification of water isabsent in Lake Revuchee.
Table 9.5 shows the characteristics of theselakes. The percentage of 137Cs in suspension is 1–2%
for Lakes Svyatskoe and Rislavskoe and 9% forLake Revuchee. The levels of 137Cs contaminationin Lake Svyatskoe (Besed River basin), Lake
Revuchee (Iput River basin) and Lake Rislavskoe
are close to the national permissible levels fordrinking water and food (137Cs in drinking water,
10 Bq/L; for fish, 370 Bq/kg). The 137Cs concentrations in bottom sediments at some sites in Lake
Revuchee (10 345–18 260 Bq/kg) and Lake
Svyatskoe (11 618–16 430 Bq/kg) are so high that
seepage from low level waste storage facilities into
the lakes is suspected.
In these lakes, 137Cs is particularly concentrated in some predatory fish species; for example,in Lake Svyatskoe the 137Cs concentration was
19 410 Bq/kg (crude weight) in perch, 17 430 Bq/kg
in pike and 5800–21 100 Bq/kg in roach. In Lake
Revuchee the corresponding values were 4150 Bq/
kg for pike and 1940–3500 Bq/kg for crucian. These

are considerably in excess of the limits of 370 Bq/kg
given in Ref. [9.35].
Lake Svyatoe, a non-draining (closed) lake in
the Mogilev region of Belarus, was selected for an
experiment on the effect of potassium on 137Cs
accumulation in fish. Potassium is chemically similar
to caesium and can replace it on sediments and inbiota. The K+ concentration in the lake water prior
to the experiment was relatively low (~1 mg/L), andthe 137Cs activity ranged from 3.8 to 4.9 Bq/L. Prior
to the experiment the 137Cs concentrations in fish
were among the highest of all aquatic systems
affected by the Chernobyl accident, being from 8.4
to 17.5 kBq/kg (wet weight) for rudd, from 12.4 to
16.7 kBq/kg for roach, from 58 to 105 kBq/kg forperch and up to 56 kBq/kg for pike. To study theeffect of the dissolved K+ concentration on 137Cs
accumulation and retention in fish, 14.5 t ofpotassium fertilizer was spread over the ice cover ofthe lake. After application of the fertilizer, thepotassium concentration in the lake water increased
to 10 mg/L. This increased the 137Cs concentration inwater to an average value of 12.7 Bq/L, as a result of137
Cs desorption from bottom sediments. In spite of
the increase in 137Cs in the water, there was a steadydecrease of 137Cs concentrations in the two fish
species under consideration during the experiment(see Fig. 9.28), to approximately 30–50% of their
original values [9.36].
Thus, by applying KCl fertilizer to the ice
covered surface of the lake, the 137Cs content in fish
was reduced by a factor of two to three, theefficiency of the countermeasure, as expected, being
reduced by desorption of 137Cs from bottom
sediments. The long retention time of potassium inthe lake water means that a single dose of fertilizer
could be effective for many years.
165

TABLE 9.5. LIMNOLOGICAL CHARACTERISTICS OF LAKES SVYATSKOE, RISLAVSKOE AND
REVUCHEE (1996)
Svyatskoe

Rislavskoe

Revuchee

Area of water surface (m2)

79 20080 000200 000

Average depth (m)

5.5

3.5

1.4

Maximum depth (m)

11

6

2

Average 137Cs density on the catchment(kBq/m2)

440

2900

1300

Concentration of dissolved 137Cs (Bq/L)

7

17

6

0.09

0.1

0.5

Concentration of 137Cs in bottom sediments(kBq/m2)

300– 1000

680– 3555

400

Concentration of 137Cs in fish
(kBq/kg dry weight)

Roach: 15.9; pike: 70.2;
perch: 58.6

European carp: 14.4

European carp: 8.8;
pike: 13.7

Concentration of(Bq/L)

137

Cs, on suspensions

9.3.5.3. Ukraine

Caesium-137 fish (Bq/kg)

During 1991–1995 a survey was conducted ofmore than 3000 water bodies located in the districtsof Zhytomyr, Kiev, Rovno, Chernihiv and otherregions that were contaminated by the Chernobyl
accident. Such screening research resulted in a‘contamination cadastre’ [9.37] of water bodies(lakes, ponds, small reservoirs) that have elevated(a)
70 00060 00050 00040 00030 000
20 000
10 000
0
0

2

4

6

8

10 12 14 16 18 20 22 24 26 28 30 32 34

Caesium-137 fish (Bq/kg)

Time (months)(b)
20 000
16 000
12 000
8000
4000
0
0

2

4

6

8

10 12 14 16 18 20 22 24 26 28 30 32 34

Time (months)

FIG. 9.28. Rate of decrease of 137Cs specific activity of fish
after adding potassium (February 1998) to Lake Svyatoewater (May 1997–September 1999). (a) Pike (Esox lucius);(b) rudd (Scardinius erythrophalmus).

166

levels of contamination. The survey identified 40
water bodies in the district of Rovno, 87 in the
district of Zhytomyr, 27 in the district of Kiev, 28 in
the Volinsky district and several water bodies inother areas where increased risks were expectedfrom the use of water. These risks involved the useof water for irrigation, fishing and fisheries, raisingof water birds, game hunting, etc. The analysis ofrisks was conservative in that dose calculations used
worst case scenarios based on maximum concentrations and, often, sporadic measurements [9.37, 9.38].
Despite the conservative nature of theanalyses, the study showed that about 2% of thesurveyed water bodies in the districts of Rovno andZhytomyr had levels of 137Cs and 90Sr in excess ofthe provisional permissible level of 2 Bq/L. Data forradionuclides in fish and birds showed a significant
bio-enhancement compared with water; forexample, the concentration of 137Cs in Lake Bile
water was 1.5 Bq/L, whereas concentrations in fish
were 450 Bq/kg and in aquatic birds were 50–75 Bq/
kg. In some other small ponds, the level of 137Cs
contamination in fish exceeded the permissiblelevels for Ukraine (150 Bq/kg).
The main source of radiation exposure forpeople living in the vicinity of these water bodies
remain:
(a)
(b)
(c)
(d)

The use of drinking water from wells;
Irrigation from these wells in horticultural
practices;
Fishing;
Raising domestic aquatic birds at these water
bodies;(e)Using water from contaminated sources forlivestock (meat and milk production).

In Ukraine some countermeasures have beentrialled at some fishery ponds in the Zhytomyr
region and near Ivankov in the Kiev region [9.39].
The most effective measure involved the use ofclean food for feeding young fish, followed byrelocation of the growing fish before harvesting
into a pond with a decontaminated bottom.
However, such measures have only been applied toexperimental fishery ponds. No chemical water
treatment for natural lakes has been practised in
Ukraine.
9.3.5.4. Overall assessment of closed lakes
The results reported in this section and in
Section 8.6.2 show that some closed lakes in the
Dnieper River basin remain hot spots. Moreover,the modelling presented in Section 4 demonstrates
that the problem will persist for some time.
The most effective countermeasure to thisproblem is to restrict use of these water bodies forfishing or other purposes noted above. There is alsoa need for continued education of the public in thesafe use of water resources and measures to reduceradiation exposure.
9.3.6.

Affected areas outside the Chernobyl
exclusion zone: Kiev reservoir

The Dnieper reservoirs are the receptors forradionuclides washed out from the CEZ. Caesium137 washed from the CEZ or directly deposited as
fallout during the accident phase is strongly
absorbed by water sediments and ultimately isdeposited on the bottom sediments of thereservoirs,
especiallythe
Kiev
reservoir.
Information on the current distribution of 137Cs on
sediments is presented in Section 4.7.3.
The current inventory of 137Cs in the Kiev
reservoir is about 75 TBq (2000 Ci), see Table 4.22,
mostly in sediments at the bottom of the reservoir.
The maximum accumulation of 137Cs is observed
near the mouth of the Pripyat River and in the zoneof deposition of the silted fraction near Strakholesie(see Section 4, Fig. 4.32). The sandy deposits on theleft bank of the reservoir have remained quite clean
during the whole post-accident period.
Representatives of the ‘green movement’
have expressed concern that sediments in the Kiev
reservoir might be resuspended during periods ofhigh flood and that this could result in levels of 137Cs
in drinking water above the permissible limit. For
this reason, the sediments are assessed in thissection as a possible local hot spot.
The reservoir, with a volume of 3.7 km3 (at thenormal operational water level), has an average
depth of about 3 m in its northern section up to themouth of the Teteriv River; the depth increases inthe southern part to about 10–12 m.
A detailed numerical analysis was carried out
using the 3-D radionuclide transport model
THREETOX [9.13]. The model was tested onmonitoring data for the Kiev reservoir and thenapplied to simulate the redistribution of radionuclides in the water and bottom sediments of thereservoir for an average spring flood (maximum
discharge, QM = 3000 m3) and a very high springflood (QM = 9000 m3). Figure 9.29 shows asimulation of the changes in the activity of bottom
sediments of the Kiev reservoir before and after
such hypothetical floods.
In the initial stages of a high flood, theprocesses of sedimentation dominate over processesof bottom erosion, and accumulation of contaminated sediments takes place. However, during thenext stage, as flow velocities increase, erosion ofbottom sediments occurs. This results in a decreaseof 137Cs activity in the bottom deposits. Finally, as
the flow rate decreases, sedimentation of suspended
material again dominates over erosion processes,
and an increase in the content of radionuclides inthe bottom sediments is observed.
The simulations show that the total amount of137
Cs suspended from the bottom of the reservoir
during the highest flood will not exceed 7% of thetotal inventory (i.e. about 5.3 TBq (140 Ci)). The
concentration of suspended 137Cs during a highflood is significantly higher than that during an
average flood (compare Figs 9.30 and 9.31);
however, the concentration in solution is lower due
to dilution. Therefore it is concluded that, duringhigh floods, resuspension of contaminatedsediments will not increase the total radionuclide
concentration in water (solution plus suspended
sediment) above the permissible level.
This analysis shows that the sediments in the
Kiev reservoir are not a hot spot because thecontamination is largely held on bottom sedimentsthat are not available for significant uptake into
biota under normal or flood conditions. Moreover,the impact of these sediments will decline with time
because of decay and burial under non-contaminated sediments.
167

FIG. 9.29. Density contours of 137Cs on the bottom sediments of the Kiev reservoir: (a) before a flood; (b) after an average
flood; and (c) after a high flood (contour of ‘1’ corresponds to 37 kBq/m2 or 10–6 Ci/m2).

9.4. URANIUM PROCESSING SITES INUKRAINE
Uranium ores have been processed in Ukraine
for over 50 years. Estimates of the quantity of waste
generated from these activities vary (because of
mixing of radioactive and non-radioactive waste atsome sites); however, the latest official figure [9.40]
is that there are 65.5 × 106 t of uranium tailings witha total activity of 4.4 PBq (120 000 Ci). The total
area of tailings impoundments is 542 ha.
An overview of uranium mining and ore
processing in Ukraine with an emphasis on radiological and environmental impacts is presented in
168

Section 6. There are two main processing sites, thePrydniprovsky chemical plant at Dniprodzerzhinsk,
which was shut down in 1991, and the hydrometallurgical plant at Zhovti Vody, which is still in
operation. In addition, there are several mining sites
where ores were or are being mined.
In the early years of uranium mining and ore
processing, little attention was paid to the environmental impact of operations or the management oftailings. Consequently, tailings were often deposited
in inappropriate locations and were not properly
rehabilitated upon closure of the site.
Recently, guidance has been provided by the
IAEA on the management of radioactive waste

FIG. 9.30. Lateral–longitudinal distribution of 137Cs (pCi/L) in solution in the upper layer of the Kiev reservoir (a) and vertical–
longitudinal distribution of 137Cs (pCi/L) on suspended sediments during peak discharge (Q = 3000 m3/s) of an average flood(b). (Note: 1 pCi/L = 0.037 Bq/L.)

FIG. 9.31. Lateral–longitudinal distribution of 137Cs (pCi/L) in solution in the upper layer of the Kiev reservoir (a) and vertical–
longitudinal distribution of 137Cs (pCi/L) on suspended sediments during peak discharge (Q = 9000 m3/s) of a high flood (b).
(Note: 1 pCi/L = 0.037 Bq/L.)

169

from the mining and milling of ores [9.41]. The
guide applies primarily to new facilities, althoughreview of existing facilities against the guidelines isrecommended:
(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

The strategy for management of waste should
be consistent with the principles of radioactive
waste management [9.2]. Two of theseprinciples are the most appropriate to long
lived radioactive waste such as uranium
tailings. These are Principle 4 (Protection of
Future Generations) and Principle 5 (Burden
on Future Generations).
Access to and dispersion of tailings needs tobe restricted for long periods into the future.
For this reason, tailings structures should havehigh stability against floods, erosion and earthquakes.
Disposal of waste below ground level
generally provides a higher degree ofprotection against surface erosion and human
intrusion and requires less maintenance.
Engineering controls may fail because ofnatural processes such as erosion. Such eventsare probabilistic in nature. Due attention
needs to be given to the probability of theevent occurring and to its likely impact on the
integrity of the disposal system.
Financial mechanisms should ideally be put inplace so that the requirements for closure andpost-closure monitoring can be met.
Waste management structures should beclosed when they are no longer needed, and tothe maximum extent possible while operations
are still continuing.
Safety assessments should be carried out tocover the operational, closure and postclosure phases of the facility. These
assessments should consider all significant
scenarios and pathways by which workers, thepublic and the environment may be subject toradiological and non-radiological hazards.
Radiological protection should be optimized
so that doses are ALARA.

The project team visited the Prydniprovsky
chemical plant and inspected several of the tailings
sites in the area. Discussions were also held withtechnical experts on both operational and administrative aspects of the operations. No visits weremade to Zhovti Vody or the uranium mines and so,for these sites, reliance was placed on information
available in the open literature.
170

There appears to be only very limited
information on the radionuclide levels in theenvironment in the vicinity of the Prydniprovsky
chemical plant or the industrial sites at Zhovti Vody.
Some information is presented in Section 6 onelevated levels of some radionuclides in theseepage, runoff and local rivers. Levels in rivers are
generally below the maximum permissible levels in
drinking water. Section 8 gives a few estimates ofdose based on a limited consideration of pathways.
Clearly there is a need for a comprehensive analysis
based on more extensive monitoring data andconsideration of all pathways, including airborne
exposures (radon and daughters), foodstuffs(especially fish), drinking water and externalradiation.
The Prydniprovsky chemical plant is part of avery large chemical complex that consists ofchemical, nuclear and metallurgical plants
bordering on the shores of the Dnieper River (seeSection 6, Fig. 6.3). Some of the plants are still in
operation, while others have closed down, leaving
the equipment and other facilities in a state ofneglect. The Prydniprovsky chemical plant siteneeds to be assessed holistically in order tounderstand the respective contributions of the
facilities to pollution of the Dnieper River basin andthe effects of interactions between the major waste
storage areas. Essentially there needs to be an
overall plan for the site, which will include rehabilitation of sites along with possible further industrial
development.
At Zhovti Vody, countermeasures have been
carried out at some mines and tailings
impoundment sites. The large KBZh tailings site,which contains 19 × 106 t of radioactive waste, hasbeen partly rehabilitated, but restoration is still
incomplete because of financial problems.
The project team considers that tailings are
the main problem at the Dniprodzerzhinsk andZhovti Vody sites due to the potential for environmental and human health impacts over many generations. The main radionuclides in the tailings, 230Th(half-life 80 000 years) and 226Ra (half-life
1600 years), affect the overall radioactivity in thetailings. Consequently, there will be little decline inradioactivity for thousands of years. Although
remedial works have been carried out at a few
locations, most of the tailings are in an unsatisfactory condition.
Tailings are deposited at a number of unsatisfactory locations within the Prydniprovsky chemicalplant. The most substantial waste pile is at thetailings D site, which contains about 1.5 PBq ofradionuclides. The tailings are covered withphosphogypsum, a fine powdery waste from thefertilizer industry, to variable thicknesses (seeFig. 9.32). The banks of the tailings D pile are steep
and on two sides drop away to the Konoplyanka
River, which is a small waterway that flows into the
Dnieper River (see Section 6, Figs 6.3 and 6.4).
Preliminary estimates were given in Section 6 ofreleases of radionuclides to the Konoplyanka River
via surface and seepage, but such estimates need tobe refined by more specialized studies. The
potential for erosion of this tailings pile over time
appears high and needs to be assessed further.
Recent assessments of the Sukachevskoe
tailings C site (see Fig. 6.3 for location) and, inparticular, its dried up beaches, suggest that this site
could be a significant source of secondary contamination because of dispersion of contaminatedphosphogypsum by wind. The Ecological Inspectionof the Dnipropetrovsk region has reported contamination of agricultural products grown on thesurrounding farming area near the villages of
Taromskoe and Sukachevka. Further work isneeded to assess the significance of this contamination.
The project team, having regard for the IAEA
guidelines and, in particular, Principles 4 and 5 ofRef. [9.2], concludes that the Dniprodzerzhinsk site
and the waste storage areas at Zhovti Vody are hot
spots.
Safety assessments need to be undertaken atthese facilities and submitted to the national
regulatory authority. In considering appropriate
countermeasures, the following guidance from the
IAEA should be considered [9.2]:
(a)

(b)

(c)

When existing waste management facilities
cannot meet the post-closure risk constraints
or dose constraints, efforts should be made tominimize risk and dose to what is reasonably
achievable. In judging what is reasonably
achievable in such cases, the dose at whichintervention would be considered today is anappropriate benchmark. This is around
10 mSv/a.
The option of relocating tailings to a morefavourable site for closure would not normallyprovide the optimum strategy because of thelarge volumes of waste to be moved.
If the cost associated with different options is
the main factor for consideration, then aquantitative cost–benefit analysis may be

used. Such an analysis should consider thetime period over which radiation doses andother impacts are to be integrated, spatial cutoff points and the monetary value of avertinga unit of collective dose.

9.5. WASTE STORAGE/DISPOSALFACILITIESThe following waste storage facilities wereconsidered as potential local hot spots:
(a)
(b)
(c)

The Ecores facility near Minsk;
RADON type radioactive waste storage sites
at Kiev and Dnipropetrovsk;
Waste storage facilities at nuclear power
plants.

Technical information on these facilities ispresented in Section 7.
9.5.1.

Ecores facility

The Ecores facility comprises two closed
trenches and two repositories that are being
progressively filled. It accepts radioactive wastefrom the nearby Sosny Institute and from more than
100 organizations from the industrial, research andmedical sectors. The facility is 2 km from the Slouch
River and within the Dnieper River basin, butremote from the Dnieper River. This facility is
below the current international standards for theengineered disposal of low and intermediate level
waste. The project team considers Ecores to be apotential hot spot with a possible medium impact at
the local level. Reconstruction of Ecores is inprogress and this will reduce the potential forhuman exposure and environmental impact.
9.5.2.

RADON radioactive waste storagesites in Ukraine

Information on the RADON radioactive
waste storage sites in Kiev and Dnipropetrovsk isprovided in Section 7. These facilities contain large
quantities of radioactive waste, including spentradiation sources and tritium bearing liquids andgases. Tritium has leaked from the Kiev radioactive
waste storage site towards the Vita River, butconcentrations in surface waters are below the
maximum permissible levels for drinking water.
171

N
1
01
2
02
05

03

3
(a)
06

04

09
07

2
08

10

3

1
1-1

m

80

06
03

07

70

10

02
01
60

50
(b)
80

m

2-2

3-3
08
03

04

07

05

09

70

60

50

Soils of protective dams

Radioactive waste

Alluvial loam

Phosphogypsum

Alluvial sand

Water level inradioactive waste

Slag

Fissured granite

Exploratory wells

FIG. 9.32. Layout (a) and cross-sections (b) of tailings D [9.45].

172

The RADON facilities in Ukraine were
designed to standards prevailing in the 1960s to
1980s and are not in accordance with modern
standards of containment. Storage tanks and otherequipment have deteriorated with time and there isa need to construct new facilities. These facilities are
considered to be potential local hot spots until themost hazardous waste, particularly liquids, istransferred to new facilities.
9.5.3.

Waste storage facilities at nuclear
power plants

At nuclear power plants, radioactive waste isstored in buildings with at least two levels ofcontainment. The risk of escape of radioactivity
from these facilities is assessed to be low. Spent fuelstorage at nuclear power plants has been a problem
in Ukraine, since storage facilities in several cases
are close to capacity and new facilities are required
to accommodate the increasing quantity of spent
fuel. Progress is being made in this area withconstruction of new facilities for dry storage of fuel.
The project team considers that waste and spent
fuel storage at nuclear power plants is satisfactory
and that such facilities should not be regarded as
actual or potential hot spots.

9.6. POTENTIAL ACCIDENTS AT NUCLEAR
POWER PLANTS
Section 5 gives detailed information on
nuclear power plants in the Dnieper River basin(and adjacent areas) and on initiatives undertaken
to improve nuclear safety. The project team’s
analysis of discharge and monitoring data for
nuclear power plants in Ukraine and the RussianFederation shows that routine discharges are
generally well below authorized limits and do notcontribute to significant contamination of theenvironment. Dose rates to residents living in thevicinity of nuclear power plants are very low (seeSection 8.2).
A major accident at a nuclear power plant,
although highly unlikely, could result in major transboundary impacts. The accident at Chernobyl
nuclear power plant unit 4 is an example of thetransboundary effects of a near worst case nuclear
disaster. Since that accident, Russian built reactors
have been subject to many national and international reviews, and upgrades have been undertakenwith the aim of improving nuclear safety.

Systems for emergency preparedness andresponse have also been introduced for Ukrainianand Russian nuclear power plants, based on the
IAEA’s recommendations (see Section 5). Strengthening of these systems requires further
development of the automatic monitoring (early
warning) system around each nuclear power plantand of the real time decision support system for offsite emergency management.
In this report we provide a preliminary
analysis of the consequences of a major nuclear
accident in terms of concentrations of 137Cs inwaterways within the Dnieper River basin. The
accident is assumed to occur at the Zaporozhe
nuclear power plant, which is situated on the bankof the Kakhovka reservoir at a distance of about
1 km from the city of Energodar (see Fig. 9.33). The
Dnieper–Bug estuary is situated downstream of the
Kakhovka reservoir and has a direct connection
with the Black Sea.
An accident at the Zaporozhe nuclear power
plant has the greatest potential for releases that willlead to direct fallout on the Dnieper River as well astransboundary impacts (via transport to the Black
Sea). In this analysis, only the water pathway isconsidered and impact is measured in terms ofconcentrations and fluxes of 137Cs. No attempt ismade to estimate radiation doses.
In 2002 the European Union decision support
system RODOS [9.42] was installed in Ukraine,
customized to the conditions of the Zaporozhe
nuclear power plant site and connected to the
Numerical Weather Prediction Model and local
monitoring systems. The Atmospheric Dispersion
Module of the RODOS system was used for thissimulation. The scenario for the release was takenfrom a number of possible default scenarios used in
the RODOS system for WWER-1000-ST2. The
source term scenario was taken from Ref. [9.43] andis described in detail in Ref. [9.44]. The hypotheticalaccident is initiated by the following combination of
events:
(a)

(b)
(c)
(d)

Loss of coolant from the primary circuit
caused by a complete instantaneous break ofan 850 mm diameter pipe;
Full loss of the electric power supplies of thenuclear power plant;
Failure to start emergency diesel generators;
Failure to get water from two backup supplies.

This combination of events results in meltingof the fuel and a steam explosion that causes
173

FIG. 9.33. The Kakhovka reservoir and the Dnieper–Bug estuary (left lower corner).

destruction of the containment. For this extreme
and hypothetical accident, Table 9.6 gives estimatesof the total released radioactivity as a fraction of thetotal radioactivity in the WWER-1000 reactor core.
The duration of the release is assumed to be 24 h.
The project team’s analysis of the possible
consequences of this accident was based on theworst source term scenarios for this type of reactor
plus the worst meteorological conditions forcontamination of the Dnieper reservoir system. The
wind velocity was low (0.5–1 m/s) and the intensityof precipitation was high (up to 10 mm/h), so thatthe released radioactivity was deposited close to thesource. The simulated fallout density for the chosen
scenario is shown in Fig. 9.34.
The data generated by this simulation weretransferred to the THREETOX model for
simulation of 137Cs dispersion in the Kakhovka
reservoir and then transport to the Dnieper–Bug
estuary. The downstream travel distance after
fallout is about 70 km in the Kakhovka reservoir
and 69 km in the Dnieper–Bug estuary.
174

Figures 9.35 and 9.36 show the dispersion withtime in the Kakhovka reservoir. For this low
probability scenario, 23 PBq of 137Cs is deposited in
the reservoir and the concentration in water soonafter the accident is more than 107 Bq/m3.
Figures 9.37 and 9.38 show dispersion in the
Dnieper–Bug estuary. The peak concentration isdelayed and reduced in magnitude. However, evenafter 300 days, the concentration is still of the orderof 104 Bq/m3.
Some of the deposited 137Cs is taken up by
sediments in the Kakhovka reservoir and the
Dnieper–Bug estuary (see Fig. 9.39(a)). However,most (14 PBq) is transported to the Black Sea,
where the maximum influx is 1.5 GBq/s (seeFig. 9.39(b)). In contrast, the total 137Cs releaseduring the Chernobyl accident was 85 PBq, yet
only 1 TBq reached the Black Sea. This showsthat proximity to the Black Sea coupled withadverse weather conditions could, in the eventof a major accident at the Zaporozhe nuclear
power plant, lead to serious transboundary

TABLE 9.6.
RADIOACTIVE RELEASE TO THE ATMOSPHERE IN AN EXTREME
HYPOTHETICAL ACCIDENT AS A FRACTION OF THE RADIONUCLIDE ACTIVITY IN THE
WWER-1000 REACTOR CORE
Release fraction of the radionuclide at each accident stage
Element released

Before explosion(0–1 h)Steam explosion(instantaneous)

After explosion(1–24 h)Total (0–24 h)

Xenon, krypton

5 × 10–5

0.7

0.16

0.86

Iodine, bromine

5 × 10

–5

0.7

0.16

4 × 10–6Tellurium

4 × 10–6Strontium, barium

2 × 10–6

Caesium, rubidium

Ruthenium0Lanthanum0

contamination. These conclusions need to beverified by more rigorous calculations for a rangeof scenarios.
It must be emphasized that the scenario
examined above is based on a hypothetical andmost improbable sequence of events and adverse
weather conditions. Nevertheless, it demonstrates
the need for an enhanced decision support systemthat includes modules that forecast direct releases

(a)

0.86
–2

0.46

0.29

–2

4 × 100.33

0.06

1 × 10–3

0.06

0.37

–3

0.37

–4

2 × 10–3

0.45

2 × 101 × 10

8 × 10–3

3 × 10

into the water and post-accident contamination ofwater bodies. Such a system, in association withother emergency control measures, could greatly
reduce the dose to individuals in the event of a
nuclear accident.
As discussed in Section 5.9.3, informationexchange between nuclear power plant emergency
units and regional authorities also needs to be
improved.

(b)FIG. 9.34. Density of 137Cs fallout (a) after 1 h and (b) at the end (24 h) of a simulated accidental release.

175Bq/m3100 000
14 000 000
13 000 000

60 000

Bq/m3

12 000 000
11 000 000

80 000

10 000 000

17 000
16 000
15 000
14 000
13 000
12 000
11 000
10 000
9000
8000
7000
6000
5000
4000
3000
2000
1000
500
250
0

50 0009 000 000
8 000 000
7 000 000m

60 0006 000 000
5 000 000
4 000 000
3 000 000
2 000 000
1 000 000
500 000

20 00040 000m

40 00030 000250 000
0
0

20 0000

20 00040 00060 00080 000100 000

120 000

140 000m

FIG. 9.35. Concentration of 137Cs in solution near the water
surface of the Kakhovka reservoir 10 days after the
beginning of a simulated accidental release.

10 0000
0

10 000

20 00030 00040 00050 00060 000m

Bq/m3
100 000

FIG. 9.38. Concentration of 137Cs in solution in the surface
waters of the Dnieper–Bug estuary 303 days after the
beginning of a simulated release.

65 00060 00055 00080 00050 00045 00040 00060 00035 0009.7. FINAL CLASSIFICATION OF HOT SPOTSm

30 00025 00040 000

20 000
15 000
10 0005000

20 000

2500
1250
0
0
0

20 00040 00060 00080 000100 000

120 000

140 000m

FIG. 9.36. Concentration of 137Cs in solution near the water
surface of the Kakhovka reservoir 104 days after the
beginning of a simulated accidental release.

A preliminary list of candidate hot spots isgiven in Section 9.2. Based on the analyses in thissection, the project team’s final classification of hot
spots is given below.
Actual hot spots:
(a)

(b)

60 000

Bq/m3
110 000

50 000100 000
90 00080 00040 00070 000m

60 00050 00030 000(c)

40 00030 000
20 000
10 000

20 000

5000
2500
0

10 0000
0

10 000

20 00030 000m

40 00050 000176

Potential hot spots:

60 000

FIG. 9.37. Concentration of 137Cs in solution in the surface
waters of the Dnieper–Bug estuary 100 days after the
beginning of a simulated release.

The Pripyat floodplain area within the CEZ.
This is assessed to be a transboundary hot spotwith a current impact and a greater impact
during times of high flooding.
The radioactive waste dumps on the former
Prydniprovsky chemical plant site in
Dniprodzerzhinsk and of the uranium
processing operations in Zhovti Vody. These
are actual national hot spots with a potential
for a major impact over a very long period if
impoundment structures erode or failcatastrophically.
Inhabited areas in the three countries withhigh levels of Chernobyl caused radioactive
contamination, including closed lakes in which
concentrations of 137Cs in fish or drinking
water exceed the permissible levels. These are
local hot spots but occur in all three countries.

(i)

The Chernobyl shelter in the event of its
collapse (transboundary hot spot).

(a)Fluxes of 137Cs (GBq/s)

Total activity of 137Cs at the bottom (PBq)

2

8000

4000

(b)

1

0

0

0

100

200
Time (days)

300

400

0

100

200

300

400

Time (days)

FIG. 9.39. (a) Total activity of 137Cs at the bottom of the Kakhovka reservoir and the Dnieper–Bug estuary (solid line: theKakhovka reservoir; dashed line: the Dnieper–Bug estuary). (b) Flux of 137Cs into the Black Sea (solid line: 137Cs in solution).

(ii)

The Chernobyl cooling pond in the event of adam failure (national hot spot).
(iii) The Ecores and RADON facilities at Kiev andDnipropetrovsk, until reconstruction iscomplete (local hot spots).
Nuclear accident: A major accident at anuclear power plant is considered to be of low
probability, having regard for major and ongoing
improvements at nuclear power plants in the
Russian Federation and Ukraine. However, a large
release would have considerable transboundary
impacts, especially in the Black Sea if the source
were in the south of Ukraine (such as theZaporozhe nuclear power plant).
The hot spots listed above would need to begiven special consideration in any prioritization ofcountermeasures to reduce radiological healthimpacts in the Dnieper River basin.

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[9.34][9.35][9.36][9.37][9.38][9.39]

Accident (the Bryansk Region), Final Report of
Project RUS/95/004, UNDP, Moscow (2001).
KONOPLEV, A.V., et al., Study of 137Cs and 90Sr
behavior in Lakes Svyatoe and Kozhanovskoe,
Bryansk region, Meteorologiyai Gidrologiya 11(1998) 45–53 (in Russian).
OSTAPENYA, A.P., “Behaviour of cesium-137 in
the lakes of different types”, paper presented at
Int. Conf. Lake Ecosystems: Biological Processes,
Anthropogenic Transformation, Water Quality,
Minsk, 2000.
KUDELSKY, A.V., SMITH, J.T., PETROVICH,
A.A., An experiment to test the addition ofpotassium to a non-draining lake as a countermeasure to 137Cs accumulation in fish, Radioprotection-Colloques 37 C1 (2002) 621–626.
SAMOILENKO,
V.M.,
TAVROV,Y.S.,
BUYANOV, M.I., Cadastre of Water Body
Radioactive Contamination for Local Water Use,
Nika Center, Kiev (1998) (in Ukrainian).
SAMOILENKO,
V.M.,
TAVROV,Y.S.,
BUYANOV, M.I., Complex Radioecological
Monitoring of Local Water Usage on the Basis of
Stochastic Hydroecological Methodology, Nika
Center, Kiev (2000) (in Ukrainian).
VOITSEKHOVITCH, O., ZHELEZNYAK, M.,
MONTE, L., “Comparative analyses of different[9.40][9.41][9.42][9.43][9.44]

modelling approaches to simulate radionuclidetransport through the Dnieper reservoirs based on
extreme flood 1999 scenario”, paper presented at
Int. Congr. on Radioecology–Ecotoxicology ofContinental and Estuarine Environments, Aix-enProvence, 2001.
Nuclear and Radiation Safety in Ukraine, Annual
Report 2001, State Nuclear Regulatory
Committee of Ukraine, Kiev (2002).
INTERNATIONALATOMICENERGYAGENCY, Management of Radioactive Waste
from the Mining and Milling of Ores, IAEA Safety
Standards Series No. WS-G-1.2, IAEA, Vienna(2002).
EHRHARDT, J., The RODOS system: Decision
support for off-site emergency management inEurope, Radiat. Prot. Dosim. 73 (1997) 35–40.
LANDMAN, G.C., Scenarios Data Sets andScenarios for RODOS, Rep. RODOS RA7-TN(00)-01, Forschungszentrum Karlsruhe, Eggenstein-Leopoldshafen (2001).
SAVUSHKIN, L.A., et al., Construction of a Set
of Typical VVER1000 Severe Accident Source
Terms for Training Applications of RODOS, Rep.
RODOS WG7_TN_98_01, Forschungszentrum
Karlsruhe, Eggenstein-Leopoldshafen (1998).

179

10. MAJOR CONCLUSIONS
10.1. INTRODUCTION
Detailed conclusions on each of the major
topics are presented at the end of each section. Thissection lists the more important conclusions foreach topic and the final classification of hot spots.
Section 11 gives recommendations for the SAP and
NAPs.

10.2. CHERNOBYL AFFECTED AREAS
(1)

(2)

(3)

(4)

(5)

High levels of radioactivity remain within the
CEZ. Important hot spots within this zone are
the floodplain along the Pripyat River, theChernobyl nuclear power plant cooling pond
and the Chernobyl shelter.
There is still transboundary transfer of radionuclides (mainly 90Sr) by rivers within the
Dnieper River basin. The most importantsource is the floodplain of the Pripyat River
within the CEZ.
The concentrations of 137Cs and 90Sr in riverwaters of the Dnieper River basin havedecreased significantly and are now below the
maximum permissible levels set by thenational authorities and recommended byexpert international organizations. Almost all
the 137Cs washed out of contaminated areas isimmobilized in bottom sediments within thereservoirs of the Dnieper River. The impact ofthese sediments is low and will decline further
with decay and further deposition of
sediments on top of the contaminatedsediments.
Lakes with no regular outflows still present a
radiological problem arising from higher
levels of 137Cs in water and fish.
The levels of radioactivity in forest foods (wildgame, mushrooms, berries) in some Chernobyl
affected areas are above permissible levels, as
are those in milk and beef produced by cattle
grazing on contaminated floodplains.

10.3. NUCLEAR POWER PLANTS
(6)

180

Routine discharges from nuclear power plants
in the Russian Federation and Ukraine are

(7)

(8)

generally well below authorized limits and do
not contribute to significant contamination of
the environment.
A legislative and regulatory basis establishedin both the Russian Federation and Ukraine
ensures that all nuclear power plants operatewith a valid licence. A legal mechanism exists
for regulatory body review and assessment ofplant safety and renewal of plant licences on aregular basis.
In recent years the safety of RBMK and
WWER reactors has been subject to considerable regulatory and international scrutiny.
Major engineering upgrades have been
undertaken to improve safety. An international in-depth safety assessment process isunder way to optimize the improvement
programmes. There is room for improvement
in emergency preparedness and response.

10.4. URANIUM MINING AND MILLING(9)Uranium mining and milling in Ukraine has
had a negative impact on the environment.
The most serious problem is caused by about
100 × 106 t of tailings and other radioactive
waste from past and current operations. Mostof the tailings dumps have not been properly
rehabilitated and will pose a long term
problem unless they are properly stabilized.
Tailings D at Dniprodzerzhinsk is considered
to have the greatest potential for pollution of
the environment because of its proximity to
the Dnieper River, the evidence of current
seepage and the possibility of catastrophic
failure of the impoundment. The situation in
the region of tailings C and adjacent to it
needs regular control, and decisions on further
use should be taken with regard to IAEA
recommendations and on the basis of a cost–benefit analysis.
(10) There is a paucity of data on the levels ofradionuclides in the vicinity of uranium mines
and mills and radioactive waste impoundments. Consequently, it is not possible toestimate the current or future dose rates fromthese sources with any degree of accuracy.

(11) There is a need to urgently start thedevelopment of modern standards on theprotection of the environment, radiation
safety and monitoring in the zone of influenceof the uranium sites, consistent with therequirements of Ukrainian law and the recommendations of international organizations
such as the IAEA.

10.5. OTHER RADIOLOGICAL SOURCES(12) Medical and industrial uses of radioisotopes
do not pose significant risks to the populationof the Dnieper River basin. Radioactive
sources with a high radioactivity could be asource of local exposure. Regulatory
authorities should ensure that they areproperly licensed and managed.
(13) There are many disposal or temporary storagesites for Chernobyl waste in Belarus, theRussian Federation and Ukraine. There is aneed to continue to monitor and characterize
the most hazardous of these sites; however,their impact appears to be quite localized anddoes not represent a major source of contamination of surface waters.
(14) There are two RADON type waste storage
facilities at Kiev and Dnipropetrovsk in the
Ukrainian section of the Dnieper River basin.
Further safety assessments need to beundertaken to assess their environmental
impact.
(15) The Ecores State facility near Minsk does notcomply with international standards for the
storage or disposal of radioactive waste. Thisfacility is a potential source of radioactive
contamination of the local population, but notof the Dnieper River basin as a whole.

10.6. HUMAN EXPOSURE TO RADIATION(16) The average dose rate to Ukrainian citizens
from natural radiation sources is about
2.5 mSv/a, which is close to the global average.
This value is also considered to be areasonable estimate of the average dose rate
to the population of the Dnieper River basin
as a whole.
(17) The inhabitants of areas contaminated withradionuclides from the Chernobyl accident in1986 are still being subjected both to external

exposure from 137Cs gamma radiation and tointernal exposure due to consumption of local
foodstuffs containing 137Cs and, to a lesser
extent, 90Sr. The most important factors
controlling the mean external dose are thesettlement type (rural or urban) and the levelof 137Cs soil deposition (in kBq/m2). Forinternal exposures, the most important factors
are the soil type and the level of 137Cs soil
deposition. On average, effective doses to the
inhabitants of rural settlements are higher
than those to urban dwellers.
(18) The average total annual doses to the
inhabitants of settlements located in the
Chernobyl accident areas, caused by environmental 137Cs and 90Sr, range from 0.1 to about
5 mSv. In many tens of settlements the averageannual exposure level still exceeds thenational action level of 1 mSv.
(19) Dosimetric models have been developed andtested to estimate past, present and futureradiation exposures from all Chernobyl
related pathways. The models predict that, by
2001, people in affected areas had alreadyreceived at least 75% of their lifetime internal
dose due to 137Cs, 134Cs, 90Sr and 89Sr in
Chernobyl fallout. Dose rates will decrease
slowly with time over the next 50 years as
deposited 137Cs (half-life 30 years) decays andis made less available by soil redistribution
processes.
(20) For critical groups in Chernobyl contaminatedareas, wild foods (e.g. forest mushrooms,
game, forest berries and fish) can make animportant contribution to dose; for example,
in one study in the Bryansk region of theRussianFederation,‘natural’foods
contributed from 50% to 80% of 137Cs intake.
The average annual internal dose due to 137Cs
was estimated to be 1.2 mSv for men and
0.7 mSv for women.
(21) In most cases, aquatic pathways (drinking
water, fish consumption and irrigation) makeonly a small contribution to the total dosefrom Chernobyl sources. At times of floodingof the Pripyat floodplain, dose rates increase
somewhat due to washout of 90Sr.
Furthermore, in some closed lakes the concentration of 137Cs remains high, and high levelsof contamination are found in fish species.
People who illegally catch and eat contaminated fish may receive internal doses in excess
of 1 mSv/a from this source.
181

(22) Routine releases of radionuclides fromoperating nuclear reactors in the Dnieper
River basin do not contribute significantly toradiation exposure of communities living intheir vicinity.
(23) More data are required in order to makereliable estimates of exposures of people
living in uranium affected areas. Estimates of
exposure from the drinking water pathway
suggest low dose rates, except in small areasthat are unlikely sources of drinking water.
(24) Further work is needed to assess the potential
short term and long term doses that might bereceived if uranium tailings impoundments
adjacent to waterways in Ukraine were to failand release tailings and/or contaminatedwater into adjacent rivers.

(b)

(c)

with a current impact and a greater impact
during times of high flooding.
The radioactive waste dumps on the former
Prydniprovsky chemical plant site in
Dniprodzerzhinsk and of the uranium
processing operations in Zhovti Vody. These
are actual national hot spots with a potential
for a major impact over a very long period if
impoundment structures erode or failcatastrophically.
Inhabited areas in the three countries withhigh levels of Chernobyl caused radioactive
contamination, including closed lakes in which
concentrations of 137Cs in fish or drinking
water exceed the permissible levels. These are
local hot spots but occur in all three countries.
Potential hot spots:(i)
10.7. GENERAL(25) Monitoring data are collected by various
agencies for different purposes; different
methodologies are used, some of which are
outdated. There needs to be harmonization of
results between the various organizations
engaged in monitoring.

The Chernobyl shelter in the event of its
collapse (transboundary hot spot).
(ii) The Chernobyl cooling pond in the event of adam failure (national hot spot).
(iii) The Ecores and RADON facilities at Kiev andDnipropetrovsk, until reconstruction iscomplete (local hot spots).

10.8. POSSIBLE ACCIDENTS
10.7.1. Classification of hot spots
Definitions appropriate to radiologicalassessment have been determined for hot spots,
transboundary hot spots, national hot spots andlocal hot spots. Based on these definitions andassessments by the project team, the following hot
spots have been identified.
Actual hot spots:
(a)

182

The Pripyat floodplain area within the CEZ.
This is assessed to be a transboundary hot spot

In addition to these actual and potential hot
spots, an accident at a nuclear power plant wasconsidered. A major accident at a nuclear power
plant is considered to be of very low probability,
having regard for major and ongoing improvements
at nuclear power plants in the Russian Federationand Ukraine. However, a large release would haveconsiderable transboundary impacts, especially in
the Black Sea if the source were in the south of
Ukraine.

11. RECOMMENDATIONS TO THE GOVERNMENTS
OF BELARUS, THE RUSSIAN FEDERATION AND UKRAINEFOR THE STRATEGIC ACTION PLAN
AND NATIONAL ACTION PLANS
11.1. CHERNOBYL AFFECTED AREAS(8)

The radiological criteria in the Chernobyl
affected countries should be harmonized.

Within the CEZ:
(1)

(1)

(2)

(3)

(4)

(5)

The engineering works on the right bank of
the Pripyat river within the CEZ should becompleted. The works were started in 1998 but
were suspended due to lack of funding.
A diversionary canal should be constructedalong the Belarus–Ukraine border between
the settlements of Krasne and Zimovische
to prevent inundation of the heavily
contaminated areas on the Pripyat River’s leftbank.
After 2007 the heavily contaminatedChernobyl cooling pond should be safely
decommissioned.
Appropriate measures need to be taken tomonitor and prevent releases of radioactivity
from the Chernobyl shelter.
Technical measures should be taken toprevent significant radionuclide dispersion
from the sites of temporary radioactive waste
storage in the floodplain of the Pripyat River.
The monitoring system for surface andunderground waters in the CEZ should be
improved and optimized.
Within inhabited areas:

(6)

(7)

In order to reduce population exposure in themost contaminated areas, the following
measures should be considered:(i) Restrict consumption of local foods (wildgame, fish, berries, mushrooms, etc.);(ii) Restrict grazing and use of vegetation on
floodplains;(iii) Provide safe water to rural communities.
The monitoring system for surface andunderground waters should be optimized. In
particular, screening studies on closed lakes in
the most contaminated areas should be
performed and their impact on population
exposure assessed.

11.2. NUCLEAR POWER PLANTS(9)

Rules and regulations should be harmonizedwithin the Dnieper River basin and madeconsistent with international best practice.
(10) Cooperation and information exchange
between regulatory organizations should be
strengthened to make use of experience
gained in implementing safety upgrade
programmes.
(11) To improve preparedness for a possible
nuclear accident, technical measures (early
warning systems, decision support systems),
institutional measures (logistics) and links
between nuclear power plants and regional
administrative units should be improved.
(12) The scope of safety analysis reports should becompliant with national requirements andconsistent with the IAEA safety standards
and current international practice.
(13) Comprehensive plant specific probabilistic
safety assessments need to be finalized for all
nuclear power plants in the region andsubjected to thorough regulatory review. The
countries with nuclear power plants would
benefit from participation in activities
organized by the IAEA on comparison ofprobabilistic safety assessment studies for
similar reactors.
(14) Plans established for safety improvements
should be carried out as a matter of urgency.

11.3. URANIUM MINING AND PROCESSING(15) An ongoing system for radioecologicalmonitoring of the environment (water, soil,
vegetation, air and food products) in theaffected regions (Zhovti Vody, mining areas
and Dniprodzerzhinsk) needs to be183

established. This should involve provision of
appropriate equipment and coordination of
the efforts of the external monitoring organizations.
(16) The pollution resulting from past and present
operations in the Dniprodzerzhinsk industrial
complex needs to be considered holistically inorder to understand its respective contribution to pollution of the Dnieper River basin
and the effects of interactions between the
major waste storage areas. Essentially, there
needs to be an overall plan for the site, which
will include rehabilitation of sites along withpossible further industrial development.
(17) Rehabilitation of non-operational uranium
tailings impoundments at Zhovti Vody andDniprodzerzhinsk needs to be completed inorder to ensure that they provide long term
containment. In any rehabilitation plan,
particular attention should be given to tailings
D and to the Konoplyanka River, which isacting as a conduit for the transfer ofpollutants from the tailings impoundment into
the Dnieper River.
(18) Current and future operations need to be
carried out in accordance with an environmental plan that includes funding provisions

184

to ensure progressive rehabilitation of closed
mines, dumps and other facilities.

11.4. GENERAL(19) Existing laws, regulations and guidelines
should be reviewed and revised:(i) To ensure that radiation safety provisions
are consistent within the region andcompliant with the latest international
standards;(ii) To apply risk assessment methodologies
to account for radioactive, chemical andbiological contamination.
(20) More detailed impact analysis of actual andpotential hot spots should be undertaken
within the framework of a specialized project.
(21) Monitoring of the environmental radioactive
contamination in the Dnieper River basinshould be improved and harmonized among
Belarus, the Russian Federation and Ukraine.
(22) Scientific research that contributes to theassessment, understanding and solution ofradiological problems in the Dnieper Riverbasin should be supported.

CONTRIBUTORS TO DRAFTING AND REVIEWMEMBERS OF THE INTERNATIONAL EXPERT TEAM
Balonov, M.

International Atomic Energy Agency

Konoplev, A.

SPA Typhoon, Russian Federation

Levins, D.

Project coordinator, Australia

Ranguelova, V.

International Atomic Energy Agency

Voitsekhovich, O.

Ukrainian Hydrometeorological Research Institute, Ukraine

Zheleznjak, M.

Institute for Problems of Mathematical Machines and Systems, Ukraine

Zhukova, O.

Republican Centre of Radiation Control and Environment Monitoring, Belarus

OTHER CONTRIBUTORS
Bohorad, V.

State Nuclear Regulatory Committee, Ukraine

Bulgakov, A.

SPA Typhoon, Russian Federation

Campbell, R.

Nuclear Installations Inspectorate, United Kingdom

Janke, R.

Gesellschaft für Anlagen- und Reaktorsicherheit, Germany

Kanivets, V.

Ukrainian Hydrometeorological Institute, Ukraine

Korovin, Y.

Cvetnye Metally Scientific and Technical Center, Ukraine

Lavrova, T.

Dnipropetrovsk State University, Ukraine

Niehaus, F.

International Atomic Energy Agency

Samiei, M.

International Atomic Energy Agency

Soroka, Y.

Zhovti Vody Radioecological Centre, Ukraine

Tsaturov, Y.

Federal Service for Hydrometeorology and Environmental Monitoring,Russian Federation

Consultants Meetings
Vienna, Austria: 15–19 April 2002, 7–11 October 2002
Fact finding missions
Radiation and waste safety issues: Moscow and Obninsk, Russian Federation; Minsk, Belarus;
Kiev, Chernobyl, Dnipropetrovsk and Dniprodzerzhinsk, Ukraine: 1–12 July 2002
Nuclear safety issues: Moscow, Russian Federation, and Kiev, Ukraine: 29 July–2 August 2002
Workshops
UNDP Hot Spots Workshop, Kiev: 9–10 September 2002
UNDP Workshop on TDA Methodology and Causal Chain Analysis, Kharkiv, Ukraine: 8 November 2002

185

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