2021-FNCA

Surveillance of radioactivity
in terrestrial environment andquality control of data
Sang-Han LEE (s.lee@kriss.re.kr)
Korea Research Institute of Standards and ScienceContents

1 Introduction
2 Current status of radioactivity monitoring구성
Case study
3 컨텐츠

4 컨텐츠 구성5 컨텐츠 구성commodities

Introduction

Radioactivity outflow in the environment
Following the Fukushima NPP disaster, Nuclear power plant operation andaccidental release from the specific source, the concerns regarding
radioactive contamination of terrestrial products have continued to spreadto the general publicThus leading to increased demand for intensive monitoring and survey ofradioactivity in the environment.
Asphalt radioactive contamination
Ironworks furnace
Ferroalloy

pig ironquicklime
Scrap
metal

Contaminationslag

Cs-137 source
Ascon
Aggregate

Major pathways of radioactive contamination to terrestrial

Radiation dose to manradionuclide

Guidance level

Food(Bq/kg, L)

Infant foods

100

Milk

100

Foods other than infant

300

General foods

100

131I

Drinks
134Cs ＋ 137Cs

10

Food imported

Milk and milk

from Japanproducts
General food

50
100

Cs-137USA

1,200 Bq/kg

Codex
EU
Korea

1,000 Bq/kg
500 Bq/kg(since Sep. 2013)
100 Bq/kg
370 Bq/kg

The Brief Information of NORM Regulation
 Definition and Registration level• Reference: IAEA RS-G-1.7, IAEA SRS-49• U-238 series, U-235 series, Th-232 series, and K-40
• The handler (operator) should be registered if they deal with raw
materials and residues over registration levels
Sort

Definition

Registration level

Bq/g

kBq

Bq/g

kBq

Raw
materials

0.1 (U, Th)
1 (K-40)100

1 (U, Th)
10 (K-40)

1,000
10,000Residues

0.5 (U, Th)
5 (K-40)-

1 (U, Th)
10 (K-40)

1,000
10,000Current status ofradioactivity monitoring inSouth Korea

Why do we need monitoring on environment?
 Ensuring terrestrial environment is safe
 Public reassurance
 Check against statutory limits and target
 Carry out dose assessments
 Long-term trends of radioactivity in environment Identify early signs of change

MarineMinistry of Ocean and Fisheries•

Korea Marine Environment Management
Corporation

Nuclear Safety and Security
Commission•

KINS (Korea Institute of Nuclear Safety)•

KHNP(Korea Hydro & Nuclear Power Co.,Ltd)• Marine• KORAD(Korea Radioactive Waste Agency)• Terrestrial• Around nuclear power plant facilities

Food
Ministry of Agriculture, Food and Rural
Affairs•

Animal and Plant Quarantine Agency

Ministry of Food and Drug Agency•

6 branch MFDA•

16 Research Institute of Public Health andEnvironment

Ministry of Environment•

National Institute of Environmental Research

Other relevant bodies such as N.G.O including
government-funded research institutes (KRISS
etc)

River
Lake

ISO 24153

11

Analytical Method
1. Non destructive methods
Gamma spectrometry (Cs-137, I-131)
Nuclear Activation Analysis, XRF etc.

2. Destructive methods
Alpha spectrometry (U-238, Pu isotopes)
Beta spectrometry (Sr-90)
AAS
ICPMS etc. (Isotope mass)

Soil sampling and analysis

Digestion
or FusionAerosols, rainwater, undergroundwater

Case study (soil, foods andatmospheric materials)

Year

137Cs

Number ofsamplestested

0.1-<100(Bq/kg)(Bq/kg)2011

23,14473

0.1-97.9

2012

26,608167

0.33-24.7

2013

27,45366

0.86-9.8

2014

27,56715

0.92-262015

31,5028

1.0-3.0

2016

32,946

7

1.0-2.0

201735,2304

1.0

2018.824,8503

1.0-28Mushroom sample (edible)

The activity concentration of 137Cs in the mushrooms(6 from Jeju Island)lichen137Cs Contribution from Fukushima NPP

 (Sampling site : Jeju Island, Korea)
May 2017

Cs-134(Bq/kg, dry wt.)

Cs-137(Bq/kg, dry wt.)N

Lentinula edodes(Shiitake)

0.17-0.29

27-37

3

March 2011
(Decay corrected)

Cs-134(Bq/kg, dry wt.)

Cs-137(Bq/kg, dry wt.)N

Lentinula edodes(Shiitake)

0.9-1.5

31-43

3

 The activity ratio of 137Cs/134Cs from Fukushima : ca. 1(Leon et al., 2012; Kim et al., 2012; Lujanien et al., 2012)

Therefore, the 137Cs contribution from Fukushima NPP accident could
estimate to be ca. 3% of total 137Cs content in the Lentinula edodes in Jeju
Island, Korea

Radioactive impact to Korea from Fukushima NPP

Lee et al., 2013 ; Park et al., 2013

Distribution of 137Cs, 241Am and 239,240Pu isotopes insurface soils

Comparison of vertical profile of radionuclide
concentration in the soils
137

0

20

Cs activity (Bq kg-1)
40

60

80

100

241

120

0.0

0

0.1

239,240

Am activity (Bq kg-1)

0.2

0.3

0.4

0.5

0.6

0

0.7

0

0
2
4

5

5

8
10
12
14

15

Depth (cm)10Depth (cm)Depth (cm)

6

10

15

16
18
20

20

20

NaRi Basin (Ulleung Island in the East Sea/Sea of Japan)
Mt. BukHan (National Park in Seoul )SeongSan Ilchulbong Peak (Jeju Island)1

Pu activity (Bq kg-1)
2

3

4

Source of artificial radionuclide in food in Korea
238Pu/239,240Pu activity ratio and 240Pu/239Pu mass ratio

Assessment of dose24

Measurement of I-131 in rainwater after Fukushima NPP
accident
Figure 1 Temporal variation of 131I concentration in rainwater in Daejeon, Korea
131I

MeasuredTime(s)2011-04-18

1,170 ± 24%

86,4002011-04-22

1,300 ± 39%

86,4002011-05-09

230 ± 36%

71,6002011-05-10

24.1 ± 59%

85,0003.0

2011-05-11

47.0± 76%

86,4002.5

2011-05-12

252 ± 50%

86,4002011-05-20<42.0

86,4002011-06-01

229 ± 37%

86,4002011-06-22

138 ± 60%

86,4002011-06-24<40.3

74,6002011-06-29<33.4

86,4002011-06-30

116 ± 58%

86,4002011-07-08

343 ± 34%

86,4002011-07-12< 60.4

86,4002011-07-13

574 ± 34%

86,400131

I (Bq/kg)(mBq/kg)

Date

2.0

The theoretical decayed concentrationof 131I for the rainout event(28 March 2011)

1.5
1.0
0.5
0.0

-1
-1
-1
-1
-1
-1
1-6
1-4
1-5
1-7
1-8
1-9
1
1
1
1
1
1
20
20
20
20
20
20
Time

Measurement of Cs-137 in rainwater after Fukushima
NPP accident

Rainwater : 0.1 ~1.0 mBq/L,
1998

Hong et al., 2006

Annual variation of Cs-137 in the fallout

Concentration of Pu-239,240 in the rainwater

239,240Pu

Date ofSampling

Rainwater
sampleweight (kg)

May 2012

31.34

7.7

2.6

1.77

Jun. 2012

53.30

2.6

1.3

1.73

Jul. 2012 a

61.06

<MDA

-

2.52

Jul. 2012 b

65.71

<MDA

-

3.48

Aug. 2012 a

83.16

<MDA

-

2.37

Aug. 2012 b

73.38

<MDA

-

3.67

Sep. 2012 a

84.26

<MDA

-

2.21

Sep. 2012 b

97.14

<MDA

-

2.27

Activity(μBq/kg)

MDA
Uncertainty(μBq/kg)(k=1)

Concentration of Pu isotopes in rainwater

Concentration of Pu-239,240 in Dry deposition

Date ofSampling

Dry deposition
sampleweight (g)Nov. 2011239,240Pu

Activity(mBq/m2)

Uncertainty
(k=1)

MDA
(mBq/kg)

0.7742

0.137

0.102

0.119

Dec. 2011

0.2913

0.153

0.092

0.089

Jan. 2012

0.7239

0.246

0.103

0.068

Feb. 2012

0.254

<MDA

-

0.121

Mar. 2012

2.91

0.680

0.171

0.068

Apr. 2012

3.02

0.669

0.203

0.097

May 2012

1.76

<MDA

-

0.063

Jun. 2012

2.33

0.478

0.166

0.117

Jul. 2012

1.06

0.120

0.076

0.076

Aug. 2012

0.77

<MDA

-

0.294

Concentration of Pu isotopes indry depositioncommodities

Natural Radiation Source• Cosmic rays : high-energy particles that originate in outer space• Cosmogenic radionuclides : 3H, 7Be, 14C, 22Na

• External exposures : soils (238U series, 232Th series, 40K), construction

materials• Internal exposures : inhalation (air dust) & ingestion (food, water)• Radon : gaseous radioactive products (decay of the radium isotopes)• Phosphate processing, Metal ore processing, Uranium mining, Zircon

sands, Titanium pigment production, Fossil fuels, Oil and gas
extraction, Building materials, Thorium compounds, Scrap metalindustry, Emissions.

Increased social interest due to radioactivity event(Radioactive asphalt) The annual radiation dose that can be received by people living in Wolgye 2-dong residential
areas is measured as 0.51-0.69 mSv.
(Annual radiation dose assumes that an adult male stays for 1 hour each day for 1 year).
 It is about a sixth to a quarter of the average annual radiation dose in Korea of 3 mSv, which isreceived from nature such as land, terrestrial , air, and space It is less than 1 mSv, the annual dose limit set by the Nuclear Safety Act.
Radiation exposure level by situation (mSv)

Air
travel(KoreaEurope)

Naturalsource(Korea)WolgyeDong(Seoul)
Chest
X-Ray

Annualdose
limit forthepublicHighland(Brazil)Computer
Tomography

Specific activity (Bq/g)

Radiation levels of major industrial raw materials

33Natural radionuclide decay series
232Th

238U

Increased social interest due to radioactivity event(household products (or commodity) around daily life : anion effectRumors spread that productsthat release anions are good for health ????

Increased social interest due to radioactivity event(household products (or commodity) around daily life : anion effectThe Brief Information of NORM Regulation
 Purpose• To prescribe those matters concerning safety management ofradiation encountered in environments• To protect the public health and the environment and improving
quality of life while contributing to public safety

 Structure and other information• 1 Act, 1 Enforcement Decree, 1 Enforcement Regulation,and 2 Notifications• Enacted in 2011, and implemented in 2012 by Nuclear Safety andSecurity Commission(NSSC)(Due to the issues of radiation exposure from the NORM products
and Fukushima accident)

37

The Brief Information of NORM Regulation
 Target of radiation• NORM : Raw materials, Residues, The Product• Cosmic radiation (flight exposure to air crew)• Terrestrial radiation (radon excluded because radonis already regulated by another act)

Cosmic ray• Radioactive materials in the scrap metal

By-product

Recycled scrap metal

Raw materials

Terrestrial radiation

The Brief Information of NORM Regulation
 Definition and Registration level• Reference: IAEA RS-G-1.7, IAEA SRS-49• U-238 series, U-235 series, Th-232 series, and K-40
• The handler (operator) should be registered if they deal with raw
materials and residues over registration levels
Sort

Definition

Registration level

Bq/g

kBq

Bq/g

kBq

Raw
materials

0.1 (U, Th)
1 (K-40)100

1 (U, Th)
10 (K-40)

1,000
10,000Residues

0.5 (U, Th)
5 (K-40)-

1 (U, Th)
10 (K-40)

1,000
10,000Assessment of dose-Raw material

 The survey on raw materials and by-products was conducted for a total of 15
companies in four areas: workplaces handling raw materials, workplaces
generating significant substances, facilities generating by-products, andworkplaces suspected of significant substances.
 The maximum radiation dose rate in areas where there is a risk of external
exposure was 0.62 μSv/h, and the maximum radiation dose was evaluatedas low as 0.21 mSv/y for the total internal and external exposure.
(KINS/GR-547, 2019)

Assessment of dose-Drinking water In the production of drinking water, 210Pb, a daughter nuclide of radon
discharged with groundwater, can be concentrated in the filter.
 However, as a result of radioactivity analysis, it did not meet the criteria fordefining by-products.
 In addition, the radiation dose to workers was 0.0039 mSv/y.
(KINS/GR-547, 2019)

Assessment of dose-processed products

 The survey on processed products is conducted to analyze the concentrationof radioactivity for a total of 513 products and evaluate the annual exposure
dose.
 The radon and toron concentrations of all 513 products were measured, andinternal exposure doses for 411 products were evaluated. (KINS/GR-547,
2019)
 Of the 411 products, 68 products exceeded the exposure dose of 1 mSv.
(17 mattresses, 14 electric mats, 8 blankets, 6 pads, 6 thermal mats, 5
pillows, 4 suit-type underwear, 4 blankets, 2 latex mattresses, 1 hot watermat, 1 sofa, etc.)(KINS/GR-547, 2019)

Assessment of dose-air transportation business According to the survey on air transportation business operators in 2019,
there are 9 business operators in Korea.
 The number of crew members was 22,484
 The business operator is using CARI-6/6M and NAIRAS as a program forevaluating the exposure dose by cosmic radiation.
 It was found that the annual average dose of crew members received 2.09
mSv.
 According to the safety instructions, the flight attendant is recommended that
does not exceed 6 mSv
 Therefore, it is investigated that no one exceeds the value.
(KINS/GR-547, 2019)

45

(Certified value or reference value)

46

47

48

* Fishbone49Equationm = x+cu(x), u(c)Uncertainty components

Statistical

Standard uncertainty

A typeui

Non-statistical

B typeFactor Ci

Combined standard uncertaintyuc

u c ( m) = u 2 ( x ) + u 2 (c )Confidence level, Degree of freedom
Expanded uncertainty U

U = 2 × u c ( m)

52

53

The laboratory shall have a procedure for monitoring the validity of results.
The resulting data shall be recorded in such a way that trends are detectable
and, where practicable, statistical techniques shall be applied to review theresults. This monitoring shall be planned and reviewed and shall include,
where appropriate, but not be limited to:.

a) use of reference materials or quality control materials;b) use of alternative instrumentation that has been calibrated to provide
traceable results;c) functional check(s) of measuring and testing equipment;d) use of check or working standards with control charts, whereapplicable;e) intermediate checks on measuring equipment;f) replicate tests or calibrations using the same or different methods;g) retesting or recalibration of retained items;h) correlation of results for different characteristics of an item;i) review of reported results;j) intralaboratory comparisons;k) testing of blind sample(s).
54The laboratory shall monitor its performance by comparison with results ofother laboratories, where available and appropriate. This monitoring shallbe planned and reviewed and shall include, but not be limited to, either orboth of the following:a) participation in proficiency testing;
NOTE ISO/IEC 17043 contains additional information on proficiency tests and proficiency testing providers.
Proficiency testing providers that meet the requirements of ISO/IEC 17043 are considered to be competent.

b) participation in interlaboratory comparisons other than proficiency
testing.

55

56

57

Crucial activities for production for CRM
ISO Guide 30~35
All or some of the following activities can be crucial in RM
production and their quality assessment can be crucial to thequality of the final RM:
 Sourcing of materials including synthesis
 Processing of materials including purification, grinding,particle size separation
 Homogeneity and stability testing Development and validation of measurement procedures,
including consideration of the traceability
 Measurement of property values and evaluation of
measurement uncertainty
 Certification and sign off of the RM
Korea Laboratory

Development of Oyster CRM (ISO Guide 35)62

Development of Sediment CRM (ISO Guide 35)

Candidate sediment

DryingGrinding

Homogenization

Bottling
Homogenization test

CRMs and international comparison exercise
 International comparison exercise materials for radioactivity measurement of(mushroom) material developed by KRISS (BIPM CCRI(II)-S15)
 International comparison exercise materials for radioactivity measurement of (rice)material developed by KRISS (BIPM CCRI(II)-S9)Radionuclide
source ID

KRISS
Seawater CRM

Sourcedescription

Seawatercontaining 137Cs

Reference date

1. Oct. 2012

Specific activity(Bq/kg)100.1

Total expanded
uncertainty (%)

1.44

Half life (yr)30.05

Measurement
technique

HPGE gamma
spectrometry

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