ORAU Team

NIOSH Dose Reconstruction Project

Technical Basis Document for the Hanford Site – Introduction

Document Number:

ORAUT-TKBS-0006-1 

Effective Date: 11/07/2003

Revision No.: 00

Controlled Copy No.: ________

Page 1 of 7 

Subject Expert: Edward D. Scalsky

Document Owner

Approval: Signature on File Date: 11/06/2003

Edward D. Scalsky, TBD Team Leader

Approval: Signature on File Date: 11/06/2003

Judson L. Kenoyer, Task 3 Manager

Concurrence: Signature on File Date: 11/06/2003

Richard E. Toohey, Project Director

Approval: Signature on File Date: 11/07/2003

James W. Neton, OCAS Health Science Administrator

Supersedes:

None

TABLE OF CONTENTS

1.0 Introduction

2.0 Site Description

3.0 Occupational Medical Dose

4.0 Occupational Environmental Dose

5.0 Occupational Internal Dose

6.0 Occupational External Dosimetry

Attachment A Description of Facilities and Processes

Attachment D Occupational Internal Dose For Monitored Workers

Attachment E Occupational External Dose for Monitored Workers
Effective Date: 11/07/2003 Revision No. 00 Document No. ORAUT-TKBS-0006-1 Page 2 of 7

RECORD OF ISSUE/REVISIONS

ISSUE 

AUTHORIZATION 

DATE

EFFECTIVE 

DATE

REV. 

NO. DESCRIPTION

11/07/2003 11/07/2003 00 New TBD for the Hanford Site – Introduction. 

Initiated by Edward D. Scalsky. 
Effective Date: 11/07/2003 Revision No. 00 Document No. ORAUT-TKBS-0006-1 Page 3 of 7

ACRONYMS AND ABBREVIATIONS

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

MDA minimum detectable activity

NIOSH National Institute for Occupational Safety and Health

ORAU Oak Ridge Associate Universities

TBD technical basis document
Effective Date: 11/07/2003 Revision No. 00 Document No. ORAUT-TKBS-0006-1 Page 4 of 7

In enacting the Energy Employees Occupational Illness Compensation Program Act of 2000 

(EEOICPA), the U.S. Congress officially recognized the hazardous nature of producing and testing 

nuclear weapons. Under the Act, workers who have developed selected types of cancer (or their 

survivors) may be entitled to compensation and medical benefits. This program is administered by 

the U.S. Department of Labor Office of Worker Compensation. The National Institute for Occupational 

Safety and Health (NIOSH), a part of the U.S. Department of Health and Human Services, is 

responsible for determining the individual worker’s dose. Oak Ridge Associated Universities (ORAU) 

leads a team to support NIOSH in conducting this major program. 

The Act requires the estimation of radiological doses from ionizing radiation received by workers in 

the nuclear weapons production programs of the U.S. Department of Energy and its predecessor 

agencies. Methods for implementing provisions of the Act have been promulgated in Title 42 of the 

Code of Federal Regulations, Part 82, “Methods for Radiation Dose Reconstruction Under the Energy 

Employees Occupational Illness Compensation Program Act of 2000.”

This technical basis document (TBD) is a specific support mechanism to the ORAU Team concerning 

documentation of historical practices at the Hanford Site. Dose reconstructors should use the 

information in this TBD to evaluate both internal and external dosimetry data for unmonitored and 

monitored workers. In addition, the document serves as a supplement to, or a substitute for, 

individual monitoring data. This document provides a site profile of Hanford that contains technical 

basis information for the ORAU Team to use to evaluate the total occupational radiation dose for 

EEOICPA claimants. 

In addition, this document provides supporting technical data to evaluate, with claimant-favorable 

assumptions, the total Hanford occupational radiation dose that can reasonably be associated with 

worker exposures. This dose results from exposure to external and internal radiation sources in 

Hanford facilities; to Hanford occupationally- required diagnostic X-ray examinations, and to on-site 

environmental releases. The discussion includes the doses that workers could have incurred while 

not monitored or that could have been missed. 

Over the years new and more reliable scientific methods and protection measures have been 

developed. The methods needed to account for these changes are also identified in this document. 

The doses are to be evaluated using the NIOSH Interactive RadioEpidemiological Program (IREP)

and the Integrated Modules for Bioassay Analysis (IMBA) computer programs. Information on 

measurement uncertainties is an integral component of the NIOSH approach. This document 

describes how the uncertainty for Hanford exposure and dose records is to be evaluated.

The document comprises six sections: this introduction, Site Description, Occupational Medical Dose, 

Occupational Environmental Dose, Occupational Internal Dose, and Occupational External Dosimetry. 

Some sections are accompanied by an attachment that provides the critical data for the specialists 

reconstructing the doses. 

Section 2, Site Description, briefly describes the facilities and processes that have been used in the 

development of nuclear weapons since the early 1940s.

Beginning in 1944, nine reactors were operated to produce plutonium by the irradiation of metallic 

uranium fuel elements. In addition to the plutonium production, other defense-related radionuclides 

were experimented with, such as the irradiation of thorium to produce 233U, irradiation of depleted 

uranium to produce 240Pu, irradiation of neptunium targets to produce 238Pu, and irradiation of 

americium to produce medical-grade 238Pu.
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In addition to the production reactors, there were seven physical testing, research, and demonstration 

reactors for testing fuel elements and fuel configurations, measuring changes due to various types of 

fuel elements, measuring the thermal impact on fission cross-sections, studying reactor physics 

technology, performing long-term testing of reactor materials, producing medical radioisotopes, and 

researching space power systems.

The reactor products had to be separated chemically for use in the weapons program. These 

chemical separations were done in the T and B Separations Canyons. The complex chemical and 

physical processes separated uranium, plutonium, and fission products. Plutonium was separated 

from the uranium and fission products by a bismuth phosphate precipitation batch process. Additional 

processing resulted in the desired final plutonium product. The chemical separations processes 

changed over the years from the bismuth phosphate precipitation process to the reduction–oxidation 

(REDOX) process to the plutonium-uranium extraction (PUREX) process.

Both REDOX and PUREX used organic solvent extraction processes. Each process improved the 

recovery of uranium, plutonium, and other radionuclides (such as neptunium).

The U plant was another facility that was used for the recovery of uranium from high-level liquid waste 

from the B and T Plants. The U Plant operated from 1952 until January 1958.

Various other facilities were built to support the separations process for uranium, plutonium, 

neptunium, and tritium.

In addition to the production and separations facilities, there were three facilities for fuel fabrication: 

the Uranium Metal Fuels Fabrication facility, the Uranium Metal Extrusion facility, and the Fuel 

Cladding facility. There were two support facilities: the Uranium Storage and Oxide Burner facility 

and the Reactor Fuel Manufacturing Pilot Plant.

In total, there were more than 500 facilities on the 600-mi2 Hanford site that contributed to the mission 

of producing plutonium, uranium, tritium, and other radionuclides not only for the weapons program 

but also for the space program and the medical profession. These facilities were used for radiation 

effects studies, nuclear physics research and development, criticality studies, calibrations, 

radiochemistry development, radiometallurgy, biochemistry, process equipment development, and 

many other applications.

Waste handling facilities on the site handled the high- and low-level radioactive wastes produced in 

the various processes mentioned above.

Section 3 Occupational Medical Dose, provides information about the dose that individual workers 

received from X-rays that were required as a condition of employment. These X-rays included 

pre-employment and annual chest X-rays during physical exams. 

The frequency of required X-rays varied over time and as a function of worker age. All workers 

received annual chest X-rays from before 1946 through 1959. From April 12, 1959, through January 

28, 1983, workers over 50 years of age received annual X-rays, while workers in the 40 to 49 age 

group received X-rays biennially, and those under the age of 40 received an X-ray every 3 years. 

This frequency changed from January 28, 1983. to March 30, 1990, during which time employees 

over 50 years of age received an X-ray biennially, the 40 to 49 age group received one every 3 years, 

and the under-40 age group received one every 5 years. From March 30, 1990, to April 22, 1997, all 

employees received an X-ray every 5 years. From April 22, 1997, to the present, X-rays have been 

given only as required.
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Both the X-ray equipment and the techniques used for taking X-rays have changed over the years 

covered by this TBD. These factors have been taken into account in determining the dose that a 

worker would have received from an X-ray. When there was a doubt about the technique used, the 

most claimant-favorable assumptions have been made to ensure that the dose is not underestimated. 

The investigated parameters include the tube current and voltage, exposure time, filtration, source to 

skin distance, the view (posterior-anterior or lateral), and any other factor that could affect the dose 

received by the worker.

The doses to other exposed organs from the chest X-ray have also been calculated. The calculated 

dose takes into account the uncertainty associated with each of the parameters mentioned above. 

Tables present the doses received by the various organs for convenient reference by the dose 

reconstructors. 

Section 4, Occupational Environmental Dose, applies to workers who were not monitored for external 

or internal radiation exposure. The environmental dose is the dose workers receive when working 

outside the buildings on the site from inhalation of radioactive materials in the air, direct radiation from 

plumes, contact with particles on the skin, and from direct exposure to radionuclides in the soil.

Exposure to these sources can result in an internal dose to the whole body or body organs from 

inhaling the radioactive materials and in a whole- or partial-body external dose from deposited 

radionuclides or submersion in a cloud of radioactive material. 

The radionuclide concentrations in Hanford areas are based on the source terms developed by 

others. Screening studies have demonstrated that 131I, 41Ar, 144Ce144Pr, 137Cs, 239Pu, 103Ru103Rh, 

106Ru106Rh, 90Sr, 90Sr90Y have contributed the greatest dose to site workers. In addition, this section 

discusses the solubility of several of these radionuclides.

Intakes of radionuclides by workers at specific locations on the site were calculated using the 

RATCHET computer program and an Excel spreadsheet. These data are presented in Attachment A 

of this section along with source term data and submersion doses. 

In addition, the section discusses the external dose to workers from ambient radiation levels on the 

site and from submersion in a cloud of radioactive material, along with the skin dose from 41Ar.

Section 5, Occupational Internal Dose, discusses the internal dosimetry program at the Hanford 

reservation. Initially (1943 to 1946) personnel monitoring was the responsibility of the Medical 

Department. At that time, there was no bioassay program to determine the internal dose workers may

have received. Therefore, claimant-favorable assumptions have been made to provide the dose 

reconstructors with the ability to determine a worker’s dose during this early period. The bioassay 

program was later developed and constantly improved over the years as technology progressed. 

Electronic databases were developed to maintain urinalysis records. In addition, this section 

discusses the various codes used to identify the specific analysis performed.

This section discusses in vitro minimum detectable activities (MDAs), the analytical methods, and the 

reporting protocols for the radionuclides encountered at Hanford. These parameters varied over the 

years for each of the evaluated radionuclides: plutonium, americium, curium, tritium, uranium, 

strontium, promethium, polonium, neptunium, and fission products. This sections discusses these 

parameters in detail.

In addition, this section discusses the in vivo MDAs, the analytical methods, and the reporting 

protocols for the X-and gamma ray emitting radionuclides. The in vivo measurement equipment and 
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techniques were developed in the late 1950s and have been in routine use at Hanford since 1960. 

There are detailed discussions of the use of the whole-body counter, the radionuclides for which it 

was used, the radionuclide-specific MDAs, and the reporting levels for the various periods during 

which these parameters changed. There are similar discussions of the in vivo chest counters, thyroid 

counters and head counters.

Detailed information is provided in the database to assist the dose reconstructors in interpreting data 

they may encounter in the worker’s records.

Discussions provide information on the specific radionuclides to which the workers in each of the 

various facilities could have been exposed. In addition, the section provides information for the 

periods of time when processes changed as a result of improvements in the processing systems.

Interferences that may be encountered in the collection and analysis of bioassay samples are 

discussed, as are the uncertainties in the bioassay measurements. Information is presented for 

workers with no confirmed intakes, but who may have been exposed in the early days when the 

detection capability and sampling techniques were poor or there were missed samples. Methods for 

evaluating potential doses that may fall in this category are presented. Additional data are provided 

for the evaluation of the worst case scenario and for unmonitored workers.

Attachment D provides many tables to aid the dose reconstructor in evaluating the potential doses 

received by workers under all circumstances. 

Section 6, Occupational External Dosimetry, discusses the program for measuring skin and 

whole-body doses to the workers. The methods for evaluating external doses to workers have also 

evolved over the years as new techniques and equipment have been developed. In addition, 

concepts in radiation protection have changed. The dose reconstruction parameters, Hanford 

practices and policies, and dosimeter types and technologies for measuring the dose from the 

different types of radiation are discussed. Attention is given to the evaluation of doses measured from 

exposure to beta, gamma, and neutron radiation. Tables present test results for various dosimeters 

exposed to different exposure geometries and radiation energies.

Sources of bias, workplace radiation field characteristics, responses of the different beta/gamma and 

neutron dosimeters in the workplace fields, and the adjustments to the recorded dose measured by 

these dosimeters during specific years are discussed in detail.

There are sources of potential dose that could have been missed because of the limitations of 

dosimetry systems and the methods of reporting low doses. This missed dose is discussed as a 

function of facility location, dosimeter type, year, and energy range. Attachment E describes the use 

of the external dosimetry technical basis parameters to facilitate the efforts of the dose reconstructors.