ORAU Team

NIOSH Dose Reconstruction Project

Technical Basis Document for the K-25 Site – Introduction

Document Number:

ORAUT-TKBS-0009-1

Effective Date: 01/06/2004

Revision No.: 00

Controlled Copy No.: ______

Page 1 of 5

Subject Experts: Joseph Alvarez and Jay Maisler

Document Owner

Approval: _Signature on Fiile __________ Date: 02/26/2004

Jay J. Maisler, TBD Team Leader

Approval: _Signature on File___________ Date: 02/27/2004

Judson L. Kenoyer, Task 3 Manager

Concurrence: _Signature on File________ Date: 03/01/2004

Richard E. Toohey, Project Director

Approval: _Signature on File ________ Date: 03/03/2004

James W. Neton, OCAS Health Science Administrator

Supersedes:

None

TABLE OF CONTENTS

Record of Issue/Revisions ...................................................................................................................2

1.0 Introduction.................................................................................................................................3

References ..........................................................................................................................................5
Effective Date: 01/06/2004 Revision No. 00 Document No. ORAUT-TKBS-0009-1 Page 2 of 5

RECORD OF ISSUE/REVISIONS

ISSUE 

AUTHORIZATION 

DATE

EFFECTIVE 

DATE

REV. 

NO. DESCRIPTION

Draft 12/05/2003 00-A New Technical Basis Document for the K-25 Site 

– Introduction. Initiated by Joseph Alvarez.

Draft 12/22/2003 00-B Incorporates OCAS review comments. Initiated 

by Joseph Alvarez.

01/06/2004 01/06/2004 00 Approved first issue. Initiated by Joseph Alvarez.
Effective Date: 01/06/2004 Revision No. 00 Document No. ORAUT-TKBS-0009-1 Page 3 of 5

1.0

The U.S. Congress officially recognized the hazardous nature of producing and testing nuclear 

weapons by enacting the Energy Employees Occupational Illness Compensation Program Act of 2000 

(EEOICPA). Workers, who have developed selected types of cancer, or their survivors may be 

entitled to compensation and medical benefits under the Act. The EEOICPA program is administered 

by the Department of Labor (DOL) Office of Worker Compensation (OWCP). The Department of 

Health and Human Service’s (HHS) National Institute for Occupational Safety and Health (NIOSH) is 

responsible for determining the individual worker’s dose.

Introduction

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

the nuclear weapons production programs of the various U. S. Department of Energy (DOE) and its 

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

Code of Federal Regulations Part 82 (42CFR Part 82), “Methods for Radiation Dose Reconstruction 

Under the Energy Employees Occupational Illness Compensation Program Act of 2000” (Federal 

Register, Vol. 67 No. 85, Thursday, May 2, 2002).

NIOSH is supported by Oak Ridge Associated Universities (ORAU) and others, the ORAU Team, in 

conducting dose reconstructions under the EEOICPA. This Site Profile represents a specific support 

mechanism to the ORAU Team concerning documentation of historical practices at the K-25 Site [also 

known as the Oak Ridge Gaseous Diffusion Plant (ORGDP) and the East Tennessee Technology 

Park (ETTP)]. This Site Profile can be used to evaluate both internal and external dosimetry data for 

monitored workers and can serve as a supplement to, or substitute for, individual monitoring data. 

This document provides a site profile of K-25 that contains technical basis information to be used by 

the ORAU Team to evaluate the total occupational radiation dose for EEOICPA claimants.

This document also provides supporting technical data to evaluate the total K-25 occupational 

radiation dose that may reasonably be associated with the worker’s radiation exposure. This dose 

results from exposure to external and internal radiation sources in K-25 facilities; to K-25 

occupationally-required diagnostic x ray examinations, and to on-site environmental releases. Also 

included are techniques to estimate the dose that may have occurred while the employee was not 

monitored, inadequately monitored, dose that may have been missed due to analytical detection 

limits, or whose monitoring records are incomplete are missing (i.e., missed dose). 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.

This Site Profile can be a tool when performing dose reconstructions for K-25 workers. The 

Integrated Modules for Bioassay Analysis (IMBA) computer code is a tool useful for internal dose 

calculations. Information on measurement uncertainties is an integral component of the NIOSH 

approach. This document describes how to evaluate uncertainty associated with K-25 exposure and 

dosimetry records..

The document is divided into five major sections; Site Description, Occupational Medical Dose, 

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

The Site Description TBD (ORAU-TKBS-0009-2) presents a brief description of the facilities and 

processes that have been used in processing uranium. The K-25 Site processed thousands of tons of 

uranium through diffusion cascades for more than 40 years beginning in February 1945. The vast 

majority of the uranium was natural uranium derived from ore, but some was recycled material 

obtained from spent reactor fuel.
Effective Date: 01/06/2004 Revision No. 00 Document No. ORAUT-TKBS-0009-1 Page 4 of 5

The Occupational Medical Dose TBD (ORAU-TKBS-0009-3) 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, annual chest x rays during physical exams, and health monitoring x rays to 

determine the effect of inhalation of uranium. The frequency of required x rays varied over time. All 

radiation workers received annual chest x rays from 1944 through 1980, but every 5 years after 1980. 

Non-radiation workers received annual chest x rays until 1960, but none after 1960. workers with a 

potential to inhale uranium dust may have had x rays as frequently as monthly in 1944 and 1945, but 

bimonthly from 1946 to 1959.

Both the x ray equipment and the techniques used for taking x rays have changed over the years 

covered by this SITE PROFILE. These factors were taken into account in estimating the dose that a 

worker would have received from the x ray. Favorable assumptions were made to ensure the worker’s 

dose was not underestimated when there was a doubt about the technique used. The parameters 

considered included 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 also takes into account the uncertainty associated with each of the parameters mentioned 

above. The doses received by the various organs in the body are presented in the tables for 

convenient reference for dose reconstruction.

The Occupational Environmental Dose TBD (ORAU-TKBS-0009-4) applies to workers who were not 

monitored for external or internal radiation exposure. The environmental dose is the dose workers 

received 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 incorporated in the soil.

Inhalation of environmental radionuclides results in internal dose to the whole body or body organs. 

Whole- or partial-body external dose results from deposited radionuclides or submersion in a cloud of 

radioactive material.

The internal dose for workers outside of the facilities was determined from the air concentrations 

resulting from the releases from stacks, individual building releases, and from the purge cascade and 

other operations at K-25. Unmonitored workers may have been exposed to occupational doses 

internally from on-site releases into the air.

The air concentration of radionuclides was determined using use well-documented source terms 

developed for the Oak Ridge Dose Reconstruction (Burmeister 1996; Burmeister 1997A; Burmeister 

1997B), coupled with some documented environmental monitoring data, to estimate radionuclidespecific airborne concentrations for 234, 235, 238U, 238, 239, 240, 241, 242Pu, 237Np, and 99Tc (Shonka 2003).

These radionuclides were determined to account for the majority of the potential missed dose from 

inhalation and submersion pathways.

The external dose to workers from the ambient radiation levels on-site and from submersion in a cloud 

of radioactive material were estimated from onsite environmental dosimeters.

The Occupational Internal Dosimetry TBD (ORAU-TKBS-0009-5) describes the internal dosimetry 

program at the K-25. A bioassay program based on urinalysis for uranium was instituted when K-25 

began processing uranium. The urinalysis techniques employed over the years followed the 

technology development for uranium detection. Urinalysis was preferred over in vivo techniques 
Effective Date: 01/06/2004 Revision No. 00 Document No. ORAUT-TKBS-0009-1 Page 5 of 5

because the in vivo minimum detectable activities were relatively high and thus of limited use for 

detecting uranium intakes. The processing of recycled uranium from spent reactor fuel introduced 

other radionuclides to K-25, in particular plutonium, americium, curium, neptunium, and 99Tc. These 

additional radionuclides were also best analyzed in urine. In general, the fraction of dose from these 

radionuclides relative to uranium was very small and usually immeasurable if the uranium dose was 

small.

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

discussed, as are the uncertainties in the bioassay measurements. Also presented is information that 

may be useful in estimating possible missed doses due to monitoring practices that were inadequate 

when compared to modern standards. Methods for evaluating potential doses that may fall in this 

category are presented.

The Occupational External Dosimetry Program TBD (ORAUT-TKBS-0009-6) discusses the program 

for measuring skin and whole body doses to the workers. The methods for evaluating external doses 

to workers evolved as new techniques and equipment were developed. Changes in techniques also 

changed as concepts in radiation protection changed. The dose reconstruction parameters, K-25 

practices and policies, and dosimeter types and technology for measuring the dose from the different 

types of radiation are discussed in this section. Attention is given to the evaluation of doses measured 

from exposure to beta, gamma, and neutron radiation.

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 be missed because of the limitations of dosimetry 

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

dosimeter type, year, and type of radiation.

REFERENCES

Burmeister, R.E., 1996, The Atmospheric Master Release List and Atmospheric Source Term for 

K-25, SRA 96-012

Burmeister, R.E., 1997, 237Np and 99Tc Released to Air and Water from Historic Operations at the 

K-25 Site and Y-12 Sites, SRA-97-003

Burmeister, R.E., 1997, Per Annum Atmospheric Releases of Uranium from the K-25 Site from 

1944 to 1995, SRA-97-011

Shonka, Joseph, 2003, Calculations for the ORGDP Technical Basis Document (TBD) – Modified 

Atmospheric Master Routine List for ORGDP and Background Gamma Radiation, SRA 03-

001