ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller I MJW Technical Services

Page 1 of 9

DOE Review Release 08/31/2012

Document Title:

Paducah Gaseous Diffusion Plant –

Introduction

Document Number: ORAUT-TKBS-0019-1

Revision: 02

Effective Date: 08/23/2012

Type of Document: TBD

Supersedes: Revision 01

Subject Expert(s): Jodie L. Phillips

Approval: Signature on File Approval Date: 08/20/2012

Jodie L. Phillips, Document Owner

Concurrence: Signature on File Concurrence Date: 08/21/2012

John M. Byrne, Objective 1 Manager

Concurrence: Signature on File Concurrence Date: 08/20/2012

Edward F. Maher, Objective 3 Manager

Concurrence: Vickie S. Short Signature on File for Concurrence Date: 08/20/2012

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 08/23/2012

James W. Neton, Associate Director for Science

New Total Rewrite Revision Page Change

FOR DOCUMENTS MARKED AS A TOTAL REWRITE, REVISION, OR PAGE CHANGE, REPLACE THE PRIOR 

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.
Document No. ORAUT-TKBS-0019-1 Revision No. 02 Effective Date: 08/23/2012 Page 2 of 9

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

09/09/2004 00 First approved issue. Initiated by Jay J. Maisler.

08/30/2006 00 PC-1 Approved page change revision to review against Worker Outreach 

comments and periodic revision. Updates required language on 

page 4 in Section 1.0. No sections were deleted. No further 

changes occurred as a result of internal formal review. This revision 

results in no change to the assigned dose and no PER is required.

Training required: As determined by the Task Manager. Initiated by 

Paul A. Szalinski. Approval: 

Signature on File 08/16/2006

Daniel Mantooth, TBD Team Leader

Richard Merrill Signature on File for 08/16/2006

John M. Byrne, Task 3 Manager

Signature on File 08/16/2006

Edward F. Maher, Task 5 Manager

Signature on File 08/17/2006

Kate Kimpan, Project Director

Signature on File 08/30/2006

James W. Neton, Associate Director for Science

04/02/2007 01 Approved Rev 01 revised to incorporate Attributions and Annotations 

Section 1.3 and update the References section. Constitutes a total 

rewrite of the document. No further changes occurred as a result of 

internal formal review. Incorporates NIOSH formal review 

comments. This revision results in no change to the assigned dose 

and no PER is required. Training required: As determined by the 

Task Manager. Initiated by Daniel S. Mantooth.

08/23/2012 02 Added reference ORAUT-OTIB-0079. Revised the description of the 

Occupational Medical Dose technical basis document. Added 

information to indicate that coworker studies are now included in the 

Internal and External technical basis documents. No changes 

occurred as a result of formal internal and NIOSH review. 

Constitutes a total rewrite of the document. Training required: As 

determined by the Objective Manager. Initiated by Jodie L. Phillips.
Document No. ORAUT-TKBS-0019-1 Revision No. 02 Effective Date: 08/23/2012 Page 3 of 9

TABLE OF CONTENTS

SECTION TITLE PAGE

Acronyms and Abbreviations ............................................................................................................... 4

1.1 Introduction .............................................................................................................................. 5

1.2 Purpose ................................................................................................................................... 6

1.3 Scope....................................................................................................................................... 6

1.4 Attributions and Annotations .................................................................................................... 8

References .......................................................................................................................................... 9
Document No. ORAUT-TKBS-0019-1 Revision No. 02 Effective Date: 08/23/2012 Page 4 of 9

ACRONYMS AND ABBREVIATIONS

DOE U.S. Department of Energy

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

kerma kinetic energy released per unit mass

LAT lateral

NIOSH National Institute for Occupational Safety and Health

PA posterior-anterior 

PGDP Paducah Gaseous Diffusion Plant

POC probability of causation

TBD technical basis document

U.S.C. United States Code

§ section or sections
Document No. ORAUT-TKBS-0019-1 Revision No. 02 Effective Date: 08/23/2012 Page 5 of 9

1.1 INTRODUCTION

Technical basis documents and site profile documents are not official determinations made by the 

National Institute for Occupational Safety and Health (NIOSH) but are rather general working 

documents that provide historic background information and guidance to assist in the preparation of 

dose reconstructions at particular sites or categories of sites. They will be revised in the event 

additional relevant information is obtained about the affected site(s). These documents may be used 

to assist NIOSH staff in the completion of the individual work required for each dose reconstruction.

In this document the word “facility” is used as a general term for an area, building, or group of 

buildings that served a specific purpose at a site. It does not necessarily connote an “atomic weapons 

employer facility” or a “Department of Energy [DOE] facility” as defined in the Energy Employees

Occupational Illness Compensation Program Act [EEOICPA; 42 U.S.C. § 7384l(5) and (12)]. 

EEOICPA defines a DOE facility as “any building, structure, or premise, including the grounds upon 

which such building, structure, or premise is located ... in which operations are, or have been, 

conducted by, or on behalf of, the Department of Energy (except for buildings, structures, premises, 

grounds, or operations ... pertaining to the Naval Nuclear Propulsion Program)” [42 U.S.C. § 

7384l(12)]. Accordingly, except for the exclusion for the Naval Nuclear Propulsion Program noted 

above, any facility that performs or performed DOE operations of any nature whatsoever is a DOE 

facility encompassed by EEOICPA.

For employees of DOE or its contractors with cancer, the DOE facility definition only determines 

eligibility for a dose reconstruction, which is a prerequisite to a compensation decision (except for 

members of the Special Exposure Cohort). The compensation decision for cancer claimants is based 

on a section of the statute entitled “Exposure in the Performance of Duty.” That provision [42 U.S.C. § 

7384n(b)] says that an individual with cancer “shall be determined to have sustained that cancer in the 

performance of duty for purposes of the compensation program if, and only if, the cancer ... was at 

least as likely as not related to employment at the facility [where the employee worked], as 

determined in accordance with the POC [probability of causation1

] guidelines established under 

subsection (c) ...” [42 U.S.C. § 7384n(b)]. Neither the statute nor the probability of causation 

guidelines (nor the dose reconstruction regulation, 42 C.F.R. Pt. 82) restrict the “performance of duty” 

referred to in 42 U S. C. § 7384n(b) to nuclear weapons work (NIOSH 2010).

The statute also includes a definition of a DOE facility that excludes “buildings, structures, premises, 

grounds, or operations covered by Executive Order No. 12344, dated February 1, 1982 (42 U.S.C. 

7158 note), pertaining to the Naval Nuclear Propulsion Program” [42 U.S.C. § 7384l(12)]. While this 

definition excludes Naval Nuclear Propulsion Facilities from being covered under the Act, the section 

of EEOICPA that deals with the compensation decision for covered employees with cancer [i.e., 42 

U.S.C. § 7384n(b), entitled “Exposure in the Performance of Duty”] does not contain such an 

exclusion. Therefore, the statute requires NIOSH to include all occupationally-derived radiation 

exposures at covered facilities in its dose reconstructions for employees at DOE facilities, including 

radiation exposures related to the Naval Nuclear Propulsion Program. As a result, all internal and 

external occupational radiation exposures are considered valid for inclusion in a dose reconstruction. 

No efforts are made to determine the eligibility of any fraction of total measured exposure for inclusion 

in dose reconstruction. NIOSH, however, does not consider the following exposures to be 

occupationally derived (NIOSH 2010):

• Background radiation, including radiation from naturally occurring radon present in 

conventional structures

• Radiation from X-rays received in the diagnosis of injuries or illnesses or for therapeutic 

reasons

 1 The U.S. Department of Labor (DOL) is ultimately responsible under the EEOICPA for determining the POC.
Document No. ORAUT-TKBS-0019-1 Revision No. 02 Effective Date: 08/23/2012 Page 6 of 9

1.2 PURPOSE

The purpose of this technical basis document (TBD) is to provide a summary of the contents of the 

five TBDs that, along with this Introduction, constitute the Paducah Gaseous Diffusion Plant (PGDP) 

Site Profile.

1.3 SCOPE

The PGDP Site Profile is divided into six major parts – this Introduction, Site Description, 

Occupational Medical Dose, Occupational Environmental Dose, Occupational Internal Dose, and 

Occupational External Dose. Some parts include an attachment that provides critical data for the 

specialists reconstructing the doses.

PGDP is one of the original sites that was designated by Congress as part of the Special Exposure 

Cohort (SEC) under EEOICPA [42 U.S.C. § 7384l(14)]. This designation is as follows:

(A) The employee was so employed for a number of work days aggregating at least 

250 work days before February 1, 1992, at a gaseous diffusion plant located in

Paducah, Kentucky, Portsmouth, Ohio, or Oak Ridge, Tennessee, and, during such 

employment—

(i) was monitored through the use of dosimetry badges for exposure at the plant of 

the external parts of employee’s body to radiation; or

(ii) worked in a job that had exposures comparable to a job that is or was monitored 

through the use of dosimetry badges.

Dose reconstruction guidance in this site profile provides a technical basis for dose reconstructions for 

nonpresumptive cancers that are not covered in the SEC class through January 31, 1992. Dose 

reconstructions for individuals employed at PGDP before February 1, 1992, but who do not qualify for 

inclusion in the SEC, can be performed using this guidance as appropriate.

The Site Description TBD (ORAUT 2012a) is a description of the facilities and processes that PGDP 

used to process and enrich uranium. The purpose of the gaseous diffusion plant has been and 

continues to be the enrichment of uranium, initially for military applications and subsequently for 

commercial nuclear reactor fuel. PGDP enriches feed material in the form of uranium hexafluoride 

gas (UF6) from approximately 0.711% 235U up to about 2.5% 235U. The enriched product from PGDP 

has been sent to other DOE gaseous diffusion plants at Piketon, Ohio, and Oak Ridge, Tennessee, 

for further enrichment. Some feed material was recycled uranium from spent reactor fuel.

The Occupational Medical Dose TBD (ORAUT 2012b) provides information about the doses individual 

workers received from X-rays that were required as a condition of employment. The PGDP 

occupational medicine program required preemployment, periodic, and termination screening chest 

X-ray examinations. The chest examinations usually consisted of one posterior-anterior (PA) in the 

early years, and both a PA and a lateral (LAT) starting in the mid-1970s and continuing into the 1980s 

and 1990s. While there are some LAT chest projections in the claim file records before the mid1970s, they were much more commonly performed after that time. Occupational exposures from 

medical X-rays were conducted on site; therefore, the dose from such procedures should be 

evaluated during the dose estimate (ORAUT 2011). In addition to parts of the body exposed in the 

primary beam of an X-ray machine, other tissues received some dose from secondary radiation. 

Secondary radiation consists of X-rays that are scattered from surrounding materials or that escape 

from the source assembly. This TBD provides tables that list estimated dose equivalents to organs of 

the body for male and female PGDP employees; these estimates are favorable to claimants. The 
Document No. ORAUT-TKBS-0019-1 Revision No. 02 Effective Date: 08/23/2012 Page 7 of 9

tables are derived from an assessment of the air kerma at the source-to-skin distance based on 

specific operating parameters for the facility, insofar as these are known.

The Occupational Environmental Dose TBD (ORAUT 2012c) applies to workers who were not 

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

received when working on the site but outside the buildings from inhalation of radioactive materials in 

the air and direct radiation exposure from sources such as the depleted uranium hexafluoride 

cylinders in storage.

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

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

were a result of the releases from stacks, individual buildings, and the purge cascade and other 

operations at PGDP. Unmonitored workers might have incurred occupational doses internally from 

onsite releases to the air. Air concentrations of radionuclides were determined using annual 

environmental reports for 1952 through 2001. Values for airborne concentrations and annual intakes 

are provided for total uranium and 99Tc.

Site annual environmental reports, health physics surveys, and other reports were reviewed for data 

that would be useful in reconstructing ambient radiation levels. Ambient radiation dose rates include 

natural background radiation and sources on the site.

PGDP personnel have annually compared these data with thermoluminescent dosimeter data from 

offsite locations and literature values for State of Kentucky and regional exposure levels. The 

determination has always been that onsite ambient radiological conditions measured at the security 

fence are not significantly different from offsite, State, and regional annual exposure levels. This is 

attributed to the geology of the region around PGDP. Exceptions to this observation have been 

monitoring locations near depleted uranium cylinder storage yards in recent years. These locations 

have shown increases in external exposure as the inventory of depleted uranium has increased. The 

approach for estimating external dose using this information is provided in the TBD.

The Occupational Internal Dosimetry TBD (ORAUT 2012d) describes the internal dosimetry program 

at PGDP. The primary method for monitoring employees for intakes of radionuclides at PGDP was 

urine bioassay, which was instituted at the start of enrichment operations and has continued to the 

present day. However, the focus of the monitoring program in the early years was the detection of 

excreted soluble uranium. When monitoring for less soluble isotopes of uranium and transuranic 

elements was necessary, in vivo methodologies were implemented to supplement the excretion data. 

These methods were primarily whole-body counting and chest (lung) counting.

Until the mid-1980s, action levels were set based on the amount of uranium excreted. Later, intakes 

and doses were assessed based on both in vivo and in vitro monitoring results. Data are available 

from 1952 to the present for in vivo and in vitro analysis records and associated interpretations.

A review of in-house procedures used to assess the concentration of uranium in urine indicates that a 

variety of quality control steps were an integral part of the process. Therefore, the in vitro results from 

in-house processing, typically reported in units of micrograms of uranium per liter, are considered to 

be generally reliable. However, interpretation of those results can be difficult, primarily because of 

uncertainties about enrichment and solubility and the contribution of environmental uranium, and 

because samples were collected at work and during the middle of the work week, which could include

cross-contamination and the inability to separate soluble and insoluble intake fractions.

Guidance on selection of source terms is provided in the TBD. Input parameters for the interpretation 

of in vivo and in vitro measurement results are presented and include instructions for assessing dose 

for monitored and unmonitored employees. The detection limits of the in vivo and in vitro 
Document No. ORAUT-TKBS-0019-1 Revision No. 02 Effective Date: 08/23/2012 Page 8 of 9

methodologies and potential missed dose are discussed. Existing data analysis is summarized, and 

significant incidents with internal dose potential are identified.

Additional data are provided for the evaluation of unmonitored workers. Attachment B to ORAUT 

(2012d) contains the coworker analyses. 

The Occupational External Dosimetry TBD (ORAUT 2012e) describes the program for measuring skin 

and whole-body doses to the workers from sources that were external to the body. The methods 

used at PGDP have evolved over the years as new techniques and equipment have been developed. 

In addition, concepts in radiation protection have changed. Dose reconstruction, PGDP 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 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 presented in detail. In addition, the sources of potential 

dose that could be missed because of the limitations of dosimetry systems and the methods of 

reporting low doses are presented as a function of dosimeter type, year, and type of radiation.

Additional data are provided for the evaluation of shallow dose and the assignment of dose to 

unmonitored workers. Attachment A to ORAUT (2012e) contains the coworker dose assignment. 

Attachment B to ORAUT (2012e) contains the skin dose assignment. 

1.4 ATTRIBUTIONS AND ANNOTATIONS

All information requiring identification was addressed via references integrated into the reference 

section of this document.
Document No. ORAUT-TKBS-0019-1 Revision No. 02 Effective Date: 08/23/2012 Page 9 of 9

REFERENCES

NIOSH (National Institute for Occupational Safety and Health), 2010, Radiation Exposures Covered 

for Dose Reconstructions Under Part B of the Energy Employees Occupational Illness 

Compensation Program Act, DCAS-IG-003, Rev. 01, Division of Compensation Analysis and 

Support, Cincinnati, Ohio, October 5. 

ORAUT (Oak Ridge Associated Universities Team), 2011, Guidance on Assigning Occupational X-ray 

Dose Under EEOICPA for X-rays Administered Off-Site, ORAUT-OTIB-0079, Rev. 00, Oak 

Ridge, Tennessee, January 3.

ORAUT (Oak Ridge Associated Universities Team), 2012a, Paducah Gaseous Diffusion Plant – Site 

Description, ORAUT-TKBS-0019-2, Rev. 03, Oak Ridge, Tennessee, August 22.

ORAUT (Oak Ridge Associated Universities Team), 2012b, Paducah Gaseous Diffusion Plant –

Occupational Medical Dose, ORAUT-TKBS-0019-3, Rev. 03, Oak Ridge, Tennessee, August 

23.

ORAUT (Oak Ridge Associated Universities Team), 2012c, Paducah Gaseous Diffusion Plant –

Occupational Environmental Dose, ORAUT-TKBS-0019-4, Rev. 03, Oak Ridge, August 24.

ORAUT (Oak Ridge Associated Universities Team), 2012d, Paducah Gaseous Diffusion Plant –

Occupational Internal Dose, ORAUT-TKBS-0019-5, Rev. 03, August 24.

ORAUT (Oak Ridge Associated Universities Team), 2012e, Paducah Gaseous Diffusion Plant –

Occupational External Dose, ORAUT-TKBS-0019-6, Rev. 04, Oak Ridge, August 24.