ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller & Associates I MJW Corporation

Page 1 of 9

Document Title:

Portsmouth Gaseous Diffusion Plant - 

Introduction

Document Number: ORAUT-TKBS-0015-1 

Revision: 01 

Effective Date: 02/12/2007

Type of Document: TBD

Supersedes: Revision 00 

Subject Expert(s): Paul J. Demopoulos

Site Expert(s): N/A 

Approval: Signature on File Approval Date: 01/31/2007

Paul J. Demopoulos, Document Owner

Approval: Richard Merrill Signature on File for Approval Date: 02/20/2007

John M. Byrne, Task 3 Manager

Concurrence: Signature on File Concurrence Date: 01/31/2007

Edward F. Maher, Task 5 Manager

Concurrence: Signature on File Concurrence Date: 01/31/2007

Kate Kimpan, Project Director

Approval: Brant A. Ulsh Signature on File for Approval Date: 02/12/2007

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-0015-1 Revision No. 01 Effective Date: 02/12/2007 Page 2 of 9

TABLE OF CONTENTS

SECTION TITLE

ACRONYMS AND ABBREVIATIONS.................................................................................................. 4

PAGE

1.0 PURPOSE ............................................................................................................................... 5

2.0 SCOPE .................................................................................................................................... 6

REFERENCES.................................................................................................................................... 9
Document No. ORAUT-TKBS-0015-1 Revision No. 01 Effective Date: 02/12/2007 Page 3 of 9

PUBLICATION RECORD

EFFECTIVE 

DATE

REV.

NO. DESCRIPTION

05/11/2004 00 First approved issue of revision 00. Initiated by Mark D. Notich.

02/12/2007 01 Approved Revision 01 revised as a result of a biennial review. Updated 

cover page. Added required standard language to the Purpose section. 

Added references to the Reference section. Constitutes a total rewrite 

of document. Incorporates internal and DOL 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 Paul J. Demopoulos. 
Document No. ORAUT-TKBS-0015-1 Revision No. 01 Effective Date: 02/12/2007 Page 4 of 9

ACRONYMS AND ABBREVIATIONS

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

DOE Department of Energy

GM Geiger-Muller 

ICPMS Inductively Coupled Plasma Mass Spectrometry

IMBA Integrated Modules for Bioassay Analysis

NIOSH National Institute for Occupational Safety and Health

ORAUT Oak Ridge Associated Universities Team

POC probability of causation

PORTS Portsmouth Gaseous Diffusion Plant

TBD technical basis document

TLD thermoluminescent detectors 

U.S.C. United States Code

§ Section
Document No. ORAUT-TKBS-0015-1 Revision No. 01 Effective Date: 02/12/2007 Page 5 of 9

1.0

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.

PURPOSE

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

As noted above, the statute 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 contains an exclusion with respect to the Naval Nuclear Propulsion Program, 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 dosimetry monitoring results are considered valid for use in 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:

] 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) define “performance of duty” for DOE employees 

with a covered cancer or restrict the “duty” to nuclear weapons work.

• Radiation from naturally occurring radon present in conventional structures

• Radiation from diagnostic X-rays received in the treatment of work-related injuries

 

1 The U.S. Department of Labor is ultimately responsible under the EEOICPA for determining the POC. 
Document No. ORAUT-TKBS-0015-1 Revision No. 01 Effective Date: 02/12/2007 Page 6 of 9

This Site Profile represents a specific support mechanism concerning documentation of historical 

practices at the Portsmouth Gaseous Diffusion Plant (PORTS). This Site Profile can be used to 

evaluate both internal and external dosimetry data for monitored workers and can serve as a 

supplement to individual monitoring data. For unmonitored workers, information is present in this 

document that will provide for estimations of internal and external doses. This document provides a 

site profile of PORTS that contains technical basis information to be used to evaluate the total 

occupational radiation dose for EEOICPA claimants.

This document also provides supporting technical data to evaluate the total PORTS 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 PORTS facilities, to PORTS 

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 an employee was not 

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

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

new and more reliable scientific methods and protection measures have been deployed. 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 PORTS 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 PORTS exposure 

and dosimetry records. Information on measurement uncertainties is an integral component of the 

NIOSH approach. This document describes how to evaluate uncertainty associated with PORTS 

exposure and dosimetry records.

2.0

The document is divided into six major sections: (1) this Introduction, (2) Site Description, (3) 

Occupational Medical Dose, (4) Occupational Environmental Dose, (5) Occupational Internal Dose, 

and (6) Occupational External Dosimetry. Some sections are accompanied by an attachment that 

provides the critical data for the specialists reconstructing the doses.

SCOPE

The Site Description TBD (ORAUT-TKBS-0015-2 [ORAUT 2006]) presents a brief description of the

facilities and processes that have been used in processing and enriching uranium. PORTS 

processed thousands of tons of uranium through diffusion cascades for 47 years beginning in 1954. 

The majority of the uranium feed materials PORTS received was slightly enriched from Paducah, but 

some was recycled material obtained from spent reactor fuel.

The Occupational Medical Dose TBD (ORAUT-TKBS-0015-3 [ORAUT 2006a]) 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. All employees were 

required to have annual chest X-rays from 1954 to 1989. In 1990, chest X-rays were offered on a 

frequency based on the age of the employee, but asbestos/beryllium workers were still required to 

have annual chest X-rays.

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. 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.
Document No. ORAUT-TKBS-0015-1 Revision No. 01 Effective Date: 02/12/2007 Page 7 of 9

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

calculated dose 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 (ORAUT-TKBS-0015-4 [ORAUT 2006b]) 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, 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 PORTS. 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 the annual environmental reports from 

1972 and 2001 and a special study of historic radiological releases (Goslow 1986) to estimate 

radionuclide-specific airborne concentrations for 234, 235, 236, 238U, Pu, Np, 99Tc, and uranium daughters 

(

231, 234Th, 234mPa). The uranium isotopes were monitored from the onset of plant operations with the 

Np, Pu, Tc, and uranium daughters being added to the monitoring program at later dates beginning in 

1967. 

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

of radioactive material were estimated from on-site environmental monitoring equipment such as 

Geiger-Muller (GM) tubes and thermoluminescent detectors (TLDs). 

Several accidental releases of uranium occurred during the operational period of PORTS. The largest 

of these releases occurred in 1978 when a 14-ton feed cylinder fell and cracked open, releasing an 

estimated 4,820 kg of uranium to the atmosphere and an additional 680 kg of uranium to the plant 

sewers. In addition, a string of accidental releases of mostly depleted uranium during the first 5 years 

of plant operation accounted for essentially all of the uranium lost to the atmosphere from 1955 

through 1958 and 20% of the losses in 1959.

The Occupational Internal Dosimetry TBD (ORAUT-TKBS-0015-5 [ORAUT 2004]) describes the 

internal dosimetry program at PORTS. The PORTS internal dosimetry program for uranium isotopes 

started when the site began operations in 1954. Routine monitoring for 99Tc began in 1965 in vivo

and 1975 in vitro. Transuranics have not been monitored routinely with the exception of 237Np. 

Urine analysis for total alpha activity began at the start of operations in 1954. Fluorimetry and gas 

flow proportional counting was employed until 1995 when Inductively Coupled Plasma Mass 

Spectrometry (ICPMS) was utilized. The frequency of urine analysis at PORTS varied considerably 

and was based on the potential for the individual to come into contact with radioactive materials. 

Additional urine analyses were performed based on recalls (lost or inadequate samples, or abnormal 

results) or supervisor’s request. Urine analysis for 99Tc began in 1965 using a liquid scintillation 

method and subsequent subtraction of the uranium/thorium complement to yield the 99Tc results. 
Document No. ORAUT-TKBS-0015-1 Revision No. 01 Effective Date: 02/12/2007 Page 8 of 9

Routine monitoring for transuranics has not been conducted at PORTS. In vivo analyses began in 

1965 to detect non-transportable or insoluble compounds such as U3O8 and 99Tc in the lungs.

Interferences that may be encountered in the collection and analysis of urine samples are discussed, 

as are the uncertainties in the urine analysis measurements. Also presented is information that may 

be useful in estimating possible missed doses due the limitation of the monitoring practices as well as 

the limitations of the equipment and techniques for radiation detection and measurement. Methods 

for evaluating potential doses that may fall into this category are presented.

The Occupational External Dosimetry Program TBD (ORAUT-TKBS-0015-6 [ORAUT 2006c]) 

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, PORTS 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 to 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 potentially missed dose is discussed as a 

function of dosimeter type, year, and type of radiation.
Document No. ORAUT-TKBS-0015-1 Revision No. 01 Effective Date: 02/12/2007 Page 9 of 9

REFERENCES

Goslow, G. A., 1986, Historical Radionuclide Release Report, GAT-1124, Goodyear Atomic 

Corporation, Piketon, Ohio, January. [SRDB Ref ID 4703] 

ORAUT (Oak Ridge Associated Universities Team), 2006, Technical Basis Document for PORTS 

Gaseous Diffusion Plant – Site Description, ORAUT-TKBS- 0015-2, rev 01, Oak Ridge, 

Tennessee. 

ORAUT (Oak Ridge Associated Universities Team), 2006a, Technical Basis Document for PORTS 

Gaseous Diffusion Plant –Occupational Medical Dose, ORAUT-TKBS- 0015-3, rev 02, Oak 

Ridge, Tennessee. 

ORAUT (Oak Ridge Associated Universities Team), 2006b, Technical Basis Document for PORTS 

Gaseous Diffusion Plant –Occupational Environmental Dose, ORAUT-TKBS- 0015-4, rev 01, 

Oak Ridge, Tennessee. 

ORAUT (Oak Ridge Associated Universities Team), 2004, Technical Basis Document for PORTS 

Gaseous Diffusion Plant –Occupational Internal Dose, ORAUT-TKBS- 0015-5, Oak Ridge, 

Tennessee. [SRDB Ref ID 20167]

ORAUT (Oak Ridge Associated Universities Team), 2006c, Technical Basis Document for PORTS 

Gaseous Diffusion Plant – Occupational External Dose, ORAUT-TKBS- 0015-6, rev 01, Oak 

Ridge, Tennessee.