ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller I MJW Technical Services

Page 1 of 45

DOE Review Release 08/31/2012

Document Title:

Paducah Gaseous Diffusion Plant –

Occupational Internal Dose

Document Number: ORAUT-TKBS-0019-5

Revision: 03

Effective Date: 08/24/2012

Type of Document: TBD

Supersedes: Revision 02, ORAUT-OTIB0037 Revision 00

Subject Expert(s): Daniel S. Mantooth, Clark B. Barton, and Tracy A. Ikenberry

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

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: 08/21/2012

Edward F. Maher, Objective 3 Manager

Concurrence: Vickie S. Short Signature on File for Concurrence Date: 08/21/2012

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 08/24/2012

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-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 2 of 45

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

09/30/2004 00 New technical basis document for the Paducah Gaseous Diffusion 

Plant – Occupational Internal Dose. First approved issue. Initiated 

by Jay J. Maisler. 

10/25/2006 01 Approved issue of Revision 01. This revision addresses the 

comment from the meeting with the United Steelworkers Local 5-550 

and SPFPA Local 111 held on 2/10/2005. Constitutes a total rewrite 

of document. Incorporates recent direction from NIOSH to include 

DOL review comments on page 5. Revisions address corrective 

actions responding to OCAS assessment and internal review 

comments from Task 5. Changes were made at the end of Section 

5.2. The original Table 5-3 has been deleted and replaced with an 

expansion of the original Table 5-4, which becomes Table 5-3. Table

5-2 has been updated to reflect new Table numbers. Incorporates 

internal and NIOSH formal review comments. This revision results in 

an increase in assigned dose and a PER is required. Training 

required: As determined by the Task Manager. Initiated by Daniel S. 

Mantooth. Approval:

Signature on File 10/12/2006

Daniel S. Mantooth, Document Owner

Signature on File 10/12/2006

John M. Byrne, Document Owner

Signature on File 10/12/2006

Edward F. Maher, Task 5 Manager

Signature on File 10/23/2006

Kate Kimpan, Project Director

Brant A. Ulsh Signature on File for 10/25/2006

James W. Neton, Associate Director for Science

01/11/2007 01 PC-1 Approved page change revision initiated to correct the title of Table

5-2 on page 10. Modified Table 5-4 on page 13 to consolidate the 

years of 1952-1998 onto the first line of the table. Added Table 5-2a 

to the List of Tables. Incorporates formal internal and NIOSH review 

comments. Includes changes to Table 5-2a (page 11). 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. Approval:

Signature on File 01/11/2007

Daniel S. Mantooth, Document Owner

Signature on File 01/12/2007

John M. Byrne, Document Owner

Signature on File 01/11/2007

Edward F. Maher, Task 5 Manager
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 3 of 45

Signature on File 01/24/2007

Kate Kimpan, Project Director

Brant A. Ulsh Signature on File for 01/31/2007

James W. Neton, Associate Director for Science

04/04/2007 02 Approved Revision 02 initiated to incorporate Attributions and 

Annotations section and improved reference citations in the text. No 

further changes occurred as a result of formal internal 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 Daniel S. Mantooth.

08/24/2012 03 Added SEC language. Added dates to Table 5-1 for C-720 

Maintenance. Clarified column titles in Tables 5-2 and 5-2a. 

Updated references. Deleted previous Table 5-3 (not used in dose 

reconstruction). Revised Table numbers. Revised in vitro

measurement in Table 5-3 for 1952 – 1988 period from 5 μg/L to 

0.005 mg/L. Moved reporting formats and codes to Attachment A. 

Added Attachment B, Internal Dosimetry Coworker Data for PGDP 

(formerly ORAUT-OTIB-0037 Rev 00). Added the option for dose 

reconstructors to use the 95th-percentile intake rate in Attachment B. 

Added Attachment C to provide dose reconstructors a general idea of 

the types of job categories, work activities, and work locations for 

which internal dose assignment might be necessary. Added Section 

5.4.5, Assessment of Intake for Unmonitored Employees. Moved 

Table 5-8, A History of Significant Events, to Attachment C. 

Incorporates formal NIOSH review comments. Constitutes a total 

rewrite of the document. Training required: As determined by the 

Objective Manager. Initiated by Jodie L. Phillips.
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 4 of 45

TABLE OF CONTENTS

SECTION TITLE PAGE

Acronyms and Abbreviations ............................................................................................................... 6

5.1 Introduction .............................................................................................................................. 8

5.1.1 Purpose........................................................................................................................ 9

5.1.2 Scope........................................................................................................................... 9

5.2 Source Term ............................................................................................................................ 9

5.2.1 Isotopic Concentrations .............................................................................................. 11

5.3 In Vitro Measurement Methods .............................................................................................. 14

5.3.1 Measurement Types and Detection Levels ................................................................. 14

5.3.2 Reporting Formats and Codes.................................................................................... 15

5.4 In Vivo Measurement Methods............................................................................................... 15

5.4.1 Measurement Types and Detection Levels ................................................................. 16

5.4.2 Reporting Formats and Codes.................................................................................... 16

5.4.3 Instructions for Addressing Possible Interferences and Uncertainties......................... 16

5.4.4 Assessment of Intake for Monitored Employees ......................................................... 16

5.4.5 Assessment of Intake for Unmonitored Employees..................................................... 17

5.5 Significant Incidents with Internal Dose Potential ................................................................... 17

5.6 Attributions and Annotations .................................................................................................. 17

References ........................................................................................................................................ 19

Glossary ............................................................................................................................................ 21

ATTACHMENT A, CODES USED IN INTERNAL DOSE RECORDS ................................................ 25

ATTACHMENT B, INTERNAL DOSIMETRY COWORKER DATA FOR PGDP ................................. 29

ATTACHMENT C, GENERAL INDICATION OF POTENTIAL FOR INTERNAL EXPOSURES.......... 44
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 5 of 45

LIST OF TABLES

TABLE TITLE PAGE

5-1 Radiological source term for PGDP processes and facilities .................................................. 10

5-2 Bounding isotopic concentrations for PGDP operations ......................................................... 12

5-2a Bounding isotopic activity concentrations for PGDP operations ............................................. 12

5-3 In vitro measurement types and detection levels for various periods...................................... 15

5-4 In vivo measurement types and detection levels for various periods ...................................... 16

A-1 In vitro record codes...............................................................................................................26

A-2 In vivo record codes...............................................................................................................28

B-1 Summary of quarterly uranium 24-hour urinary excretion rate analyses, 1952 to 1988 .......... 32

B-2 Type F uranium intake periods and rates ............................................................................... 38

B-3 Type M uranium intake periods and rates .............................................................................. 39

B-4 Type S uranium intake periods and rates ............................................................................... 40

B-5 Type F uranium intake periods and rates ............................................................................... 42

B-6 Type M uranium intake periods and rates .............................................................................. 42

B-7 Type S uranium intake periods and rates ............................................................................... 42

C-1 History of significant incidents and events.............................................................................. 45

LIST OF FIGURES

FIGURE TITLE PAGE

B-1 50th-percentile uranium urinalysis data used to estimate intakes of type F uranium 

occurring June 1, 1952, to December 31, 1988...................................................................... 37

B-2 84th-percentile uranium urinalysis data used to estimate intakes of type F uranium 

occurring June 1, 1952, to December 31, 1988...................................................................... 37

B-3 50th-percentile uranium urinalysis data used to estimate intakes of type M uranium 

occurring June 1, 1952, to December 31, 1988...................................................................... 38

B-4 84th-percentile uranium urinalysis data used to estimate intakes of type M uranium 

occurring June 1, 1952, to December 31, 1988...................................................................... 39

B-5 50th-percentile uranium urinalysis data used to estimate intakes of type S uranium 

occurring June 1, 1952, to March 31, 1980 ............................................................................ 40

B-6 50th-percentile uranium urinalysis data used to estimate intakes of type S uranium 

occurring April 4, 1980, to December 31, 1988 ...................................................................... 40

B-7 Predicted 50th-percentile urinary excretion of type S uranium from 1952 to 1988 based 

on two independent intakes, compared with bioassay data.................................................... 41

B-8 Predicted 84th-percentile urinary excretion of type S uranium from 1952 to 1988 based 

on two independent intakes, compared with bioassay data.................................................... 41
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 6 of 45

ACRONYMS AND ABBREVIATIONS

AMAD activity median aerodynamic diameter

Bq becquerel

CFR Code of Federal Regulations

CIP Cascade Improvement Program

cm centimeter

CUP Cascade Upgrade Program 

d day

DOE U.S. Department of Energy

dpm disintegrations per minute

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

g gram

GSD geometric standard deviations

hr hour

IMBA Integrated Modules for Bioassay Analysis

IREP Interactive RadioEpidemiological Program

KPA kinetic phosphorescence analysis

L liter

m meter

MDA minimum detectable amount

MDC minimum detectable concentration

mg milligram

mL milliliter

nCi nanocurie

NIOSH National Institute for Occupational Safety and Health

OCAS Office of Compensation Analysis and Support

ORAU Oak Ridge Associated Universities

ORNL Oak Ridge National Laboratory

pCi picocurie

PGDP Paducah Gaseous Diffusion Plant

POC probability of causation

ppb parts per billion

RU recycled uranium

SEC Special Exposure Cohort

TBD technical basis document

TRU transuranic
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 7 of 45

U.S.C. United States Code

UF6 uranium hexafluoride

UO3 uranium trioxide

μCi microcurie

μg microgram

μm micrometer

§ section or sections
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 8 of 45

5.1 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-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 9 of 45

5.1.1 Purpose

This technical basis document (TBD) provides technical data and other key information that will serve 

as the technical basis for evaluating internal occupational radiation dose for EEOICPA claimants who 

were employed at the Paducah Gaseous Diffusion Plant (PGDP).

5.1.2 Scope

This document discusses the radionuclides potentially encountered by PGDP employees during the 

Plant’s operational history. The PGDP mission was to enrich uranium in the form of uranium 

hexafluoride (UF6) from roughly 0.7% 235U (natural enrichment) to around 3% 235U for use in domestic 

and foreign power reactors (DOE 2000, p. 8). Enrichment operations began in 1952 in the first four 

process buildings, C-331, C-333, C-310, and C-315. From 1953 until 1977, UF6 feed material was 

produced from uranium trioxide (UO3) at the Plant. From 1953 to 1964, and from 1968 to 1977, UF6

was produced from the recycled uranium (RU) produced from spent reactor fuel. In May 1977, the 

feed plants ceased operation and all feed to the enrichment process was in the form of UF6 obtained 

from outside sources. Other chemical compounds of uranium were present throughout the Plant’s 

history including UO2F2, UF4, and UO3.

ORAUT (2012a) contains detailed information on the history of PGDP and the feed conversion and 

enrichment process.

Attributions and annotations, indicated by bracketed callouts and used to identify the source, 

justification, or clarification of the associated information, are presented in Section 5.6.

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 document is presented to provide 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.

5.2 SOURCE TERM

The radionuclides potentially encountered by PGDP employees consist primarily of the isotopes of 

uranium, 238U, 234U, and 235U. The progeny of dosimetric interest for these radionuclides include 230Th 

and 234mPa (BJC 1999, p. 8). While a range of 235U enrichment values (from natural to 3%) was 

encountered in feed and product material, the dose reconstructor should assume a nominal 

enrichment value of 2% 235U for all feed or product materials [1].
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 10 of 45

The presence of transuranic (TRU) and fission product isotopes has been known since the early days 

of operation (ORAUT 2012a). These radionuclides were present in small amounts in the feed 

material produced from RU, and include 237Np, 239Pu (PACE and University of Utah 2000), and 241Am

(Hightower et al. 2000). Technetium-99 is the fission product of concern from a dosimetry standpoint. 

During the conversion of the feed material from UO3 to UF6, the elemental species of the TRU and 

fission products react differently from a chemical standpoint. For example, 99Tc tends to form a very 

volatile fluoride; readily introduced into the enrichment cascade, it essentially follows the UF6 to the 

surge and/or product station. On the other hand, both 241Am and 239Pu form essentially nonvolatile 

fluorides. Most of these isotopes will remain in the feed conversion byproducts (i.e., ash) or in the 

feed cylinder heels, a primary source of TRU exposure from this process (Hightower et al. 2000). 

Some 241Am will appear in the cascade components as a result of the decay of 241Pu. While 237Np

forms a volatile fluoride, it rapidly oxidizes and plates on the metal cylinder walls (PACE and 

University of Utah 2000, p. 26), so the main hazard from this isotope is related to cylinder cleaning 

operations and cascade component maintenance. PGDP conducted operations to recover 99Tc (April 

1960 through June 1963) and 237Np (November 1958 through March 1962), which presented an 

increased potential to exposure from these isotopes (PACE and University of Utah 2000).

Table 5-1 lists information on the isotopic species associated with PGDP operations and facilities and 

their dates of operation (when available).

Table 5-1. Radiological source term for PGDP processes and facilities.

Building Process Datesa

Radionuclides of 

concernb Absorption typec

C-360 Product shipping and transfer U-234, -235, -236, -238 F

Np-237 M

Pu-238, -239, -240, -242 M, S

Tc-99 F, M

C-400 Converter maintenance 4/53–present U-234, -235, -236, -238 F

Converter salvage Np-237 M

CIP/CUP Phase 1 9/54–6/61 Pu-238, -239, -240, -242 M, S

CIP/CUP Phase 2 3/73–9/81 Tc-99 F, M

C-400/ Np-237 recovery 11/58–3/62 U-234, -235, -236, -238 F

C-710 Tc-99 recovery 4/60–6/63 Np-237 M

Pu-238, -239, -240, -242 M, S

Tc-99 F, M

C-409 Converter refurbish 1973–1981 U-234, -235, -236, -238 F

Np-237 M

Pu-238, -239, -240, -242 M, S

Tc-99 F, M

C-410 Green salt production 1953–1956 U-234, -235, -236, -238 F, M, S

UF6 production 1953–present Np-237 M

Tc-99/Np-237 recovery 

(MgF2)

9/61–6/63 Pu-238, -239, -240, -242 M, S

Tc-99 F, M

Th-230 S

Am-241 M

C-420 Green salt production 1956–1977 U-234, -235, -236, -238 F, M, S

Np-237 M

Pu-238, -239, -240, -242 M, S

Tc-99 F, M

Th-230 S

Am-241 M

C-331 Cascade ops/maintenance 9/52–present U-234, -235, -236, -238 F

C-333 Cascade ops/maintenance 9/52–present Np-237 M

C-335 Cascade ops/maintenance 4/54–present Pu-238, -239, -240, -242 M, S

C-337 Cascade ops/maintenance 7/54–present Tc-99 F, M
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 11 of 45

Building Process Datesa

Radionuclides of 

concernb Absorption typec

C-310 Surge and product 9/52–present U-234, 235, 236, 238 F

Tc-99/Np-237 recovery 

(MgF2)

1/63–6/63 Np-237 M

Pu-238, -239, -240, -242 M, S

Tc-99 F, M

Th-230 S

C-315 Surge and waste 9/52–present U-234, -235, -236, -238 F

Th-230 S

C-340 Metal production 12/57–12/62 U-234, -235, -236, -238 M, S

1/68–10/77 Np-237 M

Pu-238, -239, -240, -242 M, S

Th-230 S

C-720 Maintenance 1954-1961 U-234, -235, -236, -238 F, M, S

1973-1981 Np-237 M

Pu-238, -239, -240, -242 M, S

Tc-99 F, M

Th-230 S

Am-241 M

C-746 Waste metal smelting U-234, -235, -236, -238 M, S

Np-237 M

Pu-238, -239, -240, -242 M, S

Th-230 S

C-749 Uranium metal burial U-234, -235, -236, -238 M, S

Np-237 M

Pu-238, -239, -240, -242 M, S

Th-230 S

a. All dates are from DOE (2000) except those for C-409 and the Cascade Ops/Maintenance buildings, which are from 

PACE and University of Utah (2000) and ORAUT (2012a), respectively.

b. From Hill and Strom (1993, Table 16.2).

c. From BJC (1999, Table 1.7).

5.2.1 Isotopic Concentrations

At PGDP, monitoring for intakes of uranium, in vivo or in vitro, often resulted in reports of elemental 

uranium concentration in urine or the mass of elemental uranium in organs or the whole body. 

However, the internal dose assessment process requires the use of isotopic concentrations as input. 

As stated above, the chemical properties of the TRU and fission product contaminants resulted in 

changes in their relative concentrations in different parts of the process when compared to the original 

feed material. This section provides bounding estimates for radionuclide concentrations. The 

concentrations relative to the mass of total uranium and the activity of total uranium are listed in 

Tables 5-2 and 5-2a, respectively. A summary discussion on the information in the tables and its 

derivation is provided below. Details of unit conversion and data sources can be found in Barton 

(2006).

Pre-1983 Operations

Column 1, Pulverizer Operations, Ash Handling Activities, Green Salt Production, C-410 Production 

activities; Column 2, Converter Maintenance and Salvage, C-400 Cylinder Operations

The values in Columns 1 and 2 are from PACE and University of Utah (2000, Table 7.9). The 

maximum air concentration data were used to provide bounding values for TRU concentrations. The 

data in Table 7.9 is in units of μCi/cm3

, which were converted to the desired units of pCi (TRU)/g (U) 

or pCi (TRU)/pCi (U). Details of this process can be found in Barton (2006).
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 12 of 45

Table 5-2. Bounding isotopic concentrations for PGDP operations (pCi/g U).a

Radionuclide

1 2 3 4 5 6

Pulverizer 

operations, ash 

handling activities, 

green salt 

production, C-410 

production 

activities pre-1983b

Converter 

maintenance 

and salvage, 

C-400 

cylinder 

operations 

pre-1983b

Converter 

maintenance 

and salvage, 

C-400 

cylinder

operations 

post-1983c

Tc/Np 

recovery 

operations, 

C-400d

Balance 

of plant 

pre-1983d

Balance of 

plant post1983c

Np-237 3.55E+04 1.61E+06 3.81E+04 1.76E+07 1.67E+03 3.67E+00

Pu-239/240 9.00E+05 3.24E+04 7.09E+04 4.42E+06 4.11E+01 1.95E+00

Pu-238 1.94E+05 7.01E+03 1.53E+04 9.54E+05 8.89E+00 4.21E-01

Pu-242 4.46E+01 1.61E+00 3.52E+00 2.19E+02 2.04E-03 9.67E-05

Pu-241 3.51E+07 1.27E+06 2.76E+06 1.72E+08 1.61E+03 3.38E-01

Am-241 1.56E+05 5.62E+03 1.85E+03 7.65E+05 7.13E+00 4.21E+00

Th-230 1.18E+06 1.67E+05 3.64E+05 2.27E+07 2.11E+02 1.00E+01

Tc-99 1.20E+05 1.20E+05 1.20E+05 3.81E+07 1.20E+05 1.20E+05

U-234 6.81E+05 6.81E+05 6.81E+05 6.81E+05 6.81E+05 6.81E+05

U-235 4.27E+04 4.27E+04 4.27E+04 4.27E+04 4.27E+04 4.27E+04

U-238 3.27E+05 3.27E+05 3.27E+05 3.27E+05 3.27E+05 3.27E+05

U-236 9.00E+02 9.00E+02 9.00E+02 9.00E+02 9.00E+02 9.00E+02

a. Based on uranium isotopic distribution for 2% enriched U (BJC 1999, Table 1-5). Assuming enriched rather than natural 

or depleted uranium provides bounding values for intake assessments based on urine samples, as well as TRU intake 

estimates.

b. PACE and University of Utah (2000).

c. Hightower et al. (2000).

d. BJC (2000). 

Table 5-2a. Bounding isotopic activity concentrations for PGDP operations (pCi/pCi U). a

Radionuclide

1 2 3 4 5 6

Pulverizer 

operations, ash 

handling activities, 

green salt 

production, C-410 

production 

activities pre-1983b

Converter 

maintenance 

and salvage, 

C-400 

cylinder 

operations

pre-1983b

Converter 

maintenance 

and salvage,

C-400 

cylinder 

operations

post-1983c

Tc/Np 

recovery 

operations, 

C-400d

Balance 

of plant 

pre-1983d

Balance of 

plant post1983c

Np-237 3.38E-02 1.53E+00 3.63E-02 1.67E+01 1.59E-03 3.49E-06

Pu-239/240 8.56E-01 3.08E-02 6.75E-02 4.21E+00 3.91E-05 1.86E-06

Pu-238 1.85E-01 6.67E-03 1.46E-02 9.08E-01 8.46E-06 4.01E-07

Pu-242 4.24E-05 1.53E-06 3.35E-06 2.08E-04 1.94E-09 9.20E-11

Pu-241 3.34E+01 1.21E+00 2.63E+00 1.64E+02 1.53E-03 3.22E-07

Am-241 1.48E-01 5.35E-03 1.76E-03 7.28E-01 6.79E-06 4.01E-06

Th-230 1.12E+00 1.59E-01 3.46E-01 2.16E+01 2.01E-04 9.52E-06

Tc-99 1.14E-01 1.14E-01 1.14E-01 3.63E+01 1.14E-01 1.14E-01

U-234a 4.89E-01 4.89E-01 4.89E-01 4.89E-01 4.89E-01 4.89E-01

U-235a 2.17E-02 2.17E-02 2.17E-02 2.17E-02 2.17E-02 2.17E-02

U-238a 4.89E-01 4.89E-01 4.89E-01 4.89E-01 4.89E-01 4.89E-01

U-236a 6.56E-04 6.56E-04 6.56E-04 6.56E-04 6.56E-04 6.56E-04

a. Based on uranium isotopic distribution for natural U (BJC1999, Table 1-5). Assuming natural rather than enriched 

uranium provides bounding values for uranium intake estimates based on in vivo counting methods.

b. PACE and University of Utah (2000).

c. Hightower et al. (2000).

d. BJC (2000).
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 13 of 45

The maximum plutonium activity in air is reported in PACE and the University of Utah (2000) as being 

comprised of 239Pu. However, it is more consistent with all references [BJC (2000), Hightower et al. 

(2000)] to assume that the faction of the alpha activity attributed to 239Pu be considered as total alphaemitting isotopes plus 241Am. A nominal isotopic distribution for TRU in fuel-grade plutonium in 

Mansfield (1997) was used to calculate the ratios of the various isotopes from the value provided in 

the reference.

Column 1 values are applicable to pulverizer operations, ash handling activities, green salt production,

and feed material production operations in Buildings C-410 and C-420. Column 2 values are 

applicable to converter maintenance/salvage and cylinder cleaning operations in Building C-400. 

Column 4, Tc/Np Recovery Operations; Column 5, Balance of Plant

The values in Columns 4 and 5 are from BJC (2000, Table 2.4.1). This reference presents a detailed 

analysis of the mass balance of 239Pu and 237Np using individual activity analysis. Table 2.4.1 

presents the maximum concentrations (in parts per billion) of the 239Pu and 237Np for the processes 

encountered at PGDP. The remaining plutonium isotopes and 241Am concentrations are determined 

using the isotopic ratios for fuel-grade plutonium in Mansfield (1997) and as described above.

The values in Column 4 are applicable to all technetium/neptunium recovery operations in Building 

C-400, including those that might have taken place after 1983.

The values for Column 5 consist of the upper 95% bound of the average Table 2.4.1 values (minus 

those areas/processes already accounted for in Columns 1 and 2). They are applicable to pre-1983 

activities, which include Cascade Operations (Buildings C-333, C-337, C-410), Production/Handling 

UF4 (Building C-340), Connecting/Disconnecting UF6 Tails Cylinders (Buildings C-315, C-340), 

Connecting/Disconnecting Product Cylinders (Building C-310), Changing/Cleaning MgF2 Traps 

(Buildings C-410, C-310), and U Metal Production (Building C-340) (BJC 2000, Table 2.4.1).

Post-1983 Operations

Column 3, Converter Maintenance and Salvage; Column 6, Balance of Plant

The values in Columns 3 and 6 are based on Hightower et al. (2000). These values were included in 

this TBD to account for the fact that an insignificantly small percentage (0.008% of the total) of RU 

feed was introduced to the cascade after 1977 (BJC 2000, Appendix C). In addition, a two-phase 

(1954 to 1961 and 1973 to 1981) upgrade program effectively replaced the major components of the 

cascade [2]. These facts would imply that, over time, TRU and fission product contaminants would be 

greatly reduced from the process, with the exception of those entrained in the feed and tail cylinder 

heels. Only cylinder maintenance/washing operations would have a potential for exposure to these 

isotopes. Hightower et al. (2000) contains analytical data in parts per billion for 237Np, 239Pu, and 

241Am in depleted uranium cylinders and feed material. The values in Table 3, the bounding 

concentrations for UF6 feed, were used to represent Converter Salvage Operations (Column 3). As 

for the pre-1983 operations, these include converter maintenance/salvage and cylinder cleaning in 

Building C-400. The values for the remaining plutonium isotopes were determined as using the ratios 

in Mansfield (1997), as described above.

For Balance of Plant Operations (Column 6) 239Pu, 237Np, and 241Am values specified in Hightower et 

al. (2000, Table 2) were used. These data represent the concentrations of dispersed contamination in 

DUF6 cylinders and, considering the negligible quantity of RU introduced to the Plant during this 

period, is believed to bound the actual 239Pu and 237Np levels because these isotopes were primarily 

concentrated in the pulverizer ash or plated in feed cylinder walls. 

Column 6 is applicable to post-1983 activities, which include Cascade Operations (Buildings C-333, 

C-337, C-410), Production/Handling UF4 (Building C-340), Connecting/Disconnecting UF6 Tails 

Cylinders (Buildings C-315, C-340), Connecting/Disconnecting Product Cylinders (Building C-310), 
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 14 of 45

Changing/Cleaning MgF2 Traps (Buildings C-410, C-310), and U Metal Production (Building C-340) 

(BJC 2000, Table 2.4.1).

Thorium 230

Pace and University of Utah (2000) lists 230Th, a decay product of uranium, as a potential source of 

concern and provides estimates for the activity concentration in Buildings C-400 and C-410 (Columns 

1 and 2 of Table 5-2 and 5-2a). BJC (2000) and Hightower et al. (2000) offer no data on 230Th. The 

ratio of 237Np to 239Pu data from each (BJC 2000, Table 2.4.1; Hightower et al. 2000) was compared to 

the same ratio determined for the PACE and University of Utah “mixes”. The mix for which the two 

ratios compared most closely was used to determine the 230Th concentration. A detailed discussion of 

this technique is in Barton (2006).

Technetium 99

The 99Tc concentration for all operations except 99Tc recovery is assumed to remain constant 

throughout the process and is based on the reported 7-ppb maximum for the feed material (Smith 

1984). The 99Tc concentration for recovery operations is from BJC (2000).

Note: If the work location of a claimant is unknown, use Column 2 or 3 in Table 5-2 (or 

Table 5-2a), as appropriate to the times of employment [3].

When determining potential intakes of TRU/99Tc by applying the isotopic ratios in Table 5-2 to 

urinalysis data, dose reconstructors should consider that PACE and University of Utah (2000) noted 

instances in which the bioassay data in the electronic database are not consistent with original 

documents. Verify urinalysis results obtained from the electronic database against the written 

records.

5.3 IN VITRO MEASUREMENT METHODS

From the start of Plant operations in 1952, samples of urine from workers involved in enrichment 

operations were analyzed for uranium.2

 Over time, other workers were included in the monitoring 

program. In addition, special sampling occurred in response to incidents or issues (i.e., assessments 

of the radiological impacts of TRU elements and technetium); however, those analytical methods were 

typically performed off the PGDP site, at Oak Ridge National Laboratory (ORNL) during early periods 

and later at analytical services contractor locations. 

At PGDP, routine urine samples were typically single voids collected during the middle of the week. 

Each could have been measured for specific gravity, pH, sugar, and albumin levels, as well as for 

uranium content. During the early years, total uranium concentrations were measured using a 

calibrated fluorimeter with a detection level of 0.005 mg/L (PACE and University of Utah 2000, p. 40).

In later years, total uranium content was assessed by kinetic phosphorescence analysis (KPA). 

Neither methodology included isotopic determinations (BJC 1999). 

5.3.1 Measurement Types and Detection Levels

Table 5-3 lists the in vitro measurement types and detection levels during various periods. For 

samples analyzed at the site, the detection level for total uranium in urine was reported as 0.005 mg/L 

(PACE and University of Utah 2000, Section 4.2.1). If detection levels for specific methods were not 

found in the available references, levels specified as typical in ICRP (1989) were used [4].

 2 Fecal sampling was occasionally performed for special studies. However, a program for routine or diagnostic monitoring 

of fecal samples was never implemented [4].
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 15 of 45

Table 5-3. In vitro measurement types and detection levels for various periods.

a

Period

Measurement 

type Radionuclide MDCa Comments

1952–1998 PGDP 

fluorimetryb

Total uranium 0.005 mg/L

1985–1989 ORNLd U-234, -235, and -238 0.03 pCi/sample

1989–present ORNL U-234, -235, and -238 0.01 pCi/sample

1989–present Contractore U-234, -235, and -238 0.3 pCi/L

1999–present KPAc Total uranium 0.06μg/sample DR should use the cite MDAa

for all urinalysis results by 

KPA, regardless of analysis 

date

1999–present ORNL Natural uranium 0.06 mg/sample

1969–1985 PGDP gross 

betac

Tc-99 10 dpm/mL 10 dpm/mL

1985–1989 ORNL Isotopic plutonium 0.02 pCi/sample

1989–present ORNL Isotopic plutonium 0.01 pCi/sample

1985–1989 ORNL beta 

counting

Tc-99 18.1 pCi/sample

1989–present ORNL Tc-99 90.9 pCi/sample

1999–present ORNL Th-228, -230, and -232 0.014 pCi/sample

1985–1989 ORNL Np-237 0.04 pCi/sample

1989–present ORNL Np-237 0.01 pCi/sample

1985–1989 ORNL Pu-238, -239, and -240 0.02 pCi/sample

1989–present ORNL Pu-238, -239, and -240 0.01 pCi/sample

1985–1989 ORNL Am-241 0.02 pCi/sample

1989–present ORNL Am-241 0.01 pCi/sample

a. MDC = minimum detectable concentration; DR = dose reconstructor; MDA = minimum detectable amount.

b. PACE and University of Utah (2000, p. 40) documents use of fluorimetry through 1982. No definitive reference for the 

specific method used for total uranium could be found in available documentation from 1983 to 1998. It is favorable to 

the claimant to assume fluorimetry (rather than KPA) during this period.

c. BJC (1999, Table 3.9).

d. ORAUT (2007) [5].

e. ICRP (1989).

In addition, if it is not clear from the monitoring records how or where a particular claimant’s sample 

was analyzed, assume that it was analyzed in-house (i.e., at PGDP) and use the minimum detectable 

concentration (MDC) from that measurement type to assess missed dose. Finally, if a record contains 

a notation of “less than X micrograms/L” or “< x pCi/sample,” that value should reflect the MDC for 

that sample [6].

5.3.2 Reporting Formats and Codes

A variety of codes occur on urine bioassay records for PGDP. Attachment A summarizes those 

known at the date of this TBD, along with their interpretations.

5.4 IN VIVO MEASUREMENT METHODS

In vivo methods were implemented beginning in the early 1950s. These measurement methods were

used primarily in response to incidents, or for assessing the magnitude of insoluble material intakes. 

Routine in vivo counting was instituted for certain PGDP employees in the late 1960s (PACE and 

University of Utah 2000).
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 16 of 45

5.4.1 Measurement Types and Detection Levels

At PGDP, in vivo counting was performed using a mobile counter provided by the Y-12 Plant 

(sometimes referred to as the “MMES Counter”) and at other facilities. Table 5-4 lists general 

information about the detection capabilities of this counting system for various periods.

Table 5-4. In vivo measurement types and detection levels for various periods.

Period Equipment

Measurement 

type Radionuclide

MDAa

(units of 

record)

Action level 

for recount

Action level 

for work 

restriction

1965–1991 Y-12 mobile 

counterb

Chest Enriched 

uranium (U235)

0.1 mg 0.1 mg 0.24 mg

1965–1991 Y-12 mobile 

counterb

Chest Depleted 

uranium

(reported as 

“Total 

uranium”)

4 mg 4 mg 37 mg

1965–1991 Y-12 mobile 

counterc

Chest Np-237 200 pCi 1,700 pCi 17,000 pCi

1991–1995 Helgeson counterc Chest Total uranium 2 – 4 mg 2 – 4 mg 27 mg

1991–1995 Helgeson counterc Chest Enriched 

uranium

0.04 – 0.07 

mg

0.04 – 0.07 

mg

0.24 mg

>1995 No counting performed

a. MDA = minimum detectable activity or amount.

b. ORAUT (2004a) [7].

c. Hill and Strom (1993).

5.4.2 Reporting Formats and Codes

A variety of codes and reporting formats appear in the in vivo bioassay records. Attachment A lists 

the known codes with their interpretations.

5.4.3 Instructions for Addressing Possible Interferences and Uncertainties

On occasion, in vivo measurement results included 137Cs. However, those PGDP workers could have 

had body burdens of 137Cs from nonoccupational sources (e.g., fallout and consumption of specific 

foodstuffs). There is no evidence of occupational intakes of 137Cs at PGDP, so no dose of record 

should be associated with these measurement results [8].

5.4.4 Assessment of Intake for Monitored Employees

In general, available urine results should be considered the primary method of dose reconstruction. In 

vivo measurements, especially in the earlier years of operation, were not used for routine monitoring 

purposes. However, those results might be useful for verifying assessments of dose based on urine 

bioassay results, in determining likely absorption types, or in providing upper and lower limits to the 

range of possible doses [9]. When converting urine sample results from units of mass to activity, an 

assumption of enriched uranium is more favorable to the claimant because of the high specific activity 

of U-234. Urine sample results reported in units of mass can be converted to units of activity using 

the information contained in Table 5-2, which gives the specific activity for total uranium as 1.05 

pCi/μg. Intakes calculated from urine samples should be projected to the dates of any chest counts to 

determine if the chest counts results are overpredicted. Chest counts may be reported as “U-235” or 

“enriched uranium;” both are assumed to refer to the U-235 mass only. This is converted to U-235 

activity by multiplying the result (or MDA) by the U-235 specific activity of 2.16 pCi/μg, then dividing by 

0.041 pCi U-235/pCi U to get total U activity. Attachment C provides the dose reconstructor a general 
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 17 of 45

idea of the types of job categories, work activities, and work locations for which internal dose 

assignment might be necessary.

When assessing intakes from chest count results, Table 5-2a is used because in this situation the 

assumption of natural uranium is more favorable to the claimant since only the U-235 is being 

measured. The chest count result is again converted to U-235 activity by multiplying the result (or 

MDA) by the U-235 specific activity of 2.16 pCi/μg. Total uranium activity is then calculated by 

dividing by 0.0217 pCi U-235/pCi U to get total U activity.

5.4.5 Assessment of Intake for Unmonitored Employees

There are instances of energy employees who, for a variety of reasons, were not monitored for 

internal exposure during the course of their employment at a DOE facility, or whose records of such 

monitoring are incomplete or unavailable. In such cases, dose reconstructors can use data from 

coworkers to approximate an individual’s possible exposure. Attachment B provides the details of the 

calculation and assignment of intakes based on coworker data from the PGDP for estimating 

unmonitored exposures or where records of monitoring are incomplete or unavailable. Attachment C 

provides the dose reconstructor a general idea of the types of job categories, work activities, and work 

locations for which internal dose assignment might be necessary.

5.5 SIGNIFICANT INCIDENTS WITH INTERNAL DOSE POTENTIAL

During operations at PGDP, a number of incidents occurred that increased the potential for intakes of 

radioactive materials. If a claimant (or employee) recalls involvement in one or more of those

incidents, dose reconstructors can use the information in Attachment C to identify the dates, location, 

and/or source term for an incident-specific dose assessment.

5.6 ATTRIBUTIONS AND ANNOTATIONS

Where appropriate in the preceding text, bracketed callouts have been inserted to indicate 

information, conclusions, and recommendations to assist in the process of worker dose 

reconstruction. These callouts are listed in this section with information that identifies the source and 

justification for each item. Conventional references are provided in the next section that link data, 

quotations, and other information to documents available for review on the Oak Ridge Associated 

Universities (ORAU) Team servers.

[1] Barton, Clark B. ORAU Team. Sr. Health Physicist. May 2006. 

The actual enrichment of uranium found in the process areas of PGDP is unknown because 

the facility produced product with a range of enrichments over the years. A nominal value of 

2% was assumed because it is the approximate midpoint to the range, and provides a 

conservative (i.e., favorable to the claimant) result for the calculated values listed in Table 5-2

in comparison to natural uranium, which is assumed in the reference material (PACE and the 

University of Utah 2000; BJC 2000).

[2] Mantooth, Daniel S. ORAU Team. Sr. Health Physicist. May 2006. 

The references PACE and the University of Utah (2000) and DOE (2000) include discussions 

stating that the Cascade Improvement Program (CIP)/Cascade Upgrade Program (CUP)

processes that ended in 1981 involved a cell-by-cell removal and replacement of the 

compressors and converters, process piping, and support system components. The year 

1983 is an arbitrary time assumed to allow additional time to finish converter salvage line work, 

refurbishment of parts, etc.
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 18 of 45

[3] Mantooth, Daniel S. ORAU Team. Sr. Health Physicist. May 2006. 

Column 2 data, based on PACE and the University of Utah (2000) values for the period before 

1983, and Column 3 data, based on Hightower et al. (2000) values for the period after 1983, 

present the higher values for activities at the site that are not specific to one job or area.

[4] Mantooth, Daniel S. ORAU Team. Sr. Health Physicist. May 2006. 

The nominal MDA values in ICRP (1989) are greater than those typically achievable by a 

laboratory using industry-accepted methods and techniques. Missed dose estimates will be 

greater with the use of the ICRP (1989) MDA value.

[5] Mantooth, Daniel S. ORAU Team. Sr. Health Physicist. May 2006. 

Values for in vitro MDAs were often not available in references specific to PGDP. Because it 

is known that urine samples were sent to ORNL for analysis during the periods listed in

Table 5-3, it was assumed that the values reported in ORAUT (2007) would apply.

[6] Mantooth, Daniel S. ORAU Team. Sr. Health Physicist. May 2006. 

The in-house MDC values are higher than offsite laboratory results, and any level indicated 

that is higher must be used. This is to ensure the use of the number most favorable to the 

claimant.

[7] Mantooth, Daniel S. ORAU Team. Sr. Health Physicist. May 2006. 

Values for in vivo MDAs were often not available in references specific to PGDP. Because it is 

known that the Y-12 Mobile Counter was used for both the Paducah and Portsmouth sites for 

analysis during the periods listed in Table 5-3, it was assumed that the values reported in 

ORAUT (2004a) would apply.

[8] Mantooth, Daniel S. ORAU Team. Sr. Health Physicist. May 2006. 

Extensive document review found no indication that 137Cs had ever been considered an 

isotope of concern at Paducah beyond the occasional elevated individual due to dietary 

consumption and the increases due to global testing/incidents.

[9] Mantooth, Daniel S. ORAU Team. Sr. Health Physicist. May 2006. 

NIOSH (2002, Section 5.1) states: “Bioassay measurements are generally the most reliable 

data available for assessing internal exposures.” In consideration of the limited in vivo data,

those uses might be limited.
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 19 of 45

REFERENCES

Author unknown, no date, “Urinalysis Program,” from Paducah Gaseous Diffusion Plant files, 

Paducah, Kentucky. [SRDB Ref ID: 12651]

Barton, C. B., 2006, "Verifying and Expanding Paducah Occupational Internal Dose Document 

Tables," memorandum to D. S. Mantooth, Dade Moeller & Associates, Richland, Washington, 

May 2006. [SRDB Ref ID: 24017]

BJC (Bechtel Jacobs Company) 1999, Internal Dosimetry Technical Basis Document for Bechtel 

Jacobs Company LLC, BJC/OR-258. [SRDB Ref ID: 12678]

BJC (Bechtel Jacobs Company), 2000, Recycled Uranium Mass Balance Project Paducah Gaseous 

Diffusion Plant Site Report, Draft for Review, BJC/PGDP-167, Paducah Gaseous Diffusion 

Plant, Paducah, Kentucky, March 5. [SRDB Ref ID: 16498]

DOE (U. S. Department of Energy), 2000, Phase II, Independent Investigation of the Paducah 

Gaseous Diffusion Plant, Environment, Safety and Health Practices, 1952-1990, Office of 

Oversight, Environment, Safety and Health, Washington, D.C., February. [SRDB Ref ID: 

12040]

Eckerman, K. F., and R. C. Ward, 1992, DOSEXPRT - A Bioassay Dosimetry Code for Martin 

Marietta Energy Systems, Inc., ORNL/TM-11857, Martin Marietta Energy Systems, Oak Ridge 

National Laboratory, Oak Ridge, Tennessee, April. [SRDB Ref ID: 12548]

Hightower, J. R., L. R. Dole, D. W. Lee, G. E. Michaels, M. I. Morris, D. G. O'Conner, S. J. Pawel, 

R. A. Schmoyer, L. D. Trowbridge, and V. S. White, 2000, Strategy for Characterizing 

Transuranics and Technetium Contamination in Depleted UF6 Cylinders, ORNL/TM-2000/242, 

UT-Battelle, Oak Ridge National Laboratory, Oak Ridge, Tennessee, October. [SRDB Ref ID: 

23571]

Hill, R. L., and D. J. Strom, 1993, Internal Dosimetry Technical Basis Manual for Portsmouth and 

Paducah Gaseous Diffusion Plants, PNL-8723, Battelle Memorial Institute, Pacific Northwest 

Laboratory, Richland, Washington, June. [SRDB Ref ID: 12024]

ICRP (International Commission on Radiological Protection), 1989, Individual Monitoring for Intakes of 

Radionuclides by Workers: Design and Interpretation, Publication 54, Pergamon Press, 

Oxford, England.

ICRP (International Commission on Radiological Protection), 1995, Dose Coefficients for Intakes by 

Workers, Publication 68, Pergamon Press, Oxford, England.

Maisler, J., 2003, “Results of Onsite Interview at Paducah," memorandum to C. Berger, Integrated 

Environmental Management, Dayton, Ohio, November 20. [SRDB Ref ID: 13764]

Mansfield, W.G., 1997, Nuclear Emergency and Radiological Decision Handbook, ARG-RAP27 

FRMAC-NEST, Lawrence Livermore National Laboratory, Livermore, California, May. [SRDB

Ref ID: 45243]

NIOSH (National Institute for Occupational Safety and Health), 2002, Internal Dose Reconstruction 

Implementation Guideline, OCAS-IG-002, Rev. 0, Office of Compensation Analysis and 

Support, Cincinnati, Ohio, August.
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 20 of 45

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), 2004a, Technical Basis Document for 

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

Rev. 00, Oak Ridge, Tennessee, November 24.

ORAUT (Oak Ridge Associated Universities Team), 2005, Technical Information Bulletin: Analysis of 

Coworker Bioassay Data for Internal Dose Assignment, Rev. 01, ORAUT-OTIB-0019, Oak 

Ridge, Tennessee, October 7.

ORAUT (Oak Ridge Associated Universities Team), 2004b, Technical Information Bulletin:

Assignment of Environmental Internal Doses for Employees Not Exposed to Airborne 

Radionuclides in the Workplace, Rev. 00, ORAUT-OTIB-0014, Oak Ridge, Tennessee, 

June 22.

ORAUT (Oak Ridge Associated Universities Team), 2006, Y-12 National Security Complex – Internal 

Dose, ORAUT-TKBS-0014-5, Rev. 02 PC-1, Oak Ridge, Tennessee, October 10.

ORAUT (Oak Ridge Associated Universities Team), 2007, Oak Ridge National Laboratory –

Occupational Internal Dose, ORAUT-TKBS-0012-5, Rev. 01, Oak Ridge, Tennessee, 

October 1.

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 Internal Dose, ORAUT-TKBS-0019-5, Rev. 03, Oak Ridge, Tennessee, August 

24.

PACE (Paper, Allied Industrial, Chemical and Energy Workers International Union) and University of 

Utah, 2000, Exposure Assessment Project at the Paducah Gaseous Diffusion Plant, 

December. [SRDB Ref ID: 10870]

Smith, R. F., 1984, Historical Impact of Reactor Tails on the Paducah Cascade, KY/L-1239, Union 

Carbide Corporation, Paducah Gaseous Diffusion Plant, Paducah, Kentucky, March 19. 

[SRDB Ref ID: 16826]
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 21 of 45

GLOSSARY

absorption type

Categories for materials according to their speed of absorption in the body, which replaced the 

earlier inhalation clearance classes. Defined by the International Commission on Radiological 

Protection, the absorption types are F for fast absorption (formerly inhalation class D), M for 

moderate absorption (formerly inhalation class W), and S for slow absorption (formerly 

inhalation class Y). Also called solubility type.

activity median aerodynamic diameter (AMAD)

Diameter of a unit density sphere with the same terminal settling velocity in air as that of the 

aerosol particle whose activity is the median for the entire aerosol. In relation to health 

physics, normally assumed to be 5 micrometers.

bioassay

Determination of kinds, quantities, or concentrations, and in some cases locations of 

radioactive material in a living body, whether by direct measurement (in vivo measurement) or 

by analysis and evaluation of materials excreted or removed from the body (in vitro

measurement).

body burden

Amount of radioactive material in an individual's body at a particular point in time.

dose 

In general, the effects of ionizing radiation in terms of the specific amount of energy absorbed 

per unit of mass. Effective and equivalent doses are in units of rem or sievert; other types of 

dose are in units of roentgens, rads, reps, or grays. Various terms narrow the type of dose, 

and some are additive: 

• Absorbed dose is the amount of energy deposited in a substance by ionizing radiation.

• Collective dose is the sum of the doses to a specific population.

• Committed dose is the dose over time (usually 50 years for workers) to a specific organ or 

tissue from an intake of radioactive material.

• Cumulative dose is the sum of all doses to the same portion of the body or to the whole 

body over time.

• Deep dose is the dose at a 1-centimeter depth in tissue (1,000 milligrams per square 

centimeter).

• Effective dose is the sum of the equivalent doses in the principal tissues and organs of the 

body, each weighted by a tissue weighting factor that accounts for the probabilities of fatal 

and nonfatal cancers according to severity and the average length of life lost due to an 

induced cancer. It indicates the biological effect of the radiation exposure in that tissue. 

• Equivalent dose or dose equivalent is the absorbed dose in a tissue or organ multiplied by 

a weighting factor for the particular type of radiation. 

• Organ dose is the dose to a specific organ.
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 22 of 45

• Penetrating dose is that from higher energy photon (gamma and X-ray) radiation and 

neutron radiation that penetrates the outer layers of the skin. Nonpenetrating dose is that 

from beta and lower energy photon radiation. 

• Personal dose equivalent is the dose equivalent in soft tissue below a specified point on 

the body at a specified depth. 

• Shallow dose is the dose at a 0.07-centimeter depth in tissue (7 milligrams per square 

centimeter).

• Skin dose is the dose to the skin.

• Whole-body dose is the dose to the entire body excluding the contents of the 

gastrointestinal tract, urinary bladder, and gall bladder.

dose equivalent (H, DE)

Product of absorbed dose in units of rem or sievert in tissue multiplied by a weighting factor 

and sometimes by other modifying factors to account for the potential for a biological effect 

from the absorbed dose. See dose.

exposure

(1) In general, the act of being exposed to ionizing radiation. (2) Measure of the ionization 

produced by X- and gamma-ray photons in air in units of roentgens. 

insoluble material

A term loosely used to describe the relative degree of solubility of a material in body fluids. 

Recognizing that no material is absolutely insoluble, the terms low solubility or poorly soluble 

are preferable.

intake

Radioactive material taken into the body by inhalation, absorption through the skin, injection, 

ingestion, or through wounds. Depending on the radionuclide involved, intakes are in units of 

mass, activity, or potential alpha energy.

internal dose or exposure

Dose received from radioactive material in the body.

internal dose assessment

Estimation of an intake of radioactive material and the consequent internal radiation dose 

based on measurements in the work environment and/or bioassay. 

in vitro

Of or relating to a process that takes place under artificial conditions or outside a living 

organism (e.g., in the laboratory). From Latin meaning in glass.

in vivo

Of or relating to a process that takes place in a living organism. From Latin meaning in life.

lung solubility type

See absorption type.
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 23 of 45

minimum detectable amount (MDA)

Lowest amount of radioactive activity or substance amount detectable by a specific instrument 

or process. Smallest amount or activity of a radionuclide in a sample or organ that yields a 

result above the detection level with a specific probability of a Type II (false negative) error 

while accepting an specific probability of a Type I (false positive) error. 

minimum detectable concentration (MDC)

Lowest concentration of a material in a substance (e.g., urine) detectable by a specific 

instrument or process. Minimum detectable activity (or amount) in units of concentration. 

minimum reporting level 

Level below which an analytical dose is not recorded in the worker’s dose record, usually 

based on a site-specific policy decision. The recording level is not necessarily the same as 

the minimum detectable amount or activity for that measurement. Also called less-than value, 

minimum reportable dose, minimum recordable or recording dose, recording level, and 

reporting level. 

monitoring (personnel)

Periodic or continuous determination of the presence or amount of ionizing radiation or 

radioactive contamination in air, surface water, groundwater, soil, sediment, equipment 

surfaces, or personnel (for example, bioassay or alpha scans). In relation to personnel, 

monitoring includes internal and external dosimetry including interpretation of the 

measurements. 

occupational dose

Internal and external ionizing radiation dose from exposure during employment. Occupational 

dose does not include that from background radiation or medical diagnostics, research, or 

treatment.

radiation

Subatomic particles and electromagnetic rays (photons) that travel from one point to another, 

some of which can pass through or partly through solid materials including the human body. 

Radiation, as used in this document, does not include nonionizing radiation, such as radio- or 

microwaves, or visible, infrared, or ultraviolet light.

reactor tails

Recycled uranium (typically UO3) from reactor operations (typically Savannah River and 

Hanford) that contains traces of transuranic isotopes not removed during chemical processing 

(e.g., reduction-oxidation).

recording level

See minimum reporting level. 

rem

Traditional unit of radiation dose equivalent that indicates the biological damage caused by 

radiation equivalent to that caused by 1 rad of high-penetration X-rays multiplied by a quality 

factor. The average American receives 360 millirem a year from background radiation. The 

sievert is the International System unit; 1 rem equals 0.01 sievert. The word derives from 

roentgen equivalent in man; rem is also the plural.

routine monitoring

Monitoring carried out at regular intervals during normal operations.
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 24 of 45

sievert (Sv)

International System unit for dose equivalent, which indicates the biological damage caused 

by radiation. The unit is the radiation value in gray (equal to 1 joule per kilogram) multiplied by 

a weighting factor for the type of radiation and a weighting factor for the tissue; 1 Sv equals 

100 rem.

special monitoring

Monitoring in addition to the routine monitoring program carried out for special purposes such 

as estimating the amount of radionuclide deposited in a person after a known or suspected 

accidental intake or after a known or suspected environmental release. 

spot sample

In relation to bioassay, usually a single void of urine.
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 25 of 45

LIST OF TABLES

TABLE TITLE PAGE

A-1 In vitro record codes...............................................................................................................26

A-2 In vivo record codes...............................................................................................................28

ATTACHMENT A

CODES USED IN INTERNAL DOSE RECORDS 

Page 1 of 4
Document No. ORAUT-TKS-0019-5 Revision No. 03 Effective Date:

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4/2012 Page 26 of 45

Table A-1. In vitro record codes.

a,b,c,d

Form identifier

Measurement 

type

Column 

identifier Code Interpretation

WCP-455 Urine bioassay Reason for Visit 33, 35 Industrial health recheck

WCP-455 Urine bioassay Reason for Visit OB, 39, 35-1 Recall sample requested following elevated sample.

WCP-455 Urine bioassay Reason for Visit MM recall Monday morning recall sample; requested after days 

off work.

WCP-455 Urine bioassay Reason for Visit 32, 33, Term Termination samples

WCP-455 Urine bioassay Reason for Visit 30, 22 Rehire

WCP-455 Urine bioassay Reason for Visit 37, 18, Per. Periodic physical; confirmatory samples were 

collected during routine physicals; this typically did 

not pertain to those on routine monitoring program.

WCP-455 Urine bioassay Reason for Visit 26 Preemployment

WCP-455 Urine bioassay Reason for Visit 005, 07, 60, 

Exposure, 

Special, Release

Samples collected following exposure or potential 

exposure in uranium release or spill.

WCP-455 Urine bioassay Bottle No. Permanent sample number.

PGDP_HISTORICAL_URINE Urine bioassay Results There is no distinction between positive results and 

detection limits.

PGDP_HISTORICAL_URINE Urine bioassay Sample Type Physical Routine physicals included collection of bioassay 

sample (random sampling program); this typically 

did not pertain to those on routine monitoring 

program.

WCP-455 Urine bioassay Reason for Visit I.H.R. or IHR Industrial health recheck (associated with routine 

physicals)

WCP-455 Urine bioassay Top of Card “A” Refers to shift worked (“A” = day shift)

WCP-455 Urine bioassay Top of Card “B” Refers to shift worked (“B” = evening shift)

WCP-455 Urine bioassay Top of Card “O” Refers to shift worked (“O” = midnight shift)

WCP-455 Urine bioassay F, HG and 

OTHER

“B” (128) Indicates shift and hours worked.

PGDP_ANALIS_URINE Urine bioassay Results Results are given in μg/L.

5EA HPINT - Bioassay Results Report Urine bioassay Units 4 dpm/L

5EA HPINT - Bioassay Results Report Urine bioassay Units 1 dpm/mL

5EA HPINT - Bioassay Results Report Urine bioassay Units 2 dpm/d

5EA HPINT - Bioassay Results Report Urine bioassay Units 3 dpm/sample

5EA HPINT - Bioassay Results Report Urine bioassay Units 5 μg/mL

5EA HPINT - Bioassay Results Report Urine bioassay Units 6 Bq/L

ATTACHMENT A

CODES USED IN INTERNAL DOSE RECORDS 

Page 2 of 4
Document No. ORAUT-TKS-0019-5 Revision No. 03 Effective Date:

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4/2012 Page 27 of 45

Form identifier

Measurement 

type

Column 

identifier Code Interpretation

5EA HPINT - Bioassay Results Report Urine bioassay Units 7 Bq/d

5EA HPINT - Bioassay Results Report Urine bioassay Reason 3 Routine

5EA HPINT - Bioassay Results Report Fecal analysis Units 3 dpm/sample

5EA HPINT - Bioassay Results Report Fecal analysis Units 7 Bq/d

5EA HPINT - Bioassay Results Report Breath analysis Units 2 dpm/d

5EA HPINT - Bioassay Results Report Breath analysis Units 3 dpm/sample

5EA HPINT - Bioassay Results Report Breath analysis Units 4 dpm/L

5EA HPINT - Bioassay Results Report Breath analysis Units 6 Bq/L

5EA HPINT - Bioassay Results Report Breath analysis Units 7 Bq/d

WCP-885 Urine bioassay Schedule A Day sample is to be taken (1 = Monday; 

2 = Tuesday; 3 = Wednesday; 4 = Thursday)

WCP-885 Urine bioassay Schedule B Type analysis (1 = Uranium; 2 = Fluoride; 

3 = Mercury)

WCP-885 Urine bioassay Location Shifts A, B, O and D

Frequency Uranium #1 = 1 a month; Fluoride #2 = 1 a year; 

Mercury #3 = Blank

Permanent log (sample collection log) Urine bioassay Number Permanent 

sample number

Numbers are consecutive from top to bottom of page 

and continue from one page to next.

IBM Report Cards Urine bioassay A Name

IBM Report Cards Urine bioassay B Badge

IBM Report Cards Urine bioassay C Date (date shown on log)

IBM Report Cards Urine bioassay D Code for this service.

IBM Report Cards Urine bioassay E Analysis results in boxes labeled Uranium, 

Fluorides, and Mercury.

UCN-5242, “Sample Analysis 

(Medical).”

Urine bioassay Same as for 

NCP-455

Same as for 

NCP-455

This form number was in use from 1969 to 1970.

a. Sources: Maisler (2003); Eckerman and Ward (1992); Author unknown (no date).

b. Form WCP-885 is referred to as “NCP-885” in Eckerman and Ward (1992); however, they appear to be the same form.

c. Around June 1956, form WCP-455 was modified with additional columns. Individual bioassay records reviewed indicate the exact date the newly expanded form was used. This varies a 

little from person to person, but was in the middle of 1956 for all records reviewed. 

d. The bioassay records we have starting in 1977 (exact dates vary from person to person) are not copies of results recorded on bioassay cards; they are database printouts (e.g., 

“PGDP_Historical_Urine”). The uranium results are in units of micrograms per liter with results recorded to the nearest integer, i.e., 0, 1, 2, etc. 

ATTACHMENT A

CODES USED IN INTERNAL DOSE RECORDS 

Page 3 of 4
Document No. ORAUT-TKS-0019-5 Revision No. 03 Effective Date:

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4/2012 Page 28 of 45

Table A-2. In vivo record codes.

a

Form identifier

Measurement 

type

Column 

identifier Code Interpretation

In Vivo Radiation Monitoring Report Chest count Surface 

contamination

Check mark, 

yes

Surface contamination on the subject was checked. If 

measurable activity was found, it was so noted on card.

In Vivo Radiation Monitoring Report Chest count Analysis 

Sequence

These align with Output - Analysis Sequence Results 

listed at bottom of card; they are not relevant to dose 

reconstruction process.

In Vivo Radiation Monitoring Report Chest count Output–Analysis 

Sequence 

Results

A. Enriched 

Uranium

In Vivo Radiation Monitoring Report Chest count Output–Analysis 

Sequence 

Results

J. NLO 

Uranium

Refers to special spectrum region of interest for National 

Lead of Ohio, early operator of Fernald facility.

In Vivo Radiation Monitoring Report Chest count Hand-written 

notes

No Np noted Presence or absence of Np-237 was qualitatively 

evaluated.

In Vivo Radiation Monitoring Report 

(with boxes for data entry)

Chest count Hand-written 

notes

BFD Initials of whole-body counter operator (individual who 

filled out the card).

5EA HPINT–Bioassay Results Report In vivo records Units M μCi

5EA HPINT–Bioassay Results Report In vivo records Units N nCi

5EA HPINT–Bioassay Results Report In vivo records Units P pCi

5EA HPINT–Bioassay Results Report In vivo records Units D dpm

5EA HPINT–Bioassay Results Report In vivo records Units B Bq

5EA HPINT–Bioassay Results Report In vivo records Units U μg

a. Sources: Maisler (2003); Eckerman and Ward (1992); Author unknown (no date).

ATTACHMENT A

CODES USED IN INTERNAL DOSE RECORDS 

Page 4 of 4
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 29 of 45

TABLE OF CONTENTS

SECTION TITLE PAGE

B.1 Purpose ................................................................................................................................. 30

B.2 Overview................................................................................................................................ 30

B.3 Data ....................................................................................................................................... 31

B.3.1 Selected Bioassay Data.............................................................................................. 31

B.3.2 Analysis...................................................................................................................... 31

B.4 Intake Modeling...................................................................................................................... 31

B.4.1 Assumptions............................................................................................................... 31

B.4.2 Bioassay Fitting .......................................................................................................... 36

B.4.3 Uranium Material Types.............................................................................................. 36

B.4.3.1 Type F.......................................................................................................... 37

B.4.3.2 Type M......................................................................................................... 38

B.4.3.3 Type S ......................................................................................................... 39

B.5 Assignment of Intakes and Doses .......................................................................................... 41

B.5.1 Intake Rate Summary................................................................................................. 41

B.5.2 Contribution from Contaminants in Recycled Uranium................................................ 42

B.5.3 Dose Assignment ....................................................................................................... 43

LIST OF TABLES

TABLE TITLE PAGE

B-1 Summary of quarterly uranium 24-hour urinary excretion rate analyses, 1952 to 1988 .......... 32

B-2 Type F uranium intake periods and rates ............................................................................... 38

B-3 Type M uranium intake periods and rates .............................................................................. 39

B-4 Type S uranium intake periods and rates ............................................................................... 40

B-5 Type F uranium intake periods and rates ............................................................................... 42

B-6 Type M uranium intake periods and rates .............................................................................. 42

B-7 Type S uranium intake periods and rates ............................................................................... 42

ATTACHMENT B

INTERNAL DOSIMETRY COWORKER DATA FOR PGDP

Page 1 of 15
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 30 of 45

LIST OF FIGURES

FIGURE TITLE PAGE

B-1 50th-percentile uranium urinalysis data used to estimate intakes of type F uranium 

occurring June 1, 1952, to December 31, 1988...................................................................... 37

B-2 84th-percentile uranium urinalysis data used to estimate intakes of type F uranium 

occurring June 1, 1952, to December 31, 1988...................................................................... 37

B-3 50th-percentile uranium urinalysis data used to estimate intakes of type M uranium 

occurring June 1, 1952, to December 31, 1988...................................................................... 38

B-4 84th-percentile uranium urinalysis data used to estimate intakes of type M uranium 

occurring June 1, 1952, to December 31, 1988...................................................................... 39

B-5 50th-percentile uranium urinalysis data used to estimate intakes of type S uranium 

occurring June 1, 1952, to March 31, 1980 ............................................................................ 40

B-6 50th-percentile uranium urinalysis data used to estimate intakes of type S uranium 

occurring April 4, 1980 to December 31, 1988 ....................................................................... 40

B-7 Predicted 50th-percentile urinary excretion of type S uranium from 1952 to 1988 based 

on two independent intakes, compared with bioassay data.................................................... 41

B-8 Predicted 84th-percentile urinary excretion of type S uranium from 1952 to 1988 based 

on two independent intakes, compared with bioassay data.................................................... 41

B.1 PURPOSE

There are energy employees who, for a variety of reasons, were not monitored for internal exposure 

during the course of their employment at a DOE facility, or whose records of such monitoring are

incomplete or unavailable. In such cases, dose reconstructors can use data from coworkers to 

approximate an individual’s possible exposure. The purpose of this attachment is to provide the 

details of the calculation and assignment of intakes based on coworker data from the PGDP for 

estimating unmonitored exposures or where records of monitoring are incomplete or unavailable.

B.2 OVERVIEW

ORAUT-OTIB-0019, Analysis of Coworker Bioassay Data for Internal Dose Assignment (ORAUT 

2005), describes the general process for analyzing bioassay data for the assignment of doses based 

on coworker results.

Uranium urine bioassay results from 1952 through 1988 were obtained from the PGDP Dosimetry 

Section. The data were copied from working files that are the basis for the PGDP annual dose reports 

and dose histories. Some of the bioassay data were taken from handwritten logs and added to the 

electronic database. 

The database results are in units of micrograms or milligrams of total uranium per liter (μg/L or mg/L, 

respectively). All results were converted to μg/L for data analysis. There were a limited number of 

“beta” results in one of the files used (about 11%), which probably reflects measurement for 99Tc. The 

decision was made not to use these data, because most of the results (> 97%) were reported as zero. 

The uranium records provide a more robust data set for statistical analysis. 

ATTACHMENT B

INTERNAL DOSIMETRY COWORKER DATA FOR PGDP

Page 2 of 15
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 31 of 45

A statistical analysis of these data was performed in accordance with ORAUT-OTIB-0019 (ORAU 

2005). The resultant values were input to the Integrated Modules for Bioassay Analysis (IMBA) 

Expert Office of Compensation Analysis and Support (OCAS) Edition computer program. The 

bioassay data were assumed to represent excretion of 234U, which is biokinetically identical to other 

uranium isotopes and would result in the highest dose; a data fit was performed to obtain intake rates 

for assigning dose distributions. Bioassay results were converted from mass to activity before fitting.

B.3 DATA

B.3.1 Selected Bioassay Data

PGDP urinalysis data were extracted from two Microsoft® Access files provided by the PGDP 

Dosimetry Section. Table “PGDP_Historical_Urine from the PGDP_Dosimetry _Data_With_IDs 

database” was the source of urinalysis data from 1977 through 1988. Sample dates were taken from 

the Sample_Date field. Total uranium urinalysis results were taken from the Result field in the 

database; the Units field identified result units as micrograms per liter.

File “Historical_Urinalysis_Data_(unverified)” was the source of urinalysis data from October 1952 to 

mid-1977. Sample dates were taken from the Date_Sample field. Total uranium urinalysis results 

were taken from the Urinalysis_Result field in the database; there were no units associated with 

urinalysis results in this file. Comparison to results with identified units in table 

“PGDP_Historical_Urine” and with information presented in Section 5.3.1 of this TBD determined the 

results in this file were in units of milligrams per liter. Results in this file were converted to micrograms 

per liter for analysis.

Because both of the above files included PGDP uranium urinalysis data from 1977, the data were 

evaluated to identify and eliminate duplicate entries. 

B.3.2 Analysis

Because of the number of sample results, data were analyzed by quarter from the final quarter of 

1952 through 1988. The effective bioassay date was set equal to the midpoint of the analysis period. 

A lognormal distribution was assumed, and the 50th and 84th percentiles were calculated for each 

quarter, using the method described in ORAUT (2005). Table B-1 lists the statistical analysis results.

B.4 INTAKE MODELING

B.4.1 Assumptions

The IMBA Expert OCAS-Edition computer program requires urine results to be in units of activity per 

day. The total uranium results are in units of micrograms per liter; therefore, the results were 

multiplied by 1.4 to normalize them to the Reference Man excretion rate of 1,400 mL/d. Bioassay 

results were converted from mass to activity before fitting assuming 0.0389 Bq/μg, characteristic of 

low-enrichment (2%) uranium. Low-enrichment uranium feed is the default value if the specific 

location where a claimant worked is not available. 

The uncertainty for each result in the intake calculation was assumed to be normally distributed. All 

results were equally weighted by applying a uniform absolute error of 1, indicating to IMBA that all 

results are (assumed to be) equally precise. A chronic exposure pattern was assumed for PGDP 

ATTACHMENT B

INTERNAL DOSIMETRY COWORKER DATA FOR PGDP

Page 3 of 15
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 32 of 45

 Table B-1. Summary of quarterly uranium 24-hour urinary 

 excretion rate analyses, 1952 to 1988.

Effective 

sample date

50th 

percentile 

(Bq/d)

84th 

percentile 

(Bq/d)

No. of 

samples

No. of 

employees

11/14/1952 0.599 3.246 199 106

8/15/1953 0.205 0.980 1267 646

11/15/1953 0.362 1.373 1336 650

2/15/1954 0.578 2.023 1617 675

5/15/1954 0.466 1.643 1387 621

8/15/1954 0.383 0.951 1302 610

11/15/1954 0.330 1.010 1124 515

2/15/1955 0.331 1.327 1234 600

5/15/1955 0.471 1.419 1189 552

8/15/1955 0.411 1.185 1726 851

11/15/1955 0.468 1.465 1896 759

2/15/1956 0.466 1.454 2098 796

5/15/1956 0.407 0.800 1872 834

8/15/1956 0.323 0.739 1886 968

11/15/1956 0.328 0.930 1643 798

2/15/1957 0.377 0.866 1955 870

5/15/1957 0.453 1.063 2225 805

8/15/1957 0.316 0.886 2232 1005

11/15/1957 0.351 0.900 2399 967

2/15/1958 0.415 1.028 2307 889

5/15/1958 0.353 0.859 2217 939

8/15/1958 0.425 1.040 2291 899

11/15/1958 0.365 0.857 2139 846

2/15/1959 0.380 1.046 1895 818

5/15/1959 0.277 0.770 2026 916

8/15/1959 0.243 0.655 2134 961

11/15/1959 0.311 0.930 1909 873

2/15/1960 0.260 0.737 1780 885

5/15/1960 0.197 0.581 1854 1037

8/15/1960 0.195 0.558 1599 857

11/15/1960 0.287 1.119 1961 866

2/15/1961 0.297 1.083 1782 781

5/15/1961 0.190 0.551 1782 944

8/15/1961 0.176 0.529 1388 742

11/15/1961 0.340 0.977 1269 644

2/15/1962 0.447 1.284 1328 599

5/15/1962 0.412 0.950 1359 659

8/15/1962 0.302 0.797 1056 574

11/15/1962 0.369 0.911 1149 634

2/15/1963 0.343 0.929 1237 614

5/15/1963 0.327 0.807 1069 522

8/15/1963 0.228 0.597 931 521

11/15/1963 0.274 0.678 1096 569

2/15/1964 0.316 0.720 977 556

5/15/1964 0.305 0.917 1053 607

8/15/1964 0.286 0.616 624 376

ATTACHMENT B

INTERNAL DOSIMETRY COWORKER DATA FOR PGDP

Page 4 of 15
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 33 of 45

Effective 

sample date

50th 

percentile 

(Bq/d)

84th 

percentile 

(Bq/d)

No. of 

samples

No. of 

employees

11/15/1964 0.233 0.540 590 396

2/15/1965 0.213 0.461 578 434

5/15/1965 0.196 0.441 643 461

8/15/1965 0.242 0.467 424 329

11/15/1965 0.279 0.520 471 360

2/15/1966 0.326 0.672 513 393

5/15/1966 0.336 0.683 543 447

8/15/1966 0.293 0.598 536 412

11/15/1966 0.318 0.558 413 342

2/15/1967 0.305 0.612 545 418

5/15/1967 0.289 0.689 623 457

8/15/1967 0.275 0.503 368 321

11/15/1967 0.224 0.561 452 351

2/15/1968 0.241 0.523 527 410

5/15/1968 0.241 0.449 374 298

8/15/1968 0.293 0.647 416 344

11/15/1968 0.421 0.981 684 433

2/15/1969 0.529 1.165 1040 577

5/15/1969 0.394 0.840 868 514

8/15/1969 0.278 0.677 616 398

11/15/1969 0.344 0.847 707 417

2/15/1970 0.218 0.661 946 569

5/15/1970 0.228 0.636 753 482

8/15/1970 0.223 0.764 610 421

11/15/1970 0.254 0.912 228 190

2/15/1971 0.260 0.797 760 535

5/15/1971 0.208 0.634 508 371

8/15/1971 0.253 0.746 637 447

11/15/1971 0.341 0.947 536 325

2/15/1972 0.298 0.875 782 490

5/15/1972 0.163 0.570 602 369

8/15/1972 0.176 0.548 611 431

11/15/1972 0.216 0.736 654 438

2/15/1973 0.175 0.632 682 417

5/15/1973 0.248 0.624 443 300

8/15/1973 0.212 0.630 532 355

11/15/1973 0.275 0.735 493 319

2/15/1974 0.221 0.665 608 419

5/15/1974 0.177 0.546 179 161

8/15/1974 0.232 0.695 369 291

11/15/1974 0.354 0.980 549 351

2/15/1975 0.422 1.185 930 584

5/15/1975 0.347 0.818 924 591

8/15/1975 0.307 0.698 636 404

11/15/1975 0.362 0.890 778 510

2/15/1976 0.401 0.869 1025 653

ATTACHMENT B

INTERNAL DOSIMETRY COWORKER DATA FOR PGDP

Page 5 of 15
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 34 of 45

Effective 

sample date

50th 

percentile 

(Bq/d)

84th 

percentile 

(Bq/d)

No. of 

samples

No. of 

employees

5/15/1976 0.321 0.876 1035 713

8/15/1976 0.329 0.906 1025 768

11/15/1976 0.384 0.965 754 582

2/15/1977 0.260 0.879 1097 750

5/15/1977 0.334 0.972 928 634

8/15/1977 0.321 0.964 954 617

11/15/1977 0.432 1.189 1079 673

2/15/1978 0.418 1.037 1562 925

5/15/1978 0.330 0.862 1356 788

8/15/1978 0.245 0.603 1300 852

11/15/1978 0.209 0.621 1431 856

2/15/1979 0.071 0.376 857 700

5/15/1979 0.159 0.577 1301 828

8/15/1979 0.170 0.447 937 721

11/15/1979 0.258 0.658 1227 820

2/15/1980 0.229 0.674 1339 880

5/15/1980 0.117 0.330 1218 770

8/15/1980 0.120 0.318 1002 757

11/15/1980 0.109 0.232 1003 714

2/15/1981 0.100 0.297 983 681

5/15/1981 0.081 0.243 892 651

8/15/1981 0.097 0.236 1024 738

11/15/1981 0.083 0.207 847 638

2/15/1982 0.106 0.279 913 694

5/15/1982 0.061 0.199 644 466

8/15/1982 0.086 0.267 724 514

11/15/1982 0.081 0.250 686 511

2/15/1983 0.107 0.291 780 544

5/15/1983 0.116 0.307 618 466

8/15/1983 0.060 0.214 731 587

11/15/1983 0.098 0.276 695 489

2/15/1984 0.088 0.275 843 586

5/15/1984 0.069 0.245 484 369

8/15/1984 0.051 0.193 634 469

11/15/1984 0.062 0.222 732 484

2/15/1985 0.086 0.384 862 561

5/15/1985 0.055 0.249 902 610

8/15/1985 0.052 0.157 753 513

11/15/1985 0.053 0.156 1005 717

2/15/1986 0.054 0.250 926 585

5/15/1986 0.039 0.106 904 674

8/15/1986 0.072 0.240 812 600

11/15/1986 0.055 0.185 960 671

2/15/1987 0.088 0.259 1050 632

5/15/1987 0.061 0.213 1063 630

8/15/1987 0.107 0.282 1050 612

ATTACHMENT B

INTERNAL DOSIMETRY COWORKER DATA FOR PGDP

Page 6 of 15
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ATTACHMENT B

INTERNAL DOSIMETRY COWORKER DATA FOR PGDP

Page 7 of 15

Effective 

sample date

50th 

percentile 

(Bq/d)

84th 

percentile 

(Bq/d)

No. of 

samples

No. of 

employees

11/15/1987 0.091 0.229 1008 658

2/15/1988 0.114 0.425 1592 754

5/15/1988 0.119 0.341 1153 646

8/15/1988 0.089 0.257 990 607

11/15/1988 0.110 0.358 1180 729
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 36 of 45

workers; this pattern approximates a series of acute intakes with unknown intake dates. Intakes were 

assumed to be by inhalation using a default breathing rate of 1.2 m3

/hr and a 5-μm activity median 

aerodynamic diameter (AMAD) particle size distribution.

The database reported all results as “uranium.” The bioassay data were assumed to represent 

excretion of 234U. All uranium isotopes considered have long half-lives in relation to the assumed 

intake period so radioactive decay is not a consideration. In addition, all uranium isotopes are 

biokinetically identical so there is no effect on the fitting of the data for intake determination. Uranium234 was the isotope selected because it would result in the highest internal dose; the International 

Commission on Radiological Protection (ICRP) Publication 68 dose coefficients (also referred to as 

dose conversion factors) for 234U are 7% to 31% larger than those for 235U, 236U, and 238U (ICRP 

1995). Because of the isotopic compositions of the source terms, the assumption of 234U will yield 

doses that are favorable to claimants. 

PGDP received uranium and began enrichment operations in July 1952 and first withdrew enriched 

uranium in November 1952. The November 1952 period is consistent with uranium urinalysis data; 

however, the first intake period was conservatively assumed to begin on June 1, 1952.

B.4.2 Bioassay Fitting

The IMBA Expert OCAS-Edition computer program was used to fit the bioassay results to a series of 

inhalation intakes. Quarterly data from 1952 through 1988 were fit as a series of chronic intakes. 

The intake assumptions were based on patterns observed in the bioassay data. The analysis for this 

TBD used periods with constant chronic intake rates by selecting time spans for which the bioassay 

results are of similar magnitudes. The analysis started a new chronic intake period if the data 

indicated a significant sustained change in the bioassay results. By this method, the period from 1952 

through 1988 was divided into two chronic intake periods. 

B.4.3 Uranium Material Types

Section 5.2 in the body of this document indicates uranium could be present in material with all three 

lung clearance rates (F, M, and S). Therefore, all three material types were evaluated. The bioassay 

results were entered into IMBA and the 50th-percentile intakes that resulted are shown in the figures 

in this attachment. In these figures, quarterly bioassay data used in the fits are shown as blue dots 

(●), and data that are not used in the fits are shown as red dots (●). 

The type S uranium compounds present at PGDP have very long radiological half-lives, and the body 

retains the compounds for long periods. Therefore, the excretion results for different chronic intake 

periods are not independent for type S materials. For example, an intake in the 1950s could 

contribute to urinary excretion in the 1980s and later. To avoid potential underestimation of intakes 

for people who worked at PGDP for relatively short periods, each chronic intake of type S material 

was fit independently, using only the bioassay results from the single intake period. This will result in 

an overestimate of intakes for assumed type S exposures extending through both assumed intake 

periods. 

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B.4.3.1 Type F

Uranium urine results were fit using a type F material. Figure B-1 shows the fits to the 50th-percentile 

values from all intakes. The same intake periods were applied to the 84th-percentile values because 

the values followed a similar pattern, as shown in Figure B-2. These depict the expected excretion 

rates from an individual exposed for all the periods at the 50th- and 84th-percentile intake rates, 

respectively. Table B-2 summarizes the intake periods and corresponding intake rates for the 50th

and 84th percentiles. The geometric standard deviations (GSDs) were determined by dividing the 

84th-percentile intake rates by the 50th-percentile intake rates.

Figure B-1. 50th-percentile uranium urinalysis data used to estimate intakes of type F uranium 

occurring June 1, 1952, to December 31, 1988.

Figure B-2. 84th-percentile uranium urinalysis data used to estimate intakes of type F uranium 

occurring June 1, 1952, to December 31, 1988.

● quarterly bioassay value

___ fit

● quarterly bioassay value 

___ fit

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Table B-2. Type F uranium intake periods and rates.

Start date Stop date

Uranium intake rate (Bq/d)

50th percentile 84th percentile GSD

6/1/1952 3/31/1980 1.11 3.05 2.75

4/1/1980 12/31/1988 0.279 0.862 3.09

B.4.3.2 Type M

The intake periods used in the type F fits were applied to the type M material fits. Figures B-3 and B4 show the fits to the 50th- and 84th-percentile values, respectively, from all intakes. Table B-3 

summarizes the intake periods and corresponding intake rates for the 50th and 84th percentiles. The 

GSDs were determined as described for the type F intake rates.

Figure B-3. 50th-percentile uranium urinalysis data used to estimate intakes of type M uranium 

occurring June 1, 1952, to December 31, 1988. 

● quarterly bioassay value 

___ fit

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Figure B-4. 84th-percentile uranium urinalysis data used to estimate intakes of type M uranium 

occurring June 1, 1952, to December 31, 1988.

Table B-3. Type M uranium intake periods and rates.

Start date Stop date

Uranium intake rate (Bq/d)

50th percentile 84th percentile GSD

6/1/1952 3/31/1980 4.53 12.42 2.74

4/1/1980 12/31/1988 1.07 3.35 3.13

B.4.3.3 Type S

The intake periods used in the type F and M fits were applied to the type S material fits. As discussed 

above, each chronic intake period for type S material was fit independently. Figures B-5 and B-6 

show the individual fits for the 50th-percentile values. The 84th-percentile values were fit similarly. 

Table B-4 summarizes the intake rates for the 50th- and 84th-percentile values. The GSDs were 

determined as described for the type F intake rates.

Figures B-7 and B-8 show the 50th- and 84th-percentile predicted excretion rates, respectively, from 

all type S intakes.

● quarterly bioassay value 

___ fit

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● quarterly bioassay value 

● not used in fit

___ fit

Figure B-5. 50th-percentile uranium urinalysis data used to estimate intakes of type S uranium 

occurring June 1, 1952, to March 31, 1980. 

● quarterly bioassay value 

● not used in fit

___ fit

Figure B-6. 50th-percentile uranium urinalysis data used to estimate intakes of type S uranium 

occurring April 4, 1980 to December 31, 1988.

Table B-4. Type S uranium intake periods and rates.

Start date Stop date

Uranium intake rate (Bq/d)

50th percentile 84th percentile GSD

6/1/1952 3/31/1980 51.45 138.3 2.69

4/1/1980 12/31/1988 18.91 59.11 3.13

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Figure B-7. Predicted 50th-percentile urinary excretion of type S uranium from 1952 to 1988 based 

on two independent intakes, compared with bioassay data.

Figure B-8. Predicted 84th-percentile urinary excretion of type S uranium from 1952 to 1988 based 

on two independent intakes, compared with bioassay data.

B.5 ASSIGNMENT OF INTAKES AND DOSES

B.5.1 Intake Rate Summary

A summary of uranium intake rates and GSDs for periods from 1952 to 1988 is presented in Tables 

B-5, B-6, and B-7 for type F, M, and S material, respectively. These tables include potential intakes 

that may have occurred as early as June 1, 1952. When calculating doses to individuals from their 

own bioassay data, a GSD of 3 is assigned to account for biological variation and uncertainty in the 

● not used in fit

___ 2-intake estimate

● not used in fit

___ 2-intake estimate

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● not used in fit

___ 2-intake estimate
Document No. ORAUT-TKBS-0019-5 Revision No. 03 Effective Date: 08/24/2012 Page 42 of 45

models. Therefore, a minimum GSD of 3 is assigned to the coworker intake distribution. Any 

calculated GSD less than 3 is adjusted upwards to 3.

The 50th-percentile intakes were used to calculate 95th-percentile intakes based on the following 

methodology:

95th-percentile intake = 50th-percentile intake × GSD1.645

The tables listing the 50th- and 95th-percentile intakes are the values the dose reconstructor should 

use when assigning coworker intakes. The 50th-percentile intakes are assigned as a lognormal 

distribution with the associated geometric standard deviation (GSD) listed in each table. The 95thpercentile intakes are assigned using a constant distribution.

Generally speaking, the 50th-percentile coworker intakes are adequate to reconstruct a worker’s 

unmonitored internal dose. However, there are isolated instances where a worker could be assigned 

the 95th percentile coworker intake rates. The following conditions should be met for a dose 

reconstructor to apply the 95th percentile coworker intake rates:

1) A worker does NOT have internal monitoring data or has voids in his monitoring data that 

cannot be adequately reconstructed using the available internal dosimetry data; AND

2) The worker was ROUTINELY exposed to elevated internal radiation hazards. (This may be 

determined by dosimetry records, telephone interviews, and/or DOE/DOL records.)

Table B-5. Type F uranium intake periods and rates.

Start date Stop date

Uranium intake rate (Bq/d)

GSD

95th

percentile

(Bq/d)

50th

percentile

84th

percentile

6/1/1952 3/31/1980 1.11 3.05 3 6.8

4/1/1980 12/31/1988 0.279 0.862 3.1 1.8

Table B-6. Type M uranium intake periods and rates.

Start date Stop date

Uranium intake rate (Bq/d)

GSD

95th

percentile

(Bq/d)

50th

percentile

84th

percentile

6/1/1952 3/31/1980 4.53 12.42 3 27.6

4/1/1980 12/31/1988 1.07 3.35 3.1 6.9

Table B-7. Type S uranium intake periods and rates.

Start date Stop date

Uranium intake rate (Bq/d)

GSD

95th

percentile

(Bq/d)

50th

percentile

84th

percentile

6/1/1952 3/31/1980 51.45 138.3 3 313.5

4/1/1980 12/31/1988 18.91 59.11 3.1 121.6

B.5.2 Contribution from Contaminants in Recycled Uranium

Throughout the DOE complex, spent fuel from fission reactors has been processed to recover 

uranium for recycling. Because the uranium streams at PGDP could have contained recycled 

uranium, the dose from the added constituents, including plutonium, 237Np, and 99Tc, must be 

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included. See Section 5.2 of this TBD for information about intake values in relation to the uranium 

intake amounts. 

B.5.3 Dose Assignment

For most cases, individual doses should be calculated from the 50th-percentile intake rates. For 

cases in which the 50th-percentile intake rates are not appropriate as discussed above, dose 

reconstructors should use the 95th-percentile intake rates applicable to the solubility class of material 

that are provided in Table B-5, B-6, or B-7. Dose reconstructors should select the material type that is 

the most favorable to claimants. A comparison of the intake rates shows that the intake rate 

substantially increases as the material solubility decreases. However, because lower solubility 

materials remain in the lungs for longer periods, while higher solubility materials are transferred to the 

systemic organs, it is necessary to compare the annual doses on a case-by-case basis to determine 

which will deliver the larger dose to the organ of interest. Recycled uranium contaminants, when 

appropriate for the period, are a factor in this comparison.

The lognormal distribution is selected in the Interactive RadioEpidemiological Program (IREP), with 

the calculated dose entered as Parameter 1 and the associated GSD as Parameter 2. The GSD is 

associated with the intake, so it is applied to all annual doses determined from the intake period. If 

the 95th-percentile intakes are used, they are assigned as a constant distribution.

Coworker intakes can be extended out to later years if needed. However, the vast majority of PGDP

employees with a potential for radiological exposure are likely to have been monitored in recent years.

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The purpose of the following examples is to give the dose reconstructor a general idea of the types of 

job categories, work activities, and work locations for which internal dose assignment might be 

necessary.

Examples of job categories that might have little or no potential for workplace internal 

exposures:

Administrator Draftsman Program analyst 

Assistant Groundskeeper Programmer 

Business systems specialist Instructor Radio operator 

Cafeteria worker Manager Recruiter 

Checker Medical technician Scheduler 

Clerk Office supervisor Secretary 

Computer specialist Planner Telephone operator 

Dispatcher Quality assurance specialist

Assignment of environmental internal dose might be appropriate for the job categories listed above on 

a case-by-case basis (ORAUT 2004b).

Examples of job categories that generally have some potential for workplace internal 

exposures depending on job specifics:

Biologist Foreman Patrolman 

Boilermaker Foundry worker Photographer 

Bricklayer Heavy equipment operator Scientist 

Carpenter HP analyst Security guard 

Construction worker Instrument mechanic Specialist 

Driver Insulator Storekeeper 

Electrician Ironworker Supervisor 

Electronics technician Janitor Surveyor 

Engineer Laborer Technician 

Equipment operator Mechanic 

Firefighter Painter 

Examples of job categories that probably have some potential for workplace internal 

exposures:

Analytical chemist Material handler Radiation monitor 

Assembly worker Metallurgist Radiochemist 

Chemical operator Millwright Reactor operator 

Fabricator Pipefitter Steamfitter 

Glovebox worker Plumber Waste handler 

HP technician Processor Welder 

Machinist Production worker 

In general, job categories that had increased potential for exposures from external radiation were 

similar to those for internal radiation. The jobs and tasks that appear to involve the greatest potential 

for radiation exposure included ash handling (Building C-410), cylinder heel cleaning (Building C-400), 

derby processing (Building C-340), pulverizer operations (Building C-400), certain maintenance 

operations on the fluorination towers (Building C-410), maintenance on cascade equipment 

(cascades), cleaning of air filters (baghouses for Buildings C-400, C-410, C-420, and C-340), 

converter maintenance (Building C-720), flange grinding (Buildings C-340, C-400, C-410, and C-420), 

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maintenance of the hydrogenation towers (Building C-340), and decontamination building cleaning 

operations (Building C-400). Jobs and tasks classified as having moderate potential radiation 

exposures include cascade operators and instrument mechanics (cascades), green salt sweeping 

(Buildings C-410 and C-420), disassembly of compressor (Building C-720), disassembly of block 

valves (Building C-720), drumming of green salt (Building C-340), and baghouse cleaning for 

cascades (Buildings C-310 and C-315). Other jobs and tasks had lower potential for worker radiation 

exposure. In addition, due to the lack of aggressive contamination control programs, contamination 

from the operations discussed above presented potential exposures to surrounding work areas. 

Further, legacy contamination generated from these operations could have posed a potential radiation 

exposure to individuals with access to the PGDP site in later years (PACE and University of Utah 

2000).

 Table C-1. History of significant incidents and events.

a

Incident date Incident description Facility

1952–1990 Exposure to UF4, UO, and process dust 

during guard patrolling

All buildings

1952–1980 Exposure to uranium metal

July 1953 First use of reactor tails

November 1956 Fire C-310

1957–1977 Green salt, black oxides on floors and 

other surfaces

C-340

December 1962 Fire C-337

April 1968 Worker overexposure Unknown

January 1978 Fire C-315

1958 to 1962 CIP C-331, C-333, 

C-335, and C-337

1974 to 1982 CIP/CUP C-331, C-333, 

C-335, and C-337

Neptunium production C-400

1980 to 1982 Exposure to UF4 and uranium dust during 

drum crushing

C-746

a. Additional incident information can be found in Pace and University of Utah 2000 and

 BCJ 2000.

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