ORAU TEAM

Dose Reconstruction

Project for NIOSH

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

Page 1 of 43

Document Title:

Pantex Plant – Occupational Environmental Dose

Document Number: ORAUT-TKBS-0013-4 

Revision: 01

Effective Date: 06/22/2007

Type of Document: TBD

Supersedes: Revision 00

Subject Expert(s): Daniel J. Strom and Robert C. Winslow

Site Expert(s): Dillard B. Shipler

Approval: Signature on File Approval Date: 05/05/2007

John J. Fix, Document Owner

Concurrence: Signature on File Concurrence Date: 05/28/2007

John M. Byrne, Task 3 Manager

Concurrence: Signature on File Concurrence Date: 05/29/2007

Edward F. Maher, Task 5 Manager

Concurrence: Signature on File Concurrence Date: 05/31/2007

Kate Kimpan, Project Director

Approval: Brant A. Ulsh Signature on File for Approval Date: 06/22/2007

James W. Neton, Associate Director for Science

 New Total Rewrite Revision Page Change

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

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 2 of 43

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

08/24/2004 00 New technical basis document for the Pantex Plant – Occupational 

Environmental Dose. Incorporates internal review and NIOSH 

comments. Incorporates additional internal review and NIOSH 

comments. First approved issue. Initiated by Dillard B. Shipler.

06/22/2007 01 Revised to include Attributions and Annotations. Constitutes a total 

rewrite of the document. Incorporates formal internal review 

comments. No changes were needed as a result of formal NIOSH 

review. This revision results in no change to the assigned dose and 

no PER is required. Initiated by John J. Fix.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 3 of 43

TABLE OF CONTENTS

SECTION TITLE

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

PAGE

5

4.1 Introduction................................................................................................................................. 7

4.1.1 Purpose........................................................................................................................8

4.1.2 Scope...........................................................................................................................8

4.2 Internal Dose from Onsite Atmospheric Radionuclide Concentrations......................................... 8

4.2.1 Onsite Releases to Air................................................................................................10

4.2.1.1 Tritium.......................................................................................................... 15

4.2.1.2 Uranium ....................................................................................................... 15

4.2.1.3 Plutonium..................................................................................................... 16

4.2.1.4 Thorium........................................................................................................ 16

4.2.2 Rationale for Showing that Organ Doses Due to Intakes of 

Environmental Levels of Radionuclides at Pantex ARE Negligible.............................. 16

4.2.2.1 Negligible Individual Dose Level................................................................... 16

4.2.2.2 Evidence that Onsite Airborne Uranium and Thorium Levels 

Are Mostly of Natural Origin ......................................................................... 16

4.2.2.3 Upper 95% Confidence of the Mean Net Concentration ............................... 17

4.2.2.4 Dose Coefficients......................................................................................... 18

4.2.2.5 Criteria for Determining that Maximum Credible Intakes Lead 

to Doses Less than 10 μSv to Most Highly Dosed Tissue or 

Organ........................................................................................................... 19

4.2.3 Annual Intakes from Resuspension ............................................................................22

4.3 External Dose ...........................................................................................................................22

4.3.1 Ambient Radiation ......................................................................................................22

4.4 Uncertainty................................................................................................................................26

4.5 Attributions and Annotations ..................................................................................................... 27

References ........................................................................................................................................33

Glossary ............................................................................................................................................38

ATTACHMENT 4-A, RADIONUCLIDE INTAKE AND OCCUPATIONAL EXPOSURE ....................... 42
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 4 of 43

LIST OF TABLES

TABLE TITLE

4-1 Annual releases to atmosphere..............................................................................................

PAGE

11

4-2 Maximum values of 95% upper confidence intervals of means or net 

means....................................................................................................................................18

4-3 Dose conversion coefficients and air concentrations leading to 10 μSv for 

3

H, 232Th, 234U, and 239Pu........................................................................................................ 19

4-5 Climatological data for 2000 by month ................................................................................... 24

4-6 Calculated difference between onsite and offsite annual doses for the 

Pantex plant...........................................................................................................................26

4A-1 References for maximum air concentrations for tritium (oxidized), thorium, 

uranium, and plutonium used in Section 4.2.2 dose analyses ................................................ 43

4A-2 Upwind “control” (location OA-AR-13) average annual air concentration................................ 43

LIST OF FIGURES

FIGURE TITLE

4-1 Pantex Plant site ......................................................................................................................

PAGE

9

4-2 Isotopic contributions to offsite dose from Pantex operations in 2000 .................................... 10

4-3 Air monitoring stations in 2000 ............................................................................................... 13

4-4 Employment history................................................................................................................14

4-5 Pantex 238U and thorium mean environmental air monitoring data for 2000 

at seven locations ..................................................................................................................17

4-6 Pantex 238 U and thorium mean environmental air monitoring data 

(historic) at seven locations.................................................................................................... 17

4-7 IMBA equivalent dose to four tissues or organs per unit intake during 

each year for 1-μm AMAD Type W 232Th inhalation................................................................ 20

4-8 IMBA equivalent dose and average equivalent dose to bone surfaces per 

unit intake during each year for 1 μm AMAD Type W 232Th inhalation.................................... 21

4-9 MBA annual equivalent dose to bone surfaces for 10, 20, 30, 40, and 50-

year inhalation intakes of 1 Bq per year of 1 μm Type W 232Th............................................... 21

4-10 Wind rose for 2000................................................................................................................. 23

4-11 Locations of thermoluminescent dosimeters in 2000.............................................................. 25

4-12 Ambient dose rates for Pantex Plant ...................................................................................... 26
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 5 of 43

ACRONYMS AND ABBREVIATIONS

AMAD activity median aerodynamic diameter

ASER Annual Site Environmental Report

Bq Becquerel

Ci curie

CDC Centers for Disease Control and Prevention

CEDE committed effective dose equivalent

CY calendar year

DOE U.S. Department of Energy

DU depleted uranium

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

EH environment, safety, and health (DOE)

EDE effective dose equivalent

EPA U.S. Environmental Protection Agency

FD fenceline dosimeter

FL fenceline

FS firing site

g gram

GM Geiger-Mueller

h hour

3

H tritium

HE high explosive

ICRP International Commission on Radiological Protection

IMBA Integrated Modules for Bioassay Analysis (program)

m meter

mrem millirem

mL milliliter

mph miles per hour

NCRP National Council on Radiation Protection and Measurements

NIOSH National Institute for Occupational Safety and Health

OCAS Office of Compensation and Support

OD onsite dosimeter

OS off-site

PD onsite dosimeter

POC probability of causation

RBM red blood marrow

rem unit of radiation dose
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 6 of 43

Sv sievert

TBD to be determined

TBq terabecquerel

TLD thermoluminescent dosimeter

U.S.C. United States Code

yr year

μ micro, 10-6

§ section or sections
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 7 of 43

4.1 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

As noted above, the statute includes a definition of a DOE facility that excludes “buildings, structures, 

premises, grounds, or operations covered by Executive Order No. 12344, dated February 1, 1982 

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

While this definition contains an exclusion with respect to the Naval Nuclear Propulsion Program, the 

section of EEOICPA that deals with the compensation decision for covered employees with cancer 

[i.e., 42 U.S.C. § 7384n(b), entitled “Exposure in the Performance of Duty”] does not contain such an 

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

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

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

external dosimetry monitoring results are considered valid for use in dose reconstruction. No efforts 

are made to determine the eligibility of any fraction of total measured exposure for inclusion in dose 

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

derived:

] guidelines established under 

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

guidelines (nor the dose reconstruction regulation) define “performance of duty” for DOE employees 

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

• Radiation from naturally occurring radon present in conventional structures

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

 

1 The U.S. Department of Labor is ultimately responsible under the EEOICPA for determining the POC. 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 8 of 43

4.1.1

The purpose of this TBD is to describe the Pantex Plant occupational environmental doses. The Oak 

Ridge Associated Universities (ORAU) Team will use this information as needed to evaluate 

environmental doses for EEOICPA claims. 

Purpose

4.1.2

Pantex operations have played an important role in the U.S. nuclear weapons program. Historically, 

Pantex provided several roles associated with the assembly, disassembly, retrofit, and modification of 

nuclear weapon systems (Mitchell 2003). Today, Pantex continues to fabricate high explosives and to 

assemble nuclear weapons. The principal operations at this site, however, are the dismantling of 

retired nuclear weapons and the maintenance of the nation’s nuclear weapons stockpile. Pantex, 

which is operated by DOE’s Office of Defense Programs, is the only facility in the United States that 

performs these operations.

Scope

The occupational environmental dose is the dose received by workers on the site but outside facilities. 

This dose can be internal and external depending on the characteristics of the individual 

radionuclides. Radionuclides present at the Pantex Plant include tritium, uranium, plutonium, and 

thorium. Pantex neither uses or releases noble gases (BWXT Pantex 2001). While most inhaled 

radionuclides would give a dose to particular organs in the body, tritium gas would give a dose to the 

whole body. The following sections discuss radionuclides present at Pantex.

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

justification, or clarification of the associated information, are presented in Section 4.5. 

4.2 INTERNAL DOSE FROM ONSITE ATMOSPHERIC RADIONUCLIDE 

CONCENTRATIONS

The internal dose to workers outside facilities is determined from air concentrations that resulted from 

individual facility releases, ground-level releases (e.g., burning activities), and the resuspension of 

radioactive materials in soil. Unmonitored workers could have received internal or external 

occupational doses (or both) from any or all of these sources. Figure 4-1 shows the major areas of 

the Pantex Plant site. 

To determine the offsite effective dose equivalent from airborne releases, Pantex used the U.S. 

Environmental Protection Agency (EPA)-approved CAP88-PC computer model to evaluate the 

radiological dose that a member of the public could receive during the year (BWXT Pantex 2001, 

pp. 4-5). Figure 4-2 shows the percent contributions to dose that resulted (BWXT Pantex 2001). The 

results indicate the importance to dose of the various radionuclides involved in Pantex operations.

The analysis encompassed all potential environmental pathways for radioactive material released to 

the air. The source terms for releases to air result from process knowledge, the number of operations 

during the year, and other modifying factors. The source terms represent the maximum possible 

release from a point (stack or vent), an area, or both. Actual releases to the air were much less than 

the maximum estimates, which are essentially the minimum limits of monitoring or detection 

equipment. The total estimated releases and monitoring data from the site were available, but not 

specific source terms [1]. 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 9 of 43

Figure 4-1. Pantex Plant site (BWXT Pantex 2001). 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 10 of 43

Figure 4-2. Isotopic contributions to offsite dose from Pantex operations in 2000 (BWXT Pantex 

2001). 

4.2.1

Information on releases of radionuclides from Pantex facilities during the Plant’s operating period from 

1952 through 2000 was obtained from several sources, including Environmental Monitoring Reports 

(EMRs), Annual Site Environmental Reports (ASERs)(Alexander 1974, 1975, 1976, 1977; Alexander, 

Cornelius, and Horton 1978; Alexander and Cornelius 1979, 1980; Alexander and Laseter 1981; 

Laseter 1982, 1983, 1984, 1985, 1986, 1987; Laseter and Langston 1988, 1989; MHSMC 1990, 1991; 

BP and MHMSC 1992, 1993, 1994, 1995; DOE 1996, 1997; BP and MHC 1998; DOE 1999, 2000; 

BWXT Pantex 2001, 2002, 2003), annual summaries of radiological doses and releases reported to 

DOE (DOE 1982, 1984, 1992, 1994; BMI 1985, 1988, 1990a,b; PNL 1993; PNNL 1997a,b), radiation 

safety department incident records (MHSMC 1986), and radiation safety department technical basis 

manuals (Pantex 2002). Table 4-1 summarizes releases to the atmosphere from plant vents. EMRs 

and ASERs contain air release and soil monitoring data, and thermoluminescent dosimeter (TLD) 

monitoring data from on and off the site. Figure 4-3 shows air sampler locations. 

Onsite Releases to Air

A review of the references determined that the monitoring data are representative for assessing dose. 

The analysis considered the release and monitoring data, coupled with understanding of historical 

meteorology (Snyder 1993), to be adequate estimates of radionuclide-specific airborne concentrations 

for 3

H, 238Pu, 239/240Pu, 233/234U, and 238U. The uranium used in weapons at Pantex is depleted uranium 

(DU) that consists primarily of 238U and small amounts of 234U, 235U, and 236U, all of which are alpha 

particle emitters with long half-lives (BP 1992, Chapter 5). The 235U is about 1% of the total activity in 

DU [2]. Because 233U and 234U cannot readily be chemically separated, they are measured and 

reported together. In reality, there is no 233U on the Pantex Plant [3]. Though small quantities of 232Th 

were released from Pantex facilities, “monitoring of 232Th was not consistent because the releases 

were small and contributed little to dose, as well as that 232Th is a naturally occurring form of the 

element” (BWXT Pantex 2001). Total employment on the site is shown in Figure 4-4. Many 

employees in early years were not badged indicating the need for assessing missed or unmonitored 

dose (Prather 2003).
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 11 of 43

Table 4-1. Annual releases (curies) to atmosphere. 

Year Tritium

Total 

uranium

Total 

plutoniuma All others Reference

1981 9.5E-02 1.0E-05 -- -- DOE 1982

1983 5.0E-02 1.0E-05 -- -- DOE 1984

1984 1.2E-04 -- -- -- BMI 1989

1985 -- -- --

1986 1.3E-01 1.0E-05 -- -- BMI 1988

1987 9.6E-02 -- -- -- BMI 1990b

1988 1.2E-01 -- -- -- BMI 1990a

1989 4.0E+04 2.1E-05 -- -- PNL 1993

1990 2.55E+03 -- MHSMC 1991

1991 1.7E-01 -- -- -- DOE 1992

1992 1.3E-01 -- -- 3.5E-07 DOE 1994

1993 3.0E-01 -- -- -- BP and 

MHSMC 1994

1994 4.46E-01 -- -- -- BP and 

MHSMC 1995

1995 1.0E-01 -- -- -- DOE 1996

1996 1.3E-01 1.46E-04 -- 1.67E-17 232Th DOE 1997

1997 1.17E-01 1.32E-04 1.27E-09 232Th BP and MHC 

1998

1998 5.34E-02 1.78E-04 -- 1.59E-08 232Th DOE 1999

1999 1.58E+00 6.97E-05 -- 7.14E-07 232Th DOE 2000

2000 2.71E+00 6.73E-07 -- 2.76E-07 232Th, 

3.28E-06 All other 

radionuclides

BWXT 2001

a. = no releases.

It was assumed that monitoring data, particularly air monitoring data would be appropriate for dose 

reconstruction and account for resuspension of radionuclides in soil, particularly, monitoring data 

would account for the accumulation of long-lived radionuclides in soil during the life of the Plant. In 

addition, the occurrence of radioactive materials on site was time-related, as follows:

From 1958 to 1979, the primary operation at Pantex was weapons assembly (Mitchell 2003). Some 

component testing was performed. A small number of weapons were disassembled for testing and 

quality control. 

Radioactive materials began arriving at Pantex 1951 (Martin 2004). 

− In 1951, DU began arriving as new, bare metal forms (Martin 2004). 

− In 1956, tritium began arriving in sealed containers (Martin 2004).

− In 1958, plutonium began arriving in sealed metal forms (Martin 2004).

− Thorium began arriving at the plant as new, bare metal forms in the 1960s (Martin 2004). 

• From 1952-1958, the only operation at Pantex was weapons assembly (Martin 2004).

− No tritium containers were manipulated, so no tritium was released [4]. 

− No metal oxides formed or burned, so no metal oxides were released [5].

− No testing involving radioactive material was performed [6]. 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 12 of 43

− Small amounts of tritium were released when weapons were disassembled [7]. 

− There are no specific data to substantiate specific releases of tritium prior to 1972 [8]. 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 13 of 43

Figure 4-3. Air monitoring stations in 2000 (BWXT Pantex 2001).
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 14 of 43

Figure 4-4. Employment history (Mitchell 2003). 

− Some DU was released at the burning grounds with the burning of high-explosive (HE) 

components (ORAUT 2006a). 

− Some DU was released at the firing sites when HE firings involved DU components 

(ORAUT 2006a).

− Starting in 1958, all assembly and disassembly operations were on complete sealed-pit 

weapons (Mitchell 2003).

• From 1980 to 1990, disassembly of weapons was performed more often than assembly (DOE 

2001a).

• From 1990 to the present, the primary operation at the plant has been large-scale disassembly 

of weapons (DOE 2001a).

• Though 238Pu has been part of the monitoring program in recent years, the monitoring was to 

establish background concentrations in anticipation of a program that would have involved 

238Pu. However, that program never started and 238Pu was never on the Pantex Plant (Griffis 

2004).

It is evident from this information that operations that could lead to releases of radioactive materials 

were limited until about 1980 [9]. Table 4-1 lists site release data from 1981. Although operations 

have increased with time and employment, releases from operations have been relatively stable and 

remain small. As a result, atmospheric dispersion modeling was deemed unnecessary [10]. This 

selection was based on the maturity of the monitoring program, the technical level of analytical 

techniques, and the application of quality programs [11]. In other words, these are the best available 

data.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 15 of 43

Considering time-related production, time-related availability of radioactive materials on the site, and 

the small concentrations of radioactive materials in the air and soil when releases of radioactive 

materials could have occurred after 1980, initial analyses of potential intakes and resulting doses led 

the authors to believe that potential doses from intakes would be negligible [12]. Additional guidance 

for evaluation of potential intake based on the type of worker and location is provided in the 

Occupational Internal Dose section of the Pantex site profile (ORAUT 2007).

4.2.1.1 Tritium

Tritium is one of the principal nuclear materials used at the Pantex Plant. It is the heaviest and only 

radioactive isotope of hydrogen, with a physical half-life of 12.35 years. Nuclear operations involving 

tritium have occurred at Pantex since 1956. 

Tritium comes to Pantex in sealed containers that are placed into nuclear assemblies without being 

opened. Therefore, no tritium releases occur during normal assembly operations. Small amounts of 

tritium (a few microcuries per unit) are routinely released during disassembly operations [13]. 

A major unplanned accident that resulted in a tritium release occurred at Pantex on May 17, 1989, 

when a conservatively estimated 40,000 Ci were released in a Gravel Gertie cell (ORAUT 2007). It 

was assumed that all the tritium leaked from the cell and the building within 12 days; doses were 

estimated for that period. The estimated potential individual whole body-dose was 1.43 mrem at the 

closest downwind fenceline (MHSMC 1990). The estimated maximum individual onsite dose in the 

downwind direction, NNE, was about 10 times the fenceline dose (MHSMC 1990). Therefore, use a 

15-mrem dose to the whole body for a worker in the area during that period [14]. 

At the beginning of 1990, an estimated 2,550 Ci of tritium residual remained trapped in the walls and 

gravel overburden of the cell in which the 1989 release occurred (MHSMC 1991). The analysis 

conservatively assumed that this entire amount was released to the atmosphere during 1990. The 

estimated maximum individual onsite dose in the downwind direction (NNE) was 1.0 mrem. Use this 

value for a worker in the area during that period [15]. 

4.2.1.2 Uranium

Uranium arrives at Pantex as a metal (DU, primarily 238U), uncoated and unsealed (Martin 2004). 

Uranium oxidizes fairly readily in air. When aged weapons are dismantled for inspection, 

refurbishment, or disassembly, significant amounts of uranium-oxide powder can be associated with 

the parts with which it has come in contact [16]. One of type of part is HE that generally is destroyed 

by burning. During the burning, associated powdered uranium is released to the atmosphere 

(ORAUT 2007). 

The alpha-emitting radionuclides of this uranium represent a potential radiological risk if inhaled. 

Isotopes measured to be present include 233/234U and 238U. For dose reconstruction, assume that 234U,

the isotope that results in the maximum organ dose, is present at 100%. This assumption would 

result in a small, but favorable to claimant, overestimation of the actual dose (BWXT Pantex 2001).

The only unplanned release of uranium occurred on January 10, 1986, when exhaust fans were 

inadvertently turned on and off several times following a test detonation at Firing Site 23. This action 

resulted in the release of particulate material containing depleted uranium (BWXT Pantex 2004). All 

personnel in the area were upwind (NE at that time) of the release point. The release lasted a short 

time (1 to 2 minutes) (BWXT Pantex 2004). The curie activity of this release was not monitored and
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 16 of 43

soil samples could not determine event deposition because previous uncontained test shots had 

contaminated the area around the Firing Site (MHSMC 1986).

4.2.1.3 Plutonium

Plutonium concentrations are very low (e.g., around 0.01-0.02 μBq/m3

) and can probably be

accounted for by fallout from atmospheric testing, because plutonium arrives at Pantex as sealed pits, 

which preclude oxidation or other means of dispersal (BWXT Pantex 2001). Even when aged 

weapons are dismantled for inspection or refurbishment, plutonium is not available in a form for 

release [17]. 

4.2.1.4 Thorium

Thorium releases to the atmosphere have not been routinely monitored as have uranium, plutonium, 

and tritium (BWXT Pantex 2001), although monitoring for thorium has been a component of the 

Pantex Plant Environmental Monitoring Program (at least in air and soil since about 1998). Although 

thorium arrives at the Plant as an uncoated and unsealed metal, it does not oxidize readily. Even 

when aged weapons are dismantled for inspection or refurbishment, little or no thorium is available in 

a form for release. Any thorium released would likely be ThO2 and International Commission on 

Radiological Protection (ICRP) clearance Type S (ICRP 1996) [18]. 

4.2.2

4.2.2.1 Negligible Individual Dose Level

Rationale for Showing that Organ Doses Due to Intakes of Environmental Levels of 

Radionuclides at Pantex ARE Negligible

The National Council on Radiation Protection and Measurements (NCRP) has defined a negligible 

individual effective dose as 10 μSv (1 mrem) per year (NCRP 1993). It follows that an annual dose to 

an organ or tissue that is 10 μSv (1 mrem) or less is also negligible. Furthermore, a committed dose 

of 10 μSv (1 mrem) or less to an organ or tissue from intakes during a year is also negligible. If it can 

be shown that airborne concentrations of radionuclides measured in the Pantex environment are 

negligible in the sense that they produce negligible doses using these criteria, then no effort need be 

expended to assess them [19]. 

4.2.2.2 Evidence that Onsite Airborne Uranium and Thorium Levels Are Mostly of Natural 

Origin

Of the four principal radionuclides measured in the air at Pantex, 232Th and uranium occur naturally, 

while 3

H and plutonium do not occur in significant quantities in nature (BWXT Pantex 2001). A 

concentration from which a background or control value has been subtracted is called a net 

concentration. Because nonzero concentrations of 232Th and uranium are observed off the site due to 

natural sources not related to Pantex operations, it is logical to subtract such “control” values from 

observations at the Plant. Thorium and uranium emissions from Pantex operations are unlikely to 

have temporal correlation with each other because they arise from different campaigns. The 

observation that uranium air concentrations at a given sampler location are strongly correlated with 

thorium air concentrations at that location supports the hypothesis that much of the uranium and 

thorium is due to uranium and thorium in local dust, not to uranium and thorium released by Pantex 

operations. These correlation coefficients (r

2

) are 0.854 for the 2000 means and 0.895 for the historic 

means, with seven data pairs contributing to each, as shown in Figures 4-5 and 4-6, respectively.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 17 of 43

Pantex Environmental Air Monitoring Data 

for CY 2000; r^2 = 0.854

0

0.5

1

1.5

2

2.5

3

0 0.5 1 1.5 2 2.5 3

Th Mean (Bq/m3)

U Mean (Bq/m3) .

U Mean

y=x

Fit

Pantex Environmental Air Monitoring Data 

Historical Means; r^2 = 0.895

0

0.5

1

1.5

2

2.5

3

0 0.5 1 1.5 2 2.5 3

Th Historical Mean (Bq/m3)

U Historical Mean (Bq/m3) 

U Hist Mean

y=x

Fit

Figure 4-5. Pantex 238U and thorium mean 

environmental air monitoring data for 2000 at 

seven locations (BWXT Pantex 2001). 

Figure 4-6. Pantex 238 U and thorium mean 

environmental air monitoring data (historic) at 

seven locations (BWXT Pantex 2001). 

A further argument that all or virtually all of the uranium on Pantex air samples is of natural origin is 

the isotope ratio of 233/234U to 238U. For 2000, this ratio is 1.007 +0.037 (1 standard deviation), and for 

the historical data it is 0.981 +0.086 (1 standard deviation). If the uranium were DU from the vast 

majority of Pantex uranium operations, the ratio would be 0.127 (DOE 2001b). The expected value of 

this ratio is 1.000 for natural uranium, in which 234U is in secular equilibrium with 238U and their 

activities are equal.

The credible upper bound concentrations to which workers could have been exposed in a year are 

equal to the upper 95% confidence of the mean net concentration [20]: 

,95. .. net mzx cred = CC [21] (1)

A worker performing light work breathes 1.2 m3 of air per hour. Assuming a 2,000-hour work year, the 

worker takes in the radioactive material in 2,400 m3 during a year. The credible upper bound intake is 

thus

,2 400 ,95. 3

.. net Imzx cred = ×Cm (2)

4.2.2.3 Upper 95% Confidence of the Mean Net Concentration

Environmental data for Pantex referenced in Attachment 4A, Table 4A-1, was used to calculate the 

values in Equation (1). The standard error of a value is related to the standard deviation by the 

reciprocal of the square root of the number of measurements:

. . .( ) . .( )

n

CDS CES = (3)

The upper 95% confidence level of the mean is the mean increased by adding the standard normal 

deviate for 0.95; that is, 1.645 times the standard error of the mean, so that 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 18 of 43

95 CC .1 645 ×+= . .(CES ). (4)

The upper 95% confidence level of the mean net concentration (assuming the same number of 

measurements was made of each) is

( 1) .645 .{ .( )} .{ .( )} .

( .1) 645 . .( )

2 2

95,

background background

net background background

CC CESCES

CCC CCES

−= ×+ +

−= −×+

(5)

The maximum values for thorium and uranium, the two elements for which net concentrations are 

needed, are listed in Table 4A-1, as are the references for the maximum value for plutonium and 3

H.

The observed 95% upper confidence intervals of the net means were calculated for Pantex for 

calendar year 2000 and for historical means. For the latter, it was necessary to estimate the standard 

error of the mean because the standard deviations for the historic data are not given. The standard 

deviation of the population of means was assumed to be a reasonable estimate of the standard error 

of the mean of an individual measurement. Table 4-2 lists the greatest onsite (that is, “onsite” or 

“fenceline” but not “offsite”) values [22]. 

Table 4-2. Maximum values of 95% upper confidence intervals of means or net means (BWXT 

Pantex 2001). 

Nuclide Location

Historical mean 

or CY 2000

Maximum value of upper 95% 

confidence interval (μBq/m3) Type

H-3 Onsite PA-AR-06 Historical mean 819,663 Mean

Th-232 Fenceline FL-AR-10 CY 2000 2.21 Net mean

U-233/234 + U-238 Fenceline FL-AR-10 Historical mean 4.97 Net mean

Pu-239/240 Fenceline FL-AR-10 Historical mean 0.137 Mean

4.2.2.4 Dose Coefficients

The ICRP has published, and the Integrated Modules for Bioassay Analysis (IMBA) computer 

program calculates, “dose coefficients” in units of Sv/Bq. These coefficients are the committed 

equivalent dose2

The intake that leads to a dose D or HT for various dose coefficients is

, HT(τ), in organ or tissue T per unit intake hT(τ), where τ is the integration time in 

years following the intake. The integration time τ is 50 years for the Reference Worker. Dose 

coefficients depend on radionuclide, intake route (e.g., inhalation or ingestion), particle size (e.g., 1 or 

5 μm), transportability class (e.g., S, M, F), as well as the selection of biokinetic models. The most 

favorable to claimant assumptions about dose coefficients are those that result in the highest dose per 

unit intake. 

.

)(

)( )(

τ

τ

T

T

h

H

dose coefficient

D DI = = (6)

The concentration that leads to a dose D or HT for various dose coefficients is

 

1

NIOSH does not use committed equivalent dose in its dose reconstructions for probability of causation calculations. This 

quantity is introduced here as a simple bounding value to establish that airborne concentrations are too small to result in 

significant annual dose to a tissue or organ. If a committed dose value is not exceeded, an annual dose value will never be 

exceeded.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 19 of 43

. ))()(400,2(

)(

)(400,2(400,2 )

)( )( 3 3 3 τ

τ

T

T

hm

H

dosem coefficient

D

m

DI DC = = = (7)

Substituting 10 μSv for HT in the above equation gives

. ))()(400,2(

10 )10( 3 τ

μ μ hm TSv SvC = (8)

Selecting the greatest value of hT(τ) for each element, for example, thorium, uranium, or plutonium, 

intakes results in specifying values of particle size, transportability class, and radionuclide for each 

element that give “worst-case” (i.e., favorable to claimant) results; that is, the lowest concentration of 

a radionuclide that results in 10 μSv committed equivalent dose to an organ or tissue following a 

year’s breathing of that concentration in air.

If the observed Cnet,95 is less than the concentration calculated from the previous equation, 

environmental doses from that radionuclide are negligible and need not be calculated.

If the observed Cnet,95 is greater than the concentration calculated in the previous equation, annual 

equivalent doses should be examined to determine if these, when combined over the individual’s 

exposure history, result in more than 10 μSv to the tissue in any one year.

4.2.2.5 Criteria for Determining that Maximum Credible Intakes Lead to Doses Less than 10 

μSv to Most Highly Dosed Tissue or Organ

Table 4-3, Dose conversion coefficients and air concentrations leading to 10 μSv for 3

H, 232Th, 234U, 

and 239Pu, lists the air concentrations that would lead to 10 μSv committed equivalent dose, as 

calculated with IMBA. The table lists the tissues or organs receiving the highest HT(τ). These values 

are from ICRP Publication 71 for 232Th (ICRP 1996). If the 95%ile concentrations are below these 

values, the resulting doses would be below 10 μSv (1 mrem), and there is no need to reconstruct 

doses due to inhalation of environmental radionuclides. The resultant doses from the 95%ile 

concentrations are below 1 mrem for all but 232Th Type M. A discussion on why Pantex 232Th is not 

Type M follows [23]. 

Table 4-3. Dose conversion coefficients and air concentrations leading to 10 μSv for 3

H, 232Th, 234U, 

and 239Pu (ICRP 1995). 

Nuclide Details

Organ with 

highest HT(τ)

Air concentration breathed 

for 2,000 hours leading to 

10-μSv committed 

equivalent dose (μBq/m3)

Dose from 

breathing 95%ile 

concentration

(mrem)

Tritium Water vapor Small intestine 185,000,000 0.0044

Th-232 Type M, 1 μm, f1 = 5E-4 Bone surface 1.89 1.17

Th-232 Type S, 1 μm, f1 = 5E-4 Bone surface 14.4 0.15

U-234 Type S, 1 μm, f1 = .002 Lung 59.0 0.084

Pu-239/240 Type M, 1 μm, f1 = 5E-4 Bone surface 2.85 0.048

For thorium Type M (the largest upper 95% confidence level of net mean air concentration = 2.21 

μBq/m3

), indicating that a committed equivalent dose of 117 μSv (1.17 mrem) to bone surfaces would 

accumulate for each year of exposure. However, for thorium Type S, the only plausible environmental 

form of 232Th at Pantex (the largest upper 95% confidence level of net mean air concentration = 14.4 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 20 of 43

μBq/m3), indicating that a committed equivalent dose of 1.5 μSv (0.15 mrem) to bone surfaces would 

accumulate for each year of exposure. For thorium intakes, committed equivalent dose to the red 

bone marrow is always far below 10 μSv [24]. 

Because simultaneous exposure to the observed 95% upper confidence intervals of the means or net 

means of all environmental radionuclides at Pantex never leads to a committed equivalent dose to the 

most highly dosed tissue or organ that equals or exceeds 10 μSv, there is no need to reconstruct 

doses due to environmental exposures to airborne radioactive materials at Pantex.

The quantity of interest is the dose to the tissue or organ during each year, which would have 

contributions from intakes in each prior year. Figure 4-8 shows the annual contribution to equivalent 

dose to bone surfaces per unit intake for inhalation of a 1-μm AMAD Type M 232Th aerosol. The 

greatest value occurs in year 22 following intake, and the peak value is 2.41% of the average. 

Figure 4-9 shows the equivalent dose rate to bone surfaces for 10, 20, 30, 40, and 50 years of intakes 

of 1 Bq per year of the same aerosol. Figure 4-8 is derived from the results shown in Figure 4-7 by 

summing contributions to annual equivalent dose in a given year over the various years of intake. 

Figure 4-8 shows that the annual equivalent dose rate peaks at differing intervals (28, 35, 43, 49, and 

50 years, respectively) after intake begins for different intake durations, and differing intervals (18, 15, 

13, 9, and 0 years, respectively) after intake ends for the different intake durations. 

Inhalation of 1 um Type W Th-232

1E-7

1E-6

1E-5

1E-4

1E-3

0 10 20 30 40 50

Years Since Intake

Annual Equivalent Dose per Unit Intake (Sv/Bq) 

Bone Surfaces

Lung

Red Bone Marrow

Liver

Figure 4-7. IMBA equivalent dose to four tissues or organs per unit 

intake (Sv/Bq) during each year for 1-μm AMAD Type W 232Th 

inhalation. 

The concentration that, if breathed for the duration of a worker’s employment at Pantex, would yield a 

peak annual equivalent dose of 10 μSv to bone surfaces can be deduced from the data shown in 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 21 of 43

1 um Type W Th-232 Inhalation

0

0.0001

0.0002

0.0003

0.0004

0 10 20 30 40 50

Year Following Intake

Equivalent Dose to Bone Surfaces p 

Unit Intake during Year (Sv/Bq) 

Annual Sv/Bq

50-year Average (Sv/Bq)

Figure 4-8. IMBA equivalent dose and average equivalent dose to bone 

surfaces per unit intake (Sv/Bq) during each year for 1 μm AMAD Type 

W 232Th inhalation. 

0.000

0.002

0.004

0.006

0.008

0.010

0.012

0.014

0 10 20 30 40 50 60 70 80 90 100 110

Time (Years since first intake)

Annual Equivalent Dose (Sv) 

 to Bone Surfaces .

50 y

40 y

30 y

20 y

10 y

Figure 4-9. IMBA annual equivalent dose (Sv) to bone surfaces for 10, 20, 

30, 40, and 50-year inhalation intakes of 1 Bq per year of 1 μm Type W 232Th. 

Figure 4-8. They are 6.62, 3.36, 2.30, 1.78, and 1.58 μBq/m3

, respectively, for intakes lasting 10, 20, 

30, 40, or 50 years. Thus, a worker would have to breathe the 95% upper confidence level 

concentration at location FL-AR-10 for 33 years to reach a peak annual dose rate of 10 μSv in a year, 

and for 34 or more years to exceed 10 μSv in a year to bone surfaces.

As a further measure of how this calculation tends to overestimate the dose, it is implausible that 

thorium released from Pantex operations could be Type M, because thorium was not machined or cut, 

only assembled or disassembled. Thus, the only plausible means for thorium to become airborne 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 22 of 43

would be for oxidation products to become airborne [25]. The dose factor for Type S thorium is 

2.5 × 10-5/4.5 × 10-5 = 55% of the dose factor for Type M thorium. If the thorium is type S, then even a 

50-year continuous exposure to the maximum credible concentration does not lead to an annual 

equivalent dose to bone surfaces in excess of 10 μSv, as shown above.

For all other organs and tissues, combining maximum credible intakes to all radionuclides combined 

never exceeds 10 μSv in any calendar year, even for 50 years continuous exposure.

4.2.3

Soil sampling and analysis were routinely performed at the Pantex Plant (BWXT Pantex 2001). In 

addition, several special surveys were performed, but methods for soil sampling and analysis were 

not standardized throughout the DOE weapons complex until the early 1970s. In 1973, DOE 

dedicated a laboratory to soils analysis and purchased or fabricated the necessary field and 

laboratory equipment. 

Annual Intakes from Resuspension

As stated in Section 4.2.1, concentrations of radionuclides in soil were not used to determine 

resuspension as part of the concentration of radionuclides available for inhalation. This analysis 

assumed that air monitored concentrations included a real-time resuspension fraction. This 

assumption is reasonable because:

• The topography of the site and the region is very flat and dry (BWXT Pantex 2001).

• The meteorology of the site and the region is very consistent and relatively invariable (Snyder 

1993).

• Wind speed and direction are relatively consistent and constant, respectively (see Figure 4-10

and Table 4-5) (BWXT Pantex 2001).

For reconstructing potential missed or unmonitored dose, annual concentrations at all site locations 

are less than the maximums considered in the calculations of Section 4.2.2 [26]. These 

concentrations result in negligible doses. Therefore, no dose should be assigned to missed or 

unmonitored dose from resuspension of radionuclides.

4.3 EXTERNAL DOSE

Before 1989, radiation workers were the only employees monitored for radiation exposure. These 

personnel worked primarily in facilities in Zones 4 and 12 [27]. Radiation workers accounted for about 

half of the workers on the site [28]. Therefore, employees working in other areas or zones were not 

monitored. Estimated occupational environmental dose would have to be added for those employees 

who were not monitored.

Pantex workers are subjected to external doses from ambient radiation levels on the site. Ambient 

radiation levels were not reported until 1986 [29]. 

4.3.1

The environmental radiological profile for the Pantex Plant is for dose reconstruction when personal 

dosimetry or bioassay program participation was not required or was not available. ASERs were 

reviewed for data that would be useful in reconstructing ambient radiation levels. Data in these 

historical documents (see reference section for citations by year) included ambient TLD radiation 

Ambient Radiation
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 23 of 43

Figure 4-10. Wind rose for 2000 (BWXT Pantex 2001). 

measurements. An ambient radiation level program was initiated and reported beginning in 1986. 

Figure 4-11 shows the locations of the monitors and TLD dosimeters in 2000 (Laseter 1987).

The dosimetry results from the ambient environmental monitoring program for the Pantex facility were 

analyzed to determine whether there was a difference in the dose rates on the plant site and off site.

No environmental dose rates were recorded for the years prior to 1986 [30]. Prior to this time, the 

environmental data consisted of radionuclide concentrations in air, water, soil, vegetation, and 

jackrabbits [31]. Thus, the analysis is most appropriate for the years 1986 to 2002 but extrapolations 

to prior years can be made.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 24 of 43

Table 4-5. Climatological data for 2000 by month (BWXT Pantex 2001).

Month

Temperature °C (°F) Mean relative 

humidity (%)

Precipitationa

millimeters 

(inches)

Wind speed 

meters per second 

(miles per hour)

Maximum Minimum Mean monthly Mean Maximum

January 22.4 -11.3 3.8 46 3.05 4.8 15.3

(72.3) (11.7) (38.8) (0.12) (10.7) (34.0)

February 25.0 -8.5 7.7 41 0.00 5.6 15.7

(77.0) (16.7) (45.9) (0.00) (12.5) (34.9)

March 26.2 -4.7 8.4 63 105.66 5.8 16.8

(79.2) (23.5) (47.2) (4.16) (12.8) (37.4)

April 32.8 -1.7 13.9 52 7.37 6.2 15.1

(91.0) (28.9) (57.0) (0.29) (13.8) (33.6)

May 38.7 3.8 20.7 46 21.59 6.4 17.0

(101.7) (38.8) (69.3) (0.85) (14.1) (37.8)

June 34.6 11.7 25.3 75 176.02 5.9 17.5

(94.3) (53.1) (70.1) (6.39) (13.2) (38.9)

July 38.3 16.1 26.1 55 0.00 5.3 15.5

(100.9) (61.0) (79.0) (0.00) (11.8) (34.4)

August 36.6 15.9 27.5 38 0.00 5.1 12.3

(97.9) (60.6) (81.5) (0.00) (11.3) (27.3)

September 37.8 -0.1 22.7 38 0.00 5.5 14.1

(100.0) (31.8) (72.9) (0.00) (12.2) (31.3)

October 35.7 -0.1 14.7 71 134.62 5.1 14.2

(96.3) (31.8) (58.5) (5.30) (11.3) (32.7)

November 20.8 -8.5 3.5 71 0.00 4.9 13.4

(69.4) (16.7) (38.3) (0.00) (10.8) (29.7)

December 17.9 -13.6 -0.8 70 0.00 4.6 15.8

(64.2) (7.5) (30.6) (0.00) (10.3) (35.1)

Annualb 14.5 56 443.31 5.4

(57.4) (17.65) (12.1)

a. Includes water equivalent of snowfall. 

b. Annual mean of parameter (when indicated) except for precipitation. Total precipitation is indicated. Annual maximum and/or minimum 

temperatures and/or annual maximum wind speed may be obtained by reviewing the data in the appropriate column. 

The dose rate data used for the analysis was from TLD readings except for the offsite dose rates for 

1990. In 1990 there were apparent problems with the TLD system because, for most dosimeter 

locations, there was only one non-zero quarterly value (MHSMC 1991). Because the TLD data 

appeared to be in error, for 1990 only, the offsite dose rate data were obtained from bulb dosimeters 

located at the same sampling locations [32]. 

Figure 4-12 shows the average of the on-site and off site radiation doses. In 1986, the Chernobyl 

incident released sufficient radioactive materials so that a spike in environmental dose rates was 

observed in locations far removed from the Pantex site (e.g., Oklahoma City and Austin, Texas) (TDH 

1999). The dose rates shown in Figure 4-12 for 1986 may have been elevated solely due to the 

Chernobyl incident. 

Linear regression, as depicted in Figure 4-12, was performed on the dose rates reported from 1986 

through 2000 and the trend lines for offsite and onsite doses were found to converge. According to 

the trend lines, convergence occurs between 1998 and 2000, depending on which data set is used. 

According to the trend lines, as time goes backward to 1950, the difference in onsite and offsite dose 

rates increases. Of course, this trend cannot go on forever in the past but this analysis can well serve 

the purpose of estimating, favorable to claimant wise, ambient missed dose on the Pantex Plant Site. 

The difference in the slopes of the trend lines were used to estimate onsite ambient environmental 

doses back to 1950. See Table 4-6.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 25 of 43

Figure 4-11. Locations of thermoluminescent dosimeters in 2000 (BWXT Pantex 2001).

Based on the data in Table 4-6 and to be favorable to claimants, it is suggested that unmonitored or 

missed onsite ambient occupational dose for the years from 1951 through 1974 be added to a 

persons dose record at the rate of 100 mrem/year, and the unmonitored or missed onsite ambient 

occupational dose for the years from 1975 through 2000 be added to a persons dose record at the 

rate of 50 mrem/year. This would result in a maximum unmonitored or missed ambient dose of about 

3750 mrem for the 50-year period [33]. 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 26 of 43

Ambient Dose Rates for Pantex Plant

0

20

40

60

80

100

120

140

1985 1990 1995 2000 2005

Year

Dose Rate (mrem/year)

"On-site"

"Off-site"

Linear ("On-site")

Linear ("Off-site")

Figure 4-12. Ambient dose rates for Pantex Plant. 

Table 4-6. Calculated difference between onsite 

and offsite annual doses for the Pantex plant [34]. 

Year

Difference between on-site and offsite 

radiation dose rates (mrem/year)

1950 110

1955 98

1960 87

1965 76

1970 65

1975 53

1980 42

1985 31

1990 20

1995 8

2000 2

The Pantex historical personnel external dose monitoring program was reviewed and determined to 

have been properly managed in regard to storage of control badges and accounting for environmental 

exposures [35]. It is concluded that doses of record properly include occupational environmental 

doses and no adjustments of recorded doses need be made for monitored workers [36]. 

4.4 UNCERTAINTY

As discussed in the previous sections, estimates of annual intakes were based on air monitoring data 

and their sampling and analytical uncertainties. Where needed, the analysis made conservative (i.e., 

favorable to claimant) assumptions. The estimated annual concentrations based on monitoring data 

precluded the use of calculated meteorological conditions that could introduce large, additional 

uncertainties. 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 27 of 43

In instances where more detailed information is known about a particular individual or job 

classification, dose reconstruction should account for other modifying factors. For example, if (for a 

particular job classification) there is reason to believe that the actual ventilation rate for the worker 

might vary markedly from the average of 2,400 m3

/yr of exposure, the dose reconstructor should use 

professional judgment to adjust the estimated intakes as necessary, according to whether the 

individual was engaged in light or heavy work. The respiration rate is 1.2 m3

/hr for light work and 

1.7 m3

/hr for heavy work (Shleien 1992). In these cases, to estimate annual intake, sum the products 

of the fractional annual period for each job-dependent level of work and the corresponding ventilation 

rate to determine the total ventilation volume for the year in cubic meters. The annual intake is the 

product of the annual ventilation volume and the annual average concentration for the location of 

interest.

Based on TLD measurements of ambient external dose, the annual mean external gross dose (not 

net dose) on the site was 0.910 mSv with a standard deviation of 0.140 mSv. However, additional 

bias and uncertainty has been identified in TLD dosimeters. Biases and uncertainties for typical TLD 

systems have been identified as described by Fix and Stewart (ORAUT 2006b).

The factors to be applied to various dosimeters are:

• Based on the distribution of energy levels and geometry judged most likely, recorded dose 

divided by the table's bias value to calculate deep dose. 

• Range of overall bias factors based on alternative distributions of energy levels and geometry. 

• Systematic uncertainty resulting from lack of knowledge of actual distributions of energy levels 

and geometry. 

• Random uncertainty resulting from variation among workers in energy levels and geometry. 

Overall, these biases and uncertainties in external personnel dosimeters could lead to an additional 

factor-of-2 increase in the recorded dose.

For this document, no attempt has been made to quantify other uncertainties. 

4.5 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.

Dillard B. Shipler served as the initial Document Owner of this document. Mr. Shipler was previously 

employed at the Pantex site and his work involved management, direction or implementation of 

radiation protection and/or health physics program policies, procedures or practices related to atomic 

weapons activities at the site. This revision has been overseen by a new Document Owner, who is 

fully responsible for the content of this document, including all findings and conclusions. 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 28 of 43

[1] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

Detailed source terms for the Pantex Plant are classified and were not made available.

[2] Winslow, Robert C. ORAU Team. Senior Health Physicist. April 2007. 

DU contains about 99.8% 238U, 0.2% 235U, and 0.001% 234U by mass. Application of the 

specific activities of 1.24E-8 TBq/g for 238U, 8.00E-8 TBq/g for 235U, and 2.31E-4TBq/g for 234U 

results in 1.24E-6 TBq for 238U, 1.60E-8 TBq for 235U, and 2.31E-7TBq for 234U and a total 

activity of 1.49E-6 TBq. 

[3] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

Pantex internal dosimetry manuals do not even address 233U. 

[4] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

Since few devices were disassembled prior to 1980, releasable uranium oxide was available 

only in old devices, and releases of tritium occurred only during disassembly. Airborne 

radioactive materials were not deemed a potential concern until 1980.

[5] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

Uranium oxide released when old devices were disassembled was known and dispersion was 

controlled within the cells. Only small amounts of tritium were released when the container 

was disconnected from its assembly.

[6] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

Tritium reservoirs came as sealed containers and the seal was not broken during insertion.

[7] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

From review of documents and interviews of personnel (see Martin 2004, ORAUT 2006a), 

metal came as formed items, so no activities were performed that would generate oxides.

[8] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

From review of documentation and interview of personnel (see Martin 2004, ORAUT 2006a), 

no materials containing metals were burned during this period, so no oxides were formed or 

released. 

[9] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

Once tritium reservoirs were in place (inserted), valves were opened. When the device was 

disassembled, the valve was closed and the reservoir was removed. A small amount of tritium 

was released from between the reservoir and the device. These amounts are summarized in 

Table 4-1.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 29 of 43

[10] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

Specific releases of radioactive materials from Pantex facilities are classified and not available. 

Summaries are provided in annual reports except for a few historical incidents.

[11] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

This is based on review of plant documents, interviews with plant personnel, and personal and 

professional judgment.

[12] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

Considering time-related production, time-related availability of radioactive materials on the 

site, and the small concentrations of radioactive materials in the air and soil when releases of 

radioactive materials could have occurred after 1980, initial analyses of potential intakes and 

resulting doses led the authors to believe that potential doses from intakes would be 

negligible.

[13] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

The team reviewed a number of “General Radiation Survey Forms for Bays/Cells” related to

surveys of gland nut removals when disassembling tritium reservoirs. Most were “0” μCi, 

many were 10 μCi, and only a few were more than 10 μCi. The statement is a general 

statement of the reviews.

[14] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

The factor was derived based on review of many years of Pantex documentation, professional 

judgment, and favorability to claimants.

[15] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

The factor was derived based on review of Pantex documentation, professional judgment, and 

favorability to claimants.

[16] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. August 

2006. 

Uranium oxide released when old devices were disassembled was known and dispersion was 

controlled in the cells.

[17] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

Plutonium pits removed during disassembly are still sealed and, therefore, no releases of 

plutonium occur.

[18] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

This is the form of thorium that was monitored when monitoring did occur for thorium.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 30 of 43

[19] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

“Negligible doses” will not contribute to doses deemed necessary to produce cancers.

[20] Winslow, Robert C. ORAU Team. Senior Health Physicist. March 2007. 

A distribution of the environmental air samples taken outside the facility would represent the 

entire facility. While working at a facility, workers, in general, will move around, thus receiving 

exposures to different concentrations. However, a worker might spend a longer period in 

higher concentrations; the distribution would be diluted by the lower concentration areas. 

Therefore, the 95% confidence of the mean is assumed to be bounding to account for a 

worker spending the majority of the time in the higher concentration. 

[21] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

This equation is a mathematical expression of the statement preceding the equation and 

referenced above.

[22] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The Pantex Plant monitored concentrations of radionuclides in air at the site boundary and at 

select offsite locations (outside the site boundary). However, concentrations of radionuclides 

were not monitored regularly at locations within the site boundary. Areas within the site 

boundary (outside facilities) were monitored on an as-needed basis depending on the 

activities.

[23] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The argument is presented in case the form of 232Th can be shown to be type M. The 

possibility is remote but the subject is covered.

[24] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The argument is presented to clarify the situation that involves bone surface cancer versus red 

bone marrow cancer where 232Th might be thought to be a contributor.

[25] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The statement means that pure thorium metal particulates could not be released to the air. 

Only particulates of thorium oxide could be released.

[26] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The paragraph seems self-evident. The authors compared the maximum concentrations at 

various locations, which were all less than the concentrations used to demonstrate negligible 

doses in Section 4.2.2.

[27] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The history of radiation monitoring of external dose to workers is covered in ORAUT-TKBS0013-6, Rev. 00 (ORAUT 2006c), particularly in Table 6-15 and Figure 6-1.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 31 of 43

[28] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The history of radiation monitoring of external dose to workers is covered in ORAUT-TKBS0013-6, Rev. 00 (ORAUT 2006c), particularly in Table 6-15 and Figure 6-1.

[29] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

After reviewing annual environmental reports and their predecessor documents and talking 

with Plant personnel, it is evident that radioactive materials were sampled in environmental 

media but direct radiation was not monitored at all locations.

[30] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

After reviewing annual environmental reports and their predecessor documents and talking 

with Plant personnel, it is evident that radioactive materials were sampled in environmental 

media but direct radiation was not monitored at all locations.

[31] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

After reviewing annual environmental reports and their predecessor documents and talking 

with Plant personnel, it is evident that radioactive materials were sampled in environmental 

media but direct radiation was not monitored at all locations.

[32] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

According to Pantex personnel and early site environmental and external monitoring data, bulb 

dosimeters were used before other dosimeters but were kept in the system as backup as new 

dosimetry was implemented.

[33] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The evaluation was based on the data in the spreadsheet and professional judgment in 

defining the factor and rounding it to a number that is favorable to the claimant and easy for 

the dose reconstructor to use. 

[34] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The calculations were performed in a spreadsheet and the results of interest were included in 

the table and the figure to demonstrate the point. 

[35] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

All Pantex external dosimetry program documents, including Pantex (2002), were reviewed 

along with implementation reports and databases, and long-time employees were interviewed, 

as indicated in the several memoranda to file. The evidence seemed to justify the statements 

of credibility and reliance on the result of the programs as they grew and matured. 

[36] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

All Pantex external dosimetry program documents, including Pantex (2002), were reviewed 

along with implementation reports and databases, and long-time employees were interviewed, 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 32 of 43

as indicated in the several memoranda to file. The evidence seemed to justify the statements 

of credibility and reliance on the result of the programs as they grew and matured. 

[37] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

Section 4.2.2.5 discusses the potential for a small cumulative dose to bone surface because of 

dose factors and solubility factor selection.

[38] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

Because the lines converge noticeably to modern times and because the doses are relatively 

small, judgment concludes that single conservative values that are favorable to the claimant 

would be adequate rather than the imposition of a function for year-by-year doses.

[39] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

From the graph, the lines might be interpreted to converge in 2002. However, for 

conservatism and favorability to claimants, the convergence is not considered an end point 

and the proposed doses should be applied to current years.

[40] Shipler, Dillard B. Pacific Northwest National Laboratory. Principal Health Physicist. 

September 2006. 

The storage of control badges in places where environmental doses as well as work-related 

doses do not exist means that differences between badges worn by workers and control 

badges account for all exposures. Note in the paragraph above that unmonitored workers 

must have dose added to their total.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 33 of 43

REFERENCES

Alexander, R. E., 1974, Environmental Monitoring Report for Pantex Plant Covering 1973, MHSMP74-12, Mason & Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas, May 1. [SRDB 

Ref ID: 13085]

Alexander, R. E., 1975, Environmental Monitoring Report for Pantex Plant Covering 1974, MHSMP75-8, Mason & Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas, May 1. [SRDB 

Ref ID: 13087]

Alexander, R. E., 1976, Environmental Monitoring Report for Pantex Plant Covering 1975, Mason & 

Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas. [SRDB Ref ID: 13097]

Alexander, R. E., 1977, Environmental Monitoring Report for Pantex Plant Covering 1976, MHSMP77-7, Mason & Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas, March 14. 

[SRDB Ref ID: 13713]

Alexander, R. E., and V. A. Cornelius, 1979, Supplement to Environmental Monitoring Report for 

Pantex Plant Covering 1978, MHSMP-79-36, Mason & Hanger-Silas Mason Company, Pantex 

Plant, Amarillo, Texas, May. [SRDB Ref ID: 13714]

Alexander, R. E., and V. A. Cornelius, 1980, Supplement to Environmental Monitoring Report for 

Pantex Plant Covering 1979, MHSMP-80-44, Mason & Hanger-Silas Mason Company, Pantex 

Plant, Amarillo, Texas, September. [SRDB Ref ID: 13684]

Alexander, R. E., and W. A. Laseter, 1981, Environmental Monitoring Report for Pantex Plant 

Covering 1980, MHSMP-81-18, Mason & Hanger-Silas Mason Company, Pantex Plant, 

Amarillo, Texas, March. [SRDB Ref ID: 13715]

Alexander, R. E., V. A. Cornelius, and C. N. Horton, 1978, Supplement to Environmental Monitoring 

Report for Pantex Plant Covering 1977, MHSMP-78-41, Mason & Hanger-Silas Mason 

Company, Pantex Plant, Amarillo, Texas, October. [SRDB Ref ID: 13321]

BMI (Battelle Memorial Institute), 1985, Summary of the Annual Site Environmental Reports 

Submitted to the U.S. Department of Energy, January through December 1984, Pacific 

Northwest Laboratory, Richland, Washington, March. [SRDB Ref ID: 11122]

BMI (Battelle Memorial Institute), 1988, Summary of the Annual Site Environmental Reports 

Submitted to the U.S. Department of Energy, January through December 1986, Pacific 

Northwest Laboratory, Richland, Washington, October. [SRDB Ref ID: 11122]

BMI (Battelle Memorial Institute), 1990a, A Summary of the Annual Site Environmental Reports 

Submitted to the U.S. Department of Energy, January through December 1988, Pacific 

Northwest Laboratory, Richland, Washington, August. [SRDB Ref ID: 11121]

BMI (Battelle Memorial Institute), 1990b, A Radiological Monitoring Summary of the Annual Site 

Environmental Reports Submitted to the U.S. Department of Energy, January through 

December 1987, Pacific Northwest Laboratory, Richland, Washington, February. [SRDB Ref 

ID: 11120]
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BP (Battelle Pantex), 1992, Technical Basis for the Internal Dosimetry Program and the DOE Pantex 

Facility, Rev. 1. BWXT Pantex, Pantex Plant, Amarillo, Texas, February 14. [SRDB Ref ID: 

13312]

BP (Battelle Pantex) and MHC (Mason Hanger Corporation), 1998, 1997 Environmental Report for 

Pantex Plant, DOE/AL/65030-9804, Pantex Plant, Amarillo, Texas, June. [SRDB Ref ID: 

13710]

BP (Battelle Pantex) and MHSMC (Mason & Hanger-Silas Mason Company), 1994, 1993 

Environmental Report for Pantex Plant, DOE/AL/65030-9413, Amarillo, Texas, June. [SRDB 

Ref ID: 13708]

BP (Battelle Pantex) and MHSMC (Mason & Hanger-Silas Mason Company), 1992, Pantex Plant Site 

Environmental Report for Calendar Year 1991, Pantex Plant, Amarillo, Texas, December. 

[SRDB Ref ID: 13706]

BP (Battelle Pantex) and MHSMC (Mason & Hanger-Silas Mason Company), 1995, 1994 

Environmental Report for Pantex Plant, DOE/AL/65030-9506, Amarillo, Texas, June. [SRDB 

Ref ID: 13709]

BWXT Pantex, 2001, 2000 Site Environmental Report for Pantex Plant, DOE/AL/65030-9904, Pantex 

Plant, Amarillo, Texas, May. [SRDB Ref ID: 8636]

BWXT Pantex, 2002, 2001 Site Environmental Report for Pantex Plant, DOE/AL/66620-2002, Pantex 

Plant, Amarillo, Texas, December. [SRDB Ref ID: 13082]

BWXT Pantex, 2003, 2002 Site Environmental Report for Pantex Plant, DOE/AL/66620-2003, Pantex 

Plant, Amarillo, Texas, August. [SRDB Ref ID: 13080]

BWXT Pantex, 2004, Final Pantex Plant Radiological Investigation Report, AL-PX-SW-003788, 

Pantex Plant, Amarillo, Texas, January. [SRDB Ref ID: 20778]

DOE (U.S. Department of Energy), 1982, Summary of Annual Environmental Reports for CY 1981, 

Department of Energy Nuclear Sites, DOE/EP-0038/1, Office of Environment, Safety and 

Health, Washington, D.C., December.

DOE (U.S. Department of Energy), 1984, A Summary of Annual Site Environmental Reports, January 

through December 1983, DOE/EP-0049/1, Washington, D.C., January.

DOE (U.S. Department of Energy), 1992, Summary of Radionuclide Air Emissions from Department of 

Energy Facilities for CY 1991, DOE/EH-0293T, Assistant Secretary for Environment, Safety 

and Health, Washington, D.C., December. [SRDB Ref ID: 13360]

DOE (U.S. Department of Energy), 1994, Summary of Radionuclide Air Emissions from Department of 

Energy Facilities for CY 1992, DOE/EH-0360, Assistant Secretary for Environment, Safety and 

Health, Washington, D.C. [SRDB Ref ID: 13361]

DOE (U.S. Department of Energy), 1996, 1995 Environmental Monitoring Report for Pantex Plant, 

DOE/AL/65030-9602, Albuquerque Operations Office, Albuquerque, New Mexico, May. 

[SRDB Ref ID: 1291]
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 35 of 43

DOE (U.S. Department of Energy), 1997, 1996 Environmental Report for Pantex Plant, 

DOE/AL/65030-9704, Albuquerque Operations Office, Albuquerque, New Mexico, June. 

[SRDB Ref ID: 8621]

DOE (U.S. Department of Energy), 1999, 1998 Site Environmental Report, DOE/AL/65030-9904, 

Albuquerque Operations Office, Albuquerque, New Mexico. [SRDB Ref ID: 8622]

DOE (U.S. Department of Energy), 2000, 1999 Site Environmental Report for Pantex Plant, 

DOE/AL65030-9904, Albuquerque Operations Office, Albuquerque, New Mexico, May. [SRDB 

Ref ID: 8625]

DOE (U.S. Department of Energy), 2001a, Restricted Data Declassification Decisions, 1946 to the 

Present, Office of Declassification, Washington, D.C., January 1.

DOE (U.S. Department of Energy), 2001b, Guide of Good Practices for Occupational Radiological 

Protection in Uranium Facilities, DOE-STD-1136-2000, Change Notice 3, Washington, D.C., 

December. [SRDB Ref ID: 4617]

Griffis, D., 2004, "Re: FW: We need a Pantex Reviewer," e-mail to D. B. Shipler (Pacific Northwest 

National Laboratory), Pantex Plant, Amarillo, Texas, February 2. [SRDB Ref ID: 13083]

IAEA (International Atomic Energy Agency), 1996, International Basic Safety Standards for Protection 

Against Ionizing Radiation and for the Safety of Radiation Sources, Safety Series 115-1, IAEA, 

Vienna, Austria.

ICRP (International Commission on Radiological Protection), 1996, Age-dependent Doses to 

Members of the Public from Intake of Radionuclides: Part 4 Inhalation Dose Coefficients, 

Publication 71, Pergamon Press, Oxford, England.

Laseter, W. A., 1982, Environmental Monitoring Report for Pantex Plant Covering 1981, Mason & 

Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas. [SRDB Ref ID: 13716]

Laseter, W. A., 1983, Summary of On-Site Environmental Monitoring Data for Pantex Plant Covering 

1982, PXS-84-01, Mason & Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas. 

[SRDB Ref ID: 13717]

Laseter, W. A., 1984, Summary of On-Site Environmental Monitoring Data for Pantex Plant Covering 

1983, Mason & Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas, August. [SRDB 

Ref ID: 13718]

Laseter, W. A., 1985, Environmental Monitoring Report for Pantex Plant Covering 1984, Mason & 

Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas, April 22. [SRDB Ref ID: 

13433]

Laseter, W. A., 1986, Environmental Monitoring Report for Pantex Plant Covering 1985, MHSMP-86-

17, Mason & Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas, May 9. [SRDB 

Ref ID: 13089]

Laseter, W. A., 1987, Environmental Monitoring Report for Pantex Plant Covering 1986, MHSMP-87-

18, Mason & Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas, April. [SRDB Ref 

ID: 13434]
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 36 of 43

Laseter, W. A., and D. C. Langston, 1988, Environmental Monitoring Report for Pantex Plant Covering 

1987, MHSMP-88-1, Mason & Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas, 

April. [SRDB Ref ID: 13086]

Laseter, W. A., and D. C. Langston, 1989, Environmental Monitoring Report for Pantex Plant Covering 

1988, Mason & Hanger-Silas Mason Company, Pantex Plant, Amarillo, Texas, May. [SRDB 

Ref ID: 13436]

Martin, J. B., 2004, "Personal Communication with Herman Phillips," memorandum to Pantex TBD 

Files, May 27. [SRDB Ref ID: 14542]

MHSMC (Mason & Hanger-Silas Mason Company) and BP (Battelle Pantex), 1993, Pantex Plant Site 

Environmental Report for Calendar Year 1992, Pantex Plant, Amarillo, Texas, December. 

[SRDB Ref ID: 13707]

MHSMC (Mason & Hanger-Silas Mason Company), 1986, Investigation of an Unplanned Particulate 

Release at the FS-23 Interim Total Containment Test Fire Facility, Pantex Plant, Amarillo, 

Texas, February. [SRDB Ref ID: 11076]

MHSMC (Mason & Hanger-Silas Mason Company), 1990, Pantex Plant Site Environmental Report for 

Calendar Year 1989, MHSMP-90-18, Pantex Plant, Amarillo, Texas, May. [SRDB Ref ID: 

13440]

MHSMC (Mason & Hanger-Silas Mason Company), 1991, Pantex Plant Environmental Report for 

Calendar Year 1990, MHSMP-91-06, Pantex Plant, Amarillo, Texas, July. [SRDB Ref ID: 

13685]

Mitchell, K. C., 2003, Rhetoric to Reality: A Cold War Context Statement for the Pantex Plant, 1951-

1991, BWXT Pantex, Amarillo, Texas, September. [SRDB Ref ID: 24171]

NCRP (National Council on Radiation Protection and Measurements), 1993, Limitation of Exposure to 

Ionizing Radiation, Report 116, Bethesda, Maryland, June.

ORAUT (Oak Ridge Associated Universities Team), 2006a, Pantex Plant – Site Description, ORAUTTKBS-0013-2, Rev. 01, Oak Ridge, Tennessee, July 27.

ORAUT (Oak Ridge Associated Universities Team), 2006b, A Standard Methodology for 

Overestimating External Doses Measured with Thermoluminescent Dosimeters, ORAUTOTIB-0008, Rev. 01, Oak Ridge, Tennessee, May 12.

ORAUT (Oak Ridge Associated Universities Team), 2006c, Pantex Plant National Security Complex – 

Occupational External Dosimetry, ORAUT-TKBS-0013-6, Rev. 00, Oak Ridge, Tennessee, 

July 27.

ORAUT (Oak Ridge Associated Universities Team), 2007, Pantex Plant – Occupational Internal Dose, 

ORAUT-TKBS-0013-5, Rev. 00 PC-1, Oak Ridge, Tennessee, February 8.

Pantex Plant, 2002, Pantex Plant Technical Basis Manual for External Dosimetry, MNL-00051, Issue 

4, Amarillo, Texas, January 3. [SRDB Ref ID: 11068]
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 37 of 43

PNL (Pacific Northwest Laboratory), 1993, A Summary of the Radiological Doses and Releases 

Reported to the U.S. Department of Energy, January through December 1989, Richland, 

Washington, December. [SRDB Ref ID: 11118]

PNNL (Pacific Northwest National Laboratory), 1997a, A Summary of the Radiological Doses and 

Releases Reported to the U.S. Department of Energy, January through December 1994, 

Richland, Washington, November. [SRDB Ref ID: 11116]

PNNL (Pacific Northwest National Laboratory), 1997b, A Summary of the Radiological Doses and 

Releases Reported to the U.S. Department of Energy, January through December 1993, 

Richland, Washington, November. [SRDB Ref ID: 11117]

Prather, M. P., 2003, History of Radiation Exposures at Pantex, BWXT Pantex, Radiation Safety 

Department, DoRMS Database, Amarillo, Texas.

Shleien, B., editor, 1992, The Health Physics and Radiological Health Handbook, Revised Edition, 

Scinta, Silver Spring, Maryland.

Snyder, S. F., 1993, An Evaluation of Meteorologic Data Differences Between the Pantex Plant and 

Amarillo, Texas, PNL-8718, Battelle Memorial Institute, Pacific Northwest Laboratory, 

Richland, Washington, June. [SRDB Ref ID: 11071]

TDH (Texas Department of Health), 1999, Environmental Monitoring Report for 1993 - 1997, State of 

Texas, Austin, Texas, April. [SRDB Ref ID: 13100]
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 38 of 43

GLOSSARY

annual dose equivalent 

Dose equivalent received in a year, expressed in units of rem (sievert).

Atomic Energy Commission 

Original agency established for nuclear weapons and power production; a predecessor to the 

U.S. Department of Energy.

becquerel

SI unit of radioactivity equal to one transformation per second.

beta (β) dose

Designation (i.e., beta) on some Pantex external dose records referring to the dose from lessenergetic beta, X-ray, and/or gamma radiation.

beta radiation

Radiation consisting of charged particles of very small mass (i.e., the electron) emitted 

spontaneously from the nuclei of certain radioactive elements. Physically, the beta particle is 

identical to an electron moving at high velocity.

committed dose equivalent (HT,50) 

Dose equivalent to organs or tissues received from an intake of radioactive material by an 

individual during the 50-year period following the intake.

committed effective dose equivalent (HE,50) 

Sum of the products of the weighting factors applicable to each organ or tissue that are 

irradiated and the committed dose equivalent.

curie

A special unit of activity. One curie (1 Ci) exactly equals 3.7 x 1010 nuclear transitions per 

second.

deep absorbed dose (Dd) 

Absorbed dose at the depth of 1.0 cm in a material of specified geometry and composition.

deep dose equivalent (Hd) 

Dose equivalent at the respective depth of 1.0 cm in tissue.

depleted uranium (DU)

Used as components in nuclear weapons; isotopic activity fractions (NOTE: this is not the 

mass fraction) listed by Pantex as:

Isotope

234U

Activity 

fraction

0.0840

235U 0.0145

238U 0.9015

detection limit (lower)

Minimum quantifiable exposure or neutron flux that can be detected.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 39 of 43

depleted uranium analysis

Indicates that the chemical properties of uranium were used for analysis, not necessarily that 

the material in question was depleted uranium

dose equivalent (H)

Product of the absorbed dose (D), the quality factor (Q), and any other modifying factors. The 

special unit is the rem. When D is expressed in Gy, H is in sieverts (Sv). (1Sv = 100 rem).

dose of record

Dose files provided by DOE to NIOSH as part of the individual worker files. 

dosimeter

Device used to measure the quantity of radiation received. A holder with radiation-absorbing 

elements (filters) and an insert with radiation-sensitive elements packaged to provide a record 

of absorbed dose or dose equivalent received by an individual. (See film dosimeter, neutron 

film dosimeter, thermoluminescent dosimeter).

dosimetry

Science of assessing absorbed dose, dose equivalent, effective dose equivalent, etc., from 

external and/or internal sources of radiation. 

dosimetry system

System used to assess dose equivalent from external radiation to the whole body, skin, and/or 

extremities. This includes the fabrication, assignment, and processing of dosimeters as well 

as interpretation and documentation of the results.

effective dose equivalent

Sum of the products of dose equivalent to the organ or tissue (HT) and the weighting factor 

(WT) applicable to each organ or tissue.

exchange period (frequency)

Period (weekly, biweekly, monthly, quarterly, etc.) for routine exchange of dosimeters.

exposure

In the technical sense, a measure expressed in roentgens (R) of the ionization produced by 

photons (gamma and X-rays) in air. 

extremity

That portion of the arm extending from and including the elbow through the fingertips, and that 

portion of the leg extending from and including the knee and patella through the tips of the 

toes.

film

In general, a "film packet" that contains one or more pieces of film in a light-tight wrapping. 

The film when developed has an image caused by radiation that can be measured using an 

optical densitometer. (See nuclear track emulsion).

film dosimeter

Small packet of film within a holder that attaches to a wearer.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 40 of 43

flux (n/cm2-sec)

Measure of the intensity of neutron radiation in neutrons/cm2-sec. It is the number of neutrons 

passing through a sphere with a cross-sectional area of 1 cm2 of a given target in 1 second. 

Expressed as nv, where n = the number of neutrons per cubic centimeter and v = their velocity 

in cm/sec. In this sense, flux is the same as “fluence rate” as defined by the International 

Commission on Radiation Units and Measurements.

gamma ray (γ)

Electromagnetic radiation (photons) originating in atomic nuclei and accompanying many 

nuclear reactions (e.g., fission, radioactive decay, and neutron capture). Physically, gamma 

rays are identical to X-rays but have higher energy; the only essential difference is that X-rays 

do not originate in the nucleus. 

Gray

SI unit of absorbed dose. Unit symbol, Gy. 1 Gy = 100 rad.

ionizing radiation

Electromagnetic or particulate radiation capable of producing charged particles through 

interactions with matter.

neutron

Basic particle that is electrically neutral weighing nearly the same as the hydrogen atom.

neutron, fast

Neutron with energy equal or greater than 10 keV.

neutron, intermediate

Neutron with energy between 0.5 eV and 10 keV.

neutron, thermal

Strictly, neutrons in thermal equilibrium with surroundings; in general, neutrons with energy 

less than about 0.5 eV.

neutron film dosimeter

Film dosimeter that contains an Neutron Track Emulsion, type A, film packet.

nuclear track emulsion, type A (NTA)

Film that is sensitive to fast neutrons. The developed image has tracks caused by neutrons 

that can be seen by using an appropriate imaging capability such as oil immersion and a 

1000X power microscope or a projection capability.

personal dose equivalent Hp(d)

Dose equivalent in soft tissue below a specified point on the body at an appropriate depth d. 

The depths selected for personnel dosimetry are 0.07 mm and 10 mm for the skin and body, 

respectively. These are noted as Hp(0.07) and Hp(10), respectively. 

photon

Unit or "particle" of electromagnetic radiation consisting of X- and/or gamma rays. 
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 41 of 43

photon - x-ray

Electromagnetic radiation of energies between 10 keV and 100 keV whose source can be an 

X-ray machine or radioisotope.

quality factor, Q

Modifying factor used to derive dose equivalent from absorbed dose.

radiation

Alpha, beta, neutron, and photon radiation. 

radioactivity

Spontaneous emission of radiation, generally alpha or beta particles, gamma rays, and 

neutrons from unstable nuclei.

rem

Unit of dose equivalent, which is equal to the product of the number of rad absorbed and the 

"quality factor."

roentgen (R)

Unit of exposure to gamma (or X-ray) radiation. It is defined precisely as the quantity of 

gamma (or X-) rays that will produce a total charge of 2.58 x 10-4 coulomb in 1 kg of dry air. 

An exposure of 1 R is approximately equivalent to an absorbed dose of 1 rad in soft tissue for 

higher (>100 keV) energy photons.

shallow absorbed dose (Ds) 

Absorbed dose at a depth of 0.007 cm in a material of specified geometry and composition.

shallow dose equivalent (Hs) 

Dose equivalent at a depth of 0.007 cm in tissue.

shielding

Material or obstruction that absorbs (or attenuates) radiation and thus tends to protect 

personnel or materials from radiation. 

skin dose

Absorbed dose at a tissue depth of 7 mg/cm2

. 

thermoluminescent

Property of a material that causes it to emit light as a result of being excited by heat.

thermoluminescent dosimeter (TLD)

Holder containing solid chips of material that when heated will release the stored energy as 

light. The measurement of this light provides a measurement of absorbed dose. 

whole-body dose

Absorbed dose at a tissue depth of 1.0 cm (1,000 mg/cm2

); also used to refer to the recorded 

dose.

X-ray

Ionizing electromagnetic radiation that originates external to the nucleus of an atom.
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 42 of 43

ATTACHMENT 4A

RADIONUCLIDE INTAKE AND OCCUPATIONAL EXPOSURE

Page 1 of 2

TABLE OF CONTENTS

SECTION TITLE

4A.1 Radionuclide Intake................................................................................................................

PAGE

42

4A.2 External Exposure..................................................................................................................42

LIST OF TABLES

TABLE TITLE PAGE

4A-1 References for maximum air concentrations for tritium (oxidized), thorium, 

uranium, and plutonium used in Section 4.2.2 dose analyses ................................................ 43

4A-2 Upwind “control” (location OA-AR-13) average annual air concentrations .............................. 43

4A.1 RADIONUCLIDE INTAKE

Based on the information in Section 4.2.2 of this Technical Basis Document, all potential doses from 

occupational environmental intakes on the Pantex Plant are considered negligible and should be 

assigned zero dose. Some attention might be paid to claims based on bone surface cancers relative 

to the time the worker spent at the Pantex Plant [37]. As stated in Section 4.2.2, the committed dose 

from 232Th conservatively might be 117 μSv (1.17 mrem).

4A.2 EXTERNAL EXPOSURE

Ambient external doses on the Pantex site have been monitored by TLDs since 1986. Based on trend 

analysis of onsite and offsite TLD measurements, as described in Section 4.3.1, the extrapolated 

difference in offsite and onsite doses in 1951 could be as much as 100 mrem/year [38]. The trend 

lines converge in about 2000 [39]. So it is recommended that 100 mrem/year be added to 

unmonitored workers for the years 1951 through 1975 and 50 mrem/year be added to unmonitored 

workers for the years 1975 through 2000. This would result in a maximum unmonitored or missed 

ambient dose of about 3750 mrem for the 50 year period. 

The Pantex historical personnel external dose monitoring program was reviewed and determined to 

have been properly managed in regard to storage of control badges and accounting for environmental 

exposures (Pantex 2002). It is concluded that doses of record properly include occupational 

environmental doses and no adjustments of recorded doses need be made for monitored workers 

[40]. 

The following tables provide supporting data for the analyses described in the TBD:
Document No. ORAUT-TKBS-0013-4 Revision No. 01 Effective Date: 06/22/2007 Page 43 of 43

ATTACHMENT 4A

RADIONUCLIDE INTAKE AND OCCUPATIONAL EXPOSURE

Page 2 of 2

Table 4A-1. References for maximum air concentrations for 

tritium (oxidized), thorium, uranium, and plutonium used in 

Section 4.2.2 dose analyses (BWXT Pantex 2001). 

Radionuclides Tables in DOE (2001a)

Tritium (oxidized) Table 5.1, page 5-8, location PA-AR-06

Thorium-232 Table 5.3, page 5-11, location FL-AR-05

Uranium-234/234 & 238 Table 5.4, page 5-12, location FL-AR-05

Table 5.5, page 5-14, location FL-AR-05

Plutonium 239/240 Table 5.7, page 5-18, location FL-AR-08

Table 4A-2. Upwind “control” (location OA-AR-13) average annual air 

concentrations. 

Isotopes/elements

Number of 

samples

Concentration (μBq m−3) 

(mean ±standard deviation)

Previous 

3 y mean

Tritium oxide - - -

Uranium 12 2.32 ± 1.08 1.26

Plutonium - - -

Thorium 12 2.17 ± 1.37 1.85