ORAU TEAM

Dose Reconstruction

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Oak Ridge Associated Universities I Dade Moeller I MJW Technical Services

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DOE Review Release 05/07/2014

Document Title:

Site Profile for Allied Chemical Corporation 

Plant

Document Number: ORAUT-TKBS-0044

Revision: 02

Effective Date: 04/28/2014

Type of Document: TBD

Supersedes: Revision 01

Subject Expert(s): Estella L. Keefer

Approval: Signature on File Approval Date: 04/30/2014

Estella L. Keefer, Document Owner

Concurrence: Signature on File Concurrence Date: 04/28/2014

John M. Byrne, Objective 1 Manager

Concurrence: Signature on File Concurrence Date: 04/28/2014

Edward F. Maher, Objective 3 Manager

Concurrence: Vickie S. Short Signature on File for Concurrence Date: 04/28/2014

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 05/05/2014

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-0044 Revision No. 02 Effective Date: 05/05/2014 Page 2 of 42

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

02/01/2006 00 New document to establish the technical basis for the development 

of a radiation exposure matrix for Allied Chemical Corporation Plant. 

First approved issue. Training required: As determined by the Task 

Manager. Initiated by Cindy W. Bloom.

10/01/2007 01 Approved Revision 01 initiated to add text in Section 2.0 and remove 

information regarding nonuranium radionuclides in Sections 3.0 and 

5.0 to incorporate SEC evaluation report recommendation to not 

reconstruct nonuranium internal dose. Moved Figure 2-1. 

Incorporates formal internal and NIOSH review comments. Added 

reference for employee statement regarding X-rays. Constitutes a 

total rewrite of the document. The recently designated residual 

period is identified. Section 5.0, Estimating Exposures From 

Residual Radioactivity, expanded to address dose reconstruction 

methodologies for exposures received during the residual period. 

Added Attributions and Annotations section and additional 

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

Initiated by Bernard M. Olsen.

05/05/2014 02 Revision initiated to add text in Section 5.0 and to incorporate 

changes to Table 5-2 based on ORAUT-OTIB-0070, Revision 01. 

Revised Sections 2.3, 2.4, 2.5, 2.7, 3.0, 3.2, 4.0, and 5.0, including 

Tables 5-1 and 5-3, as indicated pursuant to recommendations in 

Report-SCA-TR-SP2011-0012-PA. Replaced text in Section 1.0 and 

conformed to standard presentation. Includes editorial changes. 

Incorporates formal internal and NIOSH review comments. 

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

determined by the Objective Manager. Initiated by Estella L. Keefer.
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 3 of 42

TABLE OF CONTENTS

SECTION TITLE PAGE

Acronyms and Abbreviations ............................................................................................................... 5

1.0 Introduction .............................................................................................................................. 7

1.1 Purpose........................................................................................................................ 7

1.2 Scope........................................................................................................................... 8

1.3 Special Exposure Cohort Information ........................................................................... 8

2.0 Site Description and Operational History.................................................................................. 8

2.1 Site Description ............................................................................................................ 9

2.2 Process Description.................................................................................................... 11

2.3 Source Term............................................................................................................... 17

2.4 Safety......................................................................................................................... 18

2.4.1 Visual Observation of Contamination .............................................................. 19

2.4.2 Air Activity Measurement of Contamination..................................................... 19

2.4.3 Surface Contamination Measurements ........................................................... 19

2.4.4 Decontamination............................................................................................. 20

2.5 Incidents..................................................................................................................... 20

2.6 Physical Examinations – X-Rays ................................................................................ 20

2.7 Summary Operational Period Assumptions, Workdays, Work Hours, Work 

Categories.................................................................................................................. 20

2.8 Residual Contamination.............................................................................................. 21

3.0 Estimating Internal Exposure ................................................................................................. 21

3.1 Uranium...................................................................................................................... 21

3.1.1 Uranium Urinalysis Data ................................................................................. 21

3.1.2 Uranium In Vivo Data...................................................................................... 22

3.2 Notations on Bioassay Records.................................................................................. 23

3.3 Occupational Internal Dose Reconstruction Assumptions and Summary.................... 23

4.0 Estimating External Exposure ................................................................................................ 24

4.1 Penetrating and Nonpenetrating doses....................................................................... 24

4.2 Neutron Dose ............................................................................................................. 25

4.3 Occupationally Required Medical X-Ray..................................................................... 25

4.4 Miscellaneous Information about External Dose ......................................................... 26

4.5 Occupational External Dose Reconstruction Assumptions and Summary................... 26

5.0 Estimation of Exposure from Residual Radioactivity............................................................... 26

5.1 Internal Exposure to Residual Activity......................................................................... 26

5.2 External Exposure to Residual Radioactivity............................................................... 27

5.3 Dose Reconstruction Assumptions and Summary for Residual Period ....................... 27

6.0 Attributions and Annotations .................................................................................................. 29

References ........................................................................................................................................ 30

ATTACHMENT A, APPLICATION OF RESIDUAL DOSE FACTORS................................................33

ATTACHMENT B, EXTERNAL DOSE POTENTIAL...........................................................................35

ATTACHMENT C, TIMELINE OF ACCP RADIATION EXPOSURE EVENTS (Primarily during 

the Residual Period).............................................................................................36
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LIST OF TABLES

TABLE TITLE PAGE

2-1 Radionuclide activity ratios in relation to uranium based on reported activities in ore 

concentrates, and in ACCP wastes, air, and effluents ............................................................ 17

3-1 NU specific activity and isotopic fractions............................................................................... 21

4-1 ACCP dosimeter type and reported dose quantity.................................................................. 24

4-2 External exposure summary................................................................................................... 26

5-1 Source term activity ratios relative to natural uranium ............................................................ 27

5-2 Adjustment factors to account for depletion of pre-1977 source term during the 

residual contamination period ................................................................................................ 28

5-3 Residual radiation exposure summary for January 1, 1977, to March 1, 2011........................ 28

B-1 ACCP areas and facilities with high external exposure potential ............................................ 35

B-2 ACCP job titles that involved more routine handling of uranium material................................ 35

C-1 Timeline of radiation exposure events.................................................................................... 36

LIST OF FIGURES

FIGURE TITLE PAGE

2-1 Plot plan of ACCP Metropolis, Illinois ..................................................................................... 10

2-2 Process steps for conversion from ore concentrates (yellowcake) to UF6............................... 12
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 5 of 42

ACRONYMS AND ABBREVIATIONS

ACCP Allied Chemical Corporation Plant

AEC U.S. Atomic Energy Commission

AP anterior-posterior

AWE atomic weapons employer

Ci curie

cm centimeter

DOE U.S. Department of Energy

dpm disintegrations per minute

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

ft feet

hr hour

IMBA Integrated Modules for Bioassay Analysis

in. inch

IREP Interactive RadioEpidemiological Program

keV kiloelectron-volt, 1,000 electron-volts

kg kilogram

KPA kinetic phosphorescence analysis

L liter

lb pound

m meter

mCi millicurie

MDL minimum detection level

MeV megaelectron-volt, 1 million electron-volts

MPLB maximum permissible lung burden

mrem millirem

nCi nanocurie

NIOSH National Institute for Occupational Safety and Health

NRC U.S. Nuclear Regulatory Commission

NU natural uranium

ORAU Oak Ridge Associated Universities

PA posterior-anterior

pCi picocurie

RFP Rocky Flats Plant

RMC Radiation Management Corporation

SEC Special Exposure Cohort

t ton
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 6 of 42

U.S.C. United States Code

wk week

yr year

μCi microcurie

μg microgram

§ section or sections
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1.0 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 historical 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 [AWE] facility” or a “Department of Energy [DOE] facility” as defined in the Energy 

Employees Occupational Illness Compensation Program Act of 2000 [EEOICPA; 42 U.S.C. § 7384I(5) 

and (12)]. EEOICPA, as amended, provides for employees who worked at an AWE facility during the 

contract period and/or during the residual period.

Under EEOICPA, employment at an AWE facility is categorized as either (1) during the DOE contract 

period (i.e., when the AWE was processing or producing material that emitted radiation and was used 

in the production of an atomic weapon), or (2) during the residual contamination period (i.e., periods 

that NIOSH has determined there is the potential for significant residual contamination after the period 

in which weapons-related production occurred). For contract period employment, all occupationally 

derived radiation exposures at covered facilities must be included in dose reconstructions. This 

includes radiation exposure related to the Naval Nuclear Propulsion Program and any radiation 

exposure received from the production of commercial radioactive products that were concurrently 

manufactured by the AWE facility during the covered period. NIOSH does not consider the following 

exposures to be occupationally derived (NIOSH 2010a):

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

conventional structures

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

reasons

For employment during the residual contamination period, only the radiation exposures defined in 42 

U.S.C. § 7384n(c)(4) [i.e., radiation doses received from DOE-related work] must be included in dose 

reconstructions. Doses from medical X-rays are not reconstructed during the residual contamination 

period (NIOSH 2010a). It should be noted that under subparagraph A of 42 U.S.C. § 7384n(c)(4), 

radiation associated with the Naval Nuclear Propulsion Program is specifically excluded from the 

employee’s radiation dose. This exclusion only applies to those AWE employees who worked during 

the residual contamination period. Also, under subparagraph B of 42 U.S.C. § 7384n(c)(4), radiation 

from a source not covered by subparagraph A that is not distinguishable through reliable 

documentation from radiation that is covered by subparagraph A is considered part of the employee’s 

radiation dose. This site profile covers only exposures resulting from nuclear weapons-related work.

Exposures resulting from non-weapons-related work, if applicable, will be covered elsewhere.

1.1 PURPOSE

This document provides information that may be used for dose reconstructions for AWE workers at 

the Allied Chemical Corporation Plant (ACCP) in Metropolis, Illinois. The Metropolis facility was also 

known as General Chemical Division and the Allied-Signal (later AlliedSignal) Metropolis Plant or 

Metropolis Works. AlliedSignal purchased Honeywell in 1999 and assumed that company’s name.
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1.2 SCOPE

Section 2.0 of this document describes the ACCP site and its history including information about the 

radiological processes and source terms as well as the radiological controls and monitoring practices. 

Sections 3.0 and 4.0 discuss internal and external dose assessment, respectively. Section 5.0 

provides information for assigning dose during the residual radiation period beginning in 1977 after 

the cessation of Atomic Energy Agency (AEC)-related operations.

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

justification, or clarification of the associated information, are presented in Section 6.0.

1.3 SPECIAL EXPOSURE COHORT INFORMATION

The Secretary of the U.S. Department of Health and Human Services has designated a class of 

employees from ACCP for inclusion in the Special Exposure Cohort (SEC) (Leavitt 2007). The class 

of employees for which NIOSH cannot estimate radiation doses with sufficient accuracy includes all 

employees who were monitored or should have been monitored for exposure to ionizing radiation 

while working at the ACCP in Metropolis, Illinois, for a number of workdays aggregating at least 250 

workdays from January 1, 1959, through December 31, 1976, or in combination with workdays within 

the parameters established for one or more other classes of employees in the SEC.

A decision has been made that internal dose from nonuranium radionuclides cannot be reconstructed 

with sufficient accuracy for employees of ACCP during the period 1959 through 1976 (NIOSH 2006); 

therefore only internal dose from uranium is considered in Section 3 of this site profile. 

2.0 SITE DESCRIPTION AND OPERATIONAL HISTORY

The information that follows applies to the period of AEC operations at ACCP in Metropolis, Illinois, 

from January 1, 1959, to December 31, 1976, which involved AEC-contracted conversion of uranium 

ore concentrates to uranium hexafluoride (UF6). Opening ceremonies for the ACCP fluorine plant 

occurred in October 1958 (Sloop 1978). The original license issue date was December 17, 1958 

(NRC 2003, p. 37). Four claims (claim Numbers redacted) include bioassay results in December 

1958; and one of these from December 15, 1958, has a positive result that indicates that uranium 

exposures might have occurred in late 1958, before the covered AWE period as established by the 

Office of Worker Screening and Compensation Support, which does not begin until January 1, 1959. 

The plant was closed temporarily on June 30, 1964, and AEC (1966) reported that it might reopen in 

1966. A review of available worker dosimetry records indicated that some workers might have been 

laid off or transferred around this period, but that other workers were still on the site. The reviewed 

documentation indicates that weapons-related residual contamination exists outside the listed 

operational period (NIOSH 2011). Residual contamination from previous weapons-related activities is 

indistinguishable from contamination produced during later operations. This facility is still operational, 

and the residual contamination period has been established as being from January 1, 1977, through 

March 1, 2011 (DOE 2013).

Detailed information about buildings and processes is provided in Sections 2.1, 2.2, and 2.3 based on 

descriptions written after the period of operations that is covered by this document. Individuals who 

worked at ACCP indicated that there was little variation in the processes over time. Because 

individual dosimetry results are available for the vast majority of workers at ACCP, reconstructed 

doses should be based on specific individual dosimetry.

The ACCP radiological source term started with the receipt of uranium ore concentrates. Some longlived uranium progeny were included in the concentrates (e.g., 230Th and 226Ra). Uranium chemical 
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 9 of 42

forms included oxides, fluorides, and hexafluorides, which meant that exposures could have been to 

uranium solubility types F, M, S, or a combination.

The ACCP was also known as General Chemical Division, Allied Signal Metropolis Plant, and was 

later purchased by Honeywell.

2.1 SITE DESCRIPTION

“On February 4, 1957, the Allied Chemical and Dye Corp. announced selection of Metropolis, Illinois, 

as the site of its plant to process 5,000 tons of U3O8 a year under contract with the [Atomic Energy] 

Commission[AEC]” (AEC 1957). The official plant startup date appears to be January 1, 1959, but 

there are indications that uranium and uranium workers might have been on the site in late 1958. 

One individual reported participating in opening ceremonies at the fluorine plant outside Metropolis in 

October 1958 (Sloop 1978), which indicates that uranium exposure could have occurred as early as 

October 1958.

ACCP operated its UF6 production facility using a dry conversion process (versus a wet solvent 

extraction process) to supply UF6 feed for the Paducah Gaseous Diffusion Plant through June 30, 

1964, under an AEC contract (Perkins 1982). In addition, ACCP was sampling uranium concentrates 

for other entities as of 1982.

On June 30, 1964, the plant was temporarily closed. AEC (1966) reported that the plant “may be 

reopened in 1966 for uranium hexafluoride production.” Perkins (1982) noted that ACCP resumed 

operations in February 1968, but the available dosimetry records indicate that radiological exposures 

were still occurring at the plant between June 30, 1964, and February 1, 1968. Some of the claimant 

interviews and external dosimetry records show that a number of workers were on the site during the 

shutdown and that hiring was occurring in 1967, although these records also indicate that a number of 

workers were laid off in July 1964. The available records do not indicate what activities might have 

been ongoing in the plant during the shutdown period. However, based on U.S. Department of Labor 

job descriptions associated with one claim (claim number redacted), some processing operations 

might have continued at least on a sporadic basis.

The ACCP U.S. Nuclear Regulatory Commission (NRC) license (NRC 2003, p.4) stated:

The Allied Signal Metropolis Plant is located on approximately 1,000 acres of land in 

Massac County at the southern tip of Illinois, along the north bank of the Ohio River. 

The site perimeter is formed by US Highway 45 to the north, the Ohio River to the 

south, an industrial coal blending plant to the west and privately owned, developed 

land to the east. Plant operations are conducted in a single fenced-in, restricted area 

covering 59 acres in the north-central portion of the site.

The plant is now owned by Honeywell and is still providing UF6 to gaseous diffusion plants for use in 

the commercial sector. The 1982 building locations are shown in Figure 2-1.

The following description of the buildings is from ACCP licensing documentation (NRC 2003, pp. 36–

37). The list was originally numbered 8.5.1 through 8.5.8, but has been simplified to 1 through 8 

below.

Most of the uranium processing equipment is housed in a six-story structure termed the 

Feed Materials Building where essentially all of the steps in the UF6 manufacturing

process are conducted. Other areas and buildings in which operations are conducted 
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Figure 2-1. Plot plan of ACCP Metropolis, Illinois (Perkins 1982, p. 7).
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involving the handling or processing of significant quantities of source material include 

the following:

1. A Sampling Plant which receives samples or concentrates for uranium assay 

and moisture content.

2. The Sodium Removal (pretreatment) and Uranium Recovery Facilities which 

are housed in buildings where high sodium content ore concentrates are 

treated to remove sodium impurity, and where materials are reprocessed to 

recover additional uranium.

3. The KOH [potassium hydroxide] muds washing facility which removes fluorides 

and KOH from the potassium diuranate muds generated in the fluorination 

scrubber system. The washed potassium diuranate is then processed through 

Sodium Removal. The wash liquors are neutralized at EPF [environmental 

protection facility, this facility probably did not exist during the early years].

4. The Calcining Facility which dries the incoming feed material and recovered 

uranium as the first step in ore preparation.

5. The Pond Mud Calciner Drier where hard/wet ore concentrates and KOH muds 

are processed prior to packaging for blending with additional ore concentrates 

at the Feed Materials Building for conversion to UF6.

6. The Laboratory Building which houses facilities for conducting process control, 

product, and radiological control analyses.

7. The Cylinder Wash Building where UF6 product cylinders are periodically 

washed and hydrostatically tested prior to reuse.

8. Outdoor pads for storage of drums of ore concentrates and other uranium 

bearing materials, as well as UF6 product cylinders. 

Additional plant facilities which are involved directly in the UF6 manufacturing process 

but do not involve the handling of any significant quantities of source material include a 

fluorine manufacturing building, a fluoride waste treatment facility with four large CaF2

settling tanks, a powerhouse, a reductor off-gas incinerator, and two small uranium 

settling ponds to collect any uranium spills.

ACCP was also involved in the manufacture of 30,000 lb/wk of liquid fluorine, 1,200 t/yr of sulfur 

hexafluoride, 2,500 lb/wk of antimony pentafluoride, and 10,000 lb/wk of iodine pentafluoride (Perkins 

1982). These materials were not radioactive.

2.2 PROCESS DESCRIPTION

The conversion process from ore concentrates (yellowcake) to UF6 is described below, and a process 

flow diagram is presented in Figure 2-2. As of 1982, the processing capacity was 14,000 t of uranium 

per year and the plant had processed more than 100,000 t of uranium from domestic and foreign 

uranium concentrates (Perkins 1982).

As part of an evaluation of environmental control technologies for (UF6) nuclear material conversion 

facilities, Perkins (1982) described the conversion of yellowcake to UF6 at ACCP. Although some 

changes in the process might have occurred since the first days of operation, it is likely that these 
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Figure 2-2. Process steps for conversion from ore concentrates (yellowcake) to UF6 (NRC 2003, 

p. 66).

changes would have related to ore sampling techniques, ventilation and filtration controls, and waste 

disposal practices, and that the general process was similar throughout the plant’s history. Process 

descriptions from Perkins (1982) follow.

Drums are weighed, and a falling stream method is used to obtain a representative 

sample. The airborne dusts generated in the sampling process are removed through 

the use of two baghouses in series, which discharge through a stack. Empty drums 

are air cleaned and the discharge runs through two baghouses before being 

discharged to a stack.

Concentrates that are found to contain a high percentage of sodium are pretreated in 

the sodium-removal facility. 
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Sodium Removal (Pretreatment)

Because sodium forms a compound that causes caking and sintering in the fluorination 

fluid beds, any incoming uranium concentrates containing sodium and all the uranium 

concentrates produced by the uranium recovery sections of the UF6 facility must first 

have the sodium or potassium removed before they can be processed. These 

concentrates are treated by reaction with a solution of ammonium sulfate in four 

counter current vessels to make (NH4)2U2O7 for further processing. The chemical 

reaction is

Na2U2O7 + (NH4)2SO4 → (NH4)2U2O7 + Na2SO4

The liquid effluent contains the excess (NH4)2SO4, Na2SO4, K2SO4, and uranium and 

small quantities of 226Ra and 230Th, selenium, molybdenum, and other trace impurities. 

The effluent is sent to the two uranium spill control ponds. Uranium contaminated 

storm water is also discharged to these ponds. The sludges are allowed to settle, and 

the decantate is discharged to the main discharge outfall for the plant.... When the 

minimum freeboard is reached (approximately 2 ft) on a pond, the pond is dredged and 

the sludge is sent to the pond sludge calciner.... Pond liners are inspected and 

repaired at this time. In addition, all pond liners are underlain by a gravel layer that 

allows any seepage to drain to a leak detection sump....

The (NH4)2U2O7 (ADU) [ammonium diuranate] is removed from solution in the last 

reaction vessel and is sent to the main feed preparation section of the plant.

Feed Preparation

In the feed preparation circuit, sodium-free uranium concentrate, either from the 

pretreatment section or from the sampling section, is first fed into a calciner where 

water and ammonia are removed. The off-gases containing ammonium, sulfur dioxide, 

uranium, and contaminant particles pass through two baghouses in series. 

Particulates recovered by blowback of the baghouses are collected and sent back into 

the blending feed stream....

The calcined material is blended and then agglomerated, dried, crushed, and sized 

before being sent to the reduction circuit. Wet off-gas streams join the off-gases from 

the calciner, whereas dried off-gases pass through two baghouses in series before 

discharge.... Material collected by the dry stream baghouse is fed into the blending 

feed stream.

Reduction

In the reduction circuit, Allied operates two trains in parallel, both having the same 

basic design. The U3O8 from the feed preparation circuit is fed into the reductor vessel 

where hot cracked ammonia (N2 and H2) and additional nitrogen mix with the feed to 

form a fluidized bed. The U3O8 is reduced to UO2, which is withdrawn from the bottom 

of the bed. Off-gases from the reactor include H2, N2, H2S, AsH3, vaporized S, SeH2, 

and particulates composed of UO2, unreacted U3O8 and reduced compounds of 

impurities originally in the concentrate....

The off-gases pass through two porous metal filters in series, a sulfur condenser, and 

incinerator....

Particulates collected by cleaning the filters are sent to the uranium recovery section.
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Off-gases from the oxide vacuum cleaner are sent through cyclone and two baghouses 

in series before discharge.... Residues from these collection devices are sent to the 

uranium recovery section.

Hydrofluorination

Again in the hydrofluorination circuit, two trains in parallel are in use. The UO2 from 

reduction is fed into two reactor vessels in series, which use vaporized hydrofluoric 

acid and N2 to fluidize the UO2 and permit HF to react with the material to form UF4. 

The off-gases contain the excess HF needed to give good conversion to UF4 (10% 

excess or more), volatile SiF4, BF3, and some of the molybdenum and vanadium (which 

were present as impurities in the concentrate) as volatile fluorides and oxyfluorides, 

and any remaining sulfur as H2S4. These gases first pass through two sets of porous 

carbon filters per set, where the unreacted UO2 particles, entrained UF4 particles, and 

any other particulate matter are removed. The gases then pass through two venturi 

water scrubbers where the H2O in the off-gases condenses, and finally through a 

venturi KOH scrubber and a packed tower using KOH scrubbing liquid.

The residue from the clean carbon filters is sent to uranium recovery. Liquid coming 

from the venturi water scrubbers contains hydrofluoric acid and is sent to the acid 

neutralization treatment plant, where lime is added to precipitate the fluorine as CaF2. 

The uranium content of this stream is reported to average less than 5 ppm [parts per 

million]. Silicon, boron, and some molybdenum, and vanadium, which were originally 

in the concentrate, are expected to be in the sludge. The liquid from the KOH venturi 

and packed tower is sent to the liquid treatment systems.

The vacuum cleaning off-gases from the cleaning activities necessary in the 

hydrofluorination section are routed through a cyclone and two baghouses before 

discharge.... Residues from the dust collectors are sent to the uranium recovery 

section.

Fluorination

The green salt, UF4, produced in the hydrofluorination process is fed into one of two 

fluid bed reactors used in parallel. Again, Allied uses two trains at the works. The bed 

material is CaF2, and unreacted UF4. The vessels are operated at temperatures of 

approximately 1000° F, and good temperature control is required. Fluorine, F2, from an 

on-site fluorine production facility is introduced into the reactor vessels to convert UF4

into gaseous UF6.

The off-gasses, including uranium UF6, F2, HF, unreacted UF4, and other particulates, 

and volatilized impurities ... are first cooled before passing through two sets of sintered 

nickel filters, each containing two filters. The material recovered as the filters are 

cleaned is stored, and then sent to the uranium recovery section.

The stream exiting from the filters has the UF6 removed by condensation in a set of 

three cold traps used in series. Any uncondensed UF6, F2, HF and other volatiles 

passing from the cold wraps are removed from the gas stream by a KOH spray tower, 

a KOH pack tower, and finally a KOH coke box.

Carbon dioxide in the spent scrubber liquor reacts with the uranium and potassium as 

follows.

2(UO3)

4 - + 6CO2 + 6OH- + 2K+ → K2U2O7 + 6CO3

2- +3O2 + 3H2O
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The K2U2O7 is settled from the KOH solution and sent to the pretreatment facility.

Decantate from the uranium settling section is sent to the KOH regeneration system as 

indicated previously.... The KOH is then sent back to the scrubbing system. In 

addition to CaF2 compounds of uranium, vanadium, and molybdenum, trace quantities 

of compound of silica, carbon sulfur, and other trace contaminants are expected to be 

in the sludge....

The condensed material in the three cold traps in series is melted and drained to the 

still feed tanks. Entrained hydrogen fluoride is vaporized during melting and passes to 

the off-gas system.

From the still feed tanks, the liquid is fed to a low-temperature boiler bubble cap 

column in which the impurities are volatilized and exit from the top of the column....

The liquid uranium hexafluoride passes from the low boiler column into the bubble cap, 

high boiler column. In this column, the UF6 is volatilized and exits from the top of the 

column. Non-volatilized impurities are removed from the bottom of the column and 

stored.

The gaseous UF6 from the column is condensed into two cold traps operated in series. 

The UF6 is transferred to the shipping cylinders by melting the UF6 and allowing the 

material to drain into the cylinders.

Because impurities build up on the recycled CaF2 bed material used in the fluorination 

reactors, part of the bed material must be withdrawn periodically. This “ash” [also 

referred to as spar or bed material] along with the fluorination-cleaned filter residue, is 

drummed and stored for a minimum of 6 months to permit the uranium daughters 234Th 

and 234Pa to decay. The ash is then sent to the uranium recovery section. A total 

quantity of about 0.1 ton of ash per ton of uranium processed is produced, and it 

contains approximately 1.8% of the total uranium processed and most of the uranium 

daughters originally present in the concentrate.

The dusts produced by withdrawing bed material from the reactors are passed through 

a cyclone and two baghouses in series before discharge.... The ash vacuum cleaner 

systems also discharge from this stack. Residue from cleaning these particulate 

removal devices is treated similarly to the spent bed material....

The feed preparation, reduction, hydrofluorination, and fluorination circuits are all 

located in the feed material building. This building has a complete air changeout 

approximately once every 5 minutes....

Washdown of the feed materials building is pumped from collection sumps into the 

uranium recovery ponds.

The transfer lock to fluorination discharges through two baghouses.... Again, dust 

collection residue is sent to uranium recovery.

Uranium Recovery

There are several sources of uranium-containing wastes produced by the facility, and it 

is desirable to recover the uranium from these wastes. Thus, uranium-containing dried 

sludges, spent bed material, filter residue, and various scraps and dust are sent to the 

uranium recovery circuit.
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Off-gases from storage before processing vent through the 3-1 stack. The main 

contaminants in the stack off-gases should be radon and radon daughters, if the 

radium originally in the concentrate feed goes into the ash (as was assumed in the 

previous section).

The material from storage is first dumped and ground. Dusts from this operation are 

recovered in a baghouse....

The finely ground material is leached using a sodium carbonate solution to solubilize 

the uranium as the tricarbonate complex....

After leaching, the pregnant solution is filtered. Lime is used to aid in precipitation of 

any fluoride, and the solution is again filtered. Sludge from the filters is dried. Offgases from the dryer pass through the dumping and grinding off–gas baghouse.

The dried sludge probably contains all nondecayed uranium daughters, some residual 

uranium, and some fluoride compounds. This sludge is drummed and sent to a 

licensed radioactive waste disposal facility. Approximately 1500 tons of this waste, 

containing a maximum of 46.9 Ci is produced yearly.

The uranium is precipitated from the solution using NaOH. The uranium is filtered and 

washed and then sent to the sodium removal section.

Cylinder Wash

Cylinders are returned to Allied from the enrichment facilities. These cylinders contain 

residual UF6 and the daughters of uranium that have “grown in” while the cylinders 

containing UF6 were in storage. The daughters in general are found plated out on the 

cylinder walls.

After any residual UF6 is removed from the cylinder, the cylinder is washed, using a 

solution of Na2CO3 to remove any impurities from the walls and to solubilize the 

uranium. The wash solution is filtered to remove the unleached solids, and the 

pregnant solution is pumped to join the pregnant solution in the uranium treatment 

section.

The solid residue from the filters contains daughter products of uranium, principally 

234Th and 234Pa, and is stored on-site in drums until disposal in a licensed waste 

disposal facility.

Sludge Dryer

As previously described, the process generates several sludges that contain uranium. 

Before being sent for uranium recovery, these sludges are dried in a calciner. Offgases containing SO2, HF and particulates from the calcining operation pass through a 

baghouse and a water spray tower before discharge....

The spent scrubber water, which contains uranium, fluoride compounds, and some 

sulfur compounds, is sent to the uranium recovery ponds.

The calcined sludges are drummed and stored until they can be processed in the 

uranium recovery section.
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2.3 SOURCE TERM

The plant produced UF6 from uranium ore concentrates initially for gaseous diffusion facilities and 

later also for commercial fuel fabrication facilities. The uranium conversion process at the plant has 

remained essentially unchanged since its inception. In 1982, Perkins (1982) reported that the 

concentrates initially contained 70% to 75% uranium by mass, and these concentrates included 

impurities that were dependent on the mines and mills from which the yellowcake came.

Uranium chemical forms at ACCP included all solubility types (i.e., F, M, and S). The initial design 

processing capacity was 5,000 t of uranium in a year, and by 1982 the throughput capacity had been 

increased to 14,000 t per year in what was essentially a continuous chemical process. As of 1982, 

more than 100,000 t of uranium had been processed (Perkins 1982).

The initial milling of the uranium before arrival at ACCP resulted in disequilibrium of uranium progeny 

in the concentrate. Exposure to the nonuranium radionuclides occurred at the front end of the 

processing, beginning with receipt. Increased concentrations of other radionuclides in relation to 

uranium were found in the fluorination bed ash and other solid waste streams, such as the sludge. 

Environmental air measurements in the late 1970s showed ratios of 226Ra and 230Th in relation to 

uranium that were larger than the concentrate ratios but lower than complete equilibrium ratios.

Radon concentrations would probably have been elevated during the initial opening of the drums of 

concentrate, in the feed area, and in work areas where radium would have concentrated. No 

measurements of radon concentrations have been found at this time.

Perkins (1982) summarized uranium, thorium, and 226Ra activities in ACCP effluents and wastes from 

the 1970s. These results were used to estimate ratios of the activity of other radionuclides to uranium 

in the effluent (activity ratios are listed in Table 2-1) and to reconstruct internal doses for nonuranium 

nuclides during the residual period. The ratio listed below for 230Th to NU in the concentrate was 

based on an average of yellowcake feed ratios from 33 mills (Perkins 1982, Table II-8). The 

equilibrium activity ratio of 230Th to uranium in uranium ore was about 0.4886; the milling of the ore 

usually reduced this ratio by almost a factor of 100 by removing the 230Th from the concentrate. 

It should be noted that 232Th comprised a portion of the radioactivity in the uranium concentrates, and 

although 232Th was not specifically reported for most effluents at ACCP, the water effluents for 1975 

and 1976 showed annual average activity ratios for 232Th to 234Th of 0.076 and 0.017, respectively 

(Perkins 1982, Table II-13). Assuming that 234Th is in equilibrium with 238U, and the activity fraction for 

238

U to NU from Table 3-1, the ratio of 232Th to NU based on the 1975 and 1976 water effluent results 

is 0.037 and 0.008.

Table 2-1. Radionuclide activity ratios in relation to uranium based on reported activities in ore

concentrates, and in ACCP wastes, air, and effluentsa (ORAUT 2014a).

Source

Average Largest

Th-nat:

NU

Th-230:

NU

Ra-226:

NU

Th-nat:

NU

Th-230:

NU

Ra-226:

NU

Concentrate (yellowcake feed average

for 33 mills) ND 5.20E-03 ND ND ND ND

Uranium recovery solid waste (dried 

sludge) 3.58E+00 1.90E+01 1.11E+00 ND ND ND

Solid nonsludge waste ND 5.27E-03 2.75E-04 ND ND ND

Outdoor air ND 6.70E-02 1.97E-03 ND 1.67E-01 8.46E-03

Air effluent ND 1.70E-02 2.70E-04 ND 4.75E-02 3.38E-04

Water effluent ND 3.99E-03 2.04E-02 ND 1.58E-02 5.79E-02

a. From Perkins (1982).

ND = no data provided in Perkins (1982).
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Processing at ACCP resulted in further separation of uranium and its progeny, and this could have 

resulted in increased activity ratios of nonuranium radionuclides in some areas in the plant. The 

largest disequilibrium ratios during the operational period were associated with the solid waste (dried 

sludge) from the uranium recovery facility. As stated above, these materials were barreled and 

shipped off the site as radioactive waste.

AEC and DOE recycled uranium inventory reports use the designation “JSA” to identify Allied 

Chemical Corporation (as a whole). DOE reported that the Rocky Flats Plant (RFP) shipped 71 kg 

(160 lb) of depleted recycled uranium to site designation JSA (the corporation) in 1975 (RFETS 2000, 

Appendix A, p. 74). Appendix B of the same document provides the site address as being in Idaho 

Falls, Idaho (RFETS 2000, Appendix B, p.115). Another reference that appears to summarize some 

parts of the same RFP report notes a shipment of 22,060 kg from RFP to Allied between 1955 and 

1964 (DOE ca. 2000), but this appears to be an error due to the misidentification of the next site 

designation in the RFP report, “LAB,” with “JSA.” In addition, Appendix A (RFETS 2000, Appendix A, 

p. 74) shows that this was a shipment from “LAB” to RFP. Therefore, it is assumed that contaminants 

in recycled uranium were not a significant contributor to ACCP worker radiation doses.

ACCP was licensed by the NRC to have sealed 137Cs sources up to 100 mCi each. These were used 

as level control devices and are unlikely to have contributed to internal dose.

2.4 SAFETY

Specific radiological safety measures implemented in the beginning of ACCP operations are not 

available but, as of 1958, radiological control programs in general had become more sophisticated. 

Dosimetry is available from the earliest days of covered operations for all employees who worked in 

the controlled area. The following information is based primarily on reference material from after 

1972, and it should be noted that the criteria to prompt radiological control activities could have 

differed in the early years.

Engineered confinement was and is the primary source of contamination control at ACCP. Drums, 

process vessels, lines, etc., are used to confine the materials. When unconfined uranium was 

handled, procedures called for ventilation controls to reduce exposures (Allied-Signal 1985a, p. 27).

An exception was requested from the NRC requirement to post and label individual radioactive 

material areas and containers, which was replaced by a requirement to train workers (NRC 2003, 

p. 75). Signs stated that any area or container in the plant could contain radioactive materials.

As of 1985, and probably from the earliest days of operations, protective clothing and shoes or shoe 

covers were provided to employees and visitors to ACCP to ensure that personnel were not 

inadvertently contaminated with uranium compounds (Allied-Signal 1985b, p. 49). This did not apply 

to administrative areas where contamination would not be expected. A review of claim records

supports the use of personal protective equipment during the operational period and indicates

increased personal protective equipment requirements depending on job, which included full-face 

masks, Scott Air Paks, rubber suits, plastic or rubber coveralls, and gray suit with supplied air.

Additional information indicates that at least before April 1975, all new hires at the ACCP Metropolis 

site received an introductory safety and health physics indoctrination and were issued a film badge 

and personal safety gear including hardhat, glasses, shoes, coveralls, and towels for their shower at 

the end of the workday, and employees entering the Feed Materials Building were provided with halfface respirators to carry with them for emergency use (Freeman 1975, p. 178).
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Current ACCP procedures, discussed below, include four contamination measurement and control 

parameters:

• Visual observation of contamination,

• Air concentration measurements,

• Surface contamination measurements, and

• Decontamination procedures.

2.4.1 Visual Observation of Contamination

ACCP noted that NU compounds had a low specific activity characterized by a high ratio of mass to 

activity. The ACCP uranium compounds were highly colored, which provides an immediate method 

for detecting gross surface and air contamination. For instance, yellowcake was yellow and UF6

releases appeared as white smoke due to the decomposition products, UO2F2 and HF. Procedures 

from 1985 stated that if employees detected small spills, they were responsible for cleanup (AlliedSignal 1985a). Larger leaks or spills that resulted in visible accumulation of uranium on equipment or 

on the floor required immediate decontamination, activation of the respirator lights, and possibly 

shutdown of the unit. The foremen were to prepare a health physics incident report and notify the 

health physics shift technician to initiate special air sampling and investigation as appropriate. Health 

physics personnel made a daily inspection of uranium operating areas to ensure proper 

decontamination and contamination control. These procedures were consistent with contemporary 

industrial health practices for uranium facilities (DOE 1988).

2.4.2 Air Activity Measurement of Contamination

As of 1985, stationary breathing-zone samples were collected daily from 57 stations in the UF6

building, 10 stations in the sampling plant, 2 stations in the drum dumper, 3 stations in sodium 

removal, and 2 stations in the uranium recovery unit. Summaries of some of these measurements 

can be found in the available references. As of 1985, respirators were required when either the 

average gross alpha air concentration on a floor exceeded 4 × 10-11 μCi/cm3 or when any four air 

samples on the floor exceeded that concentration. In addition, as of 1985, any single air sample 

result that exceeded 1 × 10-10 μCi/cm3 required investigation and preparation of a health physics 

incident report (Allied-Signal 1985a, p. 29).

Although some air concentration data are available for the 1970s and later, these data were not used 

to estimate worker intakes because of the abundance of bioassay data.

2.4.3 Surface Contamination Measurements

Surface contamination measurements in uranium and nonuranium areas were made routinely. 

Removable contamination was determined by taking a wipe or smear of 100 cm2 on a surface. Each 

smear was counted for alpha radioactivity and reported in dpm/100 cm2 removable alpha 

contamination. The plant lunchroom and offices or control rooms were surveyed weekly, as were the 

locker rooms and personnel exit areas. Uranium processing areas such as the Feed Materials 

Building, Sodium Removal, Uranium-Recovery Building, and Sampling Plant were surveyed monthly. 

Other nonuranium processing areas were surveyed quarterly (Allied-Signal 1985a; Honeywell 1999, 

Section 3).

As of 1985, decontamination was to be initiated when removable alpha contamination exceeded

5,000 dpm/100 cm2 in the uranium processing areas. All other areas were to be decontaminated 

when removable alpha contamination exceeded 200 dpm/100 cm2 (Allied-Signal 1985a).
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One summary of health physics data for the last half of 1991 (Wilkins 1992) noted that 1.7% of the 

2,002 weekly smears exceeded the weekly limit of 200 dpm/100 cm2 and that the highest result was 

923 dpm/100 cm2 in the lunchroom on a table. One of the 570 monthly smears and none of the 163 

quarterly smears exceeded the limit.

2.4.4 Decontamination

ACCP had detailed procedures for decontaminating spills or leaks found in the plant. These 

procedures generally included roping off the area, sweeping or vacuuming the contaminated material, 

and then washing the contaminated surface. During these procedures protective clothing was to be 

used and monitoring was to be performed (Allied-Signal 1985a; Honeywell 1999, Section 4).

2.5 INCIDENTS

The claim records include some information about incidents, but details are few and there are no 

dates or references to particular incident reports. Claim information describes spills of ore, dusty 

conditions (yellow dust), occasional leaking valves and line ruptures resulting in releases of UF4 and 

UF6, and inadequate packing that resulted in material releases, the evacuation of buildings, and 

environmental releases.

A partial history of incidents is provided in Attachment C (ORAUT 2013a). The listed events occurred 

primarily during the residual period and therefore provide a general summary of the frequency and 

types of releases and incidents for the period. This includes a release of 43 kg of UF6 due to a valve 

failure on November 12, 1968, at the ACCP (ORAUT 2013a; NRC 2010). Because all workers 

participated in a routine bioassay program (generally biweekly for plant workers and monthly for 

administration workers and more frequently if an intake was suspected), these bioassay results can 

be used for internal dose reconstructions. The direct deposition of uranium on exposed skin was 

possible, and an evaluation of the impact on skin dose is evaluated on a case-by-case basis. In such 

cases, any specific information about an incident or contamination event from claimant records should 

be considered and whether the deposition is co-located with the cancer site. A dose reconstructor 

should apply the guidance in ORAUT-OTIB-0017, Technical Information Bulletin: Interpretation of 

Dosimetry Data for Assignment of Shallow Dose, for the assignment of skin dose (ORAUT 2005).

2.6 PHYSICAL EXAMINATIONS – X-RAYS

No documented ACCP requirement for occupationally required medical X-ray examinations has been 

found, but, more than half of the claimant interviews indicate that chest X-ray examinations were 

routine and a number of the interviews indicate the frequency was annual. Information indicates that 

at least before April 1975, all new hires at the ACCP Metropolis site received a pre-employment 

physical exam which included a chest X-ray, and that repeat annual physical exams were given with 

chest X-rays included on alternate years (Freeman 1975, p. 178). Anecdotal information indicates 

that the examinations were offered annually, but were optional by 1980, and would have been done at 

Massac Memorial Hospital or perhaps a local doctor’s office according to one employee, who began 

work at ACCP in the 1970s.

2.7 SUMMARY OPERATIONAL PERIOD ASSUMPTIONS, WORKDAYS, WORK HOURS, 

WORK CATEGORIES

Because bioassay and film badge data were used to estimate internal and external exposures during 

AEC uranium operations, an estimate of the number of workdays or work hours per year is not 

necessary.
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Workers who might have had a higher external exposure potential or workers who might have 

handled radioactive materials and had a higher extremity dose potential are listed by job title in 

Attachment B. Individual dosimetry appears to be available for most workers. Therefore, the 

reconstructed external dose should be based on specific individual dosimetry.

2.8 RESIDUAL CONTAMINATION

Uranium concentrate processing continued at ACCP after 1976, and differentiation between residual 

contamination from the AWE period and contamination due to later and/or ongoing operations is not 

feasible.

3.0 ESTIMATING INTERNAL EXPOSURE

As stated in Section 1.3 above, a decision has been made that internal dose from nonuranium 

radionuclides cannot be reconstructed with sufficient accuracy for employees of ACCP during the 

AEC operations period from 1959 through 1976. The primary source of internal radiation exposure at 

ACCP was uranium dust produced from the processing of uranium concentrates to produce UF6. It is 

assumed that the uranium was of natural enrichment before 1977. Although the uranium ore 

concentrate contained uranium progeny of dosimetric interest as well as thorium (assumed to be 232Th 

and 228Th), only uranium dose can be estimated for ACCP claims for the period from January 1, 1959,

through December 31, 1976.

3.1 URANIUM

During the processing of uranium concentrates at ACCP, workers might have been exposed to a 

variety of uranium chemical forms that encompass all lung absorption types: F, M, and S. Although 

some process steps might have had more or less exposure to a given lung absorption type, it is not 

clear how well separated these areas were. In addition, workers might have worked in multiple 

uranium process areas. The selection of absorption type should depend on the organ of interest. The 

specific activity of the NU and the isotopic mass and activity fractions are listed in Table 3-1 [1]. For 

organ dose estimates, the uranium activity can be assumed to be from 234U [2]. A conversion factor is 

provided to adjust results reported as micrograms of 235U to total uranium activity in picocuries.

Table 3-1. NU specific activity and isotopic fractions.

Isotope

Activity 

fraction

Mass 

fraction

Activity ratio 

to U-235

Mass ratio 

to U-235

U-234 0.4886 5.37E-05 21.4 0.00745

U-235 0.0228 7.20E-03 1 1

U-238 0.4886 9.93E-01 21.4 138

Useful factors

NU pCi/μg 0.683

U (pCi):U-235 (μg) 94.8

3.1.1 Uranium Urinalysis Data

Individual uranium urinalysis began as early as December 1958 and was done in house. It appears 

there are bioassay data for all workers. The worker records show that bioassays were typically 

collected at hire and periodically thereafter. ACCP notes that fluorimetry was used for analyses until 

2002, when kinetic phosphorescence analysis (KPA) began (Rogers 2006). Some urinalysis data 

between 1989 to 1992 are missing, and ACCP reported that it was assumed that the missing records 

might have been water-damaged beyond recovery.

In the early years, uranium urinalysis results that were reported in microcuries per milliliter (μCi/mL) 

are misstated; the units were actually micrograms per liter (μg/L). The recording limit of 10 μg/L is 
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from the early records and is consistent with the default detection threshold for uranium urinalysis 

assumed to be 10 μg/L based on a reported sensitivity of 5 to 10 μg/L for uranium fluorimetry 

urinalysis in the early years (Wilson 1958). Beginning in late 1974, a recording limit of 5 μg/L appears 

to have been in use. ACCP reported that its minimum detection level (MDL) was 2 μg/L in the early 

1980s, but no records of MDL are available before that. In 1985, ACCP noted that routine urinalysis 

samples were to be left after 24 to 96 hours of absence from the workplace, but it is unknown when 

this procedure was implemented. In addition, as of 1985, ACCP employees were encouraged to 

leave special urine samples before their next work shift in response to known or suspected airborne 

exposures (NRC 1993, p. 50). In later years, it was noted that a result equal to 30 μg/L was cause for 

investigation.

On the computer printouts, results are sometimes noted in the comments section rather than the 

bioassay measurement section.

3.1.2 Uranium In Vivo Data

Lung counts are available for many workers beginning in late 1978, which is after the covered 

operational period. Lung counts appear to have been performed on an annual or biannual frequency 

until the mid-1980s. They appear to be less frequent in later years, but this could indicate that only 

some workers were required to have annual lung counts in later years.

ACCP claims include a letter that reports use of a uranium lung-counting system from Radiation 

Management Corporation (RMC) and analysis of the spectra using a software package called 

RMCWBC, which was based on the Oak Ridge National Laboratory program ALPHA-M (Rogers 

2006). The counting system includes an RMC-designed shadow shield and four detectors, which 

appears to have consisted of thin NaI(Tl) and thicker CsI(Na) crystals. The diameter was reported as 

5 ft but was probably 5 in. Before analysis of the spectra, the background was automatically 

subtracted. A REMCAL standard man equivalent phantom was used to calibrate the system. 

Radionuclides included 235U, 234Th, 137Cs, and 40K.

Specific ACCP criteria were given for judging the data and can be used for considering the relative 

validity of a result (Rogers 2006):

• Fit should be less than 3.0 and usually ranges between 0.5 and 1.5. An ideal fit would be 0.

• The shift value should range between +2.0 and -2.0; values outside the range of ±3.0 are 

carefully reviewed before they are accepted. MCA zero level and/or gain adjustments are 

warranted when the shift value exceeds ±2.0.

• The gain should ideally be 1.0 and a gain of 0.90 to 1.10 is considered acceptable. 

Adjustment to the gain and/or zero might be needed if the value is outside this range.

• Results with errors greater than 100% (results less than 2 times their counting standard 

deviation) were considered questionable. 

The analysis program reportedly printed a table showing all identified radionuclides and their 

estimated activities and relative 2-standard-deviation counting error in terms of a percent error. ACCP

reported that results of 235U were given in micrograms and results for other radionuclides were given 

in nanocuries. However, some records show 234Th results in micrograms. The maximum permissible 

lung burden (MPLB) was noted as 194.3 μg of 235U, or summed as 26,974 μg of total uranium (AlliedSignal 1986, p. 10). The reported 235U minimum detection level was noted as 63 μg, which was 

equated to 32% of the MPLB (NRC 1993, p. 51; Allied-Signal 1986, p. 16). In later years, it was noted 

that a result equal to 50% of the MPLB was cause for investigation.
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Unless there was a prominent low-energy peak or the detector ratios varied by more than 0.025, the 

detected uranium was assumed to be in the lung.

In general, the urinalysis results should be used to estimate intakes and the lung counts can be used 

as supporting data. The lung counts did not directly measure total uranium and, although height and 

weight were recorded and could have been used to estimate chest wall thickness, there is no 

indication that chest wall thicknesses were measured directly.

To convert 235U mass to total uranium activity, it was assumed that the uranium was of natural 

enrichment and so the 235U mass in μg should be multiplied by 2.16 pCi/μg (the specific activity of 

235U) and divided by 0.0228 (the activity fraction of 235U) (a combined factor of 94.8 [U pCi / 235U μg])

to obtain the total uranium activity in picocuries [3].

To convert 234Th to total uranium activity, it was assumed that the 234Th was in equilibrium with both 

238U and 234U, and so the mass of 234Th in micrograms should be multiplied by 2.32 × 1010 pCi/μg (the 

specific activity of 234Th) and divided by 0.4886 to obtain the total uranium activity in picocuries [4]. If 

the 234Th was given in nanocuries, it can be converted to picocuries of uranium by dividing by 4.886 × 

10-4

. Note that with a 24.1-day half-life, 234Th might not have been in equilibrium with its uranium 

parent depending on when and where an exposure occurred.

The 40K and 137Cs that were reported in lung counts are not likely to be associated with workplace 

exposures; 40K should be ignored. On occasion, in vivo measurement results included 137Cs. 

However, those workers could have had body burdens of 137Cs from nonoccupational sources (e.g., 

fallout and consumption of specific foodstuffs). There is no evidence of occupational intakes of 137Cs 

at ACCP, so no dose of record should be associated with these measurement results [5].

A handwritten note (Allied-Signal 1996) indicates that other whole-body counting systems might have 

been in use as of 1996, but there were no differences in reported sensitivity.

3.2 NOTATIONS ON BIOASSAY RECORDS

Some of the bioassay records include brief comments on the job assignment, time away from the site,

reasons for a resample such as a release, and other notations and abbreviations. These include:

• Laid off,

• Rehired,

• Trnfd [transferred],

• MTO [Morristown Office, corporate headquarters in New Jersey],

• MPLB,

• Sample type R,routine (Honeywell 2013b), and

• Sample type S, all nonroutine bioassay samples including initial samples, exit samples, and 

samples after a suspected exposure (Honeywell 2013b).

3.3 OCCUPATIONAL INTERNAL DOSE RECONSTRUCTION ASSUMPTIONS AND 

SUMMARY

The AEC operational exposure period was from January 1, 1959, to December 31, 1976. As stated in 

Section 1.3 above, a decision has been made that internal dose from nonuranium radionuclides 

cannot be reconstructed with sufficient accuracy for employees of ACCP during this period, so only 

internal dose from uranium is considered in this section.

In general, the urinalysis results should be used to estimate uranium intakes, and the lung counts can 

be used as supporting data using the guidance in ORAUT-OTIB-0060, Internal Dose Reconstruction 
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(ORAUT 2007b). The uranium photofluorimetry urinalysis reporting limit in the early years at ACCP 

was 10 μg/L [6]. The less-than results, when available in the individual dosimetry records, can be 

assumed to be uranium urinalysis detection thresholds. The uranium could have been absorption 

type F, M, or S. For activity-based dose calculations, uranium intakes can be assumed to be 234U.

To estimate uranium intakes from the lung counts, the intake of 235U should be determined and then 

adjusted to total uranium intake activity using the conversion in Table 3-1. The lung detection 

threshold was 63 μg for 235U and 5,970 pCi for total uranium.

Based on the current information, all workers were monitored for uranium intakes, so at this time no 

assumptions have been provided for unmonitored workers or unmonitored periods. This section will 

be developed further, if necessary.

4.0 ESTIMATING EXTERNAL EXPOSURE

4.1 PENETRATING AND NONPENETRATING DOSES

External dosimetry results are available for ACCP workers beginning on January 1, 1959, and include 

results for gamma, beta, and neutron exposures. ACCP reports that the data before 1970 are 

handwritten and the records do not include the company or method of measurement. Beginning in 

1969, R.S. Landauer Jr. & Company provided film badge dosimetry services and measured gamma 

and beta radiation. From about April 1976 through 1999, Eberline Instrument Company and its’ 

successors provided thermoluminescent dosimeter services. ICN Worldwide Dosimetry began 

providing thermoluminescent dosimeter services in 2000 and Landauer Dosimetry beginning in 2007. 

Neither Landauer nor Eberline reported doses below 10 mrem (Landauer report code M). Table 4-1 

lists the types of dosimeter in use and the reported dose quantities.

Table 4-1. ACCP dosimeter type and reported dose quantity.

Year Dosimeter Type Dosimeter Measured Quantity

1959–1969 Film Gamma, beta, neutron

1970–1973 Film Gamma, beta

1974–March 1976 Film Gamma, beta, period total (gamma+beta)

April 1976–1993 TLD Gamma, beta, whole body, skin total

1994–1996 TLD Deep, eye, shallow

1997–1999a TLD Deep, lens, shallow, total period extremities

2000–present TLD Deep, lens

a. Starting in 1997, the record is notated that all blank dose entries are values less than the lower 

limit of detection.

The earliest available ACCP external dosimetry results are from January 1, 1959. Badge exchange 

frequencies at ACCP were typically monthly in the available records. In the 1980s, hourly employees 

exchanged badges monthly and salaried employees changed badges quarterly.

A detection threshold of 40 mrem has been recommended for this Project (ORAUT 2006).

The majority of photons from NU have energies in the range of 30 to 250 keV, so this analysis 

assumed workers were exposed to photon energies in the 30- to 250-keV range, which is consistent 

with NIOSH (2007). Measured penetrating doses from photon radiation should be reasonably correct. 

It is possible to read a photon dose of 100 mrem to within ±15 mrem if the exposure involved photons 

with energies between several keV and several MeV (Morgan 1961, p. 13). The estimated standard 

error in recorded film badge doses from photons of any energy is ±30% (ORAUT 2006). The 

estimated error for thermoluminescent dosimeter (TLD) doses from photons is likely lower, based on 

performance testing of the TLD systems at the Savannah River Site and the Oak Ridge National 

Laboratory (ORAUT 2006, 2007c). For a dose reconstruction in which maximizing assumptions can 
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 25 of 42

be made, the uncertainty of 30% is considered an upper bound and can be applied as a factor of 1.3, 

according to current Project guidance.

Nonpenetrating dose from NU consists primarily of electrons with energies greater than 15 keV. 

Measured and missed nonpenetrating doses from electrons should be corrected to account for 

attenuation by clothing or personal protective equipment, if applicable, based on the location of the 

cancer and the workplace practices. A dose reconstructor should apply the guidance in ORAUTOTIB-0017 for assignment of skin dose from penetrating and nonpenetrating radiation (ORAUT 2005).

The assignment of external dose for periods when monitoring records are incomplete or missing 

should follow the guidance in OCAS-IG-001, External Dose Reconstruction Implementation Guideline

(NIOSH 2007). For example, cycle records for 1969 are not available for most claims, and some 

records contain quarterly dose reports for 1969 (Landauer). In the adjacent years, 1968 and 1970,

the exchange frequency appears to be monthly. Therefore, missed dose in 1969 should be assessed 

using the assumption of a monthly badge exchange frequency. If quarterly results are not available,

it could be necessary to estimate the dose based on the recorded dose in the adjacent years 1968 

and 1970.

4.2 NEUTRON DOSE

Because the uranium was mixed with material that can produce neutrons from an alpha particle 

collision, neutron dose was also considered. Although some records (from 1959 to 1969) have results 

that are recorded as neutron doses, in later years no records of neutron doses are available. Most of 

the results appear to be zeros, and it is not clear if these represent actual dosimeter results or were 

entered because there was no result. The Bridgeport Brass site profile (ORAUT 2013b) notes that the 

minimum detectable neutron dose that was reported in the early 1960s was 60 mrem.

A reasonable neutron dose estimation that is favorable to claimants is based on a cylinder containing 

1000 pounds of UF6. The alpha particles from the uranium isotopes collide with fluorine atoms to 

generate neutrons. Using MCNPX, the neutron exposure rate at one foot from the cylinder was 

calculated to be 1.36 × 10-4 rem/hr and at three feet, 3.94 × 10-5 rem/hr (ORAUT 2014b). A worker 

who is 1 foot from such a cylinder for 2,000 hr/yr would be exposed to a dose rate of 0.272 rem/yr. 

This estimated neutron dose rate is considered to be an upper bound (maximum estimate) of the 

ACCP neutron dose rate. The mode neutron dose rate was estimated as 5.91 × 10-3 rem/yr, which is

the result of applying an occupancy factor of 3 hr/wk over 50 weeks to the estimated dose rate at 3 ft

from a cylinder (ORAUT 2007a, 2014b). The minimum neutron dose rate is estimated as 0 rem/yr. 

These estimated minimum, mode, and maximum neutron dose rates should be used only for 

reconstructing doses during the listed operational period and applied in the Interactive 

RadioEpidemiological Program (IREP) as a triangular distribution. During the residual period, the 

weapons-related source materials (such as uranium and fluorine targets) needed to produce neutrons 

are not presumed to be present in amounts significant enough to warrant the estimation of neutron 

dose.

Neutron dose is assumed to be associated with neutrons of energies of 0.1 to 2 MeV.

4.3 OCCUPATIONALLY REQUIRED MEDICAL X-RAY

No definitive formal ACCP procedural information was found that indicated the type or frequency of 

occupationally required medical X-ray examinations, although the claimant interviews support an 

assumption of an annual chest X-ray examination, as does additional information (Freeman 1975). 

The type and projection of X-ray examination should be based on current Oak Ridge Associated 

Universities (ORAU) Team guidance in ORAUT-OTIB-0006, Dose Reconstruction from Occupational 
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 26 of 42

Medical X-Ray Procedures (ORAUT 2011), which at this time is a posterior-anterior (PA) radiographic 

chest examination. Organ doses can be obtained from the current revision of ORAUT-OTIB-0006.

4.4 MISCELLANEOUS INFORMATION ABOUT EXTERNAL DOSE

This section includes external dose information that could be of value for specific dose 

reconstructions. This analysis did not consider such information generically because of its limited 

applicability or because of limited details.

The fluorination bed ash contained short-lived progeny, which resulted in elevated beta and gamma 

radiation fields in the vicinity of the ash. Workers who handled this material or washed drums or 

cylinders could have received extremity doses higher than those that were measured by dosimeters 

on the trunk of the body. Extremity exposure monitoring results are not available for either the 

operational or residual period (Honeywell 2013a). Job titles that involve more routine handling of 

uranium materials are provided in Attachment B (Honeywell 2013a). Dose reconstructors should 

consult DCAS-TIB-0013, Selected Geometric Exposure Scenario Considerations for External Dose 

Reconstruction at Uranium Facilities (NIOSH 2010b) and, if applicable based on the location of the 

cancer and the workplace practices, the information in the claimant monitoring records and the job 

titles in Table B-2 to determine if adjustments for extremity dose are appropriate.

4.5 OCCUPATIONAL EXTERNAL DOSE RECONSTRUCTION ASSUMPTIONS AND 

SUMMARY

Table 4-2 summarizes assumptions about occupational external doses during the covered period from 

January 1, 1959, to December 31, 1976, at ACCP.

Table 4-2. External exposure summary.

Exposure mode Exposure type Annual exposure

Uranium processing

Penetrating (photons, 30–250 keV, APa

, acute) Based on individual dosimetry

Nonpenetrating (electrons >15 keV, acute) Based on individual dosimetry

Neutron (0.1 to 2 MeV, triangular)

Maximum: 2.72E-01 rem

Mode: 5.91E-03 rem

Minimum: 0.00 rem

PA chest radiographic 

examination

Initial (pre-employment) plus one examination 

each subsequent year of employment.

See ORAUT-OTIB-0006 

(ORAUT 2011)

a. Apply exposure DCFs for 1959 to 1975 and Hp(10) DCFs starting in 1976.

5.0 ESTIMATION OF EXPOSURE FROM RESIDUAL RADIOACTIVITY

ACCP continued to operate after the covered AWE period ended on December 31, 1976. NIOSH has 

determined the residual radiation period to be from January 1, 1977, to March 1, 2011 (DOE 2013). 

As stated in Section 2.8, differentiation between residual contamination from the AWE period and 

contamination due to later and/or ongoing operations is not feasible. The following information 

provides a method for estimating exposures during the residual radiation period due to uranium and 

nonuranium residual contamination.

5.1 INTERNAL EXPOSURE TO RESIDUAL ACTIVITY

Internal exposures due to intakes of uranium after 1976 can be estimated using the personnel 

monitoring data that was collected during this period (in vivo and in vitro data, as applicable). 

Table 5-1 can be used to account for intakes of nonuranium radionuclides during the residual 
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 27 of 42

contamination period. The values in this table are based on the highest reported ratio in the outdoor 

air and air effluent pathways from Table 2-1. The use of these pathways during the residual period is 

appropriate because they are representative of the isotopic distribution of the resuspended materials 

to which workers during the residual period would have been exposed [7]. Because no values were 

reported for 232Th, the water effluent value (Section 2.3) was used.

To account for the fact that only a portion of the internal exposure during the residual contamination 

period is from resuspended residual contamination versus exposure due to continued site operations

that are not covered by EEOICPA, calculated intakes should be adjusted by a weighting factor to 

account for the continued depletion of the pre-1977 operational source term during the residual 

period.

ORAUT-OTIB-0070, Dose Reconstruction During Residual Radioactivity Periods at Atomic Weapons 

Employer Facilities, establishes a source term depletion factor of 0.067 % of the surface activity per 

day (ORAUT 2012). Use of this depletion factor is favorable to claimants based on the depletion 

behavior that is reported above. The factors to account for depletion of the pre-1977 source term 

during the residual period are presented in Table 5-2 from ORAUT (2012).Examples of the application 

of the Table 5-1 activity ratios and Table 5-2 depletion adjustment factors to estimate intake rates are 

presented in Attachment A.

5.2 EXTERNAL EXPOSURE TO RESIDUAL RADIOACTIVITY

Individual dosimeter results are available for workers during the residual period. However, these 

results include exposure to residual contamination from the AWE operation as well as dose from 

continued commercial operations. An estimate of external dose during the residual period can be 

obtained by adjusting residual period external dosimetry results by the Table 5-2 depletion adjustment 

factors.

5.3 DOSE RECONSTRUCTION ASSUMPTIONS AND SUMMARY FOR RESIDUAL PERIOD

Table 5-3 (supplemented with the detailed guidance in Sections 3.0, 4.0, and 5.0) summarizes the 

assumptions for calculating dose for the residual exposure period from January 1, 1977, to March 1, 

2011, at ACCP.

Table 5-1. Source term activity ratios relative to 

natural uranium (based on Section 2.3).

NU 1

Th-232 0.037

Th-230 0.167

Th-228 0.037

Ra-228 0.037

Ac-228 0.037

Ra-224 0.037

Ra-226 0.00846

Pb-210 0.00846

Po-210 0.00846
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 28 of 42

Table 5-2. Adjustment factors to account for depletion of pre1977 source term during the residual contamination period.

Year Factor

1977 1

1978 7.83E-01

1979 6.13E-01

1980 4.80E-01

1981 3.76E-01

1982 2.94E-01

1983 2.31E-01

1984 1.81E-01

1985 1.41E-01

1986 1.11E-01

1987 8.67E-02

1988 6.79E-02

1989 5.32E-02

1990 4.16E-02

1991 3.26E-02

1992 2.55E-02

1993 2.00E-02

1994 1.56E-02

1996 1.23E-02

1996 9.60E-03

1997 7.51E-03

1998 5.88E-03

1999 4.61E-03

2000 3.61E-03

2001 2.83E-03

2002 2.21E-03

2003 1.73E-03

2004 1.36E-03

2005 1.06E-03

2006 through March 1, 2011 8.32E-04

Table 5-3. Residual radiation exposure summary for January 1, 1977, to March 1, 2011.

Source Exposure information Annual exposure

Uranium contamination

U-234

Internal (alpha, chronic) Inhalation intake based on individual 

bioassay results adjusted by factors in 

Table 5-2.

Nonuranium contamination

Th-232

Th-230

Th-228

Ra-228

Ac-228

Ra-224

Ra-226

Pb-210

Po-210

Internal (alpha, chronic) Inhalation intake for listed nonuranium 

radionuclides based on the assigned 

uranium intake rate and the nonuranium 

ratio values of Table 5-1.

Uranium and nonuranium 

contamination

External

Penetrating (photons, 

30–250 keV, APa, acute)

Use reported dosimetry results adjusted by 

factors in Table 5-2.

Uranium and nonuranium 

contamination 

External

Nonpenetrating

(electrons >15 keV, acute)

Use reported dosimetry results adjusted by 

factors in Table 5-2.

a. Apply Hp(10) DCFs.
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 29 of 42

6.0 ATTRIBUTIONS AND ANNOTATIONS

Where appropriate in this document, bracketed callouts have been inserted to indicate information, 

conclusions, and recommendations provided to assist in the process of worker dose reconstruction. 

These callouts are listed here in the Attributions and Annotations section, with information to identify

the source and justification for each associated item. Conventional References, which are provided in 

the next section of this document, link data, quotations, and other information to documents available 

for review on the Project’s Site Research Database (SRDB).

[1] Olsen, Bernard M. ORAU Team. Senior Health Physicist. July 2007.

The data for NU are as presented in the bioassay application Integrated Modules for Bioassay 

Analysis (IMBA).

[2] Olsen, Bernard M. ORAU Team. Senior Health Physicist. July 2007.

This assumption results in estimated organ doses that are favorable to claimants. The 

assumption that all uranium available for intake is 234U will result in slightly higher estimates of 

organ doses than if NU is assumed. For a dose reconstruction employing best-estimate 

methodology, NU can be assumed.

[3] Olsen, Bernard M. ORAU Team. Senior Health Physicist. July 2007.

The data for NU are as presented in the bioassay application Integrated Modules for Bioassay 

Analysis (IMBA).

[4] Olsen, Bernard M. ORAU Team. Senior Health Physicist. July 2007.

The activity fraction of 234U and of 238U (0.4882) in NU are as presented in the bioassay 

application, Integrated Modules for Bioassay Analysis (IMBA). The specific activity of 234Th 

(2.32 × 1010 pCi/μg) and half-lives of radionuclides are listed in any standard handbook of 

radiation protection quantities such as The Health Physics and Radiological Health Handbook, 

Revised Edition (Shleien 1992).

[5] Keefer, Estella L. ORAU Team. Senior Health Physicist. March 2014.

Review of ACCP documents do not indicate that 137Cs has been considered an isotope of 

concern at ACCP beyond the occasional elevated exposure to an individual due to dietary 

consumption and the increases due to global testing and incidents.

[6] Olsen, Bernard M. ORAU Team. Senior Health Physicist. July 2007.

The increased sensitivity of the urinalysis methods that have been used at ACCP over time is 

evident from the individual bioassay monitoring records of ACCP claimants. Results less than 

the level of detection for urinalysis results, in units of micrograms per liter (μg/L), are reported 

as <10 μg/L through approximately mid 1974, <5 μg/L from then through approximately late 

1978, and <2 μg/L after late1978.

[7] Guido, Joseph S. ORAU Team. Senior Health Physicist. July 2007.

The airborne effluent and ambient air data from Perkins (1982) was collected between 1976 

and 1979. As such, they are representative of the isotopic distribution at the start of the 

residual period.
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 30 of 42

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Leavitt, M. O., 2007, HHS Designation of Additional Members of the Special Exposure Cohort under 

The Energy Employees Occupational Illness Compensation Program Act of 2000, Designating 

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Petition SEC-00067, Rev. 0, Office of Compensation Analysis and Support, Cincinnati, Ohio, 

November 10.

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Implementation Guideline, OCAS-IG-001, Rev. 03, Office of Compensation Analysis and 

Support, Cincinnati, Ohio, November 21]

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

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

Support, Cincinnati, Ohio, October 5.

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Scenario Considerations for External Dose Reconstruction at Uranium Facilities, DCAS-TIB013, Rev. 01, Division of Compensation Analysis and Support, Cincinnati, Ohio, November 23.

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and Beryllium Contamination at Atomic Weapons Employer Facilities and Beryllium Vendor 

Facilities, Division of Compensation Analysis and Support, Cincinnati, Ohio, August. [SRDB 

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(with supporting material), Office of Nuclear Material Safety and Safeguards, Washington, 

D.C., January 30. [SRDB Ref ID: 12380]

NRC (U. S. Nuclear Regulatory Commission), 2010, “Module 6.0: Accidents and Emergencies at Fuel 

Cycle Facilities,” General Health Physics Practices for Fuel Cycle Facilities Directed SelfStudy Course, Washington, D.C., October. [SRDB Ref ID: 105118, p. 35]

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Interpretation of Dosimetry Data for Assignment of Shallow Dose, ORAUT-OTIB-0017, Rev.

01, Oak Ridge, Tennessee, October 11.

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for Overestimating External Doses Measured with Film Badge Dosimeters, ORAUT-OTIB0010, Rev. 01, Oak Ridge, Tennessee, June 5.

ORAUT (Oak Ridge Associated Universities Team), 2007a, Portsmouth Gaseous Diffusion Plant –

Occupational External Dose, ORAUT-TKBS-0015-6, Rev. 01 PC-1, Oak Ridge, Tennessee, 

August 20.

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Occupational External Dose, ORAUT-TKBS-0012-6, Rev. 01, Oak Ridge, Tennessee, 

September 10.

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Medical X-Ray Procedures, ORAUT-OTIB-0006, Rev. 04, Oak Ridge, Tennessee, June 20.

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Radioactivity Periods at Atomic Weapons Employer Facilities, ORAUT-OTIB-0070, Rev. 01, 

Oak Ridge, Tennessee, March 5.

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0001),” letter to Honeywell Metropolis Works, Cincinnati, Ohio, September 19. [SRDB Ref ID:

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Havens Laboratory and Adrian Plant, ORAUT-TKBS-0030, Rev. 01, Oak Ridge, Tennessee, 

January 24.

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Radionuclides at ACCP Based on Perkins 1982 document,” spreadsheet, Cincinnati, Ohio, 

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MCNP Calculations, Oak Ridge, Tennessee, February 24. [SRDB Ref ID: 130631]

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Conversion (UF6) Facilities, LA-9397-MS, University of California, Los Alamos National 

Laboratory, Los Alamos, New Mexico, October. [SRDB Ref ID: 12379]

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at the Department of Energy’s Rocky Flats Plant, 1953 - 1993, Golden, Colorado, June 30. 

[SRDB Ref ID: 16227]

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Metropolis, Illinois, November 10. [SRDB Ref ID: 32707]

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

Scinta, Silver Spring, Maryland.

Sloop, J. L., 1978, “Liquid Hydrogen as a Propulsion Fuel, 1945-1959, Part II: 1950 1957, 5. NACA 

Research on High-Energy Propellants,” SP-4404, National Aeronautics and Space 

Administration, Washington, D.C. [SRDB Ref ID: 24144]

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Experience and Practices in the Uranium Industry, Held in New York City, October 15 – 17, 

1958, HASL-58, U.S. Atomic Energy Commission, New York Operations Office, New York, 

New York, September, p. 77. [SRDB Ref ID: 7886, p. 89]
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 33 of 42

This attachment provides example cases to demonstrate the application of residual dose factors. In 

all cases, the internal dose should first be assessed using the worker’s urine and lung count data (if 

available) during the entire employment period or up to date of diagnosis. Once an appropriate set of 

intake regimes are determined, adjustments should be made as follows:

• Break the intake regimes into the following periods: 

– Pre 1977: Operational Period

– 1977 onward: Residual Period

• Adjust uranium intake rates after 1976 using the appropriate factor in Table 5-2 (based on 

intake year)

• Add intakes for uranium progeny based on ratios in Table 5-1 for periods after 1976

• This same approach would apply to the external dose.

Example 1: Missed or fitted chronic intake during operational and residual period.

A chronic uranium intake of 100 pCi/d is to be assigned from 1972 through 1980. Uranium intakes 

are assigned:

Year Source Term Depletion

Chronic Intake

(pCi/day)

Assigned Intake

(pCi/d)

1972 1 100 100

1973 1 100 100

1974 1 100 100

1975 1 100 100

1976 1 100 100

1977a 1 100 100

1978a 0.783 100 78.3

1979a 0.613 100 61.3

1980a 0.48 100 48

a. Add intakes for uranium progeny based on ratios in Table 5-1 for periods after 1976.

ATTACHMENT A

APPLICATION OF RESIDUAL DOSE FACTORS

Page 1 of 2
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 34 of 42

Example 2: Fitted acute intake during operational and residual period.

Three acute uranium intakes of 10,000 pCi assigned in 1973, 1977, and 1985. Uranium intakes are 

assigned:

Year Source Term Depletion

Acute Intake

(pCi/day)

Assigned Intake

(pCi/d)

1973 1 10000 10000

1974 1

1975 1

1976 1

1977a 1 10000 10000

1978a 0.783

1979a 0.613

1980a 0.48

1981a 0.376

1982a 0.294

1983a 0.231

1984a 0.181

1985a 0.141 10000 1410

a. Add intakes for uranium progeny based on ratios in Table 5-1 for periods after 1976.

Example 3: Fitted chronic and acute intakes during residual period.

A chronic uranium intake of 100 pCi/d is to be assigned from 1980 through 1990 and three acute 

uranium intakes of 10,000 pCi assigned in 1982, 1985, and 1988. Uranium intakes are assigned:

Year

Source Term 

Depletion

Chronic Intake

(pCi/day)

Assigned Intake

(pCi/d)

Acute Intake

(pCi/day)

Assigned Intake

(pCi/d)

1977a 1

1978a 0.783

1979a 0.613

1980a 0.48 100 48

1981a 0.376 100 37.6

1982a 0.294 100 29.4 10000 2940

1983a 0.231 100 23.1

1984a 0.181 100 18.1

1985a 0.141 100 14.1 10000 1410

1986a 0.111 100 11.1

1987a 0.087 100 8.7

1988a 0.068 100 6.8 10000 680

1989a 0.053 100 5.3

1990a 0.042 100 4.2

a. Add intakes for uranium progeny based on ratios in Table 5-1 for periods after 1976.

ATTACHMENT A

APPLICATION OF RESIDUAL DOSE FACTORS

Page 2 of 2
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 35 of 42

The tables below indentify the ACCP facilities and work locations that could have resulted in higher 

external exposure potential (Honeywell 2013a, 2013c). Job titles are those that are associated with 

current operations and might not include all job titles or descriptions that are associated with an area

or building during earlier periods of operation.

Table B-1. ACCP areas and facilities with high external exposure potential 

(Honeywell 2013c).

Facility or area Associated job titles

Ore Sampling Plant and Ore Storage Pads Production Supervisors

Sampling Plant Operators/Assistants

Control Lab Technicians

Feed Material Building Production Supervisors

Operators/Assistants:

Ore Prep

Greensalt

Fluorination

Distillation

Decontamination Personnel

Maintenance Mechanics

Material Handler

Electricians

Bed Material, Filter Fine Storage Building Yard Operators

Material Handler

Table B-2. ACCP job titles that involved more routine handling of uranium material

(Honeywell 2013a).

Facility/Area Associated Job Titles

Ore Sampling Plant and Ore Storage Pads Sampling Plant Assistants

Control Lab Technicians

Feed Material Building Ore Prep Assistants

Greensalt Assistants

Fluorination Assistants

Distillation Assistants

Decontamination Personnel

Maintenance Mechanics

Health Physics Technicians

Bed Material, Filter Fine Storage Building Material Handler

ATTACHMENT B

EXTERNAL DOSE POTENTIAL
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 36 of 42

Table C-1. Timeline of radiation exposure events. (ORAUT 2013a)

Incident Date Incident Description

11/12/1968

UF6 Release-Vaporizer in the distillation area of the process building. The valve in the 2" 

vapor line, and one of the two valves in the 1 1/2" feed line were the sources of the 

release. A mixed stream of liquid and vapor struck two men and both required 

hospitalization and treatment for inhalation of uranium hexafluoride vapor. Subsequent 

investigation and analysis of the incident led to the conclusion that both releases were the 

result of mechanical failure due to excessive hydrostatic pressure.

7/8/1977 UF6 Release on 6th Floor distillation as a result of operational problems associated with 

washing a low boiler condenser.

1/16/1981 Uranium Spills-Reductor-"B" Knockout Pot fire

1/27/1981 Uranium Spills-Fluorination-"C" Fluorinator, fluidizing air to fines hopper

2/3/1981 Uranium Spills-Green Salt-"B" dust collector, drain valve repaired

2/3/1981 Uranium Spills-Green Salt-"A" Pri. Dust Collector, door off

2/17/1981 Uranium Spills-Ore preparation-wet oxide DC 1 & 2 blowbacks failed

2/19/1981 Uranium Spills-Ore preparation-wet oxide DC hopper cracks

2/27/1981 Uranium Spills-Ore preparation-Calciner high level alarm failed

3/4/1981 Uranium Spills-Green Salt-"A" & "B" HF filters, bumping filters, belt off

3/18/1981 Uranium Spills-Green Salt-"B" HF filter, cap off drain line nipple

4/16/1981 Uranium Spills-Ore preparation-AC crusher low minus

5/7/1981 Uranium Spills-Ore preparation-Ore blender Conc. Screw tripped

5/15/1981 Uranium Spills-Ore preparation-Ore dryer discharge line plugged

5/31/1981 Uranium Spills-Ore preparation-Calciner wet ore feed hopper

6/10/1981 Uranium Spills-Ore preparation-Ore blender rubber boot failure

7/10/1981 Uranium Spills-Fluorination-Spar Dumper, low minus

7/21/1981 Uranium Spills-Fluorination-Gayco Fines Rotary Valve, fines hopper full

8/4/1981 Uranium Spills-Miscellaneous-Dry Scrap, overfilled drum

8/6/1981 Uranium Spills-Miscellaneous-Sampling Plant Conveyor, drum tipped over

8/15/1981 Uranium Spills-Reductor-"B" Pri. Filter inert purge, plugged

8/15/1981 Uranium Spills-Reductor-"B" Knockout Pot inert purge, plugged

8/17/1981 Uranium Spills-Reductor-"B" Pri. Filter unknown

8/20/1981 Uranium Spills-Green Salt-"A" Top Hydrofluorinator, vessel fracture

9/20/1981 Uranium Spills-Reductor-"A" Pri. Filter inert purge, plugged

10/29/1981 Uranium Spills-Miscellaneous-NaRem Slurry Pot, Fitzmill plugged

11/9/1981 Uranium Spills-Reductor-"A" Pri. Filter plugged, high pressure

11/9/1981 Uranium Spills-Green Salt-"B" Elevator, elevator full, door removed

11/13/1981 Uranium Spills-Fluorination-Spar Classifier, inspection door removed

11/30/1981 Uranium Spills-Ore preparation-Precrusher plugged minus line

12/15/1981 Uranium Spills-Green Salt-Hopper, pressure on hopper while clearing blockage

12/17/1981 Uranium Spills-Green Salt-Blender, grizzly door leaking

1/29/1982 Uranium Spills-Ore preparation-Ore Blender, overfilled, low minus

2/5/1982 Uranium Spills-Fluorination-Fines Hopper, dust collector plugged

2/10/1982 Uranium Spills-Green Salt-Vacuum Cleaner, system full

2/17/1982 Uranium Spills-Reductor-"A" Pri. Filter, cleaning out bowl

2/21/1982 Uranium Spills-Green Salt-HF filter, drain line plugged

2/27/1982 Uranium Spills-Miscellaneous-Fork truck, chain broke, ore spill on roadway

3/18/1982 Uranium Spills-Green Salt-Hopper, blockage blender line, air pressure

4/4/1982 Uranium Spills-Ore preparation-Ore Conc. Elevator, full, inspection door removed

4/15/1982 Uranium Spills-Green Salt-Dust Collector, excessive pressure

4/25/1982 Uranium Spills-Ore preparation-Shot Blaster, emptying DC hopper-doors open

6/13/1984 Uranium Spills-Ore preparation-AC Crusher, low minus

ATTACHMENT C

TIMELINE OF ACCP RADIATION EXPOSURE EVENTS (Primarily during the Residual Period)

Page 1 of 7

ATTACHMENT C

TIMELINE OF ACCP RADIATION EXPOSURE EVENTS (Primarily during the Residual Period)

Page 1 of 7
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 37 of 42

Incident Date Incident Description

5/4/1982 Uranium Spills-Ore preparation-Ore dryer discharge line plugged

5/7/1982 Uranium Spills-Ore preparation-Prep.Feed Discharge Screw, screw covers off

5/23/1982 Uranium Spills-Fluorination-"C" Fluorinator, improperly installed blank

5/25/1982 Uranium Spills-Ore preparation-Shot Blaster, blowbacks on while emptying hopper

5/30/1982 Uranium Spills-Green Salt-HF filter blender, cleaning bowl

11/30/1982 Uranium Spills-Ore preparation-Ore calciner, seals leaking

12/1/1982 Uranium Spills-Ore preparation-Calciner Discharge Elevator, overloaded

12/16/1982 Uranium Spills-Ore preparation-Ore calciner,discharge line plugged

12/29/1982 Uranium Spills-Reductor-"A" Knockout Pot, purge tap nipple broken off

1/13/1983 Uranium Spills-Ore preparation-Calciner Feed Hopper, discharge plugged

1/27/1983 Uranium Spills-Miscellaneous-Ore Conc. Drum, spill outside Sod. Rem. Bldg.

2/6/1983 Uranium Spills-Fluorination-Filter Fines Drum off, overfilled drum

2/7/1983 Uranium Spills-Miscellaneous-Sampling Plant, low minus, high air activity

2/8/1983 Uranium Spills-Miscellaneous-Sampling Plant, ore drum failure

2/17/1983 Uranium Spills-Miscellaneous-Sampling Plant, ore spill unloading truck

2/23/1983 Uranium Spills-Fluorination-"A" Fluorinator, pressure checking

3/2/1983 Uranium Spills-Fluorination-"C" Fluorinator, expansion joint leak

3/8/1983 Uranium Spills-Ore preparation-AC crusher, bad seals

3/17/1983 Uranium Spills-Green Salt-"B" Top Hydrofluorinator, sample valve open

3/29/1983 Uranium Spills-Miscellaneous-Sampling Plant, drum invertor leak

5/23/1983 Uranium Spills-Miscellaneous-Sampling Plant, overfilled drum

6/28/1983 Uranium Spills-Green Salt-Vacuum cleaner, rodding out hopper

7/4/1983 Uranium Spills-Ore preparation-AC crusher, bad seals, low minus

7/11/1983 Uranium Spills-Ore preparation-Ore blender discharge screw, overfilled drum

8/26/1983 Uranium Spills-Ore preparation-Calciner feed hopper, diverter valve failure

9/8/1983 Uranium Spills-Green Salt-Elevator, bumping filters

9/19/1983 Uranium Spills-Ore preparation-AC crusher, minus line plugged

9/30/1983 Uranium Spills-Miscellaneous-Dry Scrap, overfilled drum

10/5/1983 Uranium Spills-Miscellaneous-Dry Scrap, screen plugged

11/1/1983 Uranium Spills-Ore preparaton-Ore blender, discharge screw packing, low minus

11/15/1983 Uranium Spills-Green Salt-HF Filter, tube replacement

11/17/1983 Uranium Spills-Ore preparation-Ore blender, overfilled, discharge screw failure

11/22/1983 Uranium Spills-Ore preparation-Ore blender, overfilled

11/28/1983 Uranium Spills-Green Salt-HF Filter, drain valve leaking to dust collector

12/10/1983 Uranium Spills-Green Salt-HF Filter, bumping filters

1/12/1984 Uranium Spills-Green Salt-HF Filter, bumping, dusted at elevator

1/17/1984 Uranium Spills-Ore preparation-AC Crusher, plugged minus lines

1/17/1984 Uranium Spills-Ore preparation-AC Crusher, fines, low minus

1/24/1984 Uranium Spills-Ore preparation-Mudballer, jammed

1/25/1984 Uranium Spills-Ore preparation-Shot Blaster, dust collector door open

2/21/1984 Uranium Spills-Ore preparation-AC Crusher, fines, jammed

4/2/1984 Uranium Spills-Green Salt-"B" Bottom Hydrofluorinator, expansion joint

4/12/1984 Uranium Spills-Ore preparation-Ore Conc. Elevator, elevator full, doors removed

4/28/1984 Uranium Spills-Green Salt-"B" Bottom Hydrofluorinator, seal failure on feed rotary valve

4/30/1984 Uranium Spills-Ore preparation-Surge hopper, cracks in hopper

5/17/1984 Uranium Spills-Ore preparation-Ore blender discharge screw, packing nuts loose

6/12/1984 Uranium Spills-Ore preparation-Ore dryer, full oversize material

8/15/1984 Uranium Spills-Green Salt-"A" Top Hydrofluorinator, sample valve open

8/24/1984 Uranium Spills-Ore preparation-Ore blender, low minus

ATTACHMENT C

TIMELINE OF ACCP RADIATION EXPOSURE EVENTS (Primarily during the Residual Period)

Page 2 of 7
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 38 of 42

Incident Date Incident Description

8/24/1984 Uranium Spills-Ore preparation-Ore blender, low minus

8/30/1984 Uranium Spills-Green Salt-"A" Elevator, drum off, rotary valve plugged

9/11/1984 Uranium Spills-Ore preparation-Dry Oxide DC, discharge screw repair

9/15/1984 Uranium Spills-Ore preparation-Ore dryer, low minus

9/20/1984 Uranium Spills-Ore preparation-Ore Conc. Elevator, seals on doors

9/24/1984 Uranium Spills-Green Salt-HF Filter, heads removed

11/14/1984 Uranium Spills-Ore preparation-Ore Conc. Elevator, elevator full, doors removed

11/17/1984 Uranium Spills-Fluorination-"C" Fluorinator, pressure check, expansion joint

1/2/1985 Uranium Spills-Green Salt-"B" Bottom Hydrofluorinator, lowering grate

2/19/1985 Uranium Spills-Fluorination-"B" Fluorinator, draw off rotary valve & screw

4/11/1985 Uranium Spills-Ore preparation-AC Crusher, maint. repair, slide valve open

4/15/1985 Uranium Spills-Green Salt-Blender, low minus, dust collector full

4/22/1985 Uranium Spills-Green Salt-"B" Elevator, jammed, doors removed

4/30/1985 Uranium Spills-Green Salt-"B" Elevator, doors removed, clean out

5/23/1985 Uranium Spills-Ore preparation-Mudballer, packing failure

5/31/1985 Uranium Spills-Miscellaneous-Ore Conc. Drum, roadway spill

6/1/1985 Uranium Spills-Miscellaneous-Dry Scrap, overfilled drum, low minus

6/12/1985 Uranium Spills-Ore preparation-Ore Calciner, packing failure rotary valve

7/6/1985 Uranium Spills-Green Salt-"B" Elevator, packing failure on discharge screw

7/22/1985 Uranium Spills-Ore preparation-Ore blender, grizzly inspection door 

7/24/1985 Uranium Spills-Green Salt-"B" Bottom Hydrofluorinator, grate cleaning

7/25/1985 Uranium Spills-Reductor-"B" Reductor, clean out, low minus

7/26/1985 Uranium Spills-Ore preparation-Ore Conc. Elevator, holes in clean out doors

7/27/1985 Uranium Spills-Ore preparation-Ore Conc. Elevator, overfilled, doors removed

7/28/1985 Uranium Spills-Green Salt-Hopper, crack in hopper

8/1/1985 Uranium Spills-Ore preparation-Ore Conc. Elevator, jammed, doors removed

8/1/1985 Uranium Spills-Ore preparation-Ore Conc. Elevator, jammed, doors removed

8/7/1985 Uranium Spills-Miscellaneous-Sampling Plant, drum spill 1st floor

8/10/1985 Uranium Spills-Ore preparation-AC Crusher, minus lines plugged

8/10/1985 Uranium Spills-Ore preparation-Ore Conc. Elevator, low minus

8/11/1985 Uranium Spills-Ore preparation-Ore Calciner Feed Hopper, overfilled

8/11/1985 Uranium Spills-Fluorination-Ash Dust collector, fluidization of fluorinator

8/12/1985 Uranium Spills-Ore preparation-Calciner Feed Elevator, discharge line plugged

8/31/1985 Uranium Spills-Miscellaneous-West End FM Building, high air activity, reason unknown

9/1/1985 Uranium Spills-Ore preparation-Prep. Feed Hopper, discharge screw leak

9/10/1985 Uranium Spills-Fluorination-Fluorination Filter, excessive purge during cleaning

9/13/1985 Uranium Spills-Fluorination-Filter Fines Drum Off, excessive purge to prevent plugging

9/19/1985 Uranium Spills-Green Salt-HF Filter, head removed

10/1/1985 Uranium Spills-Fluorination-"B" Fluorinator, pressure checking

10/8/1985 Uranium Spills-Reductor-"B" Knockout Pot, cracks in vessel

10/9/1985 Uranium Spills-Reductor-"B" Knockout Pot, loose flange rotary valve

10/10/1985 Uranium Spills-Fluorination-Pri. Ash Dust Collector, excessive purge to clear discharge

10/12/1985 Uranium Spills-Miscellaneous-Soda Ash Rm., deteriorated drum ore spill

10/15/1985 Uranium Spills-Green Salt-"A" Top Hydrofluorinator, pressure check, improper blanking

10/17/1985 Uranium Spills-Fluorination-"A" Fluorinator, gasket failure on wind box

10/25/1985 Uranium Spills-Ore preparation-AC Crusher, discharge plugged

10/25/1985 Uranium Spills-Ore preparation-Rotex, port cover off

10/26/1985 Uranium Spills-Ore preparation-Calciner Feed Rotary Valve, packing leaking

10/26/1985 Uranium Spills-Ore preparation-Calciner Feed Rotary Valve, packing leaking

ATTACHMENT C

TIMELINE OF ACCP RADIATION EXPOSURE EVENTS (Primarily during the Residual Period)

Page 3 of 7
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 39 of 42

Incident Date Incident Description

10/26/1985 Uranium Spills-Green Salt-"A" Pri. Dust Collector, bumping filters, crack in dust collector

10/30/1985 Uranium Spills-Miscellaneous-Ore Conc. Drum, deteriorated drum spill on pad

11/2/1985 Uranium Spills-Miscellaneous-Ore Conc. Drum, deteriorated drum spill on roadway

11/2/1985 Uranium Spills-Miscellaneous-Ore Conc. Drum, transferring to good drum

11/3/1985 Uranium Spills-Miscellaneous-Soda Ash Rm., transferring, ore spill on floor

11/5/1985 Uranium Spills-Miscellaneous-Sampling plant, drum off, low minus

11/6/1985 Uranium Spills-Miscellaneous-Sampling plant, lab hoods, low minus

11/12/1985 Uranium Spills-Reductor-"B" Reductor, hole in purge nipple

11/24/1985 Uranium Spills-Ore preparation-Prep. Feed Hopper, loose packing bolts discharge screw

11/25/1985 Uranium Spills-Miscellaneous-Sampling plant, no gasket on dumper lip

12/2/1985 Uranium Spills-Green Salt-Blender, minus line plugged

12/2/1985 Uranium Spills-Miscellaneous-Ball Mill, dumping hard ore, low minus

12/4/1985 Uranium Spills-Green Salt-"A" Train, pressure checking, leaks located

12/5/1985 Uranium Spills-Miscellaneous-Decon. Rm., UF4 tube cleaning, low vac.

12/13/1985 Uranium Spills-Ore preparation-Mudballers, plugged discharge end

12/17/1985 Uranium Spills-Ore preparation-Mudballer, missing retainer gland

12/17/1985 Uranium Spills-Green Salt-"A" Elevator, doors removed, clean out

12/19/1985 Uranium Spills-Green Salt-"A" Elevator, doors removed, inspection of elevator

12/30/1985 Uranium Spills-Ore preparation-Mudballer, packing failure

8/20/1988 UF6 release FMB 5th floor. UF6 gas came from small portion side of column while 

washing column. PP-6 was opened and the release got worse. 

8/22/1988 UF6 release 5th floor distillation side. PP-8 valve cracked on LB Pot, inboard reflux 

valve line #3 leaked through and outboard valve leaked to atmosphere.

11/8/1989 Incident-Employee exposures during power outage of 11/8/89

2/2/1990 Incident-Potential problem with respirator while hooking up #4 LB Condenser for service.

5/22/1990 Inhalation Incident-#1 Wet Oxide dust collector

6/18/1990 UF6 Release-UF6 release from a sample pigtail at #1 fill spot. The plume exited the Feed 

Materials Building and affected other operations in the plant.

6/18/1990

UF6 Release-UF6 release from misvalving following the 1st release on this same day. 

The smaller release occurred at the #4 fill spot during routine maintenance of a sample 

adapter.

1/15/1991 Incident-UF6 cylinder was shipped to Martin Marietta with physical contamination on it.

2/6/1991

Incident-An empty cylinder with heel was received at MTW from DOE facility in Paducah. 

The cyclinder valve seal was missing. Investigation revealed that the valve cover was in 

place and the "white cup" used for a seal was present and there were no signs of foreign 

matter on the valve body.

5/15/1991 UF6 Release-FMB 4th floor distillation. Origin was FRC-406 hot box.

8/15/1991 UF6 release-Removed cylinder valve from AC-276. Smoke escaped into cylinder wash 

building.

1/13/1992 Incident-Power Outage causes material to leak out of the "spar drum off area" in the first 

floor and spread to all floor of the FMB.

2/4/1992 Incident-Employee transported to hospital wearing his plant clothing

2/10/1992

UF6 Release - Occurred from the impurities takeoff line(PP-5) on #4 low boiler

condenser. The release occurred when solid UF6, which had apparently frozen out on the 

bellows of the outboard valve of #4 low boiler condenser PP-5 line, damaged the valve 

upon reheat of the valve.

2/16/1992 Incident-Failure of the axle on the UF6 cylinder handling forklift. There was no damage 

to the cylinder nor was there any release of any UF6.

4/29/1992 External contamination-cleaning UF6 vaporizer that occurred during annual shutdown.

8/13/1992 Incident-Evidence of "yellowcake" being tracked throughout the FMB.

ATTACHMENT C

TIMELINE OF ACCP RADIATION EXPOSURE EVENTS (Primarily during the Residual Period)

Page 4 of 7
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 40 of 42

Incident Date Incident Description

8/25/1992 Incident-1A Secondary Cold trap rinse water was released to the fifth floor and ran down 

through floor openings all the way to the 1st floor of the Feeds Material Building

9/10/1992 Uranium Ore Spill-Container damaged on arrival at Sampling Plant. Appears drum hit 

edge of container wall footer and cause a split in the bottom seam of drums.

10/3/1992 Incident-Employee taken to hospital for a knee injury. She was wearing plant clothing. 

10/18/1992

A fire developed on "B" Reductor at the 5th floor. This was thought to be a H2 fire so the 

NH3 was shut off to B NH3 vaporizer. With N2 on a stream of gas/dust was seen 

escaping from under the insulation.

1/30/1993

Ore blew out of the Drum dumper hood. Electrical power to panel #8 was shut off by 

electricians to make a tie in to the new panel #38. Panel #8 supplies power for #5 and #6 

dry oxide dust collectors' blower and blow backs. Since #5 & #6 Dry Oxide Dust 

collectors supply minus for the Calciner Feed Hopper and the Calciner Feed Elevator, the 

purge on the hopper caused a positive pressure on the entire system. Being that all of 

the pieces of equipment are closed except for the drum dumper hood and invertor which 

opens into the Drum Dumper Shack, it dusted out there.

2/21/1993 UF6 Cylinder leak. The cylinder had a crack at the valve thread base. The cylinder was 

stored at the Southeast corner of the cylinder pad between the fences.

11/21/1993 Incident-Helicopter flying over plant.

4/8/1994

Incident-Health Physics not notified to renew the tank entry on the #3 boiler at the 

Powerhouse. During the shift 2 maintenance employees entered the vessel with unknown 

atmosphere. No one was injured.

7/8/1994 Fire-There was a fire on "A" reductor on the 5th floor during a power failure.

2/3/1995

UF6 Release-UF6 was released at #4 fill position at the pigtail cylinder hook-up. PP-8 on 

the #4 fill position was not closed completely and the pigtail to cylinder hook-up was not 

tight.

5/24/1995

IF5 release to process building, the plant proper, and HF fumes exiting over plant fence 

due to a hole developed in the fluorine inlet line of R-1 IF5 reactor. Emergency 

Response Plan initiated.

1/27/1998

UF6 release while maintenance personnel were removing a blank on the impurities take 

off line(PP-5) during routine maintenance. Three employees received minor HF skin 

irritations from the release. All three were wearing personal protective equipment(PPE). 

All were treated by plant first-aid personnel on-site and returned to work.

7/20/1998

UF6 Release-UF6 was discharged from the feed materials building through the east 

Kinney vacuum pump. The operator mistakenly valved the east system which was being 

heated and started the corresponding Kinney vacuum pump.

9/2/1998 Incident Investigation: Termination of UF6 Cylinder Filling. NRC issued NOV for failure 

to follow procedure

5/6/1999 Plant Emergency-UF6 release at 1 A Tertiary Cold Trap 5th Floor of the FMB. Loose 

flange and loss of minus resulted in UF6 release to the atmosphere.

5/2/2000 Plant Emergency-UF6 release at cylinder fill platform 1st Floor Distillation side of FMB. 

Pigtail plug was cleared and released material.

5/29/2001 Plant Emergency-UF6 release #1 Low Boiler Condenser on 6th Floor Distillation side of 

FMB. ERT mitigation team efforts contained the release to the FMB.

8/10/2001 Plant Emergency-UF6 release #3 Low Boiler Condenser on 6th Floor Distillation side of 

FMB. Two employees sent to the local emergency room for HF inhalation.

2/16/2002 UF6 release on the 1st Floor Distillation of the FMB. UF6 was released from the Kinney 

pump. No ERT response.

3/3/2002 OSHA Recordable-HF inhalation exposure when an employee was closing a valve on a 

GF2 cell during a flex hose failure.

12/9/2002 UF6 release on the 1st Floor Distillation of the FMB. UF6 was released from the Kinney 

pump. No ERT response.

ATTACHMENT C

TIMELINE OF ACCP RADIATION EXPOSURE EVENTS (Primarily during the Residual Period)

Page 5 of 7
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 41 of 42

Incident Date Incident Description

6/10/2003 #4 Fill Spot Pigtail UF6 Release No ERT response.

7/14/2003 Plant Emergency-HF release from a flange on the HF Vaporizers. Release was 

contained by the spray ring mitigation unit.

8/31/2003 #4 Fill Spot Pigtail UF6 Release No ERT response.

9/9/2003 OSHA Recordable-HF inhalation and dermal exposure when an employee was replacing 

a dip tube into the SGF2 Vaporizer.

9/12/2003 Plant Emergency-SbF5 release from the sampling pot of the unit. Plant voluntarily shut 

down all operations until 11/25 for safety stand down.

9/30/2003 Incident-UF6 leaked from the pigtail/PP-16 connection at #4 fill spot. Smoke accumulated 

on the first floor distillation. Haze could be seen on the north side of FMB-dist.

12/22/2003

Site Area Emergency-UF6 release exited the FMB from the Ash Dust Collector stack. 

Evacuation of the public by outside agencies and residents. Four residents reported the 

local emergency room with suspected HF inhalation exposure. Plant voluntarily shut 

down all operations for investigation until 3/12/04.

4/16/2004 Plant Emergency-Reductor Fire on 5th Floor of FMB.

3/2/2005 OSHA Recordable-Dermal HF exposure to an employee's finger during a SGF2 plant 

washout. PPE determined to have a pin hole in the finger.

7/25/2005 Environmental excursion, NRC 24 Hour Report-Failure of the Ash Vacuum Cleaner 

Secondary unit. No ERT response.

8/29/2005 OSHA Recordable-Dermal HF exposure to an employee's finger during a SGF2 plant 

washout. 

9/9/2005 Bomb Threat-Plant Emergency-A call was received that a bomb had been planted in the 

facility. It was determined to be a false alarm.

11/15/2005

Plant Emergency-UF6 release on the UF6 Vaporizer in the Basement Distillation side of 

the FMB. ERT response after containment was achieved was interrupted with the threat 

of a tornado in the area. Site remained at Plant Emergency until the weather emergency 

was cleared. ERT completed all actions including valve change out prior to the "All 

Clear".

4/4/2006

Plant Emergency-UF6 release from a utility line on the 1st Floor Distillation of the FMB. 

UF6 was allowed to enter the utility line and was released when a pressure gauge was 

replaced. NVC issued a Special Inspection Team to investigate the event.

12/14/2006 OSHA Recordable-Possible HF burn to the nose of an employee while working in the 

GF2 area.

3/6/2007 UF6 release on the 4th Floor Distillation of the FMB from a line opening on the 5A 

Primary Cold Trap. No ERT response.

3/17/2007 OSHA Recordable, LWD-HF dilute inhalation exposure during UF4 South Pad line 

breaking activities.

6/13/2007 UF6 release on the 1st Floor Distillation sampling manifold. UF6 contained with vacuum 

hose. No ERT response.

6/27/2007

Employee injury-Employee fell from the 2nd Floor manlift. Code One emergency 

response and HP contamination control response at Massac Memorial Hospital 

Emergency Room.

9/20/2007 Environmental excursion-Failure of the Ash Dust Collector Secondary unit. No ERT 

response.

10/3/2007 Plant Emergency-UF6 release on the #4 Low Boiler Condenser on the 6th Floor of the 

FMB. The release remained in the FMB and ERT mitigation controlled the leak.

12/20/2007

Plant Emergency-HF release from a railcar at the unloading platform. Release was 

contained using the spray tower mitigation system. One minor dermal HF exposure to an 

employee that was in the area when the leak was detected.

3/3/2008 Environmental-Radioactive waste shipment was received by Energy Solutions with 

contamination between the box and the flatbed trailer.

ATTACHMENT C

TIMELINE OF ACCP RADIATION EXPOSURE EVENTS (Primarily during the Residual Period)

Page 6 of 7
Document No. ORAUT-TKBS-0044 Revision No. 02 Effective Date: 05/05/2014 Page 42 of 42

Incident Date Incident Description

3/24/2008

NRC 24 Hour Report-UF4 dustout in the Basement of the FMB. Approximately 100 

pounds of UF4 was released from an open drain leg from the "A" UF4 Dust Collector. No 

ERT response.

8/29/2008 NRC 24 Hour Report-Ore concentrates dustout on the 2nd Floor of the FMB. Ore leaked 

out of the #2 Prepared Feed Mill. No ERT response.

2/17/2009 NRC 24 Hour Report-UF4 dustout in the Basement of the FMB from the UF4 elevator. No 

ERT response.

2/23/2009 NRC 24 Hour Report-UF4 dustout on the 6th Floor of the FMB from the UF4 elevator and 

conveyor system. No ERT response.

3/3/2009

Environmental excursion-Failure of the Ash Vacuum Cleaner Secondary unit. 

Decontamination required for all UF6, IF5, SbF5, and SF6 cylinders and related 

equipment.

7/10/2009 NRC 24 Hour Report-UF4 dustout on the 4th Floor of the FMB. UF4 was released from 

the UF4 mill because a cleanout door was not properly secured. No ERT response.

11/2/2009

UF6 release in the Maintenance Supervisors Office from a rupture disk holder that was 

removed from service. During inspection residual material was released. No ERT 

response.

12/7/2009 OSHA Recordable injury-HF exposure to finger when an employee was collecting UF4 

samples and the material saturated through leather gloves.

7/16/2010

NRC 24 Hour Report-UF4 dustout in the Basement of the Feed Materials Building(FMB). 

UF4 was released from the 1st Floor UF4 drum off station when a rubber boot failed. No 

ERT response.

9/6/2010 UF6 release on the 3rd Floor Distillation of the FMB from pressure tap. UF6 contained 

with a vacuum hose. No ERT response

12/22/2010 Plant Emergency-HF release from the #1 HF Storage Tank. ERT was activated and the 

release was contained with spray tower mitigation system.

8/16-8/17/84 Low boiler system high pressure incident.

ATTACHMENT C

TIMELINE OF ACCP RADIATION EXPOSURE EVENTS (Primarily during the Residual Period)

Page 7 of 7