ORAU TEAM

Dose Reconstruction

Project for NIOSH

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

Page 1 of 15

Document Title:

Internal Dosimetry Coworker Data 

for K-25

Document Number: ORAUT-OTIB-0035

Revision: 00

Effective Date: 08/09/2005

Type of Document: OTIB

Supersedes: None

Subject Expert: Robert N. Cherry

Document Owner

Approval: Signature on File Approval Date: 08/05/2005

Judson L. Kenoyer, Task 3 Manager

Concurrence: Signature on File Concurrence Date: 08/04/2005

Richard E. Toohey, Project Director

Approval: Signature on File Approval Date: 08/09/2005

James W. Neton, Associate Director for Science

 New Total Rewrite Revision Page Change

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

PLEASE DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 2 of 15

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

04/21/2005 00-A New technical information bulletin for assignment of K-25 internal 

doses based on coworker bioassay data. Initiated by Robert N. 

Cherry.

06/10/2005 00-B Incorporates internal review comments. Initiated by Robert N. 

Cherry.

07/19/2005 00-C Incorporates NIOSH review comments. Initiated by Robert N. 

Cherry.

08/09/2005 00 First approved issue. Training required: As determined by the Task 

Manager. Initiated by Robert N. Cherry.
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 3 of 15

TABLE OF CONTENTS

Section

Publication Record ..............................................................................................................................

Page

2

1.0 Purpose ......................................................................................................................................5

2.0 Overview.....................................................................................................................................5

3.0 Data............................................................................................................................................6

3.1 Selected Bioassay Data ........................................................................................................6

3.2 Analysis................................................................................................................................. 6

4.0 Intake Modeling...........................................................................................................................6

4.1 Assumptions .........................................................................................................................6

4.2 Bioassay Fitting.....................................................................................................................7

4.3 Material Types.......................................................................................................................7

4.3.1 Uranium........................................................................................................................7

4.3.2 Technetium-99 .............................................................................................................7

5.0 Assignment of Intakes and Doses...............................................................................................7

5.1 Intake Rate Summary............................................................................................................7

5.2 Contribution from Contaminants in Recycled Uranium ..........................................................8

5.3 Dose Assignment..................................................................................................................8

References ..........................................................................................................................................9

A Tables.............................................................................................................................

Attachment

10

B Figures............................................................................................................................11
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 4 of 15

LIST OF TABLES

Table

5-1 Derived uranium intake rate, 1948 to 1978...............................................................................

Page

7

5-2 Derived 99Tc intake rates..........................................................................................................7

A-1 Summary of annual uranium urinary excretion rate analyses, 1948 to 1988........................... 10

A-2 Summary of annual 99Tc urinary excretion rate analyses, 1978 to 1988................................. 10

LIST OF FIGURES

Figure

B-1 Predicted uranium bioassay results calculated using IMBA-derived U intake 

rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 50th-percentile, Type F ............................................................

Page

11

B-2 Predicted uranium bioassay results calculated using IMBA-derived U intake 

rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 84th-percentile, Type F ............................................................ 11

B-3 Predicted uranium bioassay results calculated using IMBA-derived U intake 

rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 50th-percentile, Type M ........................................................... 12

B-4 Predicted uranium bioassay results calculated using IMBA-derived U intake 

rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 84th-percentile, Type M ........................................................... 12

B-5 Predicted uranium bioassay results calculated using IMBA-derived U intake 

rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 50th-percentile, Type S ........................................................... 13

B-6 Predicted uranium bioassay results calculated using IMBA-derived U intake 

rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 84th-percentile, Type S ........................................................... 13

B-7 Predicted technetium-99 bioassay results calculated using IMBA-derived 

99Tc intake rates (line) compared with uranium bioassay results (dots), 

January 1, 1978, to December 31, 1988, 50th-percentile, Type F .......................................... 14

B-8 Predicted technetium-99 bioassay results calculated using IMBA-derived 

99Tc intake rates (line) compared with uranium bioassay results (dots), 

January 1, 1978, to December 31, 1988, 84th-percentile, Type F .......................................... 14

B-9 Predicted technetium-99 bioassay results calculated using IMBA-derived 

99Tc intake rates (line) compared with uranium bioassay results (dots), 

January 1, 1978, to December 31, 1988, 50th-percentile, Type M ......................................... 15

B-10 Predicted technetium-99 bioassay results calculated using IMBA-derived 

99Tc intake rates (line) compared with uranium bioassay results (dots), 

January 1, 1978, to December 31, 1988, 84th-percentile, Type M ......................................... 15
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 5 of 15

1.0 PURPOSE

Technical Information Bulletins (TIBs) are general working documents that provide guidance 

concerning the preparation of dose reconstructions at particular sites or categories of sites. They will 

be revised in the event additional relevant information is obtained. TIBs may be used to assist the 

National Institute for Occupational Safety and Health (NIOSH) in the completion of individual dose 

reconstructions.

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

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

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

Occupational Illness Compensation Program Act of 2000 [42 U.S.C. Sections 7384l(5) and (12)]. 

The purpose of this TIB is to provide information for the application of K-25 coworker data in

estimating unmonitored internal exposures. Some employees were not monitored for internal ionizing 

radiation exposure during the course of their employment at a U.S. Department of Energy (DOE)1

2.0 OVERVIEW

facility, or the records of such monitoring are incomplete or unavailable. In such cases, data from

monitored coworkers may be used to estimate an individual’s possible exposure.

Analysis of Coworker Bioassay Data for Internal Dose Assignment (ORAUT 2004a) describes the 

general process used to analyze bioassay data for assigning doses to individuals based on coworker 

results. Coworker Data Exposure Profile Development (ORAUT 2004b) describes the approach and 

processes to be used to develop reasonable exposure profiles based on available dosimetric 

information for workers at DOE sites.

Bioassay results were obtained from the Oak Ridge Institute for Science and Education (ORISE) 

Center for Epidemiologic Research (CER) Dosimetry Database, which contains urinalysis records 

from the K-25 site for 1948 to 1988. ORISE obtained these data from K-25 to conduct an 

epidemiological study of site workers. The urinalysis results, labeled “gross alpha,” are in units of 

disintegrations per minute per 100 mL (dpm/100 mL). Results labeled “Uranium” were also available 

that included units of mass rather than activity concentration. It is not possible to convert mass 

concentration to activity concentration accurately for dose assessment purposes without knowing the 

isotopic abundances. Therefore, only the gross alpha data were used because these data were 

adequate and complete.

A statistical analysis of the gross alpha data was performed in accordance with ORAUT (2004a). The 

resultant values were input to the Integrated Modules for Bioassay Analysis (IMBA) ExpertTM OCASEdition computer software (ACJ 2004), and a fit to the data was performed to obtain intake rates for 

assigning dose distributions. 

Technetium-99 bioassay results were similarly obtained from the ORISE CER Dosimetry Database, 

which contains 99Tc urinalysis records from the K-25 site for 1978 to 1988. During these years, 

operations with purified 99Tc were conducted which could result in intakes of 99Tc without 

commensurate intakes of uranium. The 99Tc urinalysis results are in units of dpm/mL. A statistical 

analysis of these data was performed in accordance with ORAUT (2004a). The resultant values were 

 

1 References to DOE in this document include DOE’s predecessors, the Manhattan Engineer District (1942 to 1946), the 

U.S. Atomic Energy Commission (1947 to 1975), and the Energy Research and Development Administration (1975 to 1977), 

as well as DOE (1977 to the present).
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 6 of 15

input to IMBA, and a fit to the data was performed to obtain intake rates for assigning dose 

distributions. 

3.0 DATA

3.1 SELECTED BIOASSAY DATA

Uranium urinalysis data from 1948 to 1988 were extracted from a Microsoft® Access table named 

“tblK25_Urinalysis_rawData” in a subdatabase named “K25_Urinalysis_to_COC_10-8-2004.mdb” in 

the ORISE/CER Dosimetry Database.

Technetium-99 urinalysis data were similarly extracted and analyzed for 1978 to 1988.

3.2 ANALYSIS

Bioassay data were analyzed by year. A lognormal distribution was assumed, and the 50th and 84th

percentiles were calculated for each year using the method described in ORAUT (2004a). 

Many results in the database were listed as less than (<) a value. For 1953 and 1977 through 1988, 

for every record in the “Result” field that contained the less-than symbol followed by a number, that

number was included in the ranking but not in the fit.

Tables A-1 and A-2 show the uranium and 99Tc statistical analysis results, respectively. 

4.0 INTAKE MODELING

Although K-25 operations began in early 1945, uranium bioassay results are not currently available for 

years earlier than 1948. Additional study of K-25 operations from 1945 to 1947 is necessary before 

there will be enough information for modeling for those years.

4.1 ASSUMPTIONS

Each result used in the intake calculation was assumed to be normally distributed. A uniform absolute 

error of 1 was applied to all results, thus assigning the same weight to each result. IMBA requires 

results to be in units of activity per day, so all results were normalized to 1400 mL, the volume of urine 

excreted by Reference Man in a 24-hour period.

Because of the nature of work at K-25, a chronic exposure pattern best approximates the true 

exposure conditions for most workers with a potential for intakes. Intakes were assumed to be by way 

of inhalation using a default breathing rate of 1.2 m3

/hr and a 5-μm activity median aerodynamic 

diameter particle size distribution. 

The database file for uranium lists all results as activity concentrations. Because a variety of 

enrichments is possible at the K-25 site, 234U was assumed for the IMBA intake modeling. The dose 

coefficients (also referred to as dose conversion factors) in International Commission on Radiological 

Protection (ICRP) Publication 68 for 234U are 7% to 31% larger than those for 235U, 236U, and 238U 

(ICRP 1995). Therefore, use of the 234U dose conversion factor will overestimate doses and is 

therefore a claimant-favorable assumption. 
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 7 of 15

4.2 BIOASSAY FITTING

IMBA was used to fit inhalation intakes to the bioassay results. Data from January 1948 to December 

1988 were fit as one or more chronic intakes. 

4.3 MATERIAL TYPES

4.3.1

Uranium urinalysis results were fit in IMBA using types F, M, and S materials to derive intake rates for 

1948 to 1988. The solid lines in Figures B-1 to B-6 show the individual fits to the 50th- and 

84th-percentile excretion rates. The same intake periods were applied for both percentiles because 

the bioassay values modeled followed a similar pattern. 

Uranium

4.3.2

Urinalysis results for 99Tc were fit in IMBA using types F and M materials to derive intake rates for 

1978 to 1988. [Type S material is not considered in ICRP (1995) for 99Tc.] The solid lines in Figures 

B-7 to B-10 show the individual fits to the 50th- and 84th-percentile excretion rates. The same intake 

periods were applied for both percentiles because the values followed a similar pattern. 

Technetium-99

The bioassay data showed a significant change in excretion rate between 1982 and 1983, which 

required different fits for the periods from 1978 to 1982 and from 1983 to 1988.

5.0 ASSIGNMENT OF INTAKES AND DOSES

5.1 INTAKE RATE SUMMARY

The derived 50th- and 84th-percentile uranium excretion data are relatively constant from 1948 to 

1988, as shown in Figures B-1 to B-6. Therefore, a single intake period was assumed. Table 5-1 

summarizes the derived uranium intake rate that produced the fits.

Table 5-1. Derived uranium intake rate, 1948 to 1988. 

Type F material Type M material Type S material

50th 

percentile

(dpm/d)

84th 

percentile

(dpm/d)

Geometric 

standard 

deviation

50th 

percentile

(dpm/d)

84th 

percentile

(dpm/d)

Geometric 

standard 

deviation

50th 

percentile

(dpm/d)

84th 

percentile

(dpm/d)

Geometric 

standard 

deviation

21.5 76.2 3.54 88.3 313 3.54 990 3,460 3.50

The derived 50th- and 84th-percentile 99Tc excretion data are relatively constant from 1978 to 1982 

and, at lower rates, from 1983 to 1988, as shown in Figures B-7 to B-10. Therefore, two intake 

periods were assumed. Table 5-2 summarizes the derived 99Tc intake rates that produced the fits. 

Although the modeling resulted in lower GSDs, a GSD of 3 is assigned to all of the Tc-99 intakes for 

1978 through 1988 to adequately account for uncertainty in the biokinetic modeling.

Table 5-2. Derived 99Tc intake rates. 

Years

Type F material Type M material

50th 

percentile

(dpm/d)

84th 

percentile

(dpm/d)

Geometric 

standard 

deviation

50th 

percentile

(dpm/d)

84th 

percentile

(dpm/d)

Geometric 

standard 

deviation

1978–1982 13,900 24,900 3.0 15,570 27,860 3.0

1983–1988 3,160 6,890 3.0 3,420 7,499 3.0
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 8 of 15

5.2 CONTRIBUTION FROM CONTAMINANTS IN RECYCLED URANIUM

Spent fuel from fission reactors was processed throughout the DOE complex to recover uranium for 

recycling. Because the uranium streams at K-25 contained recycled uranium at various times, the 

dose from the added constituents, including plutonium, neptunium, and 99Tc, must be included during 

dose reconstruction. ORAUT (2004c) provides information about recycled uranium at K-25. 

Results of bioassays analyzed specifically for 99Tc are available for 1978 to 1988, as noted above. 

These bioassays could have been performed for workers on decontamination efforts because “99Tc 

was concentrated at K-25 for purposes of recovery and removal” (ORAUT 2004d). 

Intake rates derived from these 99Tc bioassay results will be used for 99Tc for 1978 to 1988 rather than 

the assumed ratios of contaminant concentrations in uranium, as will be done for 99Tc for 1948 to 

1977. 

5.3 DOSE ASSIGNMENT

Doses to be assigned to individuals are calculated from the 50th-percentile intake rates. Dose 

reconstructors should select the material type that results in the largest probability of causation. 

A comparison shows that intake rates derived assuming type S material are much greater than the 

intake rates derived assuming type M or type F materials for all periods. However, because type S 

material remains in the lungs for an extended period while types F and M materials are transferred to 

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

which will deliver the largest dose to the organ of interest.

Recycled uranium contaminants, when appropriate for the period, should also be included in the 

above comparison. 

The lognormal distribution is selected in the NIOSH Interactive RadioEpidemiological Program 

(NIOSH-IREP), with the calculated dose entered as Parameter 1 and the associated geometric 

standard deviation as Parameter 2. The geometric standard deviation is associated with the intake, 

so it is applied to all annual doses determined from the intake period.
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 9 of 15

REFERENCES

ICRP (International Commission on Radiological Protection), 1959, Report of ICRP Committee II on 

Permissible Dose for Internal Radiation, Publication 2, Pergamon Press, Oxford, England. 

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

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

ORAUT (Oak Ridge Associated Universities Team), 2004a, Analysis of Coworker Bioassay Data for 

Internal Dose Assignment, ORAUT-OTIB-0019, Rev. 00, Oak Ridge, Tennessee. 

ORAUT (Oak Ridge Associated Universities Team), 2004b, Coworker Data Exposure Profile 

Development, ORAUT-PLAN-0014, Rev. 00, Oak Ridge, Tennessee. 

ORAUT (Oak Ridge Associated Universities Team), 2004c, Technical Basis Document for the K-25 

Site – Site Description, ORAUT-TKBS-0009-2, Rev. 00, Oak Ridge, Tennessee. 

ORAUT (Oak Ridge Associated Universities Team), 2004d, Technical Basis Document for the K-25 

Site – Occupational External Dose, ORAUT-TKBS-0009-6, Rev. 00, Oak Ridge, Tennessee. 
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 10 of 15

ATTACHMENT A: TABLES

Table A-1. Summary of annual uranium urinary excretion rate analyses, 1948 to 

1988. 

Year

50th percentile

(dpm/100 mL)

84th percentile

(dpm/100 mL)

1948 0.450 1.134

1949 0.239 0.827

1950 0.430 1.233

1951 0.210 0.769

1952 0.173 1.372

1953 0.378 1.577

1954 0.256 1.184

1955 0.280 1.256

1956 0.332 1.342

1957 0.519 1.994

1958 0.420 1.666

1959 0.331 1.524

1960 0.359 2.081

1961 0.567 2.867

1962 0.572 2.355

1963 0.502 1.790

1964 0.623 1.803

1965 0.740 2.922

1966 0.393 1.330

1967 0.284 1.022

1968 0.199 1.027

Year

50th percentile

(dpm/100 mL)

84th percentile

(dpm/100 mL)

1969 0.381 1.406

1970 0.352 1.341

1971 0.399 1.782

1972 0.495 1.798

1973 0.645 2.187

1974 0.424 1.409

1975 0.542 1.782

1976 0.265 0.981

1977 0.327 1.510

1978 0.159 0.767

1979 0.258 0.896

1980 0.405 1.139

1981 0.506 1.296

1982 0.506 1.166

1983 0.605 1.397

1984 0.610 1.809

1985 0.581 2.322

1986 0.657 1.643

1987 0.517 1.181

1988 0.648 1.166

Table A-2. Summary of annual 99Tc urinary 

excretion rate analyses, 1978 to 1988. 

Year

50th percentile

(dpm/mL)

84th percentile

(dpm/mL)

1978 2.804 4.602

1979 1.682 3.821

1980 0.961 2.384

1981 3.086 5.264

1982 2.444 3.560

1983 0.691 1.462

1984 0.661 1.714

1985 0.002 0.066

1986 0.553 1.000

1987 0.157 0.464

1988 0.428 0.788
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 11 of 15

ATTACHMENT B: FIGURES

Figure B-1. Predicted uranium bioassay results calculated using IMBA-derived U 

intake rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 50th-percentile, Type F. 

Figure B-2. Predicted uranium bioassay results calculated using IMBA-derived U 

intake rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 84th-percentile, Type F. 
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 12 of 15

Figure B-3. Predicted uranium bioassay results calculated using IMBA-derived U 

intake rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 50th-percentile, Type M. 

Figure B-4. Predicted uranium bioassay results calculated using IMBA-derived U 

intake rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 84th-percentile, Type M. 
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 13 of 15

Figure B-5. Predicted uranium bioassay results calculated using IMBA-derived U 

intake rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 50th-percentile, Type S. 

Figure B-6. Predicted uranium bioassay results calculated using IMBA-derived U 

intake rates (line) compared with uranium bioassay results (dots), January 1, 

1948, to December 31, 1988, 84th-percentile, Type S. 
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 14 of 15

Figure B-7. Predicted technetium-99 bioassay results calculated using IMBAderived 99Tc intake rates (line) compared with uranium bioassay results (dots), 

January 1, 1978, to December 31, 1988, 50th-percentile, Type F. 

Figure B-8. Predicted technetium-99 bioassay results calculated using IMBAderived 99Tc intake rates (line) compared with uranium bioassay results (dots), 

January 1, 1978, to December 31, 1988, 84th-percentile, Type F. 
Document No. ORAUT-OTIB-0035 Revision No. 00 Effective Date: 08/09/2005 Page 15 of 15

Figure B-9. Predicted technetium-99 bioassay results calculated using IMBAderived 99Tc intake rates (line) compared with uranium bioassay results (dots), 

January 1, 1978, to December 31, 1988, 50th-percentile, Type M. 

Figure B-10. Predicted technetium-99 bioassay results calculated using IMBAderived 99Tc intake rates (line) compared with uranium bioassay results (dots), 

January 1, 1978, to December 31, 1988, 84th-percentile, Type M.