DRAFT 

REPORT TO THE ADVISORY BOARD 

ON RADIATION AND WORKER HEALTH

National Institute for Occupational Safety and Health 

COMPARISON OF SC&A’S BLIND DOSE RECONSTRUCTION 

TO NIOSH’S DOSE RECONSTRUCTION OF CASE #[REDACT] 

FROM THE ROCKY FLATS PLANT 

Contract No. 211-2014-58081

SCA-TR-DRC2015-CN[REDACT], Revision 1

Prepared by 

Kathleen Behling 

S. Cohen & Associates 

1608 Spring Hill Road, Suite 400 

Vienna, Virginia 22182 

April 2015 

Disclaimer

This document is made available in accordance with the unanimous desire of the Advisory Board on 

Radiation and Worker Health (ABRWH) to maintain all possible openness in its deliberations. However, 

the ABRWH and its contractor, SC&A, caution the reader that at the time of its release, this report is predecisional and has not been reviewed by the Board for factual accuracy or applicability within the 

requirements of 42 CFR 82. This implies that once reviewed by the ABRWH, the Board’s position may 

differ from the report’s conclusions. Thus, the reader should be cautioned that this report is for 

information only and that premature interpretations regarding its conclusions are unwarranted.
Effective Date:

April 16, 2015

Revision No.

1 (Draft)

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S. Cohen & Associates:

Technical Support for the Advisory Board on

Radiation & Worker Health Review of

NIOSH Dose Reconstruction Program

Document No. 

SCA-TR-DRC2015-CN[REDACT]

Effective Date: 

Draft – April 16, 2015

Comparison of SC&A’s Blind Dose 

Reconstruction to NIOSH’s Dose 

Reconstruction of Case #[Redact] from the 

Rocky Flats Plant

Page 2 of 26

Task Manager:

________________________ Date: ___________

Douglas Farver, CHP

Supersedes:

Rev. 0

Project Manager:

________________________ Date: ___________

John Stiver, MS, CHP

Reviewer:

 Douglas Farver

 John Stiver

Record of Revisions

Revision 

Number Effective Date Description of Revision

0 (Draft) 02/13/2015 Initial issued.

1 (Draft) 04/16/2015 Corrects the SC&A Method A total lung dose in Table 3-1.
Effective Date:

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TABLE OF CONTENTS 

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

1.0 Relevant Background Information .......................................................................................7

2.0 Comparison of Methodology/Doses used by SC&A and NIOSH for Case #[Redact] ........9

2.1 Occupational External Dose Calculations .............................................................12

2.1.1 Recorded Photon Doses .............................................................................12

2.1.2 Missed Photon Doses .................................................................................14

2.1.3 Unmonitored Photon Doses .......................................................................14

2.1.4 Recorded Neutron Doses ...........................................................................15

2.1.5 Missed Neutron Doses ...............................................................................16

2.1.6 Unmonitored Neutron Doses .....................................................................16

2.1.7 Occupational Medical Doses .....................................................................17

2.2 Occupational Internal Doses ..................................................................................18

2.2.1 Plutonium/Americium Intakes ...................................................................18

2.2.2 Tritium Dose ..............................................................................................22

2.2.3 Depleted Uranium Dose .............................................................................23

3.0 Summary Conclusions .......................................................................................................24

4.0 References ..........................................................................................................................26
Effective Date:

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LIST OF TABLES 

Table 1-1. Comparison of SC&A’s Blind Dose Reconstruction to NIOSH’s Dose 

Reconstruction for Case #[Redact] ...............................................................................8

Table 2-1. Comparison of Data and Assumptions Used by NIOSH and SC&A ............................9

Table 2-2. Photon Energy Fractions and Organ DCFs Used by NIOSH and 

SC&A’s ‘Method A’ ...................................................................................................13

Table 2-3. Photon Energy Fractions and Organ DCFs Used by SC&A’s ‘Method B’ ................13

Table 2-4. Comparison of Recorded Photon Doses ......................................................................14

Table 2-5. Comparison of Missed Photon Doses..........................................................................14

Table 2-6. Comparison of Unmonitored Photon Doses ................................................................15

Table 2-7. Neutron Energies, ICRP CFs, and Organ DCFs Used by the Three DR Methods ......15

Table 2-8. Comparison of Recorded Neutron Doses ....................................................................16

Table 2-9. Comparison of Missed Neutron Doses ........................................................................16

Table 2-10. Comparison of Unmonitored Neutron Doses ............................................................17

Table 2-11. Comparison of Occupational Medical Doses ............................................................17

Table 2-12. Pu/Am Intake Rates Calculated by NIOSH...............................................................19

Table 2-13. Pu/Am Chronic Intakes ([redact]–[redact]) Derived by SC&A’s ‘Method A’ .........20

Table 2-14. SC&A’s ‘Method A’ OTIB-0049 Adjusted Doses ...................................................20

Table 2-15. Plutonium Intakes and Doses Calculated from Bioassay Results .............................21

Table 2-16. Type S Plutonium Intakes and Doses from Lung Counts Calculated by 

SC&A’s ‘Method B’ ...................................................................................................22

Table 2-17. Comparison of RFP Total Internal Doses .................................................................23

Table 3-1. Comparison of Total External and Internal Doses Estimated for the Lung ................24
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ABBREVIATIONS AND ACRONYMS 

Advisory Board Advisory Board on Radiation and Worker Health 

AP Anterior-Posterior 

CADW Chronic Annual Dose Workbook 

CATI Computer-Assisted Telephone Interview 

CF correction factor

D day 

DCF dose conversion factor

DOE (U.S.) Department of Energy 

DOL (U.S.) Department of Labor 

dpm disintegrations per minute 

DR dose reconstruction 

DU depleted uranium

EE Energy Employee 

EEOICPA Energy Employees Occupational Illness Compensation Program Act 

GM geometric mean 

GSD geometric standard deviation

hr hour 

ICD International Classification of Diseases 

ICRP International Commission on Radiological Protection 

IMBA Integrated Modules of Bioassay Analysis 

IREP Interactive RadioEpidemiological Program 

ISO isotropic 

keV kiloelectron volts 

LOD limit of detection

MDA minimum detectable activity

MeV million electron volts 

mrem millirem

nCi nanocuries 

NIOSH National Institute for Occupational Safety and Health 

OCAS Office of Compensation Analysis and Support 

ORAUT Oak Ridge Associated Universities Team 
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pCi/d picocuries per day 

POC probability of causation 

ppm parts per million 

rem Roentgen equivalent man 

RFP Rocky Flats Plant

ROT rotational

SD standard deviation 

SC&A S. Cohen and Associates (SC&A, Inc.) 

TBD technical basis document 

TIB technical information bulletin

WGP weapons-grade plutonium 
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1.0 RELEVANT BACKGROUND INFORMATION 

Under Contract No. 200-2009-28555, SC&A was tasked by the Advisory Board on Radiation 

and Worker Health (Advisory Board) to perform six blind dose reconstructions (DRs) at the May 

21, 2013, meeting of the Dose Reconstruction (DR) Subcommittee. SC&A was provided all of 

the Department of Energy (DOE) dosimetry records; the Department of Labor (DOL) 

correspondence, forms, and medical records; and the Computer-Assisted Telephone Interview 

(CATI) Reports that were made available to NIOSH for constructing doses in behalf of these 

cases. SC&A used two independent approaches to reconstruct occupational external and internal 

doses for the cases. Both approaches used the available dosimetry records and current guidance 

from the National Institute for Occupational Safety and Health (NIOSH). The first approach, 

which is referred to as DR–Method A, used the spreadsheets and other tools developed by 

NIOSH to calculate the doses, whereas the second approach, referred to as DR–Method B, 

manually calculated the doses using a deterministic model that is based on central values and 

first principles. 

One of the six draft blind DR reports, SC&A’s Dose Reconstruction of Case #[Redact] from the 

Rocky Flats Plant (SC&A 2014), was submitted to the Advisory Board and NIOSH on 

January 13, 2014. In this report, SC&A presents a comparison between SC&A’s and NIOSH’s 

DR methodologies, doses, and resultant Probability of Causation (POC) values for Case 

#[Redact]. Table 1-1 summarizes the external and internal occupational doses calculated by 

SC&A (using two independent methods) and the NIOSH-assigned doses for the lung cancer 

diagnosed in behalf of Case #[Redact]. A detailed comparison of the three methodologies used 

to calculate doses in behalf of this case is presented in Section 2. Section 3 of this report 

provides Summary Conclusions. 

It should be noted that an explanation is provided regarding the differences in doses and why 

they occurred; however, SC&A does not make any value judgments regarding which among 

them may be the more preferred approach. It is our position that further discussions are best 

addressed by the DR Subcommittee. 
Effective Date:

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Table 1-1. Comparison of SC&A’s Blind Dose Reconstruction to NIOSH’s Dose

Reconstruction for Case #[Redact] 

NIOSH

Lung Doses (rem)

DR–Method A

Lung Doses (rem)

DR–Method B

Lung Doses (rem)

External Dose (Occupational):

 ▪ Recorded Dose

 - Photons <30 keV 0.029 0.019 0.018

 - Photons 30–250 keV 1.487 1.440 1.551

 - Neutrons <10 keV 0.088 0.101 0.099

 - Neutrons 10–100 keV 0.026 0.021 0.021

 - Neutrons 0.1–2 MeV 0.771 0.691 0.679

 - Neutrons 2–20 MeV 0.340 0.313 0.308

 ▪ Missed Dose

 - Photons <30 keV – – 0.000

 - Photons 30–250 keV 0.037 0.048 0.038

 - Neutrons <10 keV 0.028 0.028 0.030

 - Neutrons 10–100 keV 0.009 0.006 0.006

 - Neutrons 0.1–2 MeV 0.250 0.191 0.199

 - Neutrons 2–20 MeV 0.110 0.087 0.089

 ▪ Unmonitored Dose

 - Photons <30 keV 0.001 Not considered 0.012

 - Photons 30–250 keV 0.038 Not considered 0.665

 - Neutrons <10 keV 0.002 Not considered 0.045

 - Neutrons 10–100 keV 0.001 Not considered 0.010

 - Neutrons 0.1–2 MeV 0.016 Not considered 0.318

 - Neutrons 2–20 MeV 0.007 Not considered 0.148

 ▪ Occupational Medical Dose

 - Photons 30–250 keV 0.084 0.294 0.294

Internal Dose:

 - Plutonium/Americium (Alpha) 46.033 38.676 57.114

 - DU (Alpha) Not considered Not considered 10.300

Total 49.357 41.915 71.944

POC 47.51% 56.71% 55.75%
Effective Date:

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2.0 COMPARISON OF METHODOLOGY/DOSES USED BY SC&A AND 

NIOSH FOR CASE #[REDACT] 

Case #[Redact] represents an energy employee (EE) who worked at the Rocky Flats Plant (RFP)

from [redact] through [redact], and [redact], through [redact]. According to the DOE records, 

the majority of the EE’s radiation exposure was received while working as a [redact]/ [redact], 

primarily in the [redact] buildings [redact], [redact], [redact], [redact], and [redact]. (It 

should be noted that the EE declined the telephone interview.) The EE was monitored for 

external photon and neutron radiation exposure and internal radiation exposure by urinalyses and 

lung counts. On [redact], the EE was diagnosed with lung cancer (squamous cell) (ICD-9 

Code 162.9). It should also be noted that DOE records indicate the EE was a former [redact].

For calculating radiation doses from employment at RFP, all three DR methods primarily relied 

on guidance in the six Technical Basis Document (TBD) for the RFP (which was issued as six 

separate documents numbered ORAUT-TKBS-0011-1 through ORAUT-TKBS-0011-06) and 

External Dose Reconstruction Implementation Guideline (OCAS-IG-001). Using the guidance 

provided in the relevant documents, along with the employee’s dosimetry records, NIOSH and 

SC&A’s ‘DR Method B’ employed a best-estimate approach for calculating annual organ 

doses, while SC&A’s ‘Method A’ used a minimizing approach to calculate the lung dose.

A summary of the documents, assumptions, and dose parameters used by each DR method is 

provided in Table 2-1: 

Table 2-1. Comparison of Data and Assumptions Used by NIOSH and SC&A

Parameters NIOSH SC&A’s DR–Method A SC&A’s DR–Method B

Recorded Photon Doses

Records/Guidance 

Documents

DOE records, TKBS-0011-6, IG-001, 

and Rocky Flats Workbook 4.29.

DOE records, TKBS-0011-6, and 

IG-001.

DOE records, TKBS-0011-6, and IG001.

Work Locations [redact] Facility all years of 

employment.

[redact] Facility all years of 

employment.

[redact] Facility all years of 

employment.

Energy Range/ DCF

[redact]–[redact] (Exposure):

100% <30 keV – DCF = 0.030

100% 30–250 keV – DCF = 0.986

[redact]–[redact] (Deep Dose 

Equiv):

100% <30 keV – DCF = 0.050

100% 30–250 keV – DCF = 0.695

[redact]–[redact] (Exposure):

100% <30 keV – DCF = 0.030

100% 30–250 keV – DCF =

0.986

[redact]–[redact] (Deep Dose 

Equiv):

100% <30 keV – DCF = 0.050

100% 30–250 keV – DCF =

0.695

[redact]–[redact] (Exposure):

25% <30 keV – DCF = 0.030

75% 30–250 keV – DCF = 1.13

[redact]–[redact] (Deep Dose Equiv):

25% <30 keV – DCF = 0.050

75% 30–250 keV – DCF = 0.800

Dosimeter 

Uncertainty Factor Not Applied Not Applied

[redact]–[redact] (<100 mrem) = 2

[redact]–[redact] (>100 mrem) = 1.26

[redact]–[redact] = 1.23

Dose Distribution Normal distribution; uncertainty 

based on Monte Carlo Constant; no uncertainty Constant; no uncertainty

Missed Photon Doses

Records/Guidance 

Documents

DOE records, TKBS-0011-6, IG-001, 

and Rocky Flats Workbook 4.29.

DOE records, TKBS-0011-6, and 

IG-001.

DOE records, TKBS-0011-6, and IG001.

No. of zeros 5 5 5

LOD Value 0.020 rem 0.020 rem 0.020 rem
Effective Date:

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Revision No.

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Table 2-1. Comparison of Data and Assumptions Used by NIOSH and SC&A

Parameters NIOSH SC&A’s DR–Method A SC&A’s DR–Method B

Energy Range/ DCF

[redact]–[redact] (Exposure):

100% 30–250 keV – DCF = 0.986

[redact]–[redact] (Deep Dose 

Equiv):

100% 30–250 keV – DCF = 0.695

[redact]–[redact] (Exposure):

100% 30–250 keV – DCF =

0.986

[redact]–[redact] (Deep Dose 

Equiv):

100% 30–250 keV – DCF =

0.695

[redact]–[redact] (Exposure):

25% <30 keV – DCF = 0.03

75% 30–250 keV – DCF = 1.13

[redact]–[redact] (Deep Dose Equiv):

25% <30 keV - DCF=0.050

75% 30–250 keV – DCF = 0.800

Dose Distribution Lognormal with GSD = 1.6 Lognormal with GSD = 1.52 Lognormal with GSD = 1.52

Unmonitored Photon Doses

Guidance Documents TKBS-0011-6 plutonium coworker 

model Not considered. TKBS-0011-6 plutonium coworker model

Coworker Percentile 50th percentile Not considered. 95th percentile

Period of Time 

Assigned

[redact] – 1.05 months

[redact] – 5.46 months Not considered.

[redact] – 1.1 months

[redact] – 2 months

[redact] – 4 months

[redact] – 2 months

[redact] – 6 months

Energy Range/

DCF

[redact] (Exposure):

100% <30 keV – DCF = 0.030

100% 30–250 keV – DCF = 0.986

[redact] (Deep Dose Equiv):

100% <30 keV – DCF = 0.050

100% 30–250 keV – DCF = 0.695

Not considered.

[redact]–[redact] (Exposure):

25% <30 keV – DCF = 0.03

75% 30–250 keV – DCF = 1.13

[redact]–[redact] (Deep Dose Equiv):

25% <30 keV – DCF = 0.050

75% 30–250 keV – DCF = 0.800

Dose Distribution

[redact] – Normal with SD 16%

[redact] – <30 keV Normal

 30–250 keV Triangular

Not considered. Normal with SD of 30%

Recorded Neutron Doses

Records/Guidance 

Documents

DOE records, TKBS-0011-6, IG-001, 

and Rocky Flats Workbook 4.29.

DOE records, TKBS-0011-6, and 

IG-001.

DOE records, TKBS-0011-6, and IG001.

Energy Range/ DCF 

[redact]–[redact] (Exposure):

<10 keV – DCF = 1.523

10–100 keV – DCF = 0.751

0.1–2 MeV – DCF = 0.579

2–20 MeV – DCF = 1.004

[redact]–[redact] (Deep Dose 

Equiv):

<10 keV – DCF = 1.332

10–100 keV – DCF = 0.737

0.1–2 MeV – DCF = 0.557

2–20 MeV – DCF = 0.950

[redact]–[redact] (Exposure):

<10 keV – DCF = 1.523

10–100 keV – DCF = 0.751

0.1–2 MeV – DCF = 0.579

2–20 MeV – DCF = 1.004

[redact]–[redact] (Deep Dose 

Equiv):

<10 keV – DCF = 1.332

10–100 keV – DCF = 0.737

0.1–2 MeV – DCF = 0.557

2–20 MeV – DCF = 0.950

[redact]–[redact] (Exposure):

<10 keV – DCF = 1.523

10–100 keV – DCF = 0.751

0.1–2 MeV – DCF = 0.579

2–20 MeV – DCF = 1.004

[redact]–[redact] (Deep Dose Equiv):

<10 keV – DCF = 1.332

10–100 keV – DCF = 0.737

0.1–2 MeV – DCF = 0.557

2–20 MeV – DCF = 0.950

ICRP 60 CF

<10 keV – CF = 0.0755

10–100 keV – CF = 0.0309

0.1–2 MeV – CF = 1.31

2–20 MeV – CF = 0.345

<10 keV – CF = 0.0755

10–100 keV – CF = 0.0309

0.1–2 MeV – CF = 1.31

2–20 MeV – CF = 0.345

<10 keV – CF = 0.0755

10–100 keV – CF = 0.0309

0.1–2 MeV – CF = 1.31

2–20 MeV – CF = 0.345

Dose Distribution Normal & lognormal distributions; 

uncertainty based on Monte Carlo Constant; no uncertainty Normal distribution; SD = 30%
Effective Date:

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Table 2-1. Comparison of Data and Assumptions Used by NIOSH and SC&A

Parameters NIOSH SC&A’s DR–Method A SC&A’s DR–Method B

Missed Neutron Doses

Data Used DOE records, TKBS-0011-6, IG-001, 

and Rocky Flats Workbook 4.29.

DOE records, TKBS-0011-6, and 

IG-001.

DOE records, TKBS-0011-6, and IG001.

No. of zeros 27 20 27

LOD Value 0.020 rem 0.020 rem 0.020 rem

Energy Range/ DCF

[redact]–[redact] (Exposure):

<10 keV – DCF = 1.523

10–100 keV – DCF = 0.751

0.1–2 MeV – DCF = 0.579

2–20 MeV – DCF = 1.004

[redact]–[redact] (Deep Dose 

Equiv):

<10 keV – DCF = 1.332

10–100 keV – DCF = 0.737

0.1–2 MeV – DCF = 0.557

2–20 MeV – DCF = 0.950

[redact]–[redact] (Exposure):

<10 keV – DCF = 1.523

10–100 keV – DCF = 0.751

0.1–2 MeV – DCF = 0.579

2–20 MeV – DCF = 1.004

[redact]–[redact] (Deep Dose 

Equiv):

<10 keV – DCF = 1.332

10–100 keV – DCF = 0.737

0.1–2 MeV – DCF = 0.557

2–20 MeV – DCF = 0.950

[redact]–[redact] (Exposure):

<10 keV – DCF = 1.523

10–100 keV – DCF = 0.751

0.1–2 MeV – DCF = 0.579

2–20 MeV – DCF = 1.004

[redact]–[redact] (Deep Dose Equiv):

<10 keV – DCF = 1.332

10–100 keV – DCF = 0.737

0.1–2 MeV – DCF = 0.557

2–20 MeV – DCF = 0.950

ICRP 60 CF

<10 keV – CF = 0.0755

10–100 keV – CF = 0.0309

0.1–2 MeV – CF = 1.31

2–20 MeV – CF = 0.345

<10 keV – CF = 0.0755

10–100 keV – CF = 0.0309

0.1–2 MeV – CF = 1.31

2–20 MeV – CF = 0.345

<10 keV – CF = 0.0755

10–100 keV – CF = 0.0309

0.1–2 MeV – CF = 1.31

2–20 MeV – CF = 0.345

Dose Distribution Lognormal with GSD = 1.6 Lognormal with GSD = 1.52 Lognormal with GSD = 1.52

Unmonitored Neutron Doses

Guidance Documents TKBS-0011-6 plutonium coworker 

model Not considered. TKBS-0011-6 plutonium coworker model

Coworker Percentile 50th percentile Not considered. 95th percentile

Period of Time 

Assigned

[redact] – 1.05 months

[redact] – 5.46 months Not considered.

[redact] – 1.1 months

[redact] – 2 months

[redact] – 4 months

[redact] – 2 months

[redact] – 6 months

Energy Range/

DCF

[redact] (Exposure):

<10 keV – DCF = 1.523

10–100 keV – DCF = 0.751

0.1–2 MeV – DCF = 0.579

2–20 MeV – DCF = 1.004

[redact] (Deep Dose Equiv):

<10 keV – DCF = 1.332

10–100 keV – DCF = 0.737

0.1–2 MeV – DCF = 0.557

2–20 MeV – DCF = 0.950

Not considered.

[redact]–[redact] (Exposure):

<10 keV – DCF = 1.523

10–100 keV – DCF = 0.751

0.1–2 MeV – DCF = 0.579

2–20 MeV – DCF = 1.004

[redact]–[redact] (Deep Dose Equiv):

<10 keV – DCF = 1.332

10–100 keV – DCF = 0.737

0.1–2 MeV – DCF = 0.557

2–20 MeV – DCF = 0.950

ICRP 60 CF

<10 keV – CF = 0.0755

10–100 keV – CF = 0.0309

0.1–2 MeV – CF = 1.31

2–20 MeV – CF = 0.345

Not considered.

<10 keV – CF = 0.0755

10–100 keV – CF = 0.0309

0.1–2 MeV – CF = 1.31

2–20 MeV – CF = 0.345

Dose Distribution

Based on Monte Carlo:

<10 keV – Normal

10–100 keV – Lognormal

0.1–2 MeV – Normal

2–20 MeV – Normal

Not considered. Normal with SD of 30%
Effective Date:

April 16, 2015

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Table 2-1. Comparison of Data and Assumptions Used by NIOSH and SC&A

Parameters NIOSH SC&A’s DR–Method A SC&A’s DR–Method B

Occupational Medical Doses

Guidance Documents

DOE records, TKBS-0011-3, 

ORAUT-PROC-0061, ORAUTOTIB-0079TKBS-0011-3 TKBS-0011-3, ORAUT-PROC-0061

Frequency 2 x-ray exams documented in EE’s 

records

Annually, based on Table 3-1 of 

TKBS-0011-3

Annually, based on Table 3-1 of TKBS0011-3

Dose Data TKBS-0011-3 (Table 3-6) TKBS-0011-3 (Table 3-6) TKBS-0011-3 (Table 3-6)

Dose Distribution Normal; SD = 30%. Normal; SD = 30%. Normal; SD = 30%.

Internal Doses – Plutonium/Americium

Records/Guidance 

Documents

DOE records, TKBS-0011-5, 

ORAUT-OTIB-0049, RFP Pu-Am 

Intake Calculation Tool, RFP Am 

Lung MDA Calculation Tool, IMBA

DOE records, TKBS-0011-5, 

ORAUT-OTIB-0049, RFP 

Pu-Am Intake Calculation Tool, 

IMBA, CADW

DOE records, TKBS-0011-5, ORAUTOTIB-0049, IMBA

Dose Determination 

Approach

Compared coworker dose to missed 

dose (<MDA reported values) for two 

employment periods. Compared 

intakes based on urinalyses versus 

chest counts.

Calculated intakes based on 

missed dose (<MDA reported 

values). Used IMBA and 

maximum likelihood fitting 

method to assess both urinalyses 

and chest count data.

Calculated intakes based on missed dose 

(<MDA reported values). Compared 

urinalyses results to chest count data.

Solubility Type Compared Types F, M, S, and SS 

(when applicable)

Compared Types F, M, S, and SS 

(when applicable)

Compared Types F, M, S, and SS (when 

applicable)

Missed Tritium

Records/Guidance 

Documents

DOE records, TKBS-0011-5, Tritium 

from Urine Workbook DOE records, TKBS-0011-5 DOE records, TKBS-0011-5

Dose Determination 

Approach

Assessed missed tritium from 

urinalyses results <MDA. Total dose 

<0.001 and not entered into IREP.

Assessed missed tritium from 

urinalyses results <MDA. Total 

dose <0.001 and not entered into 

IREP.

Assessed missed tritium from urinalyses 

results <MDA. Total dose <0.001 and 

not entered into IREP.

Depleted Uranium (DU)

Guidance Documents Not considered. Not considered. TKBS-0011-5, IMBA

Dose Determination 

Approach Not considered. Not considered.

Calculated DU dose based on Am-241 

lung count MDA data. Intakes entered 

into IMBA as chronic throughout entire 

employment period.

2.1 OCCUPATIONAL EXTERNAL DOSE CALCULATIONS 

2.1.1 Recorded Photon Doses 

The DOE records show that the EE was monitored on a monthly dosimeter exchange frequency 

throughout employment, and received positive recorded photon doses or doses greater than the 

limit of detection (LOD) during each year except for [redact]. All three DR methods assumed 

the EE worked in the [redact] facility and calculated recorded photon doses using guidance 

provided in the RFP Occupational External Dose TBD (ORAUT-TKBS-0011-6). Organ dose 

conversion factors (DCFs) were applied in accordance with External Dose Reconstruction 

Implementation Guideline (OCAS-IG-001), as described below. 
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NIOSH and SC&A’s ‘Method A’ assumed 100% 30–250 keV photons for reported deep dose 

measurements and 100% <30 keV photon energy ranges for reported positive shallow dose 

measurements (shallow dose minus deep dose). Both methods applied organ DCFs in 

accordance with OCAS-IG-001, Table 4.1a, Special Dose Conversion Factors for Plutonium

(page 38) for <30 keV photons and Appendix A of for 30–250 keV organ DCFs. (It should be 

noted that OCAS-IG-001 contains two tables labeled ‘4.1a;’ one on page 38 and a second on 

page 39.) In addition, NIOSH and SC&A’s ‘Method A’ followed guidance in ORAUT-TKBS0011-6, which states, for the period 1951 through 1982, the Exposure (R) to organ DCF should 

be used and, for the period 1983 through 2005, the Hp(10) organ DCF should be used. The 

photon dose parameters applied by these two DR methods are listed in Table 2-2. 

Table 2-2. Photon Energy Fractions and Organ DCFs Used by NIOSH and 

SC&A’s ‘Method A’

1979–1982 1983–1985

Energy Range <30 keV 30–250 kev <30 keV 30–250 kev

Energy Fraction 100% 100% 100% 100%

Exposure Geometry AP AP AP AP

Organ DCF 0.030 0.986 0.050 0.695

SC&A’s ‘Method B’ applied a dosimeter uncertainty factor to the measured photons, in 

accordance with guidance in ORAUT-TKBS-0011-6, Tables 6-14 and 6-15. A dosimeter 

uncertainty factor of 2 was applied during [redact]–[redact] for readings <100 mrem; for 

readings >100 mrem during [redact]–[redact], a 1.26 factor was applied; and for 1983–1998, a 

factor of 1.23 was applied. 

SC&A’s ‘Method B’ assumed a photon energy fraction of 25% <30 keV and 75% 30–250 keV, 

as recommended in ORAUT-TKBS-0011-6, Table 6-10, for plutonium workers. In addition to 

applying the organ DCF values from OCAS-IG-001, Table 4.1a (page 38) for <30 keV photons, 

this DR method assumed that the rotational exposure geometry was most appropriate for the EE. 

Therefore, the rotational correction factors cited in the second table labeled Table 4.1a,

Correction Factors for ROT and ISO DCF Values for Bone (RM and Surf), Esophagus, and 

Lung (page 39) was applied, as shown in Table 2-3.

Table 2-3. Photon Energy Fractions and Organ DCFs Used by SC&A’s ‘Method B’

1979–1982 1983–1985

Energy Range <30 keV 30–250 kev <30 keV 30–250 kev

Energy Fraction 25% 75% 25% 75%

Exposure Geometry AP ROT AP ROT

Organ DCF 0.030 0.779 0.050 0.552

ROT Correction Factor NA 1.45 NA 1.45

Adjusted Lung DCF 0.030 1.13 0.05 0.800

Using the EE’s dosimetry records and above-cited parameters, NIOSH, SC&A’s ‘Method A,’ 

and SC&A’s ‘Method B’ calculated nearly identical photon doses, as shown in Table 2-4.
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Table 2-4. Comparison of Recorded Photon Doses 

Recorded Photon Doses NIOSH

(rem)

SC&A’s ‘Method A’

(rem)

SC&A’s ‘Method B’

(rem)

<30 keV 0.029 0.019 0.018

30–250 keV 1.487 1.440 1.551

Total 1.516 1.459 1.569

NIOSH entered annual recorded photon doses into the Interactive RadioEpidemiological 

Program (IREP) as a mean value (normal distribution) with varying standard deviation (SD) 

values, based on Monte Carlo methods. Both SC&A’s ‘Method A’ and ‘Method B’ entered 

doses into IREP as a constant with no uncertainty. 

2.1.2 Missed Photon Doses 

Missed dose was assigned by all DR methods for photon doses reported as zero readings or less 

than one-half the applicable LOD value. All three DR methods also counted 5 missed readings 

and assumed an LOD value of 0.020 rem based on guidance in ORAUT-TKBS-0011-6. NIOSH 

and SC&A’s ‘Method A’ assigned the missed doses as 100% 30–250 keV, while SC&A’s 

‘Method B’ assumed 25% <30 keV and 75% 30–250 keV, which is constant with the energy 

fraction used for recorded photons. ‘Method B’s assessment of <30 keV photons resulted in 

doses <0.001, and therefore, these doses were not entered into IREP. 

A comparison of total missed photon doses calculated by the three DR methods is shown in 

Table 2-5. Although total missed photon doses are nominal and in close agreement, one would 

have expected SC&A’s ‘Method A’ and NIOSH’s doses to be identical. This was not the case,

since NIOSH utilized a Monte Carlo method for deriving dose and uncertainty. 

Table 2-5. Comparison of Missed Photon Doses 

Missed Photon Doses NIOSH

(rem)

SC&A-Method A 

(rem)

SC&A-Method B

(rem)

Lung 0.037 0.048 0.038

NIOSH’s annual doses were entered into IREP as a lognormal distribution with uncertainties 

varying at about 1.63. Both of SC&A’s DR methods entered annual missed photon doses into 

IREP as a lognormal distribution with an uncertainty of 1.520. 

2.1.3 Unmonitored Photon Doses 

NIOSH and SC&A’s ‘Method B’ assigned coworker doses to the EE for unmonitored periods of 

employment. Since SC&A’s ‘Method A’ used a minimizing approach to reconstructing doses, 

this method did not assign any unmonitored photon dose. 

Although both NIOSH and SC&A’s ‘Method B’ used the plutonium coworker model doses cited 

in Table C-4 of the RFP TBD (ORAUT-TKBS-0011-6), the two DR methods differed in their 

selection of percentile values and number of unmonitored months. NIOSH assumed that the EE, 

who worked as a [redact]/ [redact], should be assigned the 50th percentile coworker doses for 

1.05 months in [redact] and 5.46 months in [redact]. SC&A’s ‘Method B’ selected the 95th
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percentile values, based on the EE’s job duties and amount of recorded dose the EE received. 

‘Method B’ also assigned coworker doses for 1.1 months in [redact], 2 months in [redact], 

4 months in [redact], 2 months in [redact], and 6 months in [redact]. 

As with the recorded and missed photon doses, NIOSH assumed the energy range of 100% 

<30 keV and 100% 30–250 keV for the coworker photon doses. Using Monte Carlo methods, 

the <30 keV doses were entered into IREP as a normal distribution and the [redact] 30–250 keV 

photons were entered as a normal distribution, while the [redact] 30–250 keV doses were 

entered as the mode of a triangular distribution. 

SC&A’s ‘Method B’ assumed a photon energy range of 25% <30 keV and 75% 30–250 keV. 

All values were entered into IREP as the mean of a normal distribution with an SD of 30%. 

A comparison of unmonitored photon doses derived by the two DR methods is shown in 

Table 2-6. 

Table 2-6. Comparison of Unmonitored Photon Doses 

Unmonitored Photon 

Doses

NIOSH

(rem)

SC&A-Method A

(rem)

SC&A-Method B

(rem)

<30 keV photons 0.001 Not considered 0.012

30–250 keV photons 0.038 Not considered 0.665

Total 0.039 – 0.677

2.1.4 Recorded Neutron Doses 

All three DR methods assigned recorded neutron doses based on positive readings reported in the 

EE’s dosimetry records. Recorded neutron doses were calculated using guidance regarding 

energy ranges and ICRP 60 correction factors (CFs) provided in the RFP Occupational External 

Dose TBD (ORAUT-TKBS-0011-6). ORAUT-TKBS-0011-6 also recommends using the 

OCAS-IG-001 Ambient Dose Equivalent-to-Organ DCF for the period 1951 through 1982 and, 

for the period 1983 through 2005, the Deep Dose Equivalent-to-organ DCF should be used. The 

neutron dose parameters applied by all three DR methods are listed in Table 2-7. 

Table 2-7. Neutron Energies, ICRP CFs, and Organ DCFs Used by the Three DR Methods 

(Ambient Dose Equivalent) 1979–1982 (Deep Dose Equivalent) 1983–1985

Energy 

Range

<10 

keV

10–100 

keV

0.1–2 

MeV

2–20 

MeV

<10 

keV

10–100 

keV

0.1–2 

MeV

2–20 

MeV

ICRP 60 CF 0.0755 0.0309 1.31 0.345 0.0755 0.0309 1.31 0.345

Organ DCF 1.523 0.751 0.579 1.004 1.332 0.737 0.557 0.950

Using the EE’s dosimetry records and above-cited parameters, NIOSH, SC&A’s ‘Method A,’ 

and SC&A’s ‘Method B’ calculated nearly identical photon doses, as shown in Table 2-8.
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Table 2-8. Comparison of Recorded Neutron Doses 

Recorded Neutron Doses NIOSH (rem) SC&A’s ‘Method A’ (rem) SC&A’s ‘Method B’ (rem)

<10 keV 0.088 0.101 0.099

10–100 keV 0.026 0.021 0.021

0.1–2 MeV 0.771 0.691 0.679

2–20 MeV 0.340 0.313 0.308

Total 1.225 1.126 1.107

NIOSH employed Monte Carlo methods for deriving doses and uncertainty. As such, some of 

the neutron doses best fit a normal distribution and some a lognormal distribution. SC&A’s 

‘Method A’ entered doses into IREP as a constant with no uncertainty, and ‘Method B’ entered 

doses into IREP as a mean of a normal distribution with a 30% uncertainty.

2.1.5 Missed Neutron Doses 

All DR methods assigned missed neutron doses for monitored periods that were reported as zero 

readings or less than one-half the applicable LOD value. NIOSH and SC&A’s ‘Method B’

counted 27 missed readings, while SC&A’s ‘Method A’ assigned missed neutron dose to 20 

monitoring periods. NIOSH assumed an LOD value of 0.020 rem from [redact]–[redact] and 

0.032 rem from [redact]–[redact], based on guidance in Table 6-20 of ORAUT-TKBS-0011-6. 

Both of SC&A’s DR methods assumed an LOD value of 0.020 for all years. Resultant doses are 

shown in Table 2-9. 

Table 2-9. Comparison of Missed Neutron Doses 

Missed Neutron Doses NIOSH (rem) SC&A’s ‘Method A’ (rem) SC&A’s ‘Method B’ (rem)

<10 keV 0.028 0.028 0.030

10–100 keV 0.009 0.006 0.006

0.1–2 MeV 0.250 0.191 0.199

2–20 MeV 0.110 0.087 0.089

Total 0.397 0.312 0.324

NIOSH’s annual neutron doses were entered into IREP as a lognormal distribution with 

uncertainties varying at about 1.55. Both of SC&A’s DR methods entered annual missed photon 

doses into IREP as a lognormal distribution with an uncertainty of 1.520. 

2.1.6 Unmonitored Neutron Doses 

SC&A’s ‘Method A’ did not calculate any unmonitored neutron doses, since this method 

employed a minimizing approach to DR. However, both NIOSH and SC&A’s ‘Method B’ did 

assign unmonitored neutron dose based on the plutonium coworker model described in ORAUTTKBS-0011-6. Consistent with methods used for assigning unmonitored photon doses, NIOSH 

selected the 50th percentile values from Table C-4 of ORAUT-TKBS-0011-6, while SC&A’s 

‘Method B’ selected the 95th percentile values. Additional differences in dose calculations 

included NIOSH assigning unmonitored dose for 1.05 months in [redact] and 5.46 months in 

[redact], while ‘Method B’ assigned doses for [redact] and [redact]–[redact] totaling 

15.1 months. Total unmonitored neutron doses calculated by the two DR methods are presented 

in Table 2-10.
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Table 2-10. Comparison of Unmonitored Neutron Doses 

Unmonitored Neutron Doses NIOSH (rem) SC&A’s ‘Method A’ (rem) SC&A’s ‘Method B’ (rem)

<10 keV 0.002 Not considered 0.045

10–100 keV 0.001 Not considered 0.010

0.1–2 MeV 0.016 Not considered 0.318

2–20 MeV 0.007 Not considered 0.148

Total 0.026 – 0.521

NIOSH employed Monte Carlo methods for deriving doses and uncertainty. As such, the 10–

100 keV neutrons best fit a lognormal distribution and all other neutron energies fit a normal 

distribution. SC&A’s ‘Method B’ entered doses into IREP as a mean of a normal distribution 

with a 30% uncertainty. 

2.1.7 Occupational Medical Doses 

All three DR methods calculated an occupational medical dose from diagnostic x-ray procedures 

required as a condition of employment. NIOSH indicated that they followed guidance cited in

the following three guidance documents in order to calculate their occupational medical doses: 

1. ORAUT-TKBS-0011-3, Technical Basis Document for the Rocky Flats Plant –

Occupational Medical Dose, Rev. 01.

2. ORAUT-PROC-0061, Occupational Medical X-Ray Dose Reconstruction for DOE 

Sites, Rev. 03.

3. ORAUT-OTIB-0079, Technical Information Bulletin: Guidance on Assigning 

Occupational X-Ray Dose under EEOICPA for X-Rays Administered Off Site, Rev. 00.

SC&A’s DR ‘Method A’ strictly used guidance provided in the RFP TBD (ORAUT-TKBS0011-3). SC&A’s ‘Method B’ consulted ORAUT-TKBS-0011-3, as well as ORAUT-PROC0061.

NIOSH assigned dose for only the two x-ray exams that were documented in the EE’s DOE 

records. Both of SC&A’s DR methods calculated annual doses based on guidance in Table 3-1 

of ORAUT-TKBS-0011-3. This resulted in the assignment of identical doses for SC&A’s 

‘Method A’ and ‘Method B,’ with NIOSH’s occupational medical dose being 35% lower, as 

shown in Table 2-11. 

Table 2-11. Comparison of Occupational Medical Doses 

Cancer NIOSH (rem) SC&A’s ‘Method A’ (rem) SC&A’s ‘Method B’ (rem)

Lung 0.084 0.294 0.294

Each DR method entered the annual doses into IREP as a mean value with an SD of 30%. 
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2.2 OCCUPATIONAL INTERNAL DOSES 

DOE records show that the EE had in vitro bioassay monitoring for plutonium, americium, and 

tritium via urinalyses during employment at RFP. The EE was also monitored in vivo for 

plutonium and americium via chest counts. All bioassay results were below the MDA for the 

given radionuclides and bioassay method. Therefore, to account for any potential undetected 

internal doses from exposure to plutonium, americium, and tritium, all three DR methods 

assigned missed and/or unmonitored doses. In addition, SC&A’s ‘Method B’ assumed the EE 

may have been exposed to depleted uranium (DU). Details associated with the calculation of 

internal doses are provided below. 

2.2.1 Plutonium/Americium Intakes 

NIOSH 

NIOSH assessed the internal dose from exposure to plutonium and americium by calculating and 

comparing internal coworker doses and missed dose. NIOSH describes their assessment process 

in the DR Report, as cited below: 

Coworker Dose Assignment

Internal coworker dose was assessed in accordance with the Technical Basis 

Document for the Rocky Flats Plant – Occupational Internal Dose [ORAUTTKBS-0011-5]. For plutonium, Type Super S was considered to be the most 

claimant-favorable solubility type. . . . 

Missed Dose 

Intakes based on plutonium urine bioassay over-predicted intakes based on [the 

EE’s] chest counts; therefore, only the chest count data were considered. The 

mixture of weapons-grade plutonium was applied to the americium-241 intake, 

based on chest count data, to determine the plutonium -238, plutonium-239, and 

plutonium-241 intakes. For plutonium, Type Super S was considered to be the 

most claimant-favorable solubility type based on chest count data (Types M, S, 

and Super S were considered). 

[The EE] was monitored for americium by urine bioassay, only during [the EE’s]

first employment period; those bioassay results were assessed as pure americium 

(solubility Type M) associated separation activities. 

The chronic intake rate was determined using half the minimum detection activity 

(MDA) for that radionuclide and assigned as the mode dose, with the maximum 

dose being twice the mode dose. 

Internal dose based on short intake periods . . . may significantly overestimate 

the actual internal dose when based on missed dose assumptions. To assure 

reasonable potential intakes were applied, . . . the internal dose based on the . . . 
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missed dose assumptions, was compared to the dose calculated using coworker 

data. Because coworker intakes resulted in a significantly lower dose for [the 

EE’s] second employment period, those intakes were applied for that period; 

missed internal dose was applied during [the EE’s] first employment period. 

[Emphasis added.] 

In summary, NIOSH calculated internal doses for exposure to plutonium/americium using IMBA 

and the missed dose methods (i.e., based on one-half the MDA value of chest count data) for the 

employment period of [redact], through [redact]. For the [redact] employment period, internal 

doses were based on the coworker model using guidance provided in ORAUT-TKBS-0011-5, 

Table D-6, which states it represents the 95th percentile intake rate. Table 2-12 summarizes the 

intake rates used by NIOSH. 

Table 2-12. Pu/Am Intake Rates Calculated by NIOSH 

Radionuclide Time Period Calculation Method Solubility 

Type

Intake Rate 

(dpm/day)

Pu-238 [redact]–[redact] Missed Dose Super S 1.387

Pu-238 [redact]–[redact] Coworker Model Super S 10.058

Pu-239 [redact]–[redact] Missed Dose Super S 57.780

Pu-239 [redact]–[redact] Coworker Model Super S 419.000

Pu-241 [redact]–[redact] Missed Dose Super S 327.614

Pu-241 [redact]–[redact] Coworker Model Super S 2,375.728

Am-241 [redact]–[redact] Missed Dose M 2.788

Using these data, NIOSH calculated a missed plutonium dose of 5.038 rem, a coworker 

plutonium dose of 40.502 rem, and a missed americium dose of 0.493. Annual missed 

plutonium and americium internal dose values were entered into IREP as the mode of a 

triangular dose distribution. Coworker plutonium doses were entered as a constant value with no 

uncertainty. 

SC&A’s ‘Method A’ 

SC&A’s ‘Method A’ calculated plutonium/americium intakes by comparing the plutonium urine 

and chest count results and the americium urine and chest count results. A chronic intake was 

assumed to have occurred throughout the EE’s first employment period, [redact] to [redact]. 

The level of the intake was based on one-half the MDA of the analysis. 

Using IMBA and a maximum likelihood fitting method, the total plutonium intake rate was 

determined for Type S plutonium, based on both the urine and chest count data. Following the 

same method, the americium urine and chest count data were used to determine the Type S 

americium intake rate. The RFP Pu-Am Intake Calculation tool was used to determine the 

isotopic mixture for weapons-grade plutonium with Pu-241 weight percent of 0.36%. 

Table 2-13 shows the individual plutonium and americium intake rates based on the plutonium 

urine and chest count data. SC&A’s ‘Method A’ noted that the Am-241 intake rate derived 

using the urine data was consistent with the intake rate derived using the chest count data. 
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Table 2-13. Pu/Am Chronic Intakes ([redact]–[redact]) Derived by SC&A’s ‘Method A’

Radionuclide Solubility Type Intake Rate (dpm/day)

Pu-238 S 2.5

Pu-239/240 S 104.5

Pu-241 S 592.5

Am-241 S 5.04

Using the chronic annual dose workbook (CADW), annual doses were calculated from each of 

the above chronic intakes. To account for intakes of plutonium strongly retained in the lung 

(Type SS), the methods described in Section 4.0 of ORAUT-OTIB-0049 and Attachment D were 

used to modify the plutonium and americium doses derived using CADW based on a 5-year 

chronic intake. Table 2-14 shows the isotopic doses from CADW, the dose adjustment, the chest 

count adjustment factors from Attachment D, yearly fraction to account for partial year exposure 

in [redact] and [redact] (since CADW only calculates whole-year doses), and the total adjusted 

dose. 

All alpha doses were entered into IREP as a geometric mean (GM) value of a lognormal 

distribution with a GSD of 3.0. 

Table 2-14. SC&A’s ‘Method A’ OTIB-0049 Adjusted Doses

Isotopic Dose (rem) Total 

Dose 

(rem)

Dose 

Adj. 

Factor

OTIB-49

Adj.

Dose

*Chest 

Count 

Adj. 

Factor

Annual

Adj.

Dose

Frac. 

of 

Year

Total 

Adj. 

Dose 

(rem)

Pu-239 Pu-238 Pu-241 Am-241

[redact] 1.408E+00 3.891E-02 1.918E-03 7.821E-02 1.527 1.6 2.443 2.6 0.9398 0.175 0.165

[redact] 1.844E+00 5.045E-02 5.079E-03 1.015E-01 2.001 1.9 3.803 2.6 1.4625 1.000 1.463

[redact] 2.055E+00 5.586E-02 9.050E-03 1.124E-01 2.232 2.1 4.688 2.6 1.8031 1.000 1.803

[redact] 2.210E+00 5.978E-02 1.329E-02 1.204E-01 2.403 2.4 5.767 2.6 2.2182 1.000 2.218

[redact] 2.325E+00 6.269E-02 1.741E-02 1.265E-01 2.532 2.6 6.582 2.6 2.5316 1.000 2.532

[redact] 2.417E+00 6.499E-02 2.125E-02 1.312E-01 2.634 3.5 9.219 2.6 3.5458 0.532 1.885

[redact] 1.075E+00 2.771E-02 2.284E-02 5.639E-02 1.181 4.5 5.317 2.6 2.0448 0.625 1.277

[redact] 6.966E-01 1.761E-02 2.290E-02 3.617E-02 0.773 5.7 4.408 2.6 1.6954 1.000 1.695

[redact] 5.286E-01 1.324E-02 2.190E-02 2.740E-02 0.591 6.9 4.079 2.6 1.5688 1.000 1.569

[redact] 4.117E-01 1.023E-02 2.040E-02 2.130E-02 0.464 8.2 3.802 2.6 1.4622 1.000 1.462

[redact] 3.289E-01 8.109E-03 1.883E-02 1.698E-02 0.373 9.6 3.579 2.6 1.3764 1.000 1.376

[redact] 2.697E-01 6.598E-03 1.740E-02 1.391E-02 0.308 11 3.384 2.6 1.3016 1.000 1.302

[redact] 2.266E-01 5.494E-03 1.617E-02 1.166E-02 0.260 12 3.119 2.6 1.1995 1.000 1.200

[redact] 1.942E-01 4.672E-03 1.511E-02 9.985E-03 0.224 13 2.912 2.6 1.1200 1.000 1.120

[redact] 1.693E-01 4.039E-03 1.420E-02 8.692E-03 0.196 15 2.944 2.6 1.1323 1.000 1.132

[redact] 1.499E-01 3.546E-03 1.342E-02 7.685E-03 0.175 16 2.792 2.6 1.0739 1.000 1.074

[redact] 1.342E-01 3.151E-03 1.274E-02 6.871E-03 0.157 17 2.668 2.6 1.0263 1.000 1.026

[redact] 1.212E-01 2.822E-03 1.212E-02 6.199E-03 0.142 18 2.562 2.6 0.9855 1.000 0.986

[redact] 1.102E-01 2.546E-03 1.154E-02 5.625E-03 0.130 20 2.598 2.6 0.9991 1.000 0.999

[redact] 1.007E-01 2.309E-03 1.101E-02 5.136E-03 0.119 21 2.503 2.6 0.9625 1.000 0.963

[redact] 9.248E-02 2.104E-03 1.050E-02 4.710E-03 0.110 23 2.525 2.6 0.9712 1.000 0.971

[redact] 8.513E-02 1.921E-03 1.001E-02 4.329E-03 0.101 24 2.434 2.6 0.9360 1.000 0.936

[redact] 7.851E-02 1.758E-03 9.535E-03 3.988E-03 0.094 26 2.439 2.6 0.9379 1.000 0.938

[redact] 7.257E-02 1.613E-03 9.076E-03 3.681E-03 0.087 27 2.347 2.6 0.9028 1.000 0.903

[redact] 6.719E-02 1.481E-03 8.635E-03 3.405E-03 0.081 29 2.341 2.6 0.9002 1.000 0.900

[redact] 6.226E-02 1.361E-03 8.203E-03 3.150E-03 0.075 31 2.324 2.6 0.8939 1.000 0.894

[redact] 5.770E-02 1.251E-03 7.782E-03 2.917E-03 0.070 33 2.298 2.6 0.8840 1.000 0.884

[redact] 5.355E-02 1.151E-03 7.378E-03 2.705E-03 0.065 35 2.267 2.6 0.8720 1.000 0.872
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Table 2-14. SC&A’s ‘Method A’ OTIB-0049 Adjusted Doses

Isotopic Dose (rem) Total 

Dose 

(rem)

Dose 

Adj. 

Factor

OTIB-49

Adj.

Dose

*Chest 

Count 

Adj. 

Factor

Annual

Adj.

Dose

Frac. 

of 

Year

Total 

Adj. 

Dose 

(rem)

Pu-239 Pu-238 Pu-241 Am-241

[redact] 4.974E-02 1.061E-03 6.991E-03 2.508E-03 0.060 37 2.231 2.6 0.8581 1.000 0.858

[redact] 4.622E-02 9.774E-04 6.617E-03 2.327E-03 0.056 39 2.189 2.6 0.8421 1.000 0.842

[redact] 4.294E-02 9.006E-04 6.255E-03 2.161E-03 0.052 41 2.142 2.6 0.8240 1.000 0.824

[redact] 3.994E-02 8.312E-04 5.912E-03 2.007E-03 0.049 43 2.094 2.6 0.8052 1.000 0.805

[redact] 3.718E-02 7.674E-04 5.586E-03 1.866E-03 0.045 46 2.088 2.6 0.8032 1.000 0.803

38.676

SC&A’s ‘Method B’

SC&A’s ‘Method B’ performed internal dose assessments using results from the urinalyses and 

lung count monitoring methods. A comparison of these results was made, and the doses that

were considered the most scientifically sound and claimant favorable, as described below, were 

used to determine the POC.

Missed Plutonium Dose Based on Urinalyses Data. SC&A’s ‘Method B’ first assessed missed 

plutonium dose based on urinalyses results, which were all below the MDA value. Intakes were 

calculated based on one-half the MDA value of 0.24 dpm/24 hours, as specified in Table 5-5 of 

ORAUT-TKBS-0011-5 and the isotopic fractions of alpha activity in weapons-grade plutonium 

listed in Table 5-1 of ORAUT-TKBS-0011-5. A chronic inhalation of Type S plutonium was 

calculated using the last plutonium bioassay on [redact]. In order to account for Type SS 

plutonium, the Pu-239 results were multiplied by 4. Table 2-15 shows resultant intakes and 

dose.

Table 2-15. Plutonium Intakes and Doses Calculated from Bioassay Results

Isotope Absorption Type Fraction of Weapons

Grade Pu (WGP)

Excreted bioassay rate

(dpm/24 hr) Intake (dpm/d) Dose (rem)

Pu-238 Type S 0.023 0.0028 10.72 2.24

Pu-239 Type SS 0.8 0.098 369 280

Pu-240 Type S 0.18 0.022 82.88 15.8

Total = 298.04

Missed Plutonium Dose Based on Lung Count Data. SC&A’s ‘Method B’ chose to assign 

missed dose using the lung count taken on [redact], which measured exposure to Am-241 using 

a highly sensitive Phoswich detector with a high americium MDA. Table B-11 of ORAUTTKBS-0011-5 lists the MDA values for Am-241 of 0.21 nCi, given the type of detector and the 

conditions in which the test was performed. The concentration of americium in units of parts per 

million (ppm) was used to determine the associated MDA of plutonium for the lung counts, 

based on guidance in Attachment B, Table B-9, of ORAUT-TKBS-0011-5. Table B-9 

recommends multiplying the americium MDA by 20.7 in order to get the MDA for plutonium. 

This resulted in a Pu-239+240 MDA of 4.347 nCi. Using 1⁄2 MDA value for plutonium and the 

isotopic fractions of alpha activity in weapons-grade plutonium listed in Table 5-1 of ORAUTTKBS-0011-5, the IMBA program was used to derive the intakes and doses shown in 

Table 2-16.
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Table 2-16. Type S Plutonium Intakes and Doses from Lung Counts Calculated by 

SC&A’s ‘Method B’

Isotope Absorption Type Fraction of 

WGP

Lung Count Measurement of 

1⁄2 MDA (pCi)

Intake 

(pCi/d)

Dose 

(rem)

Pu-238 Type S 0.023 51 1.528 0.709

Pu-239 Type S 0.8 1774 52.44 22.1

Pu-240 Type S 0.18 399 11.77 4.98

To account for exposure to Super S highly insoluble plutonium, the annual doses from lung 

counts were multiplied by adjustment factors, which are dependent upon the number of years 

that the individual was exposed. Therefore, the adjustment factors from Table D-1, page 46 of 

ORAUT-OTIB-0049, from the chronic [redact] years column were applied. This resulted in a 

total lung dose of 55.650 rem.

After comparing the urinalyses data and lung count data, SC&A’s ‘Method B’ decided that, even 

though the resultant doses were lower, the lung count data represented a more direct bioassay 

method. Therefore, the lung count results for plutonium were entered into IREP in order to 

determine the POC.

Missed Americium Dose Based on Urinalyses Data. All urinalyses results for americium were 

below the MDA of 0.31 dpm/24hour (ORAUT-TKBS-0011-5, Table 5-6). Using 1⁄2 MDA value

and assuming a chronic inhalation of Type S Am-241, IMBA was used to calculate an intake of 

12.87 dpm/d, which resulted in 2.730 rem to the lung.

Missed Americium Dose Based on Lung Count Data. As with the plutonium dose, SC&A’s 

‘Method B’ chose to assign missed dose using the lung count taken on [redact]. The lung count 

MDA for americium is 0.21 nCi (ORAUT-TKBS-0011-5, Table 5-11). A chronic intake of 

3.11 pCi/d was calculated by the IMBA program using the 1⁄2 MDA value. Using this intake, the 

total lung dose from exposure to americium from the beginning of employment to the date of 

diagnosis is 1.464 rem.

After comparing the urinalyses data and lung count data, SC&A’s ‘Method B’ decided that, even 

though the resultant doses were lower, the lung count data represented a more direct bioassay 

method. Therefore, the lung count results for americium were entered into IREP in order to 

determine the POC.

2.2.2 Tritium Dose

All three DR methods assessed potential dose associated with exposure to tritium. The EE was 

monitored for tritium during the first employment period via three urinalyses samples. All 

results were reported as less than MDA.

Using guidance in ORAUT-TKBS-0011-5, 1⁄2 MDA value, and IMBA, all three DR methods 

calculated a chronic tritium intake for the time period of [redact]–[redact], which resulted in a

total dose <0.001 rem. Therefore, the doses from the tritium intakes were not included in the 

IREP input.
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2.2.3 Depleted Uranium Dose

Only SC&A’s ‘Method B’ assumed that the EE may have been exposed to DU while at RFP.

‘Method B’ did determine, however, that the EE would not have had exposure to thorium. 

Therefore, the TBD was reviewed to identify time periods and locations where the EE worked

and thorium exposures were not plausible, but exposures to DU were plausible.

Missed dose from exposure to DU was calculated using the MDA of the lung count data. 

Section 5.3.2.2.2 of ORAUT-TKBS-0011-5 states the following regarding the uranium MDA for 

lung counts:

U-238 worker-specific MDA can be obtained by multiplying the Am-241 workerspecific MDA by 9.4. That result is divided by 0.89 to obtain the worker-specific 

MDA for DU.

The Am-241 MDA of 0.21 nCi was used in ‘Method B’s’ assessment, based on the count 

performed on [redact]. One-half the MDA value was multiplied by the alpha activity fractions 

for DU listed in Table 5-4 of ORAUT-TKBS-0011-5. The DU daily intake rates derived using 

these MDA values in the IMBA program were as follows: 3.25 pCi/d of U-234, 0.44 pCi/d of 

U-235, and 29.26 pCi/d of U-238. Using these intakes in the IMBA program and assuming a 

chronic intake from the beginning to the end of employment produced a total missed dose to the 

lung from DU of 10.300 rem.

All alpha doses calculated by SC&A’s ‘Method B’ were entered into IREP as a mean of a 

normal distribution with an uncertainty of 30%.

Summary of Assigned Internal Doses

A summary of the total internal dose assigned by each DR method for the EE’s employment at 

RFP is provided in Table 2-17.

Table 2-17. Comparison of RFP Total Internal Doses

Radionuclide NIOSH

(rem)

SC&A-Method A

(rem)

SC&A-Method B

(rem)

Plutonium/Americium 46.033 38.676 57.114

Depleted Uranium Not considered Not considered 10.300

Total 46.033 38.676 67.414

Although all three DR methods used guidance in ORAUT-TKBS-0011-5 and compared all 

applicable solubility types, including Type Super S, differences in doses resulted from NIOSH 

using coworker data for the majority of their internal dose, while SC&A’s ‘Method A’ and 

‘Method B’ based their doses on missed chest count data. In addition, SC&A’s ‘Method B’ 

assigned dose from DU, which was not considered by NIOSH and SC&A’s ‘Method A.’
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3.0 SUMMARY CONCLUSIONS

Total external and internal doses and resultant POCs calculated by SC&A ‘Method A,’ SC&A 

‘Method B,’ and NIOSH in behalf of Case #[Redact] are presented in Table 3-1 for comparison.

Table 3-1. Comparison of Total External and Internal Doses Estimated for the Lung

Total Lung Doses NIOSH

(rem)

SC&A-Method A

(rem)

SC&A-Method B

(rem)

External Doses:

 - Photons <30 keV

 - Photons 30-250 keV

 - Neutrons <10 keV

 - Neutrons 10-100 keV

 - Neutrons 0.1-2 MeV

 - Neutrons 2-20 MeV

0.030

1.562

0.118

0.036

1.037

0.457

0.019

1.488

0.129

0.027

0.882

0.400

0.030

2.254

0.174

0.037

1.196

0.545

Occupational Medical Dose 0.084 0.294 0.294

Internal Doses:

 - Alpha 46.033 38.676 67.414

Total Lung Dose 49.357 41.915 71.944

POC 47.51% 56.71% 55.75%

As shown in Table 3-1, internal doses contributed the majority of total dose assigned by each of 

the DR methods. The most striking element of this comparison is that although SC&A’s 

‘Method A’ derived a total dose that is nearly 1.5 rem less than NIOSH’s total dose, the resultant 

POC was higher than the POC reported by NIOSH and would have resulted in a compensable 

claim. Additionally, SC&A’s DR ‘Method B’ assigned doses that were 1.5 times higher than

SC&A’s ‘Method A;’ however, ‘Method B’s’ resultant POC was nearly identical to the SC&A’s 

‘Method A’ POC. This difference in POC is primarily due to how uncertainty was defined in 

IREP. A more detailed discussion of uncertainty, as well as variables that contributed to key 

differences in dose assignments, is presented below.

 Dose Reconstruction Methodology

 – NIOSH and SC&A’s ‘Method B’ employed a best-estimate approach to dose 

reconstruction. 

 – SC&A’s ‘Method A’ employed a modestly minimizing approach to reconstructing 

doses.

 Assignment of Unmonitored Dose

 – NIOSH assigned unmonitored dose using the 50th percentile coworker values for a 

total of 6.51 months.

 – SC&A’s ‘Method B’ calculated unmonitored dose based on the 95th percentile of 

coworker data for 15.1 months.

 – SC&A’s ‘Method A’ did not assign unmonitored dose.
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 Assignment of Occupational Medical Dose

 – NIOSH assigned medical doses for only 2 documented x-ray exams, based on values 

cited in the RFP TBD. 

 – SC&A’s ‘Method A’ and ‘Method B’ assigned annual occupational medical x-ray

exams based on dose values in the RFP TBD.

 Assignment of Internal Doses

 – NIOSH assigned internal doses from monitored bioassays, which were all <MDA, 

using two methods: (1) 1st monitoring period ([redact]–[redact]) doses were based 

on missed dose approach (i.e., 1⁄2 MDA value for chest count data), and (2) 2nd

monitoring period ([redact]–[redact]) doses were based on coworker model.

 – SC&A’s ‘Method A’ and ‘Method B’ assigned coworker internal doses for both 

monitoring periods based on a missed dose method (< 1⁄2 MDA) using chest count 

data.

 Dose Uncertainty Entered into IREP 

 – NIOSH assigned internal coworker doses, which represent 82% of the total dose, as a 

constant value with no uncertainty.

 – SC&A’s ‘Method A’ assigned internal missed doses, which represented 80% of the 

total dose, as a GM of a lognormal distribution with a GSD of 3.0.

 – SC&A’s ‘Method B’ assigned internal missed doses, which represent 93% of the total 

dose, as a mean of a normal distribution with an SD of 30%.
Effective Date:

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4.0 REFERENCES

ICRP 1991. Recommendations of the International Commission on Radiological Protection, 

International Commission on Radiological Protection, Publication 60, Pergamon Press, Oxford, 

England.

OCAS-IG-001. 2007. External Dose Reconstruction Implementation Guideline, Rev. 3, 

National Institute for Occupational Safety and Health, Office of Compensation Analysis and 

Support, Cincinnati, Ohio. November 21, 2007.

ORAUT-OTIB-0049. 2010. Technical Information Bulletin: Estimating Doses for Plutonium 

Strongly Retained in the Lung, Rev. 01 PC-2, Oak Ridge Associated Universities, Cincinnati, 

Ohio. November 29, 2010.

ORAUT-OTIB-0079. 2011. Technical Information Bulletin: Guidance on Assigning 

Occupational X-Ray Dose under EEOICPA for X-Rays Administered Off Site, Rev. 00, Oak 

Ridge Associated Universities Team, Cincinnati, Ohio. January 3, 2011.

ORAUT-PROC-0061. 2010. Occupational Medical X-Ray Dose Reconstruction for DOE Sites, 

Rev. 03, Oak Ridge Associated Universities Team, Cincinnati, Ohio. March 3, 2010.

ORAUT-TKBS-0011-3. 2007. Technical Basis Document for the Rocky Flats Plant –

Occupational Medical Dose, Rev. 01, Oak Ridge Associated Universities Team, Cincinnati, 

Ohio. April 23, 2007.

ORAUT-TKBS-0011-5. 2007. Technical Basis Document for the Rocky Flats Plant –

Occupational Internal Dose, Rev. 02, Oak Ridge Associated Universities Team, Cincinnati, 

Ohio. August 17, 2007.

ORAUT-TKBS-0011-6. 2010. Technical Basis Document for the Rocky Flats Plant –

Occupational External Dose, Rev. 01, Oak Ridge Associated Universities Team, Cincinnati, 

Ohio. October 20, 2010.

SC&A 2014. SC&A’s Blind Dose Reconstruction of Case #[Redact] from the Rocky Flats Plant, 

SCA-TR-BDR2014-CN037053, Rev. 0, SC&A, Inc., Vienna, Virginia. January 13, 2014.