Review of Three Advisory Board-Selected Cases 

Reworked for the Evaluation of Westinghouse 

Nuclear Fuels Division Template Revisions 

(DCAS-PER-052, Subtask 4)

Kathleen Behling, SC&A, Inc.

Advisory Board on Radiation and Worker Health, 

Subcommittee for Procedure Reviews

May 25, 2022
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Summary of Westinghouse Nuclear Fuels 

Division operational history

 Westinghouse Nuclear Fuels Division (WNFD) received 

enriched uranium from the Atomic Energy Commission’s 

(AEC’s) Fernald plant and a shipment of plutonium from the 

West Valley facility that originated at Hanford 

 Records suggest that the plutonium also included thorium 

 AEC operations: 1971–1972 

 Residual period: 1973–1979
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DCAS-PER-052, “Westinghouse Nuclear Fuels 

Division”

 Issued March 2014 due to a June 2012 revision to the WNFD 

dose reconstruction (DR) template

 Revision resulted from identification of more than 9,600 new air 

samples 

 Discovery of new air samples significantly increased inhalation 

intakes

 Template added three categories of unmonitored workers 

(operators/general laborers, supervisors, and other) based on 

their potential for exposure
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SC&A’s review of DCAS-PER-052

 SC&A’s October 2014 review identified two findings

 Summary of findings:

– Finding 1: Guidance for adjusting intakes based on “partially 

monitored” versus “completely unmonitored” status of a worker cannot 

be followed with available data provided in the revised template

– Finding 2: The designation of Pu-241 as an alpha emitter is incorrect

 Findings discussed and closed at the April 28, 2015, SCPR 

meeting
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DCAS-PER-052 subtask 4 review of three 

reworked cases

 ABRWH selected three reworked cases for SC&A’s review in 

April 2021, based on the following criteria:

1. one case that resulted in a POC between 45% and 50%

2. one case where internal dose was assigned based on the category of 

“operator”

3. one case where internal dose was assigned based on the category of 

“other”

 SC&A reviewed reworked cases in December 2021 to 

determine if external and internal doses (case 1) and internal 

dose (cases 2 and 3) were correctly assessed in accordance 

with DCAS-PER-052
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NIOSH’s reworked DRs

 NIOSH’s rework of the cases:

– Used applicable DR tools 

– Recalculated all annual doses 

– Re-ran IREP

 Revised DR reports not sent to U.S. Department of Labor 

because the compensation decisions did not change
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Case 1 background (POC 45–50%)

 Energy employee (EE) worked at WNFD for multiple periods of 

employment

 EE was periodically monitored for radiation exposure

 Diagnosed with qualifying cancer during the employment 

period
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Comparison of NIOSH’s reworked doses 

versus original doses for case 1

Dose categories Reworked vs. original dose 

percentage

External 86% decrease

Occupational medical unchanged

Internal 284% increase

Total 172% increase

POC 90% increase
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Original case 1 external photon dose 

calculations

 During periods when no external monitoring records found, ambient 

dose was assigned

 All monitoring records showed zero readings and were treated as 

missed dose (limit of detection (LOD)/2), based on 

LOD = 0.040 rem and 19 zeros

 Glovebox correction factor of 2.19 applied

 Applied OCAS-IG-001, rev. 3, dose conversion factor (DCF) value

 Doses entered in IREP as lognormal with geometric standard 

deviation (GSD) of 1.34

 Assigned dose to the cancer site ~0.800 rem
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Original case 1 external ambient dose 

calculations

 Ambient dose assigned for each year of employment 

 DCF value of 1.0 applied

 Doses entered in IREP as normal with 30% uncertainty

 Assigned dose to the cancer site ~1.000 rem
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Original case 1 occupational medical dose 

calculations

 Medical dose calculated for each occupational x-ray 

 Dose based on ORAUT-OTIB-0006, rev. 03 PC-1

 Doses <0.001 rem

 Not entered in IREP because <0.001 rem
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Reworked case 1 external photon dose 

calculations

 Ambient dose assigned when EE not monitored

 Missed dose during residual period calculated based on 

February 2014 template values (significant decrease from 

2012)

 Applied OCAS-IG-001, rev. 3, DCF value

 Doses entered in IREP as normal with 30% uncertainty

 Assigned dose to the cancer site ~0.300 rem
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Reworked case 1 occupational medical dose 

calculations

 Medical dose calculated for each occupational x-ray 

 Dose based on ORAUT-OTIB-0006, rev. 04

 Doses <0.001 rem

 Not entered in IREP because <0.001 rem
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SC&A’s conclusions on case 1 external dose

 Reviewed the U.S. Department of Energy (DOE) files and 2012 and 

2014 WNFD templates

 Confirmed reworked external doses were based on ambient and 

residual values from the 2014 WNFD template

 Residual dose decreased due to evaluation method changed from 

using residual period dosimetry to using standard derived residual 

doses given in the updated template, in accordance with ORAUTOTIB-0070, rev. 01

 Correctly entered in the IREP table as chronic exposure with a 

normal distribution and 30% uncertainty

 Although doses calculated as stated, SC&A had two findings
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SC&A’s finding 1 on case 1 external dose

 Finding 1: Incorrect DCF was used to calculate dose

– 2014 template states exposure (R)-to-organ DCF for an isotropic 

exposure geometry to be applied

– Guidance does not specify if the DCF for the exposure or the ambient 

isotropic geometry is to be used

– Reworked case used claimant-favorable exposure DCF for anteriorposterior geometry (1.060)
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SC&A’s finding 2 on case 1 external dose

 Finding 2: NIOSH’s use of ambient dose during the operational 

period is not claimant favorable

– EE’s DOE records did not identify external dosimetry monitoring 

records for operational years

– Records show that the EE was monitored for internal exposure during 

that timeframe

– SC&A questions the assignment of ambient dose for this period, rather 

than a more claimant-favorable assignment, such as co-exposure dose
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Original case 1 recorded internal dose 

calculations

 EE had positive uranium urine bioassays during operational period

 Highest value entered in the IMBA program, which projected an 

intake of U-234 of 132,730 dpm/day 

 U-234 solubility types F, M, and S compared; type S provided for the 

largest dose 

 Recycled uranium (RU) components of the U-234 intake were 

analyzed using 2% enriched uranium

 Annual doses entered in IREP as a chronic exposure with a 

lognormal distribution and an uncertainty of 3.0

 Assigned dose of ~4.500 rem
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Original case 1 unmonitored internal dose 

calculations

 No bioassay monitoring results for 1 year

 Assigned internal dose based on facility air concentration data

 Unmonitored exposures were based on the geometric mean intake 

rate and assigned as Th-228 and Th-232

 Compared solubility types M and S; type M was considered the 

most claimant favorable 

 Assumed the thorium intakes to be 50% Th-228 and 50% Th-232

 Doses entered in IREP with a lognormal distribution and an 

uncertainty of 4.638

 Modest dose assigned
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Original case 1 missed internal dose 

calculations

 Urinalyses results during residual period less than minimum 

detectable activity (MDA)

 Chronic intake rate derived using half the MDA for plutonium 

 Assumed a 12% 10-year-old fuel-grade plutonium mixture, based 

on Hanford

 Compared solubility types M, S, and Super S; type Super S was 

most claimant-favorable solubility type

 Annual doses entered in the IREP table as a chronic exposure with 

a triangular distribution (minimum equal to zero, the mode equal to 

the dose, and maximum equal to twice mode)

 Assigned dose of ~0.300 rem
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Original case 1 unmonitored radionuclide 

dose calculations

 Template guidance: 

– Partially monitored workers with bioassays for uranium and/or plutonium 

should be assigned unmonitored exposure for those radionuclides (uranium, 

plutonium, or natural thorium) not monitored

– Dose should be based on 95th percentile intake

 Unmonitored Th-228/232 exposures assessed using the 95th 

percentile intake rate for operational period

 Solubility types M, S, and Super S considered, with type M resulting 

in the most claimant-favorable dose

 Thorium intakes were assumed to be 50% Th-228 and 50% Th-232

 Entered in IREP as a chronic exposure as a constant

 Total dose assigned <0.100 rem
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Reworked case 1 recorded internal dose 

calculations

 Rework identified three positive uranium urine bioassays during operational period

 Highest value entered in IMBA, which projected a U-234 intake of 132,730 dpm/day 

 Adjustment for bioassay monitoring period resulted in inhaled intake of 53,273 dpm/day

 U-234 solubility types F, M, and S compared; type S provided for the largest dose 

 RU components of the U-234 intake were analyzed using 2% enriched uranium, 

12% 10-year-old fuel-grade plutonium, and natural thorium 

 RU ratio for each radionuclide that resulted in the largest intake was applied

 Annual doses entered in IREP as a chronic exposure with a lognormal distribution and 

an uncertainty of 3.0

 Assigned dose of ~17.500 rem 
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Reworked case 1 unmonitored radionuclides 

dose calculations

 2012 WNFD template separated unmonitored workers into three 

categories based on potential for exposure: 

– Operators/general laborers (95th percentile of air sample data) 

– Supervisors (50% of operator dose)

– Other workers (10% of supervisor dose)

 EE considered a “supervisor”

 Calculated unmonitored dose based on plutonium mixture

 Solubility types M and S, with type M resulting in the most claimant- favorable dose

 Entered in IREP as a chronic exposure as a constant

 Total dose assigned ~1.000 rem
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SC&A’s conclusions on reworked case 1 

internal dose

 Reviewed DOE records, 2012 WNFD template, reworked CADW 

files, and IREP and confirmed that correct intake values were used 

to calculate recorded internal dose

 SC&A concurs with selection of “supervisor” for unmonitored dose 

based on DOE files and computer-assisted telephone interview

 SC&A verified unmonitored radionuclides: 

– Type M solubility resulted in the higher dose 

– Dose data appropriately entered in IREP table

– Doses were assessed to the date of cancer diagnosis

 SC&A noted Pu-239 intake values for both 2% and 12% ratios 

entered in IREP (slight overestimate)

 SC&A had no findings about the assessment of internal dose
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Case 2 background (operator)

 EE worked at WNFD for ~20 years of employment

 EE was not monitored for radiation exposure

 Diagnosed with qualifying cancers ~10 years after termination
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Comparison of NIOSH’s reworked doses 

versus original doses for case 2

Dose categories Reworked vs. original dose 

percentage

External ~60% decrease

Occupational medical No change 

Internal * ~16,600% increase

Total ~374% increase

POC ~158% increase

* SC&A evaluated only doses assigned for internal exposure, as specified by PER-052.
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Original case 2 internal dose calculations

 No monitoring, internal dose based on gross alpha air sampling data 

during operational period

 Calculated unmonitored dose based on the geometric mean intake rate of 

9.122 dpm/day inhalation and 0.182 dpm/day ingestion 

 Using CADW, compared plutonium, uranium, and thorium mixture 

intakes, with plutonium resulting in highest dose

 12% 10-year-old plutonium mixture ratios applied

 Solubility types M and S were evaluated, with type M resulting in the most 

claimant-favorable dose

 Doses were entered in IREP as lognormal distribution and GSD of 4.638

 Total dose of <0.050 rem assigned
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Reworked case 2 internal dose calculations

 EE considered “operator” based on job title

 Used CADW to compare plutonium, uranium, and thorium 

mixture intakes, with plutonium resulting in highest dose

 12% 10-year-old plutonium mixture ratios applied

 Operational intakes used for operational and residual periods 

 Solubility types M and S were evaluated, with type M resulting 

in the most claimant-favorable dose

 Doses were entered in IREP as constant

 Assigned total dose of ~5.500 rem
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SC&A’s conclusions on reworked case 2 

internal dose

 Reviewed 2012 WNFD template, reworked CADW files, and IREP 

and confirmed that correct intake values were used to calculate 

internal dose

 SC&A concurs with selection of “operator” for unmonitored dose

 SC&A verified: 

– Plutonium type M solubility resulted in the highest dose 

– Dose data appropriately entered in IREP table

– Doses were assessed to the date of cancer diagnosis

 SC&A had no findings about the assessment of internal dose for 

case 2
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Case 3 background (other)

 EE worked at WNFD for multiple decades

 EE was not monitored for radiation exposure

 Diagnosed with qualifying cancer during employment
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Comparison of NIOSH’s reworked doses 

versus original doses for case 3

Dose categories Reworked vs. original dose 

percentage

External ~15% decrease

Occupational medical ~50% increase

Internal * ~700% increase

Total ~12% increase

POC ~10% decrease

* SC&A evaluated only doses assigned for internal exposure, as specified by PER-052.
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Original case 3 internal dose calculations

 No monitoring, internal dose based on gross alpha air sampling data 

during operational period

 Calculated unmonitored dose based on the geometric mean intake rate of 

9.122 dpm/day inhalation and 0.182 dpm/day ingestion 

 Using CADW, compared plutonium, uranium, and thorium mixture 

intakes, with plutonium resulting in highest dose

 12% 10-year-old plutonium mixture ratios applied

 Solubility types M and S were evaluated, with type M resulting in the most 

claimant-favorable dose

 Doses were entered in IREP as lognormal distribution and GSD of 4.638

 Total dose of <0.050 rem assigned
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Reworked case 3 internal dose calculations

 EE considered “other” worker based on job title

 Used CADW to compared plutonium, uranium, and thorium 

mixture intakes, with plutonium resulting in highest dose

 12% 10-year-old plutonium mixture ratios applied

 Operational intakes used for operational and residual periods 

 Solubility types M and S were evaluated, with type M resulting 

in the most claimant-favorable dose

 Doses were entered in IREP as constant

 Assigned total dose of ~0.200 rem
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SC&A’s conclusions on reworked case 3 

internal dose

 Reviewed 2012 WNFD template, reworked CADW files, and IREP 

and confirmed that correct intake values were used to calculate 

internal dose

 SC&A concurs with selection of “operator” for unmonitored dose

 SC&A verified: 

– Plutonium type M solubility resulted in the highest dose 

– Dose data appropriately entered in IREP table

– Doses were assessed to the date of cancer diagnosis

 SC&A had no findings about the assessment of internal dose for 

case 3 (criterion 3)
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Summary conclusions for three cases reviewed 

under DCAS-PER-052

 SC&A reviewed three cases based on these criteria:

1. one case that resulted in a POC between 45% and 50%

2. one case where internal dose was assigned as “operator” category 

3. one case where internal dose was assigned as “other” category

 SC&A had two findings about the rework of case 1:

– Finding 1: Incorrect DCF was used to calculate dose

– Finding 2: NIOSH’s use of ambient dose during the operational period 

is not claimant favorable

 Internal doses for cases 2 and 3 were reevaluated in 

accordance with DCAS-PER-052
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Observation 1: Inadequate reviews of DR 

methodology templates

 During this review, SC&A became aware that, not only was the 

WNFD template modified in 2012, as addressed in PER-052, but 

the template was also revised in 2014 and 2016

 Since DR templates are not formally published, the Board is not 

aware of their existence or changes introduced in these templates 

unless a PER is issued (only when doses increase) or SC&A 

reviews a case from a site where the template is used for DR

 SC&A recommends that the Board:

– Be provided with a complete list of sites where DRs are being 

performed using a template

– Be informed when these templates are revised
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Questions?