Evaluation of Available Survey Data 

for the Central Facilities Area at 

Idaho National Laboratory

Douglas Farver, CHP

S. Cohen and Associates

Contractor to:

Advisory Board on Radiation and Worker Health/ABRWH

Center For Disease Control and Prevention

November 10, 2015
Introduction and Background

• At the July 8, 2015, INL WG Meeting, SC&A presented a status update 

on their evaluation of the INL SEC Petition Evaluation Report for SEC00219, originally issued by NIOSH on March 14, 2015, and revised on 

July 21, 2015.

• SC&A recommended that the available survey data for the Central 

Facilities Area (CFA), both during operations and prior to demolition 

and dismantlement (D&D), be evaluated to determine the actinide to 

Sr-90 and actinide to Cs-137 ratios and compare these ratios to the 

values in Tables 5-22 and 5-23 of ORAUT-TKBS-0007-5. 

• This presentation provides a summary of NIOSH’s proposed methods 

for bounding operational period internal doses for the CFA, a review 

of the available survey data, and a comparison of the derived values 

to the values in Tables 5-22 and 5-23 of ORAUT-TKBS-0007-5. 

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Proposed Methodology to 

Assess Actinide Intakes

• Section 7.2.5.2, SEC-00219 ER - describes NIOSH’s methods 

for bounding operational period internal dose for CFA

• Potential missed intakes of uranium, thorium, and 

plutonium for CFA workers are of particular interest

• Proposed method uses mixed fission product (MFP) and 

mixed activation product (MAP) intakes determined from 

the beta-gamma bioassay data to assess actinide intakes 

using the actinide to Sr-90 and actinide to Cs-137 ratios 

and Tables 5-22 and 5-23 of ORAUT-TKBS-0007-5 

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Maximum Ratios from

Tables 5-22 and 5-23 

4 

Radionuclide* Actinide to Sr-90 

Ratios (Table 5-22) 

Actinide to Cs-137 

Ratios (Table 5-23) 

Ac-227 2.30E-10 2.10E-10 

Th-228 2.30E-07 2.10E-07 

Pa-231 3.80E-09 3.5E-09 

U-234 1.40E-03 1.30E-03 

Np-237 3.70E-06 3.5E-06 

Pu-238 1.50E-02 1.40E-02 

Am-241 1.40E-04 1.30E-04 

Cm-244 4.90E-05 4.70E-05 

* The actinide isotopes listed are the predominant alpha-emitting 

actinides in the source term.
CFA Survey Data

• Conducted a search of the SRDB for radiological 

surveys of the CFA facilities

• 1954–1956 Contamination Surveys of CFA-669 

Hot Laundry and CFA-674A Chemical Engineering 

Lab (SRDB 139224)

• Post D&D soil sample results from excavation of 

the contaminated sanitary sewer line on the 

north side CFA-669 (SRDB 088224)

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Contamination Survey Data

• Only beta-gamma and alpha results greater than 

background levels (beta-gamma and alpha) at the 

same sample location were considered. 

• Eighty-five contamination survey results were found 

that met our criteria (listed in Appendix A of report).

• Six smear results from April 12, 1954, are not 

consistent with the other results and may have the 

alpha and beta-gamma results transposed. They 

were not included in the analyses.

• Original survey results are given in units of cpm. 

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Contamination Survey Data (continued)

• 1972 interoffice memo states smear counting 

equipment in use was acquired 1952–1958 (SRDB 

143623)

• 1970 results datasheets show the “counter yield” 

for beta-gamma and alpha results as 0.08 and 

0.27, respectively (SRDB 138318)

• Assuming the counting equipment used in 1970 is 

similar to the equipment used for the original 

surveys, SC&A applied the counter yield to 

original cpm results to obtain activity results in 

dpm/100 cm2

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Chemical Engineering Lab Survey

8 
Hot Laundry Survey

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D&D Soil Samples

• 19 soil samples from the excavation of the 

contaminated sanitary sewer line on the north 

side CFA-669

• Analyzed for alpha and gamma spectrum and 

strontium-90

• The U-234 and Th-228 levels were not 

significantly different from environmental 

levels 

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Comparison of Sr-90 and Cs-137 

with Actinide Results

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Cm-244 Pu-238 Sr-90 Cs-137 

Soil Sample Mean 

(pCi/g) 2.78E-02 3.83E-02 3.59E+00 5.41E-01 

Actinide/Sr-90 7.72E-03 1.07E-02 N/A N/A

Actinide/Cs-137 5.13E-02 7.09E-02 N/A N/A
Contamination Survey Results

2 2 

24

18

5 5 5 5 

1 1 

2 

0 

8 

1 

0

5

10

15

20

25

30

0.005 0.01 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 1 1.5

Frequency Distribution of Alpha/Beta-Gamma Ratios 

• 35% are between <5.0E-03 and 5.0E-02; same order of 

magnitude as the maximum intake ratios for Pu-238 

and U-234 from Tables 5-22 and 5-23.

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Soil Sample Results

Comparison of Maximum Intake Ratio and

Soil Sample Ratios

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SC&A NIOSH SC&A/NIOSH

Cm-244 Pu-238 Cm-244 Pu-238 Cm-244 Pu-238

Actinide/Sr-90 Ratio 7.72E-03 1.07E-02 4.90E-05 1.50E-02 1.58E+02 7.13E-01

Actinide/Cs-137 Ratio 5.13E-02 7.09E-02 4.70E-05 1.40E-02 1.09E+03 5.06E-01

• SC&A’s Cm-244 values are 2 to 3 orders of magnitude 

higher than the NIOSH values.

• SC&A’s Pu-238 values show relatively good agreement, 

within 50% of the NIOSH values.
Summary 

• Analyses of the smear data and soil sample results 

indicated general agreement in the magnitude of the 

maximum contamination ratios for U-234 and Pu-238 

given in Tables 5-22 and 5-23 of ORAUT-TKBS-0007-5.

• There are several limitations in the data used:

 The survey data found was very limited and from period of 

early operations. 

 The survey data is written given in units of cpm. Instrument 

parameters uncertain.

 The soil samples were collected during D&D operations. 

Prefer characterization survey, prior to D&D.

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Comments and Questions?

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