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Response to NIOSH’s Review of

SC&A’s Nevada Test Site Resuspension 

Issues Status Report

Presentation to the

Nevada Test Site Work Group

Lynn R. Anspaugh

SC&A, Inc.

Contractor to:

Advisory Board on Radiation and Worker Health

Centers for Disease Control and Prevention

January 5, 2017
SC&A’s Task

• Review the calculation of doses from the 

resuspension of radionuclides deposited 

on the ground.

• In essence, this amounts to the review of 

ORAUT (2012), Technical Basis 

Document, Revision 3, on Occupational 

Environmental Dose.

• There was also a review of how doses 

were actually being calculated by dose 

reconstructors.

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Recent Documents

• ORAUT (2012) Technical Basis Document, Revision 3, on 

Occupational Environmental Dose

• SC&A (2015) Status Report on Resuspension Issues at the Nevada 

Test Site

• NIOSH (2016) NTS Resuspension Issues and Comments Matrix

• Strenge (2016) NIOSH Response to Short-lived Radionuclide 

Issues Raised in Comment 5 of SC&A’s NTS Resuspension Issues 

Report

• Rollins (2016) NIOSH Response to Inconsistency Issues Raised in 

Comment 8 of SC&A’s NTS Resuspension Issues Status Report

• SC&A (2016) Response to NIOSH’s Review of SC&A’s Nevada Test 

Site Resuspension Issues Status Report

• SC&A (2016) Memo: SC&A’s Position on Comment 8 –

Resuspension Issues at the Nevada Test Site

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Major Events at the NTS

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Sept 1992, 

All testing ends

January 1951, Atmospheric testing began

July 1962, Atmospheric testing ends

January

1963

December 1992, End of SEC 

classes

NIOSH unable to calculate internal dose

Highest air 

sample for Pu

NIOSH

resuspension

window

Claimants whose work time falls within the circle are 

not treated equally.
The last half of 1962 was a busy 

time at the NTS.

• Thirty underground tests were conducted 

during that six months.

• Preparations were underway for 46 

additional tests in 1963.

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SC&A’s Recommendation 1 to 

Members of the NTS WG

Change the time period of reconstruction of 

occupational environmental dose to

July 17, 1962, through December 31, 1992.

(The same method can be used as for the 

time period from January 1, 1963, through 

December 31, 1992.)

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SC&A does not agree with the 

optimistic statement about the 

performance of bioassays.

• NIOSH itself has identified that there were 

not enough bioassay data to allow for the 

reconstruction of internal dose.

• Investigations have shown that not all 

persons entering tunnels were identified 

and not all were sent for bioassays.

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SC&A’s Recommendation 2 to the 

Members of the NTS WG

Provide a more valid statement about the 

likelihood of identification and bioassay 

results:

“These workers may have been 

identified on the rosters that were 

published before the event, and these 

workers may have had bioassay 

results in the DOE records.”

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The aim of the NIOSH calculations 

is to reproduce concentrations of 

radionuclides in air.

• Relies upon measurements of plutonium 

in air starting in 1971.

• Corrects for other long-lived 

radionuclides based upon measured 

concentrations in soil in the 1980s.

• Corrects for short-lived radionuclides on 

the basis of the Hicks’ tables. 

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Derivation of concentrations of 

radionuclides in air at times prior 

to 1971 depend upon use of the 

Anspaugh resuspension equation.

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Resuspension at early times is 

much more important.

11

From page 67 in ORAUT (2012)
An Example of the Hicks’ Tables

12

From Hicks (1981).
The Hicks’ tables were normalized 

to an external gamma-exposure 

rate of 1 mR/hr at H+12 hours with 

use of the Beck tables.

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An Example of the Beck Tables

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From Beck (1980)
The Hicks’ tables were provided 

for use in calculations of dose 

downwind from the NTS.

• It was necessary to correct for 

fractionation, which is the chemical and 

physical separation of nuclides according 

to volatility.

• The Small Boy calculations were done 

with the assumption that 0.4 of the 

refractories were present downwind.

• The refractories must be assumed to 

have remained on the NTS.

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Four steps are needed to correct 

for fractionation on site.

1. Starting with the calculations for 0.4 of 

refractories present in Hicks, add back in 

the 0.6 of refractory radionuclides 

missing to create an unfractionated 

source term.

2. Renormalize the unfractionated source 

term to 1 mR/hour at H+12.

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Four Steps (concluded)

3. Starting with the now unfractionated 

source term, add in the 0.6 of refractory 

nuclides that are presumed to have 

remained on the NTS.

4. Renormalize the refractory-enhanced 

source term to an external gammaexposure rate of 1 mR/hour at H+12.

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It does not appear that the 

renormalizations were done.

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SC&A’s Recommendation 3 to the 

Members of the NTS WG 

NIOSH and contractors should redo the 

calculations for correction of fractionation 

to include all four steps. This requires the 

additional steps of renormalizing the source 

term after each addition of refractory 

elements. 

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A central problem is that the 

NIOSH and Strenge (2016) 

calculations are not transparent.

• The descriptions are not clear.

• Intermediate results are not shown.

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What is the miracle?

IMBA was run to determine the relative 

importance of 177 radionuclides to 26 ICRP 

organs for 10 one-year periods:

111111 × 2222 × 1111 = 46,020 IMBA runs

And Strenge did it for 5 scenarios:

111111 × 2222 × 1111 × 55 = 222211, 111111 IMBA runs

It does not seem possible.

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Integration of Equation A-2 from 

ORAUT (2012).

“Integrating Equation A-2...from 0 to 

365 days and dividing the result by 365 

(the value that represents the 

integrated total dose for one year), it 

was determined that for the first year 

after detonation the lung dose from 

90Sr represented 0.0000738...of the 

dose from all 177 radionuclides.”

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The meaning of time 0 is unclear.

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From Page 70 of ORAUT (2012).
The previous statement is not 

correct.

Dividing by 365 does not give an integral.

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. . .

From SC&A (2016), page 24.
SC&A’s Recommendation 4 to the 

Members of the NTS WG

NIOSH and contractors should be very 

specific about how their calculations were 

made and provide the results of all 

intermediate calculations so that SC&A and 

others can verify the calculations.

This may require that one or more DVDs be 

provided, as the intermediate data are likely 

voluminous.

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SC&A’s Recommendation 5 to the 

Members of the NTS WG

NIOSH and contractors should also consider 

the source term for the Sedan event, which 

was a large thermonuclear event on July 6, 

1962.

The Sedan source term is different than one 

for a fission event.

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Sedan was a major event.

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Photos courtesy of National Nuclear Security 

Administration / Nevada Site Office
The NIOSH calculations do not 

consider contaminating events 

post July 1962.

• There were 225 underground shots that 

vented during 1963-1970.

• There were 5 Plowshare events during 

1964–1968 that released 105 to 106 Ci at 

H+12.

• The Baneberry vent released nearly 107 Ci 

at H+12.

• There were 25 tests of nuclear rocket 

engines during 1963–1970.

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Baneberry was a massive vent that 

occurred on December 18, 1970.

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Photo courtesy of National Nuclear Security Administration /

Nevada Site Office
SC&A’s Recommendation 6 to the 

Members of the NTS WG.

The impacts of hundreds of releases of large 

quantities of short-lived radionuclides in the 

1962–1970 period should be considered in a 

more serious manner so that exposures to 

claimants are considered fairly.

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