Draft Memo – Mound Neutron Issues 1 SC&A – October 4, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

DRAFT MEMO 

TO: Mound Work Group 

FROM: Ron Buchanan, SC&A 

DATE: October 4, 2011 

SUBJECT: SC&A’s Response to NIOSH Evaluation of Remaining Neutron Issues at the 

Mound Laboratory 

There are three remaining open action items related to neutrons at Mound. These issues are 

listed below, along with the most recent actions related to them. 

1. Action item - The Mound Work Group (WG) recommended that NIOSH compare the 

two MCNP analyses and determine the reason(s) for the difference in results. NIOSH 

should respond that they either disagree with adjustment factors or that they will make 

revisions to their current approach. 

a. SC&A issued “Draft White Paper: Sensitivity of NTA Film to Neutron Sources at 

Mound Laboratory,” Rev. 1, on July 22, 2010. This report concluded: 

 

For periods from August 1949 until January 24, 1956, the correction 

factors listed in Table 2 for the “observer“ exposed to 210Po-Be shielded 

by 8 inches of water should be applied to neutron doses during each 

period listed at the top of this table. From January 24, 1956, until August 

8, 1965, the correction factors listed in Table 2 for the “observer” 

exposed to 238PuF4 shielded by 8 inches of water should be used. From 

August 8, 1965, until the end of 1977, the correction factors listed in 

Table 3 for the “observer” exposed to 238PuF4 shielded by 8 inches of 

water should be applied to neutron doses during each period listed at the 

top of this table. 

b. NIOSH issued “NIOSH Evaluation of NTA Neutron Film Fading at Mound: 

Response to SC&A Issues and Recommendations” in December, 2010. This report 

concluded: 

NIOSH disagrees that 8-inches of water shielding is a reasonable 

assumption. Based on information gathered in discussions with Mound 

workers during outreach meetings we continue to believe that 4-inches of 

water shielding is a reasonable and claimant-favorable assumption. 

Furthermore, as we have stated in the past, negotiations over the 

numerical value of the correction factors are not a legitimate SEC issue, 

but rather it is an issue more appropriately considered in the TBD context. 

Nevertheless, discussions of this issue have continued to be pursued. 
Draft Memo – Mound Neutron Issues 2 SC&A – October 4, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

However, we also note that in either case the correction factors are almost 

the same. So strictly in the interest of coming to agreement we accept this 

SC&A recommendation and will apply the 8-inch water shielding 

correction factors published in Tables 2 and 3 of the SC&A report and 

reproduced in the third column of the Table 1. 

SC&A Response to Action Item #1

SC&A agrees with NIOSH’s decision on this issue.

2. Action item – NIOSH is to respond to the WG questions concerning NTA film track 

fading and adjustment factors. 

a. SC&A issued “Draft White Paper: Sensitivity of NTA Film to Neutron Sources at 

Mound Laboratory,” Rev. 1, on July 22, 2010. This report concluded: 

Based on this derivation, we predict fading of 34% after 1 week and 87% 

after 2 weeks, a minor discrepancy with the Mound report. 

and, 

Given the range of results of the track fading studies and our subsequent 

analysis, we recommend that the most claimant-favorable correction 

factors be applied to the neutron doses prior to July 15, 1968. The Mound 

procedure to correct future NTA film reports—applying a correction of 

33% to 1-week films, and 56% to 2-week and 4-week films—is consistent 

with the assumption that the entire dose is received at the beginning of the 

1-week or 2-week monitoring periods, but that it is delivered uniformly 

during each workday to workers on a 4-week monitoring schedule. This 

suggests that the study cited in the dosimetry supervisor’s July 15, 1968, 

memo may have involved exposing films daily for a 4-week period, with 

results that were in complete agreement with our analysis of the July 1, 

1968, report. The corrections that were applied by Mound following July 

15, 1968, should be applied retrospectively to earlier neutron doses 

measured at Mound. These corrections are in addition to the correction 

factors derived from Tables 2 and 3. 

b. NIOSH issued, “NIOSH Evaluation of NTA Neutron Film Fading at Mound: 

Response to SC&A Issues and Recommendations” in December 2010. 

i. This report noted, “NIOSH believes that an error exists in the SC&A analysis 

when they state, “Based on this derivation, we predict fading of 34% after 1 week 

and 87% after 2 weeks.” 

ii. As a result, this report then concluded, “In light of the publication by Kahle et al. 

(1969) and the apparent error in the SC&A analysis, NIOSH continues to support 
Draft Memo – Mound Neutron Issues 3 SC&A – October 4, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

the fading values of 33% in the first week after exposure and 56% after two 

weeks.” 

c. Bob Anigstein of SC&A sent an e-mail to the Mound WG on December 29, 2010, 

stating: 

I have just reviewed the report, “NIOSH Evaluation of NTA Neutron Film 

Fading at Mound: Response to SC&A Issues and Recommendations, 

December, 2010” (the footer has a date of November 3, 2010). NIOSH 

highlighted a typo on p. 9 of my and Dick Olsher's “Draft White Paper: 

Sensitivity of NTA Film to Neutron Sources at Mound Laboratory,” 

Rev. 1, dated July 22, 2010. Our report erroneously stated that the 

predicted fading of NTA film after 2 weeks is 87%. The correct value is 

57%, which is obtained from our Equation 6, and is consistent with the 

56% reported by Mound. 

d. Given that the apparent discrepancy between value of the fading correction factors 

NIOSH proposed to be applied to NTA film results, and the values calculated by 

SC&A was the result of a typographical error, it appears to NIOSH that we and 

SC&A are in agreement on this issue. We therefore propose that the Mound Working 

Group discuss this issue for possible closure. 

SC&A Response to Action Item #2

SC&A agrees with NIOSH’s decision on this issue, but SC&A notes that while the Mound 

TBD-6, page 30, recommends these fading values be applied for NTA film for the period 

1949–1976, NIOSH’s Mound neutron evaluation white papers of March 18, 2009, and 

December 9, 2009, both recommend 9%/wk fading correction factor. 

3. Action Item - Review NTA data for 1951–1960. 

a. SC&A has expressed concerns about NIOSH’s proposed strategy to use categorical 

data from the Health Physics Progress reports for this time period. SC&A also 

suggested that we use the actual neutron dosimetry data to make a neutron coworker 

model. 

 

b. NIOSH maintains that the use of categorical data is both viable and claimantfavorable. However, in the interest of coming to closure on this issue, we 

investigated the possibility of using the actual neutron dosimetry data, as suggested 

by SC&A. Unfortunately; we have been unable to locate the cycle-by-cycle neutron 

dosimetry results for this time period in spite of multiple records searches requested 

of DOE Legacy Management. In the interest of completeness, we have one more 

request pending with DOE Albuquerque Operations Office, but we are not optimistic 

that this request will produce the required records. In the event that it does, we will 

revisit this issue. In the absence of this data, NIOSH plans to use the approaches we 

have previously proposed. 
Draft Memo – Mound Neutron Issues 4 SC&A – October 4, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

c. NIOSH also notes that the time period in question (1951–1960) largely overlaps the 

currently existing SEC classes for the Mound Laboratory, which includes all workers 

who meet the usual SEC criteria. Should the Working Group adopt SC&A’s position 

on this issue—that the methods NIOSH proposes for estimating unmonitored neutron 

dose are unacceptable—it would not result in the addition of any workers to the SEC 

(except for any hypothetical worker who began employment in the beginning of 1960 

and doesn’t qualify for the current 1959–1980 SEC class). On the other hand, should 

such a SEC basis be adopted, the result would be to deny unmonitored neutron 

exposure to the workers who don’t qualify for the current SEC classes. 

SC&A Response to Action Item #3

SC&A does not see that the lack of badge cycle data is needed to use the neutron dose data 

already available. NIOSH lists matched neutron-photon doses for each year for 1949–1977 

in Table 4-4, page 21, of their December 9, 2009, white paper. These individual NTA 

recorded neutron doses could be used to create a coworker database, instead of using the 

categorical data presently recommended by NIOSH. The number of matched neutron-photon 

pair data in Table 4-4 appear be sufficient to provide reasonable neutron dose statistics for 

coworker purposes.