TBD-6000 Work Group

Report on Resolution of Findings 

for SC&A Review of 

Appendix BB, Rev. 2

Paul L. Ziemer, WG Chair

March 22, 2017
Background on Activities Related to 

Appendix BB, Rev. 2

 May 26, 2016: NIOSH issued Appendix BB, Rev. 2 

 Sept. 6, 2016: SC& A issued memo discussing their review of 

Rev. 2. 

 Nov. 4, 2016: NIOSH Response to SC&A review of Appendix 

BB, Rev. 2

 Dec. 9, 2016: SC&A Reply to NIOSH Response paper

 Dec. 14, 2016: Dr. Daniel McKeel submitted Critique of 

Appendix BB, Rev. 2, including comments on subsequent SC&A 

review and follow-up of DCAS response.

 Work Group met December 14, 2016
Background on Activities Related to 

Appendix BB, Rev. 3

 February 9, 2017: Appendix 3 Issued by NIOSH 

 February 22 2017: SC&A was tasked to “identify any 

questions or concerns you might have regarding the 

resolution of issues covered by this revision.”

 February 23, 2017: SC&A completed “preliminary” review of 

Rev. 3. They stated: “All but one of the substantive issues 

that can have an impact on future DRs of GSI workers have 

been addressed. The outstanding issue is the failure to 

identify the neutron doses in Tables 5, 6, 8, and 9 as ambient 

dose equivalents (H*[10]). 

 The Work Group has not been involved in this recommended 

wording change.
Issues Identified in SC&A Memo of 

September 6, 2016

 SC&A reviewed all of the 10 previously closed findings from 

Rev. 1 to assure that they had been correctly implemented in 

Rev. 2.

 SC&A agreed that Findings 2 through 9 had been 

appropriately implemented.

 For Finding 1, dealing with neutron dose rates, SC&A 

recommended that NIOSH assign doses based on actual 

neutron energies rather than the simplifying assumption that 

all neutrons were in the 100 keV to 2 MeV range.

 For Finding 10, SC&A recommended that the footnotes to 

Tables 8 & 9 be revised to clarify which DCF’s are to be used. 

They also recommended that the maximum DCF from the <30 

keV photon range should be used for betatron operator dose.
Details for Finding 1

 NIOSH indicated that neutron doses derived from 

MCNPX simulations should be assumed to originate 

from neutrons with energies in the range of 100 keV 

to 2 MeV.

 SC&A found that using more exact energy ranges 

resulted in 45% higher neutron doses to the lungs of 

a betatron operator during uranium radiography and 

37% higher doses during steel radiography. For a 

layout man, doses were 20% higher.

 Although doses were quite small in both cases, 

SC&A recommended use of the more claimant 

favorable values.
Resolution for Finding 1

 NIOSH/DCAS indicated that because neutron 

doses are small, it is not necessary to assign the 

four neutron energy intervals proposed by SC&A.

 They proposed using one energy range, the 2 to 20 

MeV range. This results in a claimant favorable 

simplification.

 SC&A pointed out that for certain organs, the 2 to 20 

MeV range was not claimant favorable. They noted 

use of the 0-10 keV range would be most favorable 

when all organs are considered.

 NIOSH/DCS agreed with this approach and the 

Work Group concurred.
Details for Finding 10

 The original finding addressed the use of effective 

doses from hypothetical residual radiation after 

betatron shutdown. No DCF’s were provided. 

 Rev. 2 used air kerma and provided DCF’s. 

However, the dosimetric quantity was not identified 

as air kerma, leading to ambiguity as to which DCF’s 

were to be used.

 Also, since the residual radiation was hypothesized 

to have an energy of 30 keV, the maximum DCF 

rather than the average for <30 keV should be used.
Resolution for Finding 10

 NIOSH reviewed the DCF’s and realized that the 

appropriate value would be that of a 30 keV monoenergetic photon rather than from the zero to 30keV 

range. The 30 keV mono-energetic DCF 

corresponds to the maximum DCF for the 30 keV

range. 

 Using the 30 keV DCF then changes the limiting 

exposure scenario for the skin of the hands and 

forearms. As a result, the Table 9 values in 

Appendix BB will change to the Betatron operator 

values instead of the layout man for 1964-1966.
Resolution for Finding 10 

(continued)

 Based on the DCF discussion, NIOSH/DCAS 

recommended the following changes to Appendix B:

1. Change the footnote of Table 8 and the text on page 

15 from <30 keV to 30 keV.

2. Change the Betatron Operator Dose values for the 

last three years (1964-1966) in Table 9.

3. Change the footnote for Table 9 to indicate 30 keV.

4. Change the paragraph following Table 9 to reflect 

the above changes.

 SC&A agreed with these changes and the WG 

concurred.
Work Group 

Recommendation to Board

1. The TBD-6000 Work Group recommends

that the ABRWH approve the proposed

resolutions and closure of all findings for

the revision of Appendix BB.