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Weldon Spring Site 

SEC-00143

Working group:

Michael H. Gibson-Chair

Richard A. Lemen, Ph.D., M.S.P.H.

James Melius
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WS WG Meetings

• 19 Oct 2010: WS 1st WG meeting

• 25 Jan 2011: WS 2nd WG meeting

• 9 May 2011: WS 3rd WG meeting

• 13 Sept 2011: WS 4th WG meeting

• 29 Nov 2011: WS 5th WG meeting by phone

• 7 Dec 2011: AB meeting discussion

• 14 Feb 2012: WS 6th WG meeting by phone.
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Petitioner’s Th-232 Concerns

• 7 Dec 2012: AB meeting – Petitioner referenced 

several documents that might indicate Th-232 

was processed in large quantities before 1963. 

• 22 Feb 2012: NIOSH issued response and 

found no additional indications that Th-232 was 

processed in large quantities before 1963.
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Summary of SEC Issues

for 1957-1967

1. Accuracy and completeness of internal 

data (1a), external dose data (1c), air 

data (1b), and coworker data (1d).

2. Lack of egress monitoring.

3. Lack of dose records for 1967.

4. No radon/thoron measurements.
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SEC issues (continued)

5. Validity of method used to assign 

recycled uranium intakes.

6. Lack of neutron dose data.

7. Lack of air measurements at quarry and 

raffinate pits during 1957-1967.

8. Impact of accidents/incidents on dose 

reconstruction.

9. Geometry/extremity correction factors.
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Site Profile Issues

• There were 28 site profile issues identified.

• These site profile issues have been 

incorporated into the SEC issues, or have 

been addressed and closed, or are being 

addressed by changes in the WS TBD and 

PERs.

• SC&A tracked the site profile issues along 

with the SEC issues.
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SEC Issues

• All SEC issues were addressed in the WG 

meetings and closed, except the following:

 #1b - Thorium air data DWE error analyses

 #4 - No radon/thoron measurements
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Status of Pending SEC Issues

#1b Thorium air data DWE error analyses: 

• No thorium bioassay data (1966 chest counts not 

used).

• Gross-alpha activity air samples available.

• Assume 100% thorium activity.

• Original calculational and transcriptional error 

analyzed.

• These errors are called “blunders” in the scientific 

literature. They are not gross mistakes, but common 

errors).
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SEC Issue 1b Air Data (continued)

• Need to determine impact of errors on derived daily 

weighted average (DWA) air concentrations.

• 9/07/2011: NIOSH issued white page addressing 

DWA errors.

• 9/272011: SC&A issued response to NIOSH’s recent 

paper. SC&A recommended:

DR implementation method be provided

The representativeness of the limited data be 

addressed.
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SEC Issue 1b Air Data (continued)

• 11/28/2011: NIOSH issued revised white page 

addressing DWA errors with DR implementation 

recommendations.

• 11/29/2011: DWA errors discussed at WS WG 

meeting.

• 11/29/2011: SC&A tasked with analyses of NIOSH’s 

revised DWE paper.

• 1/17/2012: SC&A issued revised white page 

addressing DWA errors and DR implementation 

recommendations.
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SEC Issue 1b Air Data (continued)

• 2/12/2012: DWE error issue discussed during WG 

meeting and SC&A to issue summary response.

• 2/21/2012: SC&A drafted summary response:

Type and magnitude of errors similar to other 

studies and at Fernald.

Corrections are applicable to DR.

Quantity of representative data for thorium DWE 

error analyses limited, but additions resources 

would not have significant impact.
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Status of Pending SEC Issues

#4. No radon/thoron measurements:

• NIOSH performed analyses of potential 

environmental and indoor radon/thoron intakes 

and issued response on 4/21/2011.

• SC&A evaluated recommended model and found it 

to bound the potential intakes.

• The WS radon model is more conservative than 

previously proposed DOE site radon models in that 

it does not include any lost of radon/thoron through 

ventilation.

• WG recommends discussion with AB.
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Summary of WS SEC

• WS WG, NIOSH, and SC&A have been 

actively working on SEC (and site profile) 

issues during the last several years.

• 9 SEC issues and 28 Site Profile issues 

have been addressed except for the use 

of radon/thoron model.