1

Weldon Spring Site 

SEC-00143

Working group:

Michael H. Gibson-Chair

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

Robert W. Presley
2

Brief Review of the Weldon Spring (WS) Site

• 1941-1946 Explosive production for Army

• 1946-1954 Idle

• 1954-1957 Land acquisition &

plant development

• June 1957-12/31/1966 Uranium operations

• 12/31/1967 Plant transferred to DOD

• 1967-1969 DOD prepares plant, then terminates

• 1975-1985 Monitoring and Maintenance

• 1985-2002 WSSRAP- D&D of plant, quarry & pits. 

Material placed in engineered disposal cell.
3

WS Site During Operations

(ORAUT-TKBS-0028-2, page 9)
4

Engineered Disposal Cell 2008
5

Recap of WS Site Profile and SEC 

Activities

• June 2005: NIOSH issued TKBS-0028-1 

through 6

• March 2009: SC&A issued WS site profile 

review

• Sept 2009: SEC-00143 qualified

• April 2010: NIOSH issued Evaluation Report 

(ER) for SEC-00143

• 19 Oct 2010: WS 1st WG meeting

• 25 Jan 2011: WS 2nd WG meeting

• 9 May 2011: WS 3rd WG meeting.
6

Summary of SEC Issues

for 1957-1967

1. Accuracy and completeness of internal 

and external dose data (including air & 

coworker data).

2. Lack of egress monitoring.

3. Lack of dose records for 1967.

4. No radon/thoron measurements.
7

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 and extremity monitoring.
8

Site Profile Issues

• There were 28 site profile issues identified.

• Most of these site profile issues have been 

incorporated into the SEC issues, or have 

been addressed, or are being addressed.
9

Status of SEC Issues

1. Accuracy and completeness of data:

Accuracy of data:

• Dose reconstructors use only photocopies 

of the original Weldon Spring data sheets.

• Electronic or CER databases are not used 

for dose reconstruction (DR).

Completeness of data:

• Not yet verified.

• Presently being addressed.
10

2. Lack of egress monitoring:

• Sufficient bioassay data to reconstruct 

dose if ingestion did occur.

• External exposures addressed by 

monitoring and skin dose calculations.

• Issue has presently been closed.
11

3. Lack of dose records for 1967:

• Indications are that 1967 may have been 

a transition year. Operational-period 

external and internal data sufficient to 

bound doses incurred during 1967.

• Issue has presently been closed.
12

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 presently reviewing NIOSH’s 

response and its SEC implications.
13

5. Validity of method used to assign recycled 

uranium intakes:

• Method is presently being addressed to 

determine if consistent and appropriate 

intakes are being applied during DR.
14

6. Lack of neutron dose data:

• There is a lack of neutron dose data at 

Weldon Spring.

• Fernald neutron dose method can be 

used as surrogate because of similar 

materials.

• SC&A/NIOSH presently evaluating 

Weldon Spring neutron dose assignment 

method.
15

7. Lack of air measurements at quarry and 

raffinate pits during 1957-1967:

• Measures performed in later period are 

applicable to operational period because 

quarry and pits not released to DOD and 

conditions remained fairly constant.

• Issue has presently been closed.
16

8. Impact of accidents/incidents on dose 

reconstruction:

• Bioassay data available for workers with 

accidents in claims reviewed.

• Accidents/incidents are factored into DR 

process on an individual case basis.

• NIOSH to provide statement concerning 

claimant favorability from using group 

bioassay monitoring.
17

9. Geometry and extremity monitoring:

• NIOSH is currently evaluating methods 

used at other DOE uranium sites for 

dosimetry geometry and extremity 

monitoring and the impact on recorded 

doses at the Weldon Spring site.
18

Summary of WS SEC

• WS Working Group, NIOSH, and SC&A 

have been actively working on SEC (and 

site profile) issues during the last year.

• Progress has been made for each of the 

nine SEC issues (and also the site profile 

issues).

• Several important areas are yet to be 

evaluated and completed.