ML20140B761
| ML20140B761 | |
| Person / Time | |
|---|---|
| Issue date: | 06/03/1997 |
| From: | Joseph Holonich NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Rael G ENERGY, DEPT. OF |
| References | |
| REF-WM-69 HLWR, NUDOCS 9706060315 | |
| Download: ML20140B761 (3) | |
Text
Mr. George Rael. Director U.S. Department of Energy June 03, 1997 e
Albuquerque Operations Office.
ERD /UMTRA P.O. Box 5400 Albuquerque, NM 87185-5400
SUBJECT:
REVIEW OF PROJECT INTERFACE DOCUMENT 14-S-08 FOR THE MAYBELL, COLORADO SITE
Dear Mr. Rael:
i By letter dated May 3, 1996, the U.S. Department of Energy (DOE) submitted l
Project Interface Document (PID) No.14-S-08, for the Maybell. Colorado l
Uranium Mill Tailings Remedial Action (UMTRA) Project site. The PID requests U.S. Nuclear Regulatory Commission approval for decreasing the "by-dry-weight" l
bentonite content of the radon barrier from 10 percent to seven percent. To concur with PID No. 14-S-08, the staff requested: 1) that DOE provide information on its procedures to ensure that the permeability of the as-l constructed radon barrier is 510~' cm/sec: and 2) that DOE commit to sample and measure Ra-226 concentrations at a minimum of 30 locations after placement of the frost barrier, and provide the data to NRC as soon as possible.
DOE l
provided the information requested to close these issues in its correspondence l
dated December 16, 1996.
The enclosed Technical Evaluation documents the staff's review of the l
responses provided by DOE, Based on its analyses, the staff concurs with DOE s request for the stated decrease in the bentonite content of the radon barrier. DOE has committed to provide a discussion of the " borrow" and "as-placed" frost barrier Ra-226 analyses in its Completion Report.
Also, as stated by DOE, the measured cover Ra-226 concentrations will be used in the final radon barrier calculation.
l If you have any questions concerning this subject, please contact the NRC Project Manager, Mr. Robert Carlson. at (301) 415-8165.
Sincerely.
Oos'8ph"b.MoTSNifli, Chief Uranium Recovery Branch gg60gggg970603 Division of Waste Management
,/
Office of Nuclear Material Safety M N j[p [f WM-69 PDR and Safeguards l
Enclosure:
As stated A0
.p i
W cc:
L.
Woodworth. DOE Alb S. Hamp DOE Alb E. Artiglia, TAC Alb DJSTRIBUTION (w/encil: file?Csitet NMSS r/f URB r/f PUBLIC CCain RIV t
l AGarcia~~
CNWRA ACNW RTinsley CAbrams OCn n (w/o encl):
" 73 MFederline p
DOCUMENT NAME: S:\\DWM\\ URB \\RDC\\MAYBELL.P08 0FC URB URS e /
URB f i
NAME
[ M lson Dd$ M
/$ M ch DATE 06/oS/97 06/0 7/97 06/6/97 v
u v
l OF; ICTAL RECORD COPY
l a
t PROJECT INTERFACE DOCUMENT (PID) REVIEW TECHNICAL EVALUATION PID NO:
14-S-08 j
SITE:
M6ybell. C0 l
PROJECT MANAGER:
Robert Carlson TECHNICAL REVIEWER (S):
Elaine Brummett. Health Physicist Dan Rom. Geotechnical Engineer
SUMMARY
AND CONCLUSIONS:
The U.S. Department of Energy (DOE) by its letters dated May 3. May 13. and December 16. 1996, requested formal concurrence for a Class I specification change through Project Interface Document (PID) No. 14-S-08.
DOE requests concurrence for decreasing the "by-dry-weight" bentonite content of the radon Based on its review of DOE barrierfrom10percenttosevenaercent.h-S-08.
submittals, the staff concurs on )ID No. 1 TECHNICAL EVALUATION:
. ased on its review of DOE's original submittal of May 3 and May 13. 1996, the B
staff had identified a need for additional information on two items.
Staff concerns with PID No.14-S-08 were discussed at length during conference l
calls between NRC and DOE Uranium Mill Tailings Remedial Action (UMTRA)
Project personnel on August 19 and 27. 1996.
To concur on PID No. 14-S-08.
the staff requested: 1) that DOE 3rovide information on its procedures to ensure that the 3ermeability of t1e as-constructed radon barrier is 510~'
cm/sec; and 2) tlat DOE commit to sample and measure Ra-226 concentrations at a minimum of 30 locations after placement of the frost barrier, and provide l
this data to the NRC as soon as possible.
DOE provided the information requested to close these issues in its correspondence dated December 16. 1996.
The staff reviewed and found the information acceptable. These items are considered resolved as discussed below.
Radon Barrier Permeability Radon barrier samples containing 7% Wyoming bentonite were compacted to 95%
dry density and optimum moisture content determined by ASTM D698.
A triaxial permeability of 10~7 cm/sec was the targeted value that DOE wanted to achieve on laboratory samples under conservative conditions.
As a conservative approach. DOE measured the permeability of the radon barrier lab samples under saturated conditions, an unlikely condition because of the frost barrier I
covering the radon barrier material.
Saturated permeability of the samples ranged from 2.79 x 10-8 cm/sec to 1.97 x 10" cm/sec with a geometric mean of 7.65 x 10-8 cm/sec.
Based on its review, the staff finds that DOE's response provides reasonable assurance that the radon barner permeability will be 5 10'7 cm/sec.
Enclosure l
l
y
,.i Samolina and Measurina Ra-226 Concentrations after Placement of Frost Barrier.
After 31acement. DOE will collect twenty-five frost barrier Ra-226 samples from t7e middle of the frost barrier.
These locations will be the same as where previous radiological sam)les were taken for contaminated materials.
It will be assumed that the radon Jarrier has the same Ra-226 concentrations as the frost barrier.
Since the radon barrier is a mixture of Rob Pit overburden material and bentonite. this assumption is considered conservative.
Measured Ra-226 concentrations will be used in the final radon barrier calculation.
The staff concurs with the understanding that the " borrow" and "as placed" frost barrier Ra-226 analyses will be discussed in DOE's Completion Re) ort.
Also, as stated by DOE. the measured cover Ra-226 concentrations will 3e used in the final radon barrier calculation.
REFERENCE:
- Letter from DOE PID No. 14-S-08. Class I t signation and request for NRC formal cor,1currence. May 3.1996.
- Letter from DOE. PID No. 14-S-08. (;lculations for the Maybell radon barrier design. May 13, 1996.
- Letter from DOE. PID No.14-S-08. Responses to staff issues. December 16, 1996.
2