ML20203P973
| ML20203P973 | |
| Person / Time | |
|---|---|
| Issue date: | 04/17/1986 |
| From: | Nataraja M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Martin D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-58 NUDOCS 8605080456 | |
| Download: ML20203P973 (2) | |
Text
V'M Rgcord Fiji WM IR6 pct WM ACTION 86279 DISTRIBMT Dodet No
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WM r/f M-58' APR 171986, PkR hEG
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N w MTokar PEnapp JLinehan MEMORANDUM FOR:
' Daniel E. Martin, Section Leader PJustus Uranium Recovery Projects Section M
tion) ro e s r c W1 Docket No.
m FROM:
Mysore S. Nataraja, Section Leader PDR /
1 Rock Mechanics Section LPDR.
Engineering Branch, WM Distribution:
I i
SUBJECT:
REVIEW 0F SHIPROCK DYNAMIC STABILITY INfDWMION 7
(Return to WM,623 SS)
REFERENCES:
1.
Memo dated June 3, 19857 Eo~m~T.' Greeves D 1
L. Higginbotham;
Subject:
Geotechnical Engineering Technical Evaluation Memorandum (TEM) for Review of Shiprock Remedial Action Plan 2.
Memo dated February 18, 1986, from M. Knapp to L. Higginbotham; Subject; Peview of " Supplemental Seismic Studies performed in Support of the Remedial Action Plan at the Shiprock Tailings Site" i?:
i In response to your TAR No. WM-86279, WMEG has reviewed the dynamic slope stability information submitted by the DOE in connection with the NRC's concurrence for the proposed Remedial Action Plan (PAP) at the Shiprock site.
The TEM (Reference 1) identified that the seismic design criterion for the Shiprock site was not finalized and the dynamic stability analysis should be revised when the seismic design criterion is finalized. After reviewing the DOE's supplemental seismic studies, WMGT has stated that a 6.2 magnitude earthquake resulting in a peak horizontal acceleration of 0.21g at the Shiprock site would be an acceptable seismic design criterion (Reference 2).
The dynamic slope stability information, reviewed for this TAR, pertains to evaluation of the stability of slopes as per the revised seismic design criterion.
As per the revised seismic criterion, the peak horizontal acceleration of the MCE (Maximum Credible Earthquake - Design Seismic Event) is 0.21. The 9
dynamic stability of the slope of the remediated tailings pile is evaluated by pseudo-static method of analysis using a seismic coefficient of 0.14, which is 67 percent of 0.21.
The selection of the seismic coefficient is in accordance with the provisions of NRC's SRP for UMTRCA projects and DOE's design manual for UMTRCA projects. The seismic coefficient used in the dynamic analysis reviewed in the TEM (Reference 1) was 0.13.
Therefore, the scope of the present review is to evaluate the effect of increasing the seismic coefficient 8605080456 860417 PDR WASTE W"
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NAME :BJagannath/cj: MTokar
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_2-from 0.13 to 0.14 on the results 'of the dynamic stability of.the slopes as determined by pseudo-static method of analysis. The long tenn stability of the slope is critical, and DOE's analyses indicate a reduction in the f actor of safety against failure from 1.16 to 1.14 for an increase in seismic coefficient from 0.13 to 0.14.
The revised factor of safety for long term stability of the slope (1,14), is greater than 1.0 and is acceptable to the NRC. Based on independent review of the information, WMEG concurs with the-DOE's conclusion on the long term safety of the slopes under the MCE event.
This review was performed by Dr. Banad Jagannath and he may be contacted at extension 74629.
OmGINAL SIGNED BY Mysore S. Nataraja Mysore S. Nataraja, Section Leader Rock Mechanics Section Engineering Branch, WM l
0FC : WMEG
- WMEG
- WMEG NAME :BJagannath/cj: MTckar
- MNataraja DATE : 4/ /86
- 4/ /86
- 4/ /86
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