ML20236T516
| ML20236T516 | |
| Person / Time | |
|---|---|
| Issue date: | 11/17/1987 |
| From: | Derek Widmayer NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Dunkelman M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-43 NUDOCS 8712010325 | |
| Download: ML20236T516 (2) | |
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NOV 17 SBT WM Retrad W. WS Pre;tet J D: d iba. __ __-_ f MEMORANDUM FOR: Maxine Dunkelman, Project Manager PN Operations Branch UOR - -
Division of Low _ Level Waste Mahsgsment_. ._.-.
and Decommissioning, NMSS _. . _ __ _ _ . _ _ _ _ _ _
FROM: Derek A. Widmayer, Civil Engineer'.'.E!. , .
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. Technical: Branch Division of Low-Level Waste Management and Decommissioning, NMSS
SUBJECT:
GE0 TECHNICAL ENGINEERING REVIEW 0F LOWMAN PRELIMINARY FINAL CADSAR I have completed my review of the subject document and have enclosed my one comment. Please contact me at X74263 if you have any questions.
Original Sig:ned BY Derek A. Widmayer, Civil Engineer Technical Branch-Division of Low-Level Waste Management
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and Decommissioning, NMSS
Enclosure:
As stated DISTRIBUTION:
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,DATE :11/\1/87
'11//-f87 0FFICIAL RECORD COPY 8712010325 871117 PDR WASTE WM-43 PDR
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Comment GT/1: Slope Stability Analysis - Static Conditions In the draf t Comparative Analysis of the Disposal Site Alternatives Report (CADSAR) for the UMTRA Project Lowman Site, it is stated that the major geotechnical consideration at the site is foundation stability. It is explained that steep slopes and the presence of potentially weak residual soils will require careful consideration during the the design of the stabilized pile.
The preliminary final CADSAR states that the major geotechnical consideration at the site is foundation stability of the steeper slopes under earthquake loading. It is explained that liquefaction does not appear to present a problem as the soils become dense to very dense near the groundwater table.
The discussicm in the preliminary final CADSAR represents an important change in the characterization of the proposed disposal site at Lowman.
While the importance of the stability of the steeper slopes under earthquake loading has increased due to an increase in the magnitude of the design bases earthquake, the stability of the foundation soils under static loading conditions should still receive careful consideration. The first soil layer is described in Section 3.2 of the preliminary final CADSAR as a " loose to medium-dense silty and clayey sand," and the area labeled as a recharge zone in Figure 3.6 may be susceptible to saturation under certain conditions. Therefore, the potential for liquefaction still exists for the reasons stated in the draft CADSAR. The ground and surface water flow systems and the soils require full characterization in the steeper areas of the disposal site so that the slope stability analysis will fully consider the static loading conditions.
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