ML20041C515
| ML20041C515 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 02/26/1982 |
| From: | Kay J YANKEE ATOMIC ELECTRIC CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-02-04.D, TASK-2-4.D, TASK-RR FYR-82-83, NUDOCS 8203020136 | |
| Download: ML20041C515 (3) | |
Text
YANKEE ATOMIC ELECTRIC COMPANY pk g,
1671 Worcester Road, Framingham, Massachusetts 01701 2 C.
, ANKEE, fg82-23 Fe brua ry 26, 1982 A
g RECEtVED United States Nuclear Regulatory Commission f
MAR 011982> E8 Washington, D. C.
20555 5 NttetIstan tenmus Attention:
Mr. Dennis M. Crutchfield, Chief meus masass a Operating Reactors Branch #5 Division of Licensing ff Re f e renc e :
(a)
License No. DPR-3 (Docket No. 50-29)
Subject:
SEP Topic Assessment Completion (Topic II-4.D)
Dear Sir:
Enclosed please find our assessment of the following topic:
II-4.D Stability of Slopes We t ru st this information is satisf actory; however, if you have any questions, please contact us.
Ve ry truly yours, YANKEE ATOMIC ELEC1RIC COMPANY
.d.KQ
. A. Kay Senior Engineer - Licensing JAK: dad Enc losure ed ft 68 I
t f 8203020136 820226 i
PDR ADOCK 05000029 t
P PDR
SEP SAFETY TOPIC EVALUATION
~
TOPIC II-4.D STABILITY OF SLOPES INTRODUCTION The objective of this topic is to assure that safety-related structures, systems, and components are adequately protected against failure of natural or man-made slopes at the Yankee plant in Rowe, Massachusetts.
CRITERIA The criteria for this safety topic are:
1.
Standard Review Plan, Section 2.5.5, Stability of Slopes.
2.
Appendix A to 10CFR, Part 100.
DISCUSSION Representative natural slopes to the south and east of the plant are addressed. These slopes begin to rise up at a distance of from 150 to 500 feet from plant structures. The slopes rise from approximately 1130 feet MSL to almost 1800 feet MSL.
The slope angles are generally less than 200 These slopes consist primarily of glacial till overlying competent bedrock as determined by field surveys, borings, and seismic surveys (Weston Geophysical 1979,1979a; Geotechnical Engineers,1980). The field surveys showed there were no sandy terraces above the glacial till and very few groundwater discharges on the upper slopes.
Bedrock field mapping shows that failure along bedrock foliation planes is unlikely.
The Wright (1974) Program was used to investigate deep-seated circular failure surfaces. The assumption was made that the ground water level was at the ground surface with ground water seepage generally following the contours.
The minimum static factor of safety computed for deep-seated slip surfaces in the till is 1.5 or greater. This factor of safety is acceptable and meets current criteria for good performance of natural slopes.
Liquefaction of the glacial till slope materials is not considered possible under dynamic loading conditions because the lodgment till exhibits dilatant behavior in shear.
No major landslides have been observed in the Deerfield River Valley in glacial till with slopes less than 200 CONCLUSION The till slopes, overlying competent bedrock, south and east of the Yankee plant, generally have slope angles of less than 200 These till slopes have factors of safety for deep-seated slip surfaces of 1.5 or greater. There are very few ground water discharges on the upper slopes and there are no sandy terraces above the till slopes.
Since no major landslides 0
occur in the local valley at slopes less than 20 and in the absence of prevalent ground water discharges, it is concluded that the natural slopes are not susceptible to deep-seated slope failure and therefore do not pose a 1
th reat to the Yankee plant.
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REFERENCES 1.
Geotechnical Engineers, Inc. (CEI),1980, Report on Foundation i
Investigation, Fire Water Tank, Rowe Atomic Plant, Rowe, Massachusetts, Submitted to Yankee Atomic Electric Company, February 1980.
2.
Weston Ceophysical Corporation,1979, " Geology and Seismology, Yankee Rowe Nuclear Power Plant," Prepared for Yankee Atomic Electric Company, January 1979.
3.
Weston Geophysical Corporation, 1979a, In-situ Velocity Measurements, Yankee Nuclear Power Station, Rowe, Massachusetts, Prepared for Yankee Atomic Electric Company, March 1979.
4.
Wright, S.
C., 1974, SSTAB1 - A Ceneral Computer Program for Slope Stability Analysis, Dept. of Civil Engineering, Univ. of Texas at Austin.
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