ML19259B236
| ML19259B236 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 01/09/1979 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Dunn C DUQUESNE LIGHT CO. |
| References | |
| TAC-6605, NUDOCS 7901170431 | |
| Download: ML19259B236 (4) | |
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UNITED STATES
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January 9, 1979 Docket No. 50-334 Mr. C. N. Dunn, Vice President Operations Division Duquesne Light Company 435 Sixth Avenue Pittsburgh, Pennsylvania 15219
Dear Mr. Dunn:
We have reviewed Supplement No. 2 to Soil Study - Category I Structures (Response to NRC Meeting on 11/15/77), Beaver Valley Power Station - Unit 1, dated May 1, 1978.
The enclosure to this letter identifies additional information on Supplement No. 2 that we require to complete our review. As noted in the enclosure, we request that you conduct a liquefaction analysis of the area just northwest (riverward) of Category 1 structures where borings (B108 and B109) indicate the continuation of the loose granular zone. This area is characterized as having less confining pressures than are indicated at Elevation 735 under Category 1 structures. This analysis should be completed by mid January 1979. Accordingly, we have tentatively established January 23 or 24,1979 as a date for a meeting at the site to discuss the results of the liquefaction analysis, review the site area, and discuss the need for a stability analysis. We believe you should be able to respond to these requests with no additiot.al field or laboratory investigations by using presently available infomation.
Sincerely
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g:<M&z-p A. Schwencer, Chief Operating Reactors Branch #1 Division of Operating Reactors
Enclosure:
As Stated cc: w/encisoure See next page 790117oy3 /
a Duquesne Light Company 2-January 9, 1979 cc: Gerald Charnoff, Esquire fir. James A. Werling Jay E. Silberg, Esquire Plant Superintendent Shaw, Pittman, Potts & Trowbridge Beaver Valley Power Station 1800 ft Street, N.W.
P. O. Box 4 Washington, D. C.
20036 Shippingport, Pennsylvania 15077 Karin Carter, Esquire Special Assi stant Attorney General Bureau of Administrative Enforcement 5th Floor, Executive House Harrisburg, Pennsylvania 17120 fir. J. M. Cumiskey Stone & Webster Engineering Corporation P. O. Box 2325 Boston, liassachusetts 02107 Mr. J. D. Woodward R&D Center Westinghouse Electric Corporation Building 7-303 Pi ttsburgh, Pennsylvania 15230 B. F. Jones Memorial Library 663 Franklin Avenue Aliquippa, Pennsylvania 15001 f1r. Jack Carey Technical Assistant Duquesne Light Company P. O. Box 4 Shippingport, Pennsylvania 15077 Mr. R. E. Martin Duquesne Light Company 435 Sixth Avenue Pi ttsburgh, Pennsylvania 15219 flarvin Fein Utility Counsel City of Pittsburgh 313 Ci ty-County Buil ding Pi ttsburgh,Pennsyl vania 15219
REQUEST FOR ADDITIONAL INFORMATION BEAVER VALLEY POWER STATION, UNIT N0. 1 DOCKET N0. 50-334 SOIL STUDY 362.1 Basic information covering cyclic triaxial test sample preparation and testing procedures has not been provided. The omission of this information has delayed the completion of our safety evaluation.
Specifically, the following information should be provided.
(a) The technique used to reconstitute the samples.
(b) What is the basis for anistropically consolidating the test specimens? What anisotropic consolidation stresses were applied to each sample?
362.2 Provide adopted soil parameters, coefficients and equations used to establish shear stresses on Figure 4.
362.3 Sufficient data is not provided in your Supplement No. 2 - Soil Study to determine whether there is an error in labeling of points representing test no.1 and test no. 2, figure 6.
Please clarify.
Provide a summary sheet for Appendix B test results similar to the summary presented in Appendix A with the addition of information pertinent to the settlement study.
Provide a discussion of how the average change in peak pore pressure ratio of 0.16 for 8 cycles was determined and why the maximum value should not be used to predict the settlement under dynamic loading.
- ' 362.4 The margin of safety against liquefaction failure indicated in the submitted analysis is greatly influenced by the confining pressures which result from plant grade at Elevation 735 (See FSAR Figure 2.6-3).
liowever, just northwest (riverward) of Category I structures, where many borings (e.g., B108 and B109) indicate the continuation of the loose granular zone, the confining pressure appears to be significantly less where plant grade is at Elevation 706.
Provide an analysis of liquefaction potential in this area using both the analytical method submitted in Supplement No. 2 and the observational method which uses standard penetration test data records from available borings.
If potential liquefaction of this area it indicated by your analysis provide a stability analysis that adopts conservative assumptions and which evaluates the impact on Unit 1 Category I structures and conduits resulting from the loss of lateral support following liquefaction of the plant area having final grade at Elevation 706.
Detailed soil profiles and sections indicating the involved structures and conduits would be required.