ML19254F562
| ML19254F562 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 10/15/1979 |
| From: | Andognini G BOSTON EDISON CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-02, IEB-79-2, NUDOCS 7911120037 | |
| Download: ML19254F562 (2) | |
Text
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BOSTON EDISON COMPANY UENERAL QFFicEs 800 GQYLSTON STREET BOSTON. MAssAcNusETTs 02199 G. CARL ANDOGNtNS SUPERINTENDENT NUCLEAR OPERATIONS DEPANTMENT October 15, 1979 BEco. Ltr. #79-189 Mr. Boyce H. Grier, Director Office of Inspection and Enforcement Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA.
19406 License No. DPR-35 Docket No. 50-293 Subj ect:
IE Bulletin 79-02 Reference (a):
Supplement No. I to IE Bulletin 79-02, Revision No. 1, dated August 20, 1979
Dear Sir:
Boston Edison has reviewed Reference (a) and would like to offer the following comment with respect to the anchor bolt factor of safety.
It is our opinion that an interim threshold factor of safety for continued operation of 2.0 is overly conservative for the following reasons:
a) the governing loading condition, which includes the Design Basis Earthquake, is an extremely low-probability event for the life of the plant and, even more so, for the short period of time until appropriate modifications are made; b) there is an inherent conservatism in every aspect of the design of a nuclear power plant such as Pilgrim 1 the effects of which are compounded and reflected in the final design; c) in the case of Pilgrim 1, which is scheduled for a refueling outage in January 1980, the probability of experiencing even an OBE (let alone the DBE) between now and the start of the outage is almost non-existent.
For the above reasons Boston Edison plans to proceed as follows:
- as an interim measure only, a factor of safety for the concrete expansion anchor bolts of 1.25 will be used to determine system operability.
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IL BOSTON EDISDN COMPANY Mr. Boyce H. Grier October 15, 1979 Page 2 - a minimum f actor of saf ety of 2.0 for the anchor bolts will be used for normal operating loading conditions to determine system operability. - as stated in Reference (a) all affected systems will be upgraded to the required factors of safety of 4 or 5 expeditously for normally accessible supports and by the end of the next refueling outage for nonaccessible supports. It is Boston Edison's firm belief that the health and safety of the public will not be significantly increased by following the approach outlined above. If you have any questions please do not hesitate to call us. Very truly yours, ,l u + '/ / cc: United States Nuclear Regulatory ru lo.icn Office of Inspection and Enfor ement Division of Reactor Operatica Inspection Washington, D. C. 20555 13\\\\ \\ll}}