ML13317A763
| ML13317A763 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/08/1981 |
| From: | Baskin K Southern California Edison Co |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-03-06, TASK-3-6, TASK-RR NUDOCS 8112100248 | |
| Download: ML13317A763 (2) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 K. P. BASKIN TELEPHONE MANAGER OF NUCLEAR ENGINEERING, December 8, 1981 (213) 572-1401 SAFETY, AND LICENSING Director, Office of Nuclear Reactor Regulation Attention:
D. M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555 8
Gentlemen:
I i
NW
Subject:
Docket No. 50-206 SEP Topic 111-6 Seismic Design Considerations San Onofre Nuclear Generating Station Unit 1 Enclosed is a report which provides the results of the seismic reevaluation of several structures at San Onofre Unit 1. Specifically, results for the circulating water system intake structure, reactor auxiliary building, ventilation equipment building and seawall are provided. Results for the remaining structures at San Onofre Unit 1 will be provided in accordance with our letter dated November 3, 1981.
As discussed in the enclosed report, conceptual modifications have been identified for the circulating water system intake structure, reactor auxiliary building and ventilation equipment building in order to meet the reevaluation criteria. As discussed in the enclosed report, although portions of these structures do not meet the reevaluation criteria, it is concluded that they will not collapse in the event of a 0.67g Housner earthquake. This conclusion is based on conservatisms in the analysis methods and acceptance criteria and experience of structures in past earthquakes. Therefore, the modifications when implemented will serve to restore the design margin for the higher seismic condition.
In light of this, it is concluded that San Onofre Unit 1 can continue to operate until the modifications to these structures have been implemented without undue risk to the health and safety of the public.
In accordance with our letter dated July 7, 1981, we have evaluated the conceptual modifications to these structures to determine whether they are likely to be impacted by other SEP topic evaluations. In the case of the circulating water system intake structure, it is concluded that there is a high potential that these modifications will be impacted by the results of SEP PO A
PDR1
9 Mr. D.
December 8, 1981 Topics 111-2, Wind and Tornado Loadings, III-4.A, Tornado Missiles, and III-4.C, Internally Generated Missiles. In light of this, these modifications will be considered during the SEP integrated assessment. For the reactor auxiliary building and ventilation equipment building, it is concluded that the modifications will not be impacted by the results of other SEP topic evaluations. Therefore, it is our intention to implement these modifications during the first plant outage of sufficient duration following completion of design and procurement. It is currently anticipated that this will permit implementation during the steam generator inspection outage scheduled to occur prior to June 1, 1982.
If you have any questions regarding this information please let us know.
Subscribed on this _
_day of 1981.
Very truly yours, By K. P. Ba kin Manager of Nuclear Engineering, Safety, and Licensing Subscribed and sworn to before me this f day of
, 1981.
Notar ublic in and for the County of Los A geles, State of California i
OFFIIAL SEAL AGNES CRABTREE NOTARY PUBLIC - CALIFORNIA PRINCIPAL OFFICE IN LOS ANG ES COUNTY '
My Commission Exp. Au&.27, 1982 l*4lsinaUalanrJ ut gltgIiUsgla 3t llaitir