ML13330A118
| ML13330A118 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/24/1980 |
| 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 8009300362 | |
| Download: ML13330A118 (3) | |
Text
Southern California Edison Company P. O. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 K. P. BASKIN TELEPHONE MANAGER OF NUCLEAR ENGINEERING, September 24, 1980 (213) 572-1401 SAFETY, AND LICENSING Director of Nuclear.Reactor Regulation Attention: D. M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 San Onofre Nuclear Generating Station Unit 1 My letter to Mr. D. L. Ziemann dated April 28, 1980 provided a detailed description of the program initiated for -the seismic reevaluation of balance of plant structures at San Onofre Unit 1. Mr. D. G. Eisenhut's letter of August 4,,1980 requested that we provide our plans and schedule for an expanded program.to include the seismic evaluation of balance of plant piping and equipment. This letter provides the current status of the structural evaluations and a summary of a program for the evaluation of piping and equipment. As discussed with the NRC Staff, submittal of this response has been delayed two days.
The seismic reevaluation program for balance of plant structures at San Onofre Unit 1 was initiated in June 1980. To date this program has included (1) development of criteria, (2) determination of analytical methods, (3) data gathering, (4) preliminary modeling and (5) preliminary analysis of masonry walls. Analytical calculations and checking of mathematical models is scheduled to begin in mid-October. It is expected that preliminary in-structure response spectra for the various structures will be available in January and February of 1981. The detailed evaluation of the structures are scheduled for completion in June of 1981.
As you are aware, prior to initiation of the Systematic Evaluation Program (SEP), we were proceeding with a program for the seismic reevaluation of the balance of plant at San Onofre Unit 1. At the time of its suspension, the main efforts of this program had been directed toward scoping and scheduling the seismic analyses. It was estimated at that time that the V
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Director of Nuclear Reactor Regulation September 24, 1980 analysis of all equipment required to get to a "warm" shutdown (temperature about 350 0F) would take approximately 19 months after in-structure response spectra were available. Based on this experience, it is concluded that an evaluation of all safety-related piping and electrical and mechanical equipment cannot be completed by the January 1, 1982 date identified in Mr.
Eisenhut's August 4 letter. We would anticipate such an evaluation to take two to three years.
In light of the above and of the NRC Staff's desire to perform seismic analyses of San Onofre Unit 1 on a schedule consistent with the SEP, it is proposed that the expanded scope of the balance of plant seismic reevaluation be limited to a subset of a complete list of equipment based on NRC Regulatory Guide 1.29. SCE proposes to assess the seismic design of San Onofre Unit I based on the evaluation of a sample of representative piping systems and mechanical and electrical equipment. The method of selection of this representative equipment would be similar to the method used by the NRC for the seismic review of Dresden 2 as described in NUREG/CR-0891, Seismic Review of Dresden Nuclear Power Station Unit 2 for the Systematic Evaluation Program. It is our intention to retain seismic design experts to conduct this review. We will work with the NRC Staff to establish as soon as possible mutually acceptable consultants for this purpose. It is anticipated that a report similar to NUREG/CR-0891 for San Onofre Unit I will be generated by January 1, 1982.
The qualification of electrical and mechanical equipment items which might be identified by the above seismic review may, as appropriate, be performed on a generic basis with other SEP plants. The feasibility of the generic program is currently being pursued with the other members of the SEP Owners Group.
Finally, Mr. Eisenhut's August 4 letter indicates that required modifications are to be completed during the next refueling outage following January 1, 1982 or no later than January 1, 1983. Since potential modifications have not been identified, it is not possible to address this issue at this time. The ability to install modifications within one year of completion of the analyses is dependent on a number of variables, including the extent of required modifications, material and component availability and system and regional reliability considerations. While it is our intention to perform all required modifications as soon as practicable, a firm commitment to complete such modifications by January 1, 1983 is not possible at this time. It is more appropriate to discuss this with the NRC Staff following completion of the analyses and identification of required modifications.
Director of Nuclear Reactor Regulation September 24, 1980 If you have any questions on this matter, please let us know.
Subscribed on this day of 1980.
By oMSubscribed and sworn tobeor me AGNES CRABTREE this ay of NOTARY PUBLIC -CALIFORNIA PRINCIPAL OFFICE IN LOS ANGELES COUNTY My Commission Exp. Aug.27, 19821 Notar/Publid in and for the County of L6s Angeles, State of California