ML13324A522
| ML13324A522 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/14/1984 |
| From: | Baskin K Southern California Edison Co |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8412180299 | |
| Download: ML13324A522 (2) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE KENNETH P. BASKIN ROSEMEAD, CALIFORNIA 91770 TELEPHONE VICE PRESIDENT 818-302-1401 December 14, 1984 Director, Office of Nuclear Reactor Regulation Attention:
Mr. Darrell G. Elsenhut, Director Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
Subject:
Docket No. 50-206 Seismic Operability Criteria and Reporting Requirements San Onofre Nuclear Generating Station Unit 1 Your letter of November 21, 1984 authorizing resumed power operation of San Onofre Unit 1, included guidance to be used for determining operability and reportability under the unit's technical specifications as well as the application of reportability requirements for future work under the ongoing seismic reevaluation program. Our letter dated November 30, 1984 indicated that. further clarification and amplification was needed concerning the reporting requirements. The purpose of this letter is to clarify which structures, systems and components are considered to have 0.67g Housner seismic requirements and to describe the procedures to be followed during continuation of the seismic reevaluation program to determine reportability.
As you know, the unit has now been returned to service with certain structures, systems and components upgraded to withstand a 0.67g Housner seismic event. Included are (1) all safety related structures except the South Turbine Extension; (2) the Reactor Coolant System Pressure Boundary; and (3) those systems and components necessary to achieve and maintain a safe hot standby condition. For these structures, systems and components, operability for the purpose of the unit's technical specifications will be determined using the 0.67g Housner seismic upgrade criteria. If it is determined that the 0.67g criteria are no longer satisfied, then the appropriate reports will be submitted in accordance with 10 CFR 50.72(b)(ii)(B) and 10 CFR 50.73(a)(2)(ii)(B).
For remaining Seismic Category A structures, systems and components that continue under evaluation as part of the seismic reevaluation program, your letter requests that a report be submitted if the analysis indicates the seismic capability is less than 0.5g. Since the reevaluation program is intended to determine the need for modification to meet the 0.67g criteria, and will not specifically address the 0.5g capability, the application of this requirement will be as follows.
If in the course of performing the analyses to determine the need for upgrades to meet the 0.67g criteria, the decision is made to backfit, then an assessment of the capability to meet 0.5g criteria P4121j30299 941214 Ad, PDR DOCV'I PDR
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Mr. D. G. Eisenhut
-2 will be made. The assessment will be conducted using current O.5g criteria such as those used in preparing our report on non-upgraded system capability submitted.on November 3, 1984. If the results of the assessment are that the 0.5g criteria are not met, then reports in accordance with the above cited regulations will be made.
It should be noted that this process will provide notification to the NRC of structures, systems and components, which, in their current configuration, would not meet a 0.5g test based upon current 0.5g return to service criteria. It would not provide any information on the original plant design.
If you wish to discuss the above, please let me know.
Very truly yours,