ML13310B015
| ML13310B015 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/30/1983 |
| From: | Krieger R Southern California Edison Co |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-06-04, TASK-2.E.4.2, TASK-6-4, TASK-RR, TASK-TM NUDOCS 8310140223 | |
| Download: ML13310B015 (2) | |
Text
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Southern California Edison Company P.0 BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 September 30, 1983 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 Gentlemen:
Subject:
Docket No. 50-206 SEP Topic VI-4, Containment Isolation System (Electrical)
San Onofre Nuclear Generating Station Unit 1 By letter dated November 22, 1982, we provided responses related to your draft evaluation of the subject topic.
Included in our responses was a commitment to install six inside containment isolation valves on the steam generator sample and blowdown lines (Enclosure 2, Item lb - response d.ii).
Installation of these valves would provide redundant isolation for these lines in the event of a containment isolation signal.. This commitment was originally made in order to satisfy the General Design Criteria (GDC) for Nuclear Power Plants (TO CFR Part 50, Appendix A) and also to alleviate the situation of having a containment isolation system valve set overridden by a single switch.
Upon reevaluation of the above discussed commitment, it has been determined that in our initial evaluation of this topic, these penetrations were erroneously evaluated against GDC 55 (i.e., this design criteria requires one automatic isolation valve inside containment and one automatic isolation valve outside containment). Further review has determined that the governing design criteria for these penetrations is GDC 57 (i.e., one automatic isolation valve located outside containment). The present plant configuration conforms to this design criteria. Additionally,Section II.E.4.2 of NUREG-0737 provides guidance in the area of reopening of containment isolation valves. This requirement states that reopening of containment isolation valves shall require deliberate operator action. This requirement is satisfied by the fact that two actions are required to open each line; namely, one actioh to override the containment isolation signal and one action to open each valve.
83 10f14 0223 093 DR ADOCK 05000206 PDR
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Mr. D.
September 30, 1983 Based on these considerations, no.additional modifications to the present plant configuration are necessary to meet NRC requirements.. If you have any questions or desire additional information, please contact me.
Very truly yours, R. W. Krieger Supervising Engineer San Onofre Unit 1 Licensing