ML13330B398
| ML13330B398 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/29/1988 |
| From: | Medford M SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8810030395 | |
| Download: ML13330B398 (2) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 M. 0. MEDFORD TELEPHONE MANAGER OF NUCLEAR ENGINEERING (818) 302-1749 AND LICENSING September 29, 1988 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 ATWS Mitigation System San Onofre Nuclear Generating Station Unit 1 By letter dated October 15, 1985 SCE provided to the NRC plans and a schedule to attain full compliance with the requirements of 10 CFR 50.62 (the ATWS rule).
San Onofre Unit 1 currently has provisions for automatic initiation of auxiliary feedwater that are diverse from the reactor protection system. A detailed description of this system and the design modifications to provide a diverse turbine trip were provided to the NRC by SCE letter dated January 29, 1988. As indicated in our October 15, 1985 letter, SCE intended to install the diverse turbine trip equipment during the Cycle 10 refueling outage. This schedule was in compliance with the implementation requirements of 10 CFR 50.62(d), i.e., no later than the second refueling outage after July 26, 1984. The NRC provided their agreement with that schedule by letter dated July 24, 1987. It was also indicated in that letter that schedules to the third refueling outage would be considered based on delays that have impacted utility implementation schedules.
Subsequently, SCE incorporated the third refueling outage schedule into the Integrated Implementation Schedule (UIS) (i.e., the ATWS modifications were moved from the Cycle 10 refueling outage to the Cycle 11 refueling outage),
and indicated this in the semiannual IIS letter dated November 4, 1987. This was reiterated in SCE's January 19, 1988 letter, which provided the description of the design modifications. This schedule was determined by the IIS analytical ranking process which evaluates the safety implications of modifications and determines the schedule for implementation.
This deferment resulted from the introduction of higher priority modifications to Cycle 10.
These higher priority projects are the improvement of the Steam/Feedwater Flow Mismatch Trip in the Reactor Protection System and the Automatic Termination of Safety Injection Pumps on Low RWST Level.
8910030395 500290 PDR ADOC PNU
Document Control Desk September 29, 1988 Based on this status, and the number of higher priority items scheduled for the Cycle 10 refueling outage, SCE delayed implementation of the ATWS modifications to Cycle 11.
In view of the NRC letter dated July 24, 1987, SCE considered this deferment to be acceptable to the NRC. However, SCE has not obtained NRC concurrence with this extension in accordance with the requirements of the ATWS rule. Therefore, SCE requests NRC approval to delay implementation of ATWS modifications to the Cycle 11 refueling outage.
If you have any questions or require additional information, please let me know.
Very truly yours, 1184P:MJT cc: 3. B. Martin, Regional Administrator, NRC Region V F. R. Huey, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3