ML13324A898
| ML13324A898 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/20/1986 |
| From: | Medford M SOUTHERN CALIFORNIA EDISON CO. |
| To: | Thompson H Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML13324A899 | List: |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.2, TASK-TM GL-82-28, NUDOCS 8606240406 | |
| Download: ML13324A898 (2) | |
Text
Southem California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 M.O.MEDFORD TELEPHONE MANAGER. NUCLEAR LICENSING June 20, 1986 (818) 302-1749 Director, Office of Nuclear Reactor Regulation Attention:
Mr. H. L. Thompson, Director Division of PWR Licensing - A U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
Subject:
Docket No. 50-206 Inadequate Core Cooling (ICC) Instrumentation San Onofre Nuclear Generating Station Unit 1
References:
- 1. Letter, D. G. Eisenhut, NRC, to All Licensees of Operating Westinghouse and CE PWR's, Inadequate Core Cooling Instrumentation System (Generic Letter No. 82-28),
December 10, 1982
- 2. Letter, M. 0. Medford, SCE, to 3. A. Zwolinski, NRC, NUREG-0737, Item II.F.2 -
Inadequate Core Cooling (ICC)
Instrumentation, October 8, 1985 Reference 1 provided SCE with a request to provide the details of our plans to install a reactor coolant inventory tracking system and the results of a review of the conformance of all components of the ICC instrumentation system to the design requirements of NUREG-0737, Appendix B.
This scope of the review was to include the subcooling margin monitors, core-exit thermocouples, and the reactor coolant inventory tracking system.
Subsequent SCE letters deferred our response to Reference 1 due to seismic outage considerations. Our response was rescheduled as part of the Integrated Living Schedule (ILS) Cycle 9 refueling outage activities.
Reference 2 specified that SCE would provide a response by March 1, 1986. Subsequently, due to resolution of items associated with return to service, the response was delayed. Accordingly, please find enclosed SCE's response to Reference 1 entitled "Inadequate Core Cooling Instrumentation, Response to NRC Generic Letter No. 82-28."
The enclosed report concludes that the cost of installation of a reactor coolant inventory tracking system at San Onofre Unit 1 far exceeds the expected benefits of such a system. This conclusion is'based upon probabilistic risk assessment, plant-specific design features, and existing ICC instrumentation adequacy. Based upon this report, SCE concludes that no additional inadequate core cooling instrumentation is required at San Onofre Unit 1.O 8606240406 860620 PDR ADOCK 05000206 P
Mr. H.
June 20, 1986 It should be noted that we are committing to an upgrade of the core-exit thermocouple system to meet the requirements of NUREG-0737, Appendix B by installing qualified cables and connectors and will draft an operating procedure for the loss of recirculation. These upgrades provide further assurance that the existing ICC instrumentation capability at San Onofre Unit 1 will provide accurate post-accident indication of the core conditions and the operators are prepared to respond to a small break loss of coolant accident. The schedule for the core-exit thermocouple upgrade will be included in the next revision to the ILS. The development of the procedure will occur as part of the next general EOI update.
If you have any questions regarding any of the information discussed herein, please let me know.
Subscribed on this 2 day of 1986.
Respectfully submitted, SOUTHERN CALIFORNIA EDISON COMPANY By:
M. 0. Medford Manager, Nuclear L4censing Subscribed and sworn to before me this V
day of
, / 97 OFFICIAL SEAL C. SALLY SEBO 9 Notary Public-Califomnia LOS ANGELES COUNTY My Comm. Exp. Apr. 20, 1990 Notary Public in Ad f6r the County of Los Angeles, State of California Enclosure