ML13324A730
| ML13324A730 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/10/1985 |
| From: | Medford M SOUTHERN CALIFORNIA EDISON CO. |
| To: | Zwolinski J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML13323A457 | List: |
| References | |
| TASK-2.K.3.05, TASK-TM GL-83-10-D, GL-83-10D, GL-85-12, NUDOCS 8510160046 | |
| Download: ML13324A730 (4) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 M.O.MEDFORD TELEPHONE MANAGER. NUCLEAR LICENSING (818) 302-1749 October 10, 1985 Director, Office of Nuclear Reactor Regulation Attention: J. A. Zwolinski, Chief Operating Reactors Branch No. 5 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 TMI Action Item II.K.3.5, "Automatic Trip of Reactor Coolant Pumps" San Onofre Nuclear Generating Station Unit 1
References:
- 1. Letter, D. G. Eisenhut, NRC, to All Licensees With Westinghouse (W) Designed Nuclear Steam Supply Systems (NSSS's), Resolution of TMI Action Item II.K.3.5, "Automatic Trip of Reactor Coolant Pumps," (Generic Letter No.83-10d)
February 8, 1983
- 2. Letter, M. 0. Medford, SCE, to W. A. Paulson, NRC, TMI Action Item II.K.3.5, Automatic Trip of Reactor Coolant Pumps, October 1, 1984
- 3. Letter, H. L. Thompson, Jr., NRC, to All Licensees With Westinghouse (W) Designed Nuclear Steam Supply Systems (NSSS's), Implementation of TMI Action Item II.K.3.5, "Automatic Trip of Reactor Coolant Pumps," (Generic Letter No. 85-12), June 28, 1985
- 4. Letter, D. M. Crutchfield, NRC, to R. Dietch, SCE, IE Bulletin 79-06C, Item 1, Automatic Trip of Reactor Coolant Pumps, June 9, 1981 Reference 1 requested that we establish satisfactory setpoints for reactor coolant pump (RCP) trip or develop the technical basis for allowing continued RCP operation in the event of a small break LOCA at San Onofre Unit 1. Reference 2 responded by providing our final plans and schedule for 8510160046 851010 PDR ADOCK 05000206 P
- 1 Mr. 3.
October 10, 1985 resolution of the subject issue for San Onofre Unit 1. Reference 3 was received when our response to Reference 1 was in the final stages of preparation; therefore, this letter and enclosures address Reference 3 to the extent possible without delaying our response to Reference 1.
The report entitled "Evaluation of RCP Restart Criteria for San Onofre Unit 1" (Enclosure 1) dated August 1985, was prepared for SCE by Westinghouse Electric Corporation in support of our response to Reference 1.
The report provides the justification for the San Onofre Unit 1 response to SBLOCA vs non-LOCA events for which continued RCP operation is desirable. The report presents the results of our systematic evaluation of an appropriate RCP restart criterion for San Onofre Unit 1. Based on this evaluation, the use of a subcooling criterion will result in the restart of the RCP's for those non-LOCA events for which continued RCP operation is beneficial.
In accordance with the guidance of Reference 1, we are implementing the revisions to the steam generator tube rupture (SGTR) emergency operating instruction (EOI) stated in the enclosed report. It is anticipated that the revisions to the SGTR EOI will be issued and the operators trained by the end of the refueling outage scheduled to begin November 30, 1985. When these EOI revisions and any other required EOI revisions are implemented, the subject TMI Action Item will be considered resolved for San Onofre Unit 1.
Reference 1 indicated that for certain plants RCP trip was still expected to occur on the low pressure trip setpoints presently proposed by Westinghouse for the design basis steam generator tube rupture. It was also indicated that this was an unacceptable condition and that licensees should develop a more discriminating criterion that would allow RCP operation for tube leaks up to the design basis SGTR. As you know, a similar RCP trip was approved for use at San Onofre Unit 1 by Reference 4 and was implemented as an interim measure to resolve the concerns of IE Bulletin 79-06C. However, Reference 1 indicated that the requirements set forth therein supercede the actions required in IE Bulletins79-05C and 79-06C. Since the results in indicate that this trip is unnecessary, the RCP trip on safety injection caused by low reactor coolant system pressure will be removed. This modification will be scheduled in accordance with the Integrated Living Schedule.
Reference 1 also requested design information pertaining to the quality of the instrumentation that will signal the need for RCP restart following trip. The subcooling margin monitor will be utilized to determine if the RCP's should be restarted. The appropriate design information is provided in Enclosure 2, RCP Restart Instrumentation Design Information, San Onofre Unit 1.
Finally, our review of Reference 3 indicates that the above discussion and enclosed information provide most of the information requested therein. The remaining information regarding instrumentation reliability and
Mr. J.
October 10, 1985 identification of RCP trip components, will be provided by December 2, 1985.
The consideration of uncertainties of the WOG analyses is not applicable to San Onofre Unit 1.
If you have any questions regarding the above discussed information, please let me know.
Very truly yours, Enclosure cc: F. R. Huey, USNRC Senior Resident Inspector, San Onofre Units 1, 2 and 3
ENCLOSURE 1