ML13324A930
| ML13324A930 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 07/30/1986 |
| From: | Medford M Southern California Edison Co |
| To: | Lear G Office of Nuclear Reactor Regulation |
| References | |
| TAC-62010 NUDOCS 8608040196 | |
| Download: ML13324A930 (2) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 M. 0. MEDFORD TELEPHONE MANAGER, NUCLEAR LICENSING July 30, 1986 (818) 302-1749 Director, Office of Nuclear Reactor Regulation Attention: G. E. Lear, Director PWR Project Directorate No. 1 U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
Subject:
Docket No. 50-206 San Onofre Nuclear Generating Station Unit 1 By "05000362/LER-1985-036, :on 851223,determined That Shutdown Cooling Sys HX Isolation Valves 3HV-8150 & [[SSC" contains a listed "[" character as part of the property label and has therefore been classified as invalid. Not Fully Closed Per Tech Specs.Caused by Premature Actuation of Valve Motor Operator Position Indication Limit Switches|letter dated June 5, 1986]], the NRC staff requested that we review their evaluation of certain technical issues related to the November 21, 1985 Water Hammer Event. Our comments on the evaluation were provided by letter dated July 1, 1986. The purpose of this letter is to update our comments on three of the items in our letter of July 1, 1986; specifically, Item 6 of the enclosure relating.to labeling of the vital bus availability lights, Item 8 relating to the schedule for submittal of the results of the study to enhance the second source of offsite power, and Item 17 relating to testing of the Remote Surveillance Panels and the Safeguard Load Sequencing System (SLSS).
In regard to Item 6 relating to the vital bus availability lights, a concern that the label indication may not be large enough to read from all areas of the control room was raised. This was not considered to be an immediate safety concern and our rationale to support this position was provided.
As indicated in our response, the Control Room Design Review Team was to evaluate the vital bus indication configuration to determine the feasibility of making a short term enhancement of the labels. This evaluation has been completed and it was concluded sufficient space exists both above and below the vital bus indicating lights to permit installation of labels that can be distinguished from all parts of the control room. Fabrication of these labels is currently in progress and they will be installed by August 15, 1986.
Item 8 of the enclosure indicated that the results of the study to provide a means of enhancing the availability of the second source of offsite power would be provided by July 30, 1986. Additional time will be required to complete the study. It is now -expected that the required information will be provided to the NRC by August 29, 1986.
8608040196 60730 POR ADOCK 05000206 r
S PDR
Mr. G.
July 30, 1986 As indicated in Item 17 of our July 1, 1986 letter, SCE was to perform a Loss of Power (LOP) test from approximately 25% power. This was to provide an integrated test of the Low Voltage Auto Transfer System (LOVATS) and to observe the response of the Remote Surveillance Panels and the SLSS.
Through internal review prior to conducting this test, however, it was determined that performance of an LOP test would result in residual steam in systems connected to the turbine and/or condenser overpressurizing the LP turbine casing rupture discs prior to restoration of the main circulating water system to service. In light of the resultant consequences of performing an LOP test, the benefits of the test results are not justified. SCE has therefore deleted the 25% LOP test.
As discussed below, testing completed to date will ensure operability of the systems involved.
Design changes to the LOVATS have been individually tested during this outage. This testing has not identified any deficiencies and is considered sufficient to demonstrate the LOVATS operability.
A series of tests have been performed on the remote surveillance panels in order to detect any deficiencies which may have caused the false indication of safety injection during the water hammer event. Although no anomolies were detected during testing, the testing is considered sufficiently comprehensive to identify any problems in the panels or the SLSS. It is therefore concluded that the faulty indication during the water hammer event was a result of a spurious signal and was not indicative of a design or electronic deficiency. The series of tests performed on the panels verifies proper operation of the SLSS and confirms all associated relays function properly. Accordingly, this item is considered closed.
If you have any questions or desire additional information, please let me know.
Very truly yours cc:
Mr. J. B. Martin, Regional Administrator, NRC, Region V Mr. A. C. Chaffee, Regulatory Projects Branch, Region V Mr. Gary Zech, Office of Inspection and Enforcement Mr. F. R. Huey, NRC Senior Resident Inspector, SONGS 1, 2 and 3