ML13317B071
| ML13317B071 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/26/1982 |
| From: | Baskin K Southern California Edison Co |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8204070525 | |
| Download: ML13317B071 (2) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 K. P. BASKIN MANAGER OF NUCLEAR ENGINEERING, March 26, 1982 572-1401 SAFETY, AND LICENSING 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 Contact Stress on Safety Injection Valves MOV-850A, B, C San Onofre Nuclear Generating Station Unit 1 In our October 16, 1981 letter on the Safety Injection System Modification, we indicated that average contact stress across the valve seat faces of MOV-850A, MOV-850B, and MOV-850C were expected to be below the galling limit. As stated in that letter, the valves have a wider seating surface than the hydraulically a.ctuated valves and thus are expected to have average contact stress below the 10,000 psi galling limit. We also indicated that the manufacturer of the valve motor operator provided written confirmation that the operator can generate sufficient thrust to open the valves under the maximum expected differential pressure of 1685 psi.
We have continued our evaluation of the valve contact stress in order to confirm that it is below 10,000 psi.
It was expected that detailed drawings of the valves could be located to provide valve seat dimensions for calculation of average contact stress. However, we have not been able to locate detailed drawings in our files or from the manufacturer.
In order to complete our evaluation we will disassemble one of the valves during the current outage, measure the required dimensions and calculate the average contact stress. We will advise you of the results of our evaluation prior to resumption of power operation from the current outage, and if the average contact stress is in excess of the 10,000 psi galling threshold, we will also advise you of any required corrective actions.
Mr. D.
March 26, 1982 If you have any questions or desire further information concerning the actions discussed above, please contact me.
Very truly yours, cc: R. H. Engleken, Director USNRC DIE, Region 5