ML13326A903
| ML13326A903 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/28/1992 |
| From: | Quay T Office of Nuclear Reactor Regulation |
| To: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| Shared Package | |
| ML13326A904 | List: |
| References | |
| TAC-M83164, NUDOCS 9211020303 | |
| Download: ML13326A903 (3) | |
Text
'5CtPkREGUI UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 October 28, 1992 Docket No. 50-206 Mr. Harold B. Ray Senior Vice President Southern California Edison Company Irvine Operations Center 23 Parker Street Irvine, California 92718
Dear Mr. Ray:
SUBJECT:
SAN ONOFRE UNIT 1 REFUELING WATER STORAGE TANK EVALUATION (TAC NO. M83164)
A Safety Evaluation is enclosed that responds to your request for relief from San Onofre Unit 1 Reactor Water Storage Tank repair requirements. In letters dated April 26, 1992 and June 26, 1992 you analyzed the significance of leakage from the Refueling Water Storage Tank that had been discovered on March 19, 1992. American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Article IWA-5250 of Section XI requires repair of tank defects. You requested to continue power operations at Unit 1 through the remainder of the current fuel cycle without repairing the tank. Permanent shutdown of the Unit 1 reactor is scheduled to occur when the reactor fuel is depleted at the end of 1992.
Our evaluation of your relief request included a review of the submittals referenced above, several telephone conferences, an onsite inspection of the tank, and several meetings with your staff. We concurred with your conclusion that the leakage was caused by localized corrosion of exterior tank surfaces and that no significant wastage of additional material is likely to occur in the near term from that corrosion mechanism. However, the margin for the tank to withstand buckling during a seismic event was found to be less than the safety factor required by the applicable code. Strengthening the tank to code requirements would be required if power operations were to continue past December 1992.
9211020303 921028 PDR ADOCK 05000206 P
Mr. Harold B. Ray
-2 The existing buckling margin is sufficient to justify short term power operations and the normal post-shutdown activities leading to reactor defueling. If continued, long-term use of the tank for safety functions is proposed after reactor defueling, measures to improve resistance to buckling will be required. In the interim, your request for relief from the ASME Code through December 1992 is approved.
Sincerely Theodore R. Quay, Director Project Directorate V Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation
Enclosure:
Safety Evaluation cc w/enclosure:
See next page
- e 0
Mr. Harold B. Ray San Onofre Nuclear Generating Southern California Edison Company Station, Unit No. 1 cc:
Mr. Howard J. Wong Mr. Richard J. Kosiba, Project Manager U.S. Nuclear Regulatory Commission Bechtel Power Corporation Region V 12440 E. Imperial Highway 1450 Maria Lane, Suite 210 Norwalk, California 90650 Walnut Creek, California 94596 Mr. Robert G. Lacy Manager, Nuclear Department San Diego Gas & Electric Company P. 0. Box 1831 San Diego, California 92112 Resident Inspector/San Onofre NPS c/o U.S. Nuclear Regulatory Commission P. 0. Box 4329 San Clemente, California 92674 Mayor City of San Clemente 100 Avenida Presidio San Clemente, California 92672 Chairman, Board of Supervisors County of San Diego 1600 Pacific Highway, Room 335 San Diego, California 92101 Regional Administrator, Region V U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 Mr. Hank Kocol Radiologic Health Branch State Department of Health Services Post Office Box 942732 Sacramento, California 94234 Mr. Don J. Womeldorf Chief, Environmental Management Branch California Department of Health Services 714 P Street, Room 616 Sacramento, California 95814