ML14135A264
| ML14135A264 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/04/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Dietch R Southern California Edison Co |
| References | |
| TASK-05-07, TASK-5-7, TASK-B-68, TASK-OR, TASK-RR LSO5-81-12-006, LSO5-81-12-6, NUDOCS 8112090173 | |
| Download: ML14135A264 (5) | |
Text
December 4, 1981 Docket No. 50-206 LS05 12-006 Mr. R. Dietch, Vice President C
1 Nuclear Engineering and Operation Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770
Dear Mr. Dietch:
SUBJECT:
SYSTEMATIC EVALUATION PROGRAM TOPIC V-7, REACTOR COOLANT PUMP OVERSPEED - SAN ONOFRE Enclosed is a copy of our evaluation of Systematic Evaluation Program (SEP)
Topic V-7. This topic is being reviewed generically by NRC under generic issue B-68 "Pump Overspeed During LOCA."
For the reasons described in the enclosed SER this topic is considered complete.
Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
Enclosure:
As. stated cc w/enclosure:
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 December 4, 1981 Docket No. 50-206 LS05-81-12-006 Mr. R. Dietch, Vice President Nuclear Engineering and Operation Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770
Dear Mr. Dietch:
SUBJECT:
SYSTEMATIC EVALUATION PROGRAM TOPIC V-7, REACTOR COOLANT PUMP OVERSPEED -
SAN ONOFRE Enclosed is a copy of our evaluation of Systematic Evaluation Program (SEP)
Topic V-7. This topic is being reviewed generically by NRC under generic issue B-68 "Pump Overspeed During LOCA,"
For the reasons described in the enclosed SER this topic is considered complete.
Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch No, 5 Division of.Licensing Enclosure; As stated cc w/enclosure:
See next page
Mr. R. Dietch cc Charles R. Kocher, Assistant General Counsel James Beoletto, Esquire Southern California Edison Company Post Office Box 800 Rosemead, California 91770 David R. Pigott Orrick, Herrington & Sutcliffe 600 Montgomery Street San Francisco, California 94111 Harry B. Stoehr San Diego Gas & Electric Company P. 0. Box 1831 San Diego, California 92112 Resident Inspector/San Onofre NPS c/o U. S. NRC P. 0. Box 4329 San Clemente, California 92672 Mission Viejo Branch Library 24851 Chrisanta Drive Mission Viejo, California 92676 Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County-of San Diego San Diego, California 92101 California Department of Health ATTN: Chief, Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 95814 U. S. Environmental Protection Agency Region IX Office ATTN:
Regional Radiation Representative 215 Freemont Street San Francisco, California 94111
SYSTEMATIC EVALUATION PROGRAM TOPIC V-7 SAN ONOFRE TOPIC:
V-7, REACTOR COOLANT PUMP OVERSPEED I.
INTRODUCTION The purpose of this topic review is to assure that, in the-event of
.a major LOCA, a reactor c6olant pump-assembly is not driven to a,
speed which would cause a structural failure of the unit and result in missiles which would increase the consequences of a LOCA.
II. REVIEW-CRITERIA Standard Review Plan (SRP) Section 5.4.1.1, Regulatory Guide (R. G.)
1.14..
III.
RELATED SAFETY TOPICS AND INTERFACES III-10.B, Pump Flywheel Integrity IV. REVIEW GUIDELINES See evaluation V.
EVALUATION A review of reactor coolant pump overspeed due to LOCA is part of an ongoing generic review. The related generic task it B-68, "Pump Over speed During LOCA."
The results of the NRC generic investigation to date have not identified additional protective measures that should be required to prevent excessive pump overspeed during a LOCA.
The staff safety evaluation of the San Onofre 1 Pump Flywheel Integrity (SEP Topic III-10.B) was issued on November 8, 1979. As noted in the topic assessment, the staff concluded from its review that the integrity of the flywheels on the primary coolant pumps will be adequately main tained by an Inservice Inspection Program in compliance with the recom mendations of Regulatory Guide 1.14. The reports of inservice inspections that have been performed on the San Onofre Nuclear Generating Station Unit No. 1 since October, 1970 show compliance with the guidelines set forth in the guide. However, it is recommended that additions be made to the Technical Specification or the Inservice Inspection Program to reflect compliance with the recommendations of Regulatory Guide 1.14. These additions should follow those originally proposed by the licensee but not yet incorporated by the staff.
-2 The pfobability of attaining an overspeed following a LOCA which is sufficient to cause loss of flywheel integrity is very remote. This probability would be the product of the conditional probabilities of a break of a large primary system coolant pipe, the probability of failure of the pipe restraints so that the break could become a double ended guillotimrbreak (calculations show a significantly smaller over speed for a realistically constrained guillotine break) and the pro bability of a loss of electric power to the pump so that there is no electric braking effect ahd the pump is permitted to accelerate freely.
Also, the pump would haVe to remain free spinning. Seizing of the shaft or motor components could prevent overspeed.
On the basis of low probability of the sequence of events necessary.and because of the licensee's performance of an inservice inspection program for the flywheel, continued-operation of the San Onofre 1 reactor is acceptable. If upon completion of the staff's generic review of Task B-68, new requirements are determined to be necessary to minimize pump overspeed in the event of a LOCA, these new requirements will be reviewed for applicability on all operating reactors.