ML17258A359
| ML17258A359 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/27/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Maier J ROCHESTER GAS & ELECTRIC CORP. |
| References | |
| REF-GTECI-B-68, REF-GTECI-PV, REF-GTECI-SY, TASK-05-07, TASK-5-7, TASK-B-68, TASK-OR, TASK-RR LSO5-81-11-071, LSO5-81-11-71, NUDOCS 8112030470 | |
| Download: ML17258A359 (6) | |
Text
November 27, 1981 Docket No. 50-244 LS05-81-11-071 Mr. John E. Maier Vice President Electric and Steam Production Rochester Gas 8 Electric Borp.
89 East Avenue Rochester, New York 14649
Dear Mr. shier:
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SUBJECT:
SYSTEMATIC EVALUATION TOPIC V-7, REACTOR COOLANT PUMP OVERSPEED - GINNA 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 8-68 "Pump Overspeed During LOCA".
For the r easons described in the enclosed SER this topic is considered complete.
Sincerely,
Enclosure:
As stated cc w/enclosure:
See next page Dennis M. Crutchfield, Chief Operating Reactors Branch No.
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SYSTEMATIC EVALUATION PROGRAH TOPIC V-7 GINNA 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 coolant pump assembly is not driven to a
speed which would cause a structural failure of the unit and result in missiles which could 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 111-10.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 is B-68,
':Pump
The resul ts 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 pump flywheel integrity at Ginna has been assured by an inservice inspection of the flywheel to detect flaws which could lead to flywheel failure..
The staff safety evaluation of the Ginna Pump Flywheel ISI program was issued on June 22, 1981.
The probability of attaining an overspeed following a LOCA which is
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1 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 guillotine break (cal,culations show a significicantly smaller over-speed for a realisticall'y constrained guillotine break) and the probability of a loss of electric power to the pump so that there is no electric braking effect and 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.
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On the basis of low probabi'lity of the sequence of events necessary and because of the licence's performance of an inservice inspection program for the flywheel, continued operation of the Ginna reactor is acceptable.
If upon completion of the staff's generic review of task B-68, new re-quirements are determined to be necessary to minimize pump overspeed in the event of a LOCA, these new requirements will be reviewed for appli-cability on all operating reactors.