ML18143A882
| ML18143A882 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 12/14/1971 |
| From: | Amish K Rochester Gas & Electric Corp |
| To: | Morris P US Atomic Energy Commission (AEC) |
| References | |
| Download: ML18143A882 (4) | |
Text
4 89 EAST AVENUE,ROCHESTER ARE VIS o,c, 6y 11
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December 14, 1971 t
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OC ER GAS AND ELECTRIC CORPORATION D
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. A ISH SR9!IDR VIC PR SIDENT 4,
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III/IIL SECTION V
Dr. Peter A. Morris, Director Division of Reactor Licensing U.S. Atomic Energy Commission 7920 Norfolk Avenue
- Bethesda, Maryland 20014
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Rochester Gas and Electric Corporation Docket No. A8 244 So-
Subject:
Failure of "C" Safety, Injection Pump Regulatory to Start on Test R. E. Ginna Nuclear Power Plant Unit No.
1 File Cy
Dear Dr. Morris:
At about 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br /> on December 5, 1971, during the performance of the routine monthly surveillance test, No. PT-2. 1 Safety Injection System, the "C" Sa'fety Injecti'on Pump motor tripped automatically when nearly up to speed.
This was a manual start with the electric feed coming from 480 volt Bus No. 16.
The "A" and "B" Safety Injection Pumps had been successfully tested preceding the failure of the "C" to start.
I A second attempt produced the same result.
The investigation which followed revealed that the "B" phase series overcurrent tripping device, which has a long time delay and instantaneous
- element, was tripping out the motor on starting current because of leakage in the time delay dashpot.
The electric feed to this pump motor was then transferred to the alter-nate source, 480 volt Bus No. 14, which also has a three phase protection.
The motor was turned by hand and the leads from Bus No.
14 were meggared before the motor was energized.
The "C" injection pump start was success-ful and the surveillance test was completed.
As a recheck, the faulty relay was reinstalled and again the injection pump motor tripped as before.
Removal of the "B" phase protection but-leav-ing the other two phases with overcurrent protection permitted the proper function of the breaker during motor startup.
The Plant Operations Review Committee reviewed the occurrence and agreed that overcurrent protection on two phases of the breaker from Bus No.
16 was adequate.
A replacement overcurrent device with the same type long time delay and instantaneous overcurrent element was installed on the "C" Injection Pump Motor primary breaker of Bus No.
16 on December 10, 1971.
The Safety Injection Pump was tested and operated successfully with this new unit.
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" R5CHESTER GAS AND E RIC CORP.
j DATE December 14, 197 1 To Dr. Peter A. Morris L
SHEET NO.
2 This type of failure of a protective device appears to be relatively rare as we have only had one previous experience some years ago at one of our fossil plants.
An inspection of these devices is made annually in addition to the routine monthly surveillance test of this system.
Very truly yours, eith W. Amish
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