ML20084A725
| ML20084A725 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 07/25/1975 |
| From: | Lang L ROCHESTER GAS & ELECTRIC CORP. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20084A720 | List: |
| References | |
| AO-75-12, NUDOCS 8304050572 | |
| Download: ML20084A725 (1) | |
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,7 ROCHESTER GAS AND ELECTRIC CORPORATION e 69 EAST AVENUE, ROCHESTER, N.Y. lY49 ta t e rwo.c anta coor m 546 27oo Ginna Station
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July 25, 1975 I
Mr. James P. O'Reilly, Director E J{,)
3 Directorate of Regulatory Operations H. 3301975 '
Region I U. S. Atomic Energy Commission 631 Park Avenue
A King of Prussia, Pa.
19406 C
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Sub,1ect: Abnormal Occurrence 75-12: Failure of Undervoltage Relay During Monthly Surveillance Test Ginna Station i
Docket #50-24h
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Dear Mr. O'Reilly:
During the performance of the Monthly Surveillance Procedure FT-9, "Under-voltage and Underfrequency Protection" on July 25, 1975, upon opening the knife switches for the solenoid coil of primary undervoltage device 273/11B, it was discovered that the device armature did not drop down to assume its' de-energized position. As a result of this failure to operate, the Reactor l
Trip Undervoltage Protection signal was not generated to this relay. The knife switches were in: mediately opened again, and this second time the relay operated properly. The other three undervoltage relays on the 4160 volt bus were tested and they operated properly, i
l R'G & E Relay Department was contacted and a relay man cane to the station to investigate the failure.
A scale accumulation was noted on the armature plunger opposite the area of f'
the upper guide bearing. This accumulation was similar to that reported as abnormal occurrence 73-1 on May 29, 1973.and 7h-19 on December 5, 1974. All
' four undervoltage relays were removed, one at a time, and the scale accumulation
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was removed and the plunger polished. Upon returning the devices to services,
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the applicable section of PT-9 procedure was performed to verify operability.
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Very truly yours,.
DR O
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Lee S. Lang Assistant Superintendent ec: Mr. J.F.0' Leary,'NRC n
Mr. G.J.Swarthout, RG&E Mr.:L.D.Whitc,;Jr. RG&E.
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