ML20138Q875
| ML20138Q875 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/07/1985 |
| From: | Kober R ROCHESTER GAS & ELECTRIC CORP. |
| To: | NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| NUDOCS 8511180301 | |
| Download: ML20138Q875 (3) | |
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cy ROCHESTER GAS AND ELECTRIC CORPORATION e 89 EAST AVENUE, ROCHESTER N.Y. 14649-0001 ROGER W KOBER VICE PRESIDENT T E L F NON 6 ELECTRIC 6e STEAM PRODUCTION aat 4 coct ne 546-2700 November 7, 1985 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555
Subject:
Follow-up Summary of Unusual Event at R.E. Ginna Nuclear Power Plant on November 6, 1985 Docket No. 50-244 In accordance with the NUREG-0654 reporting requirements, which require a written summary of closecut or class reduction conditions, the following is submitted for the Unusual Event declared at R.E. Ginna Nuclear Power Plant on November 6, 1985:
On November 6,
1985 at 0455 hours0.00527 days <br />0.126 hours <br />7.523148e-4 weeks <br />1.731275e-4 months <br /> with the reactor at 100%
power, an alarm (second alarm) and deluge of fire system S-05, Cable Tunnel Fire Suppression System was received in the control Room.
Approximately 5 seconds later another alarm (first alarm) was received for S-05.
The Control Room Operators immediately dispatched the fire brigade to the cable tunnel area.
The Fire Brigade Captain reported that the suppression system had deluged and that the only evidence of fire was a electrical insulation burning smell in the area.
Inspections were made on each cable tray and no evidence of electrical insulation burning was found.
The fire brigade continued to investigate the deluge.
At 0505 hours0.00584 days <br />0.14 hours <br />8.349868e-4 weeks <br />1.921525e-4 months <br />, the Shift Supervisor declared an Unusual Event in accordance with SC-100, Ginna Station Event Evaluation and Classification, for a suspected fire lasting ten minutes or more.
At approximately 0530 hours0.00613 days <br />0.147 hours <br />8.763227e-4 weeks <br />2.01665e-4 months <br />, the fire brigade declared the suspected fire to be under control and secured the deluge.
A continuous fire watch was posted in the area, as required with the automatic fire system out of service, by Plant Technical Specifi-cations.
g1180301 851107 S
ADOCK 05000244 Y[t)
ROCHESTER GAS AND ELECTRIC CORP.
5HEET NO. 2 DATE Novertber 7,1985 To U.S. Nuclear Regulatory Cmmission During the deluge, at approximately 0500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br />, a Control Room 480 Volt Ground annunciator began alarming intermittently.
Electricians were called in to investigate the cause and location of the ground.
At approximately 1120 hours0.013 days <br />0.311 hours <br />0.00185 weeks <br />4.2616e-4 months <br />, the ground was i
traced to the Intermediate Building Sub-basement Sump Pump number 2, powered from Bus 15, a 480 Volt Non-Safeguard Eus.
The ground was caused by the deluge water from the fire system actuation.
At 0830 hours0.00961 days <br />0.231 hours <br />0.00137 weeks <br />3.15815e-4 months <br /> at the daily plant staff priority meeting, a decision was made to maintain the Unusual Event Classification until the 480 Volt ground was located and isolated, and a check of the circuitry of S-05 was completed to ascertain whether the deluge was spurious.
In an effort to duplicate the sequence of alarms and actuation of the fire signaling system, a review of circuit diagrams was j
made coupled with experimental testing on a system mock-up.
j Based on this review and testing it has been concluded that a spurious signal spike on the second alarm module most likely caused this event.
i At 1220 hours0.0141 days <br />0.339 hours <br />0.00202 weeks <br />4.6421e-4 months <br />, the Shift Supervisor declared, with Superin-tendent approval, the Unusual Event terminated, in accordance with SC-110, Ginna Status Event Evaluation for Reducing the Classifi-cation.
During this event, the reactor was maintained at 100%
power.
Subsequent investigation and actions taken did not effect plant operation or compromise plant safety.
Proposed corrective action being implemented include the following:
1.
Investigation is continuing on the failure mode of the fire system.
The vendor is being contacted for his input into the problem resolution.
l 2.
The cable tunnel is being dried out.
This will be followed i
by reinstating of the fire signaling systems for this area j
and checkout of the system.
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ROCHESTER GAS AND ELECTRIC CORP.
SHEET NO. 3 DATE Novenber 7,1985 TO U.S. Nuclear Regulatory Camussion l
V truly yours, Y ef Ye YW Roger W.
Kober xc:
U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 4
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