PNO-I-87-117, on 871219,reactor Manually Scrammed After Mechanical Vibrations from Turbine Bldg Felt in Control Room.Caused by Feedwater Control Valve Stem Separation from Disc.Outage Dependent on Availability of Repair Parts
| ML20237E031 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 12/21/1987 |
| From: | Cook W, Jerrica Johnson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| References | |
| PNO-I-87-117, NUDOCS 8712280100 | |
| Download: ML20237E031 (1) | |
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DCS No:
50220871219 l
Date: December 21,-1987 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-I-87-117
.This preliminary notification constitutes EARLY notice of events of P0.SSIBLE safety k
or public interest significance.
The information is as initially received without verification or evaluation, and is basically all that is known by the Region I staff on this date.
Facility:
Niagara Mohawk Power Corporation Licensee Emergency Classification:
Nine Mile Point Unit 1 Notification of Unusual Event Scriba, New York Alert Docket No. 50-220 Site Area Emergency General Emergency X
Not Applicable
Subject:
FORCED OUTAGE GREATER THAN 48 HOURS At 6:15 p.m. on 12/19, control room operators 'at Unit 1 manually scrammed the rea'ctor
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from approximately 98% power.
Operators scrammed the reactor after feeling mechanical vibrations in the control room, coming from the adjacent turbine building complex.
Prior to the manual scram, operators had observed minor reactor vessel' level oscillations and had received No. 13 feedwater pump lube oil and seal pressure alarms and high pressure feedwater heater level alarms. Operators had been detailed to investigate the cause of these alarms when the vibrations were felt concurrent with the receipt of fire detection systems alarms in two different locations in the turbine building.
Immediately after the scram, the minor level oscillations were no longer observed and the vibrations in the' turbine building stopped.
At the time of the event, operators in the turbine building witnessed excessive vibration of high pressure feedsater piping.
The fire detection system alarms were attributed to asbestos particles made airborne due to the high pipe vibrations.
No fires were detected.
Preliminary investigation by the licensee on 12/20 determined that the stem of the No.
13A feedwater control valve separated from the disc and the No. 13 feedwater pump outboard bearing was damaged. Walkdown of feedwater piping to date has identified a leaking flange connection on the feedwater flow element. The outage duration is unspecified as of this time and is primarily dependent on availability of repair parts.
The resident inspectors are onsite reviewing licensee actions.
This PN is issued for information only. The State of New York has been notified.
CONTACT: William Cook Jon Johnson 8-315-342-4041 488-1234 c
O y l 8712280100 871221
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