PNO-I-87-064, on 870711,reactor High Pressure Scram Experienced from Approx 3% Power.Caused by Fatigue Failure of Electrohydraulic Control Line to Turbine Control Valve 4. Repairs May Include Addl Structural Support

PNO-I-87-064:on 870711,reactor High Pressure Scram Experienced from Approx 3% Power.Caused by Fatigue Failure of Electrohydraulic Control Line to Turbine Control Valve 4. Repairs May Include Addl Structural Support

ML20235M823
Person / Time
Site:	Nine Mile Point
Issue date:	07/13/1987
From:	Ccok W, Roxanne Summers NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
References
PNO-I-87-064, PNO-I-87-64, NUDOCS 8707170335
Download: ML20235M823 (1)

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DCS No: 50410870711 Date: July 13, 1987 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-I-87-64 1

This preliminary notification constitutes EARLY notice of events of POSSIBLE. safety 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: Licensee Emergency Classification:

Niagara Mohawk Power Corporation X Notification of Unusual Event Nine Mile Point Nuclear Station, Unit 2 Alert Scriba, New York Site Area Emergency -

DN 50-410 General Emergency Not Applicable

Subject:

UNSCHEDULED SHU1DOWN IN EXCESS OF 48 HOURS I i

1 At 10:19 a.m. on July 11, 1987, Unit 2 experienced a. reactor high pressure scram from fl approximately 3% power. The cause of the scram was due to a fatigue failure of an electro-hydraulic control (EHC) line to the No. 4 Turbine Control Valve. The resulting loss of hydraulic fluid pressure caused the closure'of the No. I bypass valve which resulted in the high pressure reactor condition. All plant systems responded to the reactor scram as designed. Unit 2 will remain shut down while. repairs are made to the -1 ruptured EHC line. These repairs may include additional structural support to prevent I additional fatigue failures. At this time reactor startup is also prohibited by plant I technical specifications, since service water temperature (77 F) is in excess of the f maximum allowable (76 F).

The resident inspector is on site monitoring the licensee's actions.

The State of New York has been notified.

CONTACT: W. Coot R. Summers i 315-342-4041 488-1115 j DISTRIBUTION:

H. St. MNBB Phillips - E/W Willste Mail: ADM:DMB Chairman Zech EDO NRR NMSS DOT:Trans only Comm. Bernthal PA OIA RES Comm. Roberts OGC AE00 NRC Ops Crt Comm. Carr ACRS Air Rights INPO----

SECY SP NSAC----

CA PDR Regional Offices TMI Resident Section RI Resident Office j Licensee:

(Reactor Licensees)

Region I Form 83 (Rev. July 1987) '

I I

h{717 i35 070713 },

PNO Er/ og pop 0 I d}

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