PNO-II-87-032, updates PNO-II-87-029.Util Determined That Partial Closure of Isolation Valve Which Brought About Reactor Scram on 870516 Caused by Shearing of Valve Stem Above Backseat.Metallurgist Evaluating Break

From kanterella
Jump to navigation Jump to search
PNO-II-87-032:updates PNO-II-87-029.Util Determined That Partial Closure of Isolation Valve Which Brought About Reactor Scram on 870516 Caused by Shearing of Valve Stem Above Backseat.Metallurgist Evaluating Break
ML20214W235
Person / Time
Site: Surry Dominion icon.png
Issue date: 05/21/1987
From: Cantrell F, Croteau R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
References
PNO-II-87-032, PNO-II-87-32, NUDOCS 8706150166
Download: ML20214W235 (1)


_ _ _ _ _ _ - _ _ _ _ _

May 21, 1987 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-II-87-32 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verifi-cation or evaluation, and is basically all that is known by the Region II staff on this date.

FACILITY: Virginia Electric & Power Co. Licensee Emergency Classification:

Surry Unit 1 Notification of Unusual Event Docket No: 50-280 Alert Surry, Virginia Site Area Emergency General Emergency X Not Applicable

SUBJECT:

UNSCHEDULED SHUTDOWN EXCEEDING 48 HOUR--UPDATE This PN updates PN0-II-87-29, issued May 18.

Virginia Power has determined that the partial closure of a hot leg loop isolation valve, which brought about the Unit 1 reactor scram on May 16, was caused by the shearing of the valve stem above the backseat. The stem material is 17-4 pH stainless steel. The failure appears to be similar to one which occurred at Surry in 1975.

A licensee metallurgist is on site evaluating the break. An NRC materials specialist is also on site observing the licensee's actions.

This information is current as of 2 p.m. (EDT) today.

The Connonwealth of Virginia has been informed.

Contact:

R. Croteau, 242-4668 F. S. Cantrell, 242-5534 DISTRIBUTION:

H. Street MNBB Phillips E/W Willste Mail:

Chairman Zech NO- NRR TE- NMSS XffMiDMB Conin Roberts PA OIA RES D0T: Trans Only Comm. Asselstine MPA AE0D Applicable State Comm. Bernthal ELD Comm. Carr Air Rights INP0 STf SECY SP NSAC ACRS ,n .$ f R Regions: M. 8 - E 'E b Licensee: JL!70 (ReactorLicensees)

Applicable Resident Site h @ -

I

\

i

., )

8706150166 870521 NO-II-97-032 PDR I \

. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . N ZE3'f