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
(Redirected from PNO-II-87-032)
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