ML20248L902

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PNO-78-049:on 780315,letdown Valve Failed Closed W/Rcs in Solid Water,Cold Shutdown Condition & Average Temp of 158 Degrees F.Analysis Reveals No Excessive Stresses Were Incurred by Reactor Vessel or RCS Piping
ML20248L902
Person / Time
Site: North Anna Dominion icon.png
Issue date: 03/16/1978
From: Klingler G, Nolan F, Sniezek J
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
References
PNO-78-049, PNO-78-49, NUDOCS 9806120046
Download: ML20248L902 (1)


Text

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PRELIMINARY NOTIFICATION d~

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March 16, 1978 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PN

_This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by IE staff as of this date.

FACILITY: Virginia Electric and Power Company

' North Anna, Unit No. 1 Docket No. 50-338 Louisa County, Virginia

SUBJECT:

OVERPRESSURIZATION OF REACTOR COOLANT SYSTEM On March 15, a letdown valve failed closed with the reactor coolant system (RCS) temperature of 158in adegrees solid water, F. cold shutdown condition and an average 570 psig over a period of about five minutes and reportedly remainedRCS pre  :

above the Technical Specification limit of 460 psig for less than one minute. =

but a pressurizer power-operated relief valve failed to actuate at itsR C2

(  ! set point of 410 psig due to an omis'sion in the setpoint calibration procedure.

incurred by the reactor vessel or RCS piping. Analysis by the licensee l reveal Media interest is anticipated due to current interest in the North Anna b facility.

A news release is not planned by the licensee nor NRC.

Commonwealth of Virginia has been notified, The g s t

Region II (Atlanta) received initial notification of this occurrence by telephone-from station management at 2:40 p.m. on March 15.

is current as of 8:10 a.m. on March 16. This information

Contact:

GKlingler, IE x28019 FNolan, IE x28019 JSniezek, IE x28019 Distribution: Transmitted H St /L ',2 7 Chairman Hendrie Commissioner Kennedy Comniissioner Bradford "

S. J. Chilk, SECY C. C. Kammerer, CA Commissioner Gilinsky (For Distribution)

Transmitt'ed: MNBB / M A P P Bldg lL F .

L. V. Gossick, ED0 E. Volgenau IE E. G. Case, NRR S. H. Hanauer, ED0 Region ( ,I 1 M J. J. Fouchard, PA SS Bldg I M N R. Hartfield, MIPC C. V. Smitn, NMSS (MAIL)

_ R. G. Ryan, OSP T. J. McTiernan, 01A H. K. Shapar, ELD R. Minogue, SD PRELIMINARY NOTIFICATION 9806120046 78031b PDR I&E PNO-78-049 PDR

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