PNO-V-88-059, on 881024,licensee Determined That Reactor Coolant Unidentified Leakage Was 1.06 Gpm.Leakage Could Not Be Reduced.Reactor Was Shut Down.No Entry Inside Shield Permitted.Repair Method to Be Determined Upon Next Entry

PNO-V-88-059:on 881024,licensee Determined That Reactor Coolant Unidentified Leakage Was 1.06 Gpm.Leakage Could Not Be Reduced.Reactor Was Shut Down.No Entry Inside Shield Permitted.Repair Method to Be Determined Upon Next Entry

ML20205M985
Person / Time
Site:	Rancho Seco
Issue date:	10/25/1988
From:	Ang W, Qualls P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-88-059, PNO-V-88-59, NUDOCS 8811030386
Download: ML20205M985 (1)

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O M

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-88-59 Date 10/25/88 l This preliminary notification constitutes EARLY notice of events of POSSIBLE sefety or I public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by Region Y staff on this date.

FACILITY: SACRAMENTO MUNICIPAL UTILITY DISTRICT Emergency Classification RANCHO SECO UNIT 1 X Notification of Unusual Event DOCKET NO. 50-312 - ~ Alert HERALD, CA Site Area Emergency l

General Emergency Not Applicable

SUBJECT:

SHUTDOWN DUE TO UNIDENTIFIED LEAKAGE GREATER THAN 1 GPM On October 24, 1988, at 2249 PDT, with the reactor at 92% power, the licensce determined that reactor coolant unidentified leakage was 1.06 GPH. At 0249 PDT, on October 25, 1988, the licensee determined that the leakage could not be reduced below the 1 GPM technical specifications limit, and an Unusual Event was declarad at that time. In accordance with technical specification 3.1.6 a reactor shutdown cas commenced at 0402 PDT. A containment entry detennined that the leak was on the north side of the pressurizer, inside the bioiogical shield ring. Due to reactor power, no entry inside the shield was permitted. Another containment entry is scheouled later this morning to determine the location and the size of the leak. At '

that time the licensee will determine the repair method and evaluate the need to place the plant in cold shutdown. The reactor reached hot shutdown conditions at 0843 PDT. r All plant equipment functioned as designed during the controlled shutdown. ,

The licensee has issued a press release. Region V has responded to press inquiries.

This information is current as of 0900 PDT.

CONTACT: W. Ang P. Quall:;

FTS 463-3726 1-209-748-2791/92 ,

DISTRIBLTION BY 5520: FAX TO:

Date Time Date Time Chairman Zech EDO RI INPO Corvn. Roberts AE0D R!l NSAC Com Carr PA0 R!!! LICENSEE l Com Rogers SLITP RIV RESIDENT INSPECTOR  ;

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CA ARM MAIL T0:

FOR 01 DCS (Original) ,

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ACRS RES GPA i RV FORM 211 l Revised: 8/19/87 p g 0811030386 001025

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