PNO-V-86-009, on 860227,unusual Event Declared When Small Leak from Pressurizer Instrument Top Weld Discovered. Borating Began to Achieve Necessary Shutdown Margin.Cooldown & Leak Repair Planned

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PNO-V-86-009:on 860227,unusual Event Declared When Small Leak from Pressurizer Instrument Top Weld Discovered. Borating Began to Achieve Necessary Shutdown Margin.Cooldown & Leak Repair Planned
ML20154B295
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 02/27/1986
From: Chafee A, Qualls P
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-86-009, PNO-V-86-9, NUDOCS 8603040276
Download: ML20154B295 (1)


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PRELIMINARY NOTIFICATION OF EVT.NT OR l'> USUAL OCCirdRENCE--PNO-V-86-09 Date: 02/27/86 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public intcrest significance. The information presented is as initially received without verification or ovaluation and is basically all that is known by Region V staff on this date.

FACILITY: Southern California Edison Company Licensee Emergency Classification San Onofre Unit 3 X Notification of Unusual Event DOCKET NO. 50-362 Alert Site Area Emergency General Emergency

_ Not Applicable

SUBJECT:

PRESSURE BOUNDARY LEAKAGE During the evening of February 26, 1986, with the unit in Mode 3 at about 2220 psig and 535*,

i tha licensee calculated, based on higher than normal airborne activity in the containment, that a prirary leak of about 0.1 gpm existed. On the rovning of February 21, a containment entry was mada. A small leak from a pressurizer instrument top weld was discovered. At 1250 PST on Fcbrucry 27, 1986, the licensee declared an Unusual Event. At 1330 PST the licensee began bsrcting to schieve the necessary shutdown margin to place the plant in cold shutdown as r: quired by Technical Specification 3.4.5.2. At 1445 PST the licensee had achieved the n:caccary nargin and began to implement his plant cooldown procedure. Also, at 1445 PST the licensee terminated the Unusual Event. Current licensee plans are to cooldown and repair the ic k.

Tha unit had been in Mode 3 since February 21, 1986, to repair a problem with the main trcn:former.

Tha licensee is notfying local media.

Thio information is current as of 3:00 pm February 27, 1986.

CONTACT: A. Chaffee P. Qualls FTS 463-3753 FTS 463-3759 DISTRIBUTION l H St. HNBB Phillips E/V W111ste Air Rights ##7 Mails Chairman Palladino EDO NRR IE NMSS ADM DMB Comm. Zech PA OIA RES DOT Trans Only l Comm. Bernthal MPA AF0D l Ccmm. Roberts ELD Comm. Asselstine RegionsA SECY INP0'/ TY NSAC % 3 0 i ACRS Licensee ~ </f y c.

! CA (Reactor Licensees) REGION V: FORM 211 PDR Resident Inspector _ (Revised 3/14/83) I l

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, 0603040276 060227 l l PDR 1&E l PNO-V-06-OO9 PDR [] { ( l 1