PNO-V-90-047A, on 901120,updates Occurrence of Inadvertent Actuation of Safety Injection & Containment Spray Sys

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PNO-V-90-047A:on 901120,updates Occurrence of Inadvertent Actuation of Safety Injection & Containment Spray Sys
ML20062G375
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 11/21/1990
From: Andrew Hon, Johnson P, David Proulx
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-90-047A, PNO-V-90-47A, NUDOCS 9011290150
Download: ML20062G375 (1)


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PRELIMINARY NOTIFICATION OF. EVENT'OR UNUSUAL 00'.URRENCE--PN0-V-90-47A Date:-11/21/90

. ThispreliminarynotificationconstitutesEkRLYnoticeofeventsofPOSSIBLEsafety or public interest significance. 1The information presented is as initially received without verification or evaluation ~ and is basically all that is known by Region V

' staff on this date.

. FACILITY: ' SOUTHERN CALIFORNIA EDIS'ON Emergency Classification San'0nofre Unit 2 Notification of Unusual Event Docket No. 50-361 Alert San Clemente, California Site Area Emergency General Emergency x Not Applicable

SUBJECT:

- INADVERTENT ACTUATION OF, SAFETY INJECTION AND CONTAINMENT SPRAY -- UPDATE f0n November 20. 1990 at 9:46 a.m..(PST) an inadvertent actuation of the Safety Injection and Containment Spray systems occurred at San Onofre Nuclear Generating Station Unit 2, while the plant was operating at 100% power. Up to 5000 gallons of borated water were sprayed into containment before operation of the Containment Spray system was terminated.

Based upon the_ licensee's experience from a similar event in March 1984 and prelimi-naryLenalysis of plant operating conditions,.the licensee continued power operation of Unit 2 while conducting a more detailed evaluation. This evaluation included an. inspection, by three teams of. technical containment (outside the biological shield)This .

personnel, of identified inspection conditions noinside the apparent adverse effects as 0 result of this event. The inspection revealed minor puddles of water inside the containment, no apparent-p'roblems with water intrusion into elec-trical components, anil near-normal containment humidity conditions. The inspection also indicated (becarse spray was terminated before full flow was established) that the spray pattern wss concentrated in the! outer portions of containment, with less

flow directed toward the center. The licensee is currently developing an action plan '

defining additional short-term and long-term actions to monitor for possible residual

, effects from this event.

Region V and NRR will continue to actively follow the licensee'i actions. This information is current as of 3:00 p.m. (PST) November 21,:1990.

CONTACT:

A. Hon P. Johnson D. Proulx (71() 492-2641 FTS 463-3745 FTS 463-3767 i

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