PNO-V-90-047, on 901120,actuation Signal Initiated by Plant Protection Sys While Testing PPS Channel

PNO-V-90-047:on 901120,actuation Signal Initiated by Plant Protection Sys While Testing PPS Channel

ML20062G757
Person / Time
Site:	San Onofre
Issue date:	11/20/1990
From:	Andrew Hon, Johnson P, David Proulx NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-90-047, PNO-V-90-47, NUDOCS 9011300197
Download: ML20062G757 (2)

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PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-90-4'/ Date: 11/20/90

This preliminary notification constitutes EARLY notice of events 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 Region V staff on this date.

FACILITY: SOUTHERN CALIFORNIA EDIS0N Emergency Classification San Onofre 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

-On 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 JStation Unit 2, while the plant was operating at 100% power.

The actuation' signal was initiated by the Plant Protection System (PPS) while an instruhient and control (!&C) technician was performing a PPS matrix test. The ,

actuation resulted when the 18C technician began testing _one PPS channel after

. neglecting to rese_t the previous channel. This satisfied the 2 out-of 4 logic to actuate the Safety injection and Containment, Spray systems. These systems operated

'for about one-to two minutes before being reset. Up to 5000 gallons of borated '

water were sprayed into. containment before operation of the Containment Spray system was terminated'

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A similar event-in Maren,'1984 resulted in.the spraying of approximately 6000 gallons'into the'U. nit 2l containment, inspection and evaluation by the licensee following.-that event LindicatedJnoTdeleterious effects from the spray actuation. ,

Based in part on this previous experience, the licensee intends to continue power operation of Unit 2, but will make-a containment entry at 4:00 p.m. (PST) to-inspect for potential. damage totany plant components. ,Further : licensee actions will be '

determined based 1upon the'results of these inspections'.

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thN actuation. initiated a frimo? te alarm in the State-of California Emergency 0perations Center. 'The licensee informed the' State authorities that an emergency situation did not exist. '

'RegionVwasfirstinformedbythe'ResidentInspector,bytelephoneat10:15a.m.

(PST) on Ncvember 20, 1990.- This .information is current as of 2:30 p.m. (PST),

November 20, 1990. -

CONTACT:

A. Hon .

P.h-JMinson D. rod x .  :

(714)492-2641 FTS '4'63-3745 FTS 463-3767 Oh

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DISTRIBUTION BY 5520:= FAX TO:

Date 101o Timed: Date -It/M Time $3.f,nny '

'Chairmin Carr ED. RI INPO / V '

Com. Rogers _

AEOD RII NSAC Comm. Curtiss PAO: RIII LICENSEE-Comm. Remick . SLITP RIV RESIDENT INSPECTOR <

.NRR- HQS. OPERATIONS OFFICER CA- , NMSS PDR(202)634-3343

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RV FORM 211 Revised: 8/19/87

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