PNO-III-87-153, on 871216,during Testing of Closing Function of Eight Msivs,Outboard MSIV on Steam Line C Opened, Indicating Fast Closure Solenoid Malfunctioned.Solenoids Replaced on Affected Misv.Investigation Continuing

PNO-III-87-153:on 871216,during Testing of Closing Function of Eight Msivs,Outboard MSIV on Steam Line C Opened, Indicating Fast Closure Solenoid Malfunctioned.Solenoids Replaced on Affected Misv.Investigation Continuing

ML20237E744
Person / Time
Site:	LaSalle
Issue date:	12/21/1987
From:	Forney W, Ring M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-87-153, NUDOCS 8712290164
Download: ML20237E744 (1)

iPREl3MINARY NOTIFICATION OF EVENT OR UNUSUAL'0CCURRENCE--PN0-III-87-153 Date December

• This preliminary notification constitutes EARLY notice of events of POSSIBLE safety

,;or'public-interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III - 4n r

-staff on this date.

! Facility: Commonwealth Edison Company Licensee Emergency Classification:

LaSalle Unit 1 Notification of an Unusual Event Marseilles, IL 61341 Alert Site Area Emergency =

Docket No. 50-373 General Emergency X Not Applicable

Subject:

SOLEN 0ID MALFUNCTION ON MAIN STEAM ISOLATION VALVE On December 16, 1987, while the plant was in the hot shutdown mode, the licensee tested the closing function of the eight Unit 1 Main Steam Isolation Valves (MSIVs). All eight were closed using the slow closure solenoids. The fast closure solenoids were then actuated.

~

-When.the slow closure switch was released, one of the valves -- the outboard MSIV on the C steam line -- opened, indicating that the fast closure solenoid had malfunctioned. The licensee attempted to close the valve two additional times and it drifted back open.

- The unit remained shut down for. investigation of the MSIV problem. The fast acting solenoids were replaced on the affected MISV. The fast acting solenoid was disassembled and a gummy substance was observed on some of the internal components. The licensee inspected three other solenoids and also found the gummy substance, but to a lesser extent.

1 The licensee has replaced the remaining seven solenoids on Unit 1. Five solenoids, including the'one which malfunctioned are being returned for analysis to the vendor, Automatic Switch Co'. -(Asco).

The licensee has tested the MSIVs on Unit 2, which is in operation, and no problems were observed.

The Senior Resident Inspector and an inspection specialist from the regional office monitored the-licensee's evaluation. (The specialist had led two Augmented Inspection Teams at Perry to investigate MSIV closure problems there. Reference PN0-III-87-146, 138, and 138A.)

Region III (Chicago) issued a Confirmatory Action Letter-(CAL) on December 18, 1987, to document the licensee's agreement to a program to evaluate the MSIVs and increase surveillance testing of the valves. The licensee met the terms of the CAL, and Region III authorized the restart of Unit 1 on December 19, 1987.

The State of Illinois will be notified. This information is current as of 9 a.m.,

December 21, 1987.

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g%41tuJ&nq Forne'y'(FTS 388-559)

CONTACT: M. Ring (FTS 388-5602)

DISTRIBUTION:

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.ACRS Licensee N O Region IV PDR Resident Inspector Region V HQS.. 0perations Officer JG/JL, 8712290164 B71221 Region III

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