PNO-III-86-062, on 860627,while Operating at 68% Power, Lightening Strike Caused Unit to Automatically Trip.Shutdown Was Due to Failure of Some Primary Sys Instruments,Causing Reactor Protection Sys to Trip Unit.State of Il Notified

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PNO-III-86-062:on 860627,while Operating at 68% Power, Lightening Strike Caused Unit to Automatically Trip.Shutdown Was Due to Failure of Some Primary Sys Instruments,Causing Reactor Protection Sys to Trip Unit.State of Il Notified
ML20212E882
Person / Time
Site: Zion File:ZionSolutions icon.png
Issue date: 06/30/1986
From: Burgess B, Guldemond W
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-86-062, PNO-III-86-62, NUDOCS 9711040092
Download: ML20212E882 (1)


PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-!!!-86 62 Date June 30, 1986 This prelininary notification constitutes EARLY notice of events of POSSIBLE safety

[a j or public interest significance. The information is as initially received without verification or evaluation and is basicall g lh that is known by the Region !!!

V y staff on this date. } c ~. "

Facility: Comonwealth Edison Company Licensee Emergency Classification:

Zion Unit 2 q" y. n NotMiqaQionofanUnusual7 vent Zion, IL 60099 Alert Site Area Emergency Docket No: 50-304 GeneralwEmergency

. XX Not ApRI'icable

Subject:

LIGHTkiNG STRIKE At5:30a.m.(CDT), June 27, 1986, while operating at 68 percent power, a lightning strike caused the unit to automatically trip. The shutdown was due to a fcilure of some primary system instruments, causing the reactor protection system to trip the unit on

, over-temperature differential temperature.

The instrumentation affected by the lightning were: onetransmitter(DLoopaccumulator i level) and several-temperature detectors in three of four hotlegs on the Reactor Coolant i l' System.

The lightning also caused the actuation of the overvoltage protection system for seven out of 10 rod control power supplies. Although the lightning actuated the power supplies, the control rods may have already tripped because of the over-temperature differential temperature trip, All other safety systems functioned as designed. The unit is currently in cold shutdown to (e)

(/

replace the temperature detectors. Startup is tentatively scheduled for July 5,1986. The Resident inspectors _will follow the licensee's course of action.

The State of Illinois will be notified.

Region !!! (Chicago) was first infonned of the lightning strike at 7:30 a.m., (CDT),

June 27, 1986. Tnis information is current as of 1:30 p.m., (CDT), June 30, 1986..

CONTACT: B. Burgess W. Guldemond FTS 388-5689 FTS 388-5574 l

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DISTRIBUTION:

H. St. -

Chairman Palladino E00 pA NRR E/W Willste Mail: ADM:DMB )fdY IE- NMSS 00T:Trans only

.Comm. Zech- ELO OIA RES Com. Bernthal Com. - Roberts Com. Asselstine SP Regional Offi.ces ACRS

.SECY, INP0 NSAC CA R!li Resident Office POR . Licensee: (Corp. Office - Reactor Lic. Only)

Region !!! .

. N e r 1985 r* [;0 04 k C/R Distribution: Chm, Cmrs PE, GC, CA, ACRS, Historian, SECY, Records.

y 9710gH2 860630 PND-ILI-86-062 PDR

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