PNO-III-86-116, on 861015,while Operating at 95 Percent Power,Licensee Declared Unusual Event After Both Trains of Control Room Ventilation Sys Rendered Inoperable.Caused by Test Procedures Failed to Require Control Valve Be Reset

PNO-III-86-116:on 861015,while Operating at 95 Percent Power,Licensee Declared Unusual Event After Both Trains of Control Room Ventilation Sys Rendered Inoperable.Caused by Test Procedures Failed to Require Control Valve Be Reset

ML20212E668
Person / Time
Site:	Duane Arnold
Issue date:	10/17/1986
From:	Boyd D, Guldemond B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-86-116, NUDOCS 9711040017
Download: ML20212E668 (1)

~P fEllMIRRY NMit/E@ff0TWTGWGM unuguas uwucumgEnPm- All-o 10 vate uttocer u , ivoo 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 111 staff on this date.

( Fm:ility: lowa Electric Light & Power Co. Licensee Emergency Classification:

U Duane Arnold Energy Center Notification of an Unusual Event Palo, IA 52324 _X_ Alert Site Area Emergency Docket No. 50-331 General Emergency Not Applicable

Subject:

CONTROL ROOM VENTILATION SYSTEM IN0PERABLE At11a.m.(CDT), October 15, 1986, while operating at about 95 percent power, the licensee declared an unusual event after both trains of the Control Room Ventilation System were rendered inoperable.

The unit is expected to be shutdown for more than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> while the licensee replaces charcoal filters in the ventilation system (this system is designed to provide purified

. air to the control room in the event of an emergency.)

The problem occurred as licensee per'sonnel were checking the charcoal bed temperature sensor to verify that it would actuate the deluge system control valve (the deluge system dumps water on the charcoal in the event of fire.)

The deluge system was isolated to assure that the system would not actually activate. After testing the system, test procedures failed to require the control valve be reset. When the common deluge isolation valve was opened, the open control valve allowed the charcoal beds to be flooded with water.

9 With for operation. bothTheunitachievedcoldshutdownat10:47a.m.(CDT),onOctober unusual event was terminated at that time.

trains of the system inoperable, the 16, 1986. The unit wa The licensee is currently replacing the flooded charcoal filters. The resident inspector is followino the licensee's course of action.

The State of Iowa will be notified.

Region 111 (Chicago) first learned of this event at 11:38 a.m. (CDT), October 15, 1986.

This information is c.urrent as of 11 a.m. (CDT), October 17, 1986.

CONTACT: 0. Boyd FTS 388-5546 B. Guldemond FTS 388-5574 0

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-Comm. Carr SP Regional Offices ACRS SECY INP0 NSAC CA Rlll Resident Office PDR Licensee: (Corp. Office - Reactor Lic. Only)

/G Region III

( Rev. November 1985

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SEcy, p'ecords. ACRS' Storian 971104bo17 dl61 17 PDR ISE PNO-III-86-116 PDR

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