05000344/LER-1981-021, Forwards LER 81-021/03L-0.Detailed Event Analysis Encl

Forwards LER 81-021/03L-0.Detailed Event Analysis Encl

ML20031G502
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	10/09/1981
From:	Yundt C PORTLAND GENERAL ELECTRIC CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20031G503	List: 05000344/LER-1981-021, Forwards LER 81-021/03L-0.Detailed Event Analysis Encl 05000344/LER-1981-021-03, /03L-0:on 810910,inadequate Ventilation Found for Train a Preferred Instrument & Control Power Buses.Caused by Insufficient ESF Ventilation Due to Fire Barriers Between a & B Trains.Room Ventilation Will Be Upgraded
References
CPY-769-81, NUDOCS 8110220490
Download: ML20031G502 (3)

LER-1981-021, Forwards LER 81-021/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3441981021R00 - NRC Website

text

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Portland General Electric Company Trojan Nuclear Plant P.O. Box 439 Rainier, Oregon 97048 (503)S56-3713 October 9, 1981 CPY-769-81 CD

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Mr. R. H. Engelken, Director 9

US Nuclear Regulatory Commission y.

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1450 Maria Lane - Suite 210 Walnut Creek, CA 94596-5368 1

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Dear Sir:

NOT InaccordancewiththeTrojanPlantOperatingLicense,'AWedh US NRC Technical Specifications, Paragraph 6.9.1.9.c, attache s

Licensee Event Report No. 81-21, concerning a situation where Technical Specifications 3.8.2.1 and 3.8.2.3 were not met when it was determined that inadequate ventilation for the "A" train preterred instrument and control power buses existed as a result of the installation of a three-hour fire barrier between the "A" and "B" instrument and control power trains.

Sincerely, 1

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$n C. P. Yundt General Manager C$?HXD CPY/MLD:na Attachmeuts c: LER Distribution List

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REPORTABLE OCCURRENCE 1.

Report No.:

81-21 2.

a.

Report Date:

October 9,1981 b.

Occurrence Date:

September 10, 1981 3.

Facility: Trojan Nuclear Plant, PO Box 439, Rainier, OR 97048 4.

Identification of Occurrence:

Technical Specifications 3.8.2.1 and 3.8.2.3 were not met when it was determined that inadequate ventilation for the "A" train preferred instrument and control power buses existed as a result of the installation of a three-hour fire barrier between the "A" and "B" instrument and contral power trains.

5.

Conditions Prior to Occurrence:

Prior to the occurrence the plant was in Mode 1 at '.00% power.

6.

Description of Occurrence:

In response to the NRC Fire Protection SER dated March 9s 1978, Item 3.2.2 and letter of March 18, 1980 requiring a three-hour rated fire barrier between trains of ESF electrical equipment, a fire wall was built to provide separation of the "A" and "B" train preferred instrument and control power buses. The instal-lation of this wall created a new room which enclosed those buses for the "A" train.

During operation, high ambient temperatures in the room led to an engineering investigation which revealed that the ventilation equipment in the room was not capable of maintaining room tempera; ares in the recommended range for ESF-related equipment operation and was not seismically qualified.

7.

Designation of Apparent Cause of Occurrence:

The cause of the occurrence was an inadequate interdisciplinary review which resulted in an incomplete safety evaluation for the plant design change that created the fire Farrier.

Calcu-lations of cooling requirements for the installed heat loads vs.

cooling capability of the installed ventilation equipment were not performed.

In addition, the ventilation support system's seismic qualification was not verified.

The supply of cooling water to the cooler was not safety grade, nor was the motor supplied with Class IE power.

8.

Analysis of Occurrence:

There was no ef f ect on plant or public safety since the redundant train of preferred instrument and control power was available at all times.

e Page Two 9.

Corrective Action

Initial action taken was to install portable blowers through the open doors of the fire barrier and institute an hourly fire inspection by plant Security personnel. After an engineering analysis to determine air flow and cooling requirements in the

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room, a 100-square-foot area of the fire barrier was removed at the points of air flow entry and exit.

Upon completion of this modification to the barrier, temperatures us the room dropped rrom 100*F to approximately 75'F.

Action is now being taken to incree.se the cooling capability of the room ventilation and provide support systems that meet ESF design criteria. Upon completion of these modifications, the three-hour fire barrier will be restored and an addendum to this report will be forwarded to the NRC confirm *ng this fact.

The Plant Review Board has reviewed this incident for their use in subsequent plant modification reviews.

The need to subject proposed designs to a thorough interdisciplinary review as required by Nuclear Projects Engineering Procedures in order to identify all possible system design interfaces has been emphasized to all design engineering personnel.

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