05000344/LER-1981-026, Forwards LER 81-026/03L-0.Detailed Event Analysis Encl

Forwards LER 81-026/03L-0.Detailed Event Analysis Encl

ML20033B662
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	11/23/1981
From:	Yundt C PORTLAND GENERAL ELECTRIC CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20033B663	List: 05000344/LER-1981-026, Forwards LER 81-026/03L-0.Detailed Event Analysis Encl 05000344/LER-1981-026-03, /03L-0:on 811022,during Partial Loss of Electric Power,Both Centrifugal Charging Pumps Operated at Reduced Flow Due to Closing of Miniflow Valve.Valve Reopened & Special Watch Posted
References
CPY-919-81, NUDOCS 8112010621
Download: ML20033B662 (3)

LER-1981-026, Forwards LER 81-026/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3441981026R00 - NRC Website

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3 Portland G ieral Electric Company Trojan Nuclear Plant P.O. Box 439 Rainier, Oregon 97048 (503) 556-3713 November 23, 1981 CPY-919-81 cs

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US Nuclear Regulatory Commission g"r h

Mr. R. H. Engelken, Director a

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Region V - Suite 21c

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NOV3 019816 1450 Maria Lane y,,,

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Dear Sir:

'3 In accordance with the Trojan Plant Operating License, Appendix A, NRC Technical Specification 6.9.1.9.c attached is Licensee Event Report No. 81-26, concerning a situation where the plant was operating with centrifugal charging pump (CCP) miniflow recirc isolation valve M0-8110 closed, which could have caused damage to a CCP.

Sincerely, 6

C. P. Yundt General Manager CPY/MLD/ WON:mae Attachments c:

LER Distribution List XiU;9:rzj dC :21 !!d 22 /,01 isi 8'

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WH 03Assau 8112010621 011123 PDR ADOCK 05000344 S.

PDR

'e REPORTABLE OCCURRENCE 1.

Report No.:

81-26 2.

a.

Report Date:

November 23, 1981 b.

Occurrence Date: October 22, 1981 3.

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

Identification of Occurrence:

Following a partial loss of plant electrical power and resulting reactor trip, both Centrifugal Charging Pumps (CCPs) were operated at reduced flow due to miniflow recirculation valve MO-8110 being closed.

5.

Conditions Prior to Occurrence:

The plant was operating in Pode 3 following a reactor trip.

6.

Description of Occurrence:

CCP miniflow recirc valve, MO-8110, had been closed several weeks earlier to increase "B" CCP charging flow to match the 120 gpm letdown flow. At 1410 a reactor trip occurred due to the loss of 12.47kV bus H1, causing the loss of 4160V ESF bus Al and subsequent "A" emergency diesel generator auto start and normal shutdown sequencer actuation. This started the "A" CCP. When the "A" CCP was shut off at 1524, charging flow dropped to zero and motor current on the "B" CCP was fluctuating. The "A" pump was then restarted and the "B" pump was tripped. The "B" CCP was later tested satisfactorily.

The apparent cause of fluctuating motor current was inadequate flow through "B" CCP due to both pumps operating with MO-8110 closed.

7.

Designation of Apparent Cause of Occurrence:

The cause of this event was that normal operating procedures did not explicitly state that the plant should not be operated with MO-8110 closed.

8.

Significance of Occurrence:

This evene had no effect on either plant or public safety. The "A" CCP operated satisfactorily and subsequent testing of the "B" CCP showed that it was operable with no apparent damage incurred.

9.

Corrective Action

The "B" CCP was tagged out after fluctuating motor current was ob se rved. No problems were noted and the pump performance test was completed with satisfactory results.

The miniflow recirc valve was reopened and Operations personnel were instructed to keep it open.

Permanent corrective action includes a requirement in the Operations

" Night Orders" that a special watch be posted at the CCP control board whenever its miniflow valve is isolated. Additionally, a precaution warning against closing a CCP miniflow valve will be added to the applicable system normal Operating Instruction.

The plant Emergency Instructions had previously been revised to incorporate these concerns as a result of USNRC Bulletin 80-18.