05000344/LER-1981-012, Forwards LER 81-012/03L-0.Detailed Event Analysis Encl

Forwards LER 81-012/03L-0.Detailed Event Analysis Encl

ML20030B251
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	07/23/1981
From:	Yundt C PORTLAND GENERAL ELECTRIC CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20030B252	List: 05000344/LER-1981-012, Forwards LER 81-012/03L-0.Detailed Event Analysis Encl 05000344/LER-1981-012-03, /03L-0:on 810626,during RCS Level Reduction, Operating RHR Pump Began Cavitating & Was Stopped to Prevent Pump Damage.Caused by Inadequate Venting of Pressurizer. Procedures Will Be Reviewed W/Personnel
References
CPY-519-81, NUDOCS 8108060256
Download: ML20030B251 (3)

LER-1981-012, Forwards LER 81-012/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3441981012R00 - NRC Website

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{E-Portland General Electric Company Trojan Nuclear Plant P.O. Box 439 Rainier, Oregon 97048 (503)556-3713 July 23, 1981 CPY-519-81

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n-Mr. R. H. Engelken, Director hL Nuclear Regulatory Commission, Region V s-tm 0 519M* d

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1990 North California Boulevard

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Walnut Creek, CA 94596 v.s. $in v.

Dear Sir:

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In accordance with the Trojan Plant Operating License, Appendix

,I Technical Specifications, Paragraph 6.9.1.7, attached is Licensee Event Report No. 81-12, concerning a situation where the Technical Specification limits for maintaining reactor coolant system flow were not met.

Sincerely, C.

. Yundt General Manager CPY GB:mae Attachments c:

LER Distribution List

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N1 9' Lt 81080602S6 4

PDR ADOCK 0 PDR 8/ W

REPORTABLE OCC 1RENCE 1.

Report No.:

81-12 2.

a.

Report Date:

July 23, 198 b.

Occurrence Date: June 26,1981 3.

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

Identification of Occurrence:

The west residual heat removal (RHR) p.ap was stopped due to indication of pump cavitation. This resulted in h ss of heat removal flow for a period of approximately one hour and fitteen minutes. This exceeds the Technical Specification limit of one hour without reactor coolant sys-tem (RCS) flow.

5.

Conditions Prior to Occurrence:

The plant was in Mode 5 with RCS temperatu-e at 140*F and one train of RHR operating. RCS letdown was being diva.:ed to the hold up tank (HUT) to reduce RCS level below reactor coolant. imp (RCP) height in prepara-tion for working on the seal.

6.

Description of Occurrence:

While reducing RCS level, with the RCS le4el standpipe indicating ap-proximately 66', tb RHR pump appeared tc de cavitating as indicated by I

fluctuating motor ca..ent.

Piverting to 6.he HUT was terminated and, when the moter current did not stabilize, the RHR pump was stopped and RCS charging was established.

The standpipe 1cvel continued to decre

,e and further investigation found the pressurizer vent valve isola'ed. The vent was opened and standpipe level began dropping rapidly The reactor vessel head vent was opened and standpipe level stabilt.ed at approximately 61'.

The RHR suction taps off the RCS piping at just above the 60' level.

Pre-vious experience indicates that cavit rtion may occur when RCS level approaches this point.

An attempt to restart the RHR pump f 11ed due to air entrained ir the RHR suction line. The RHR hot leg saction isolation valves were closed and the RWST suction valve was openel in order to provide a positive suction head to the RHR pumps. Bott pumps indicated flow when jogged and the normal valve lineup was res ared. The RHR pump was success-fully restarted one hour and fif teen minutes af ter it was stopped.

7.

Designation of Apparent Cause of Oijurrence:

The cause of this occurrence is pe: sonnel error.

The procedure for draining the RCS specifies that tt a pressurizer vent valve be opened.

However, personnel performing this evolution did not check to ensure that the valve was open. Without the proper pressurizer vent path line-up, the RCS standpipe level read higher than the actual RCS level.

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Reportable Occurrence Page Two 8.

Significance of Occurrence:

This event had no effect on either plant or public safety. The plant l

was in Cold Shutdown and no reactivity changes were taking place.

Coolant temperature increase was determined to be less than 10*F.

9.

Corrective Action

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Immediate corrective action was to properly vent and reestablish level in the RCS.

Long-term corrective actions are to review the pertinent l

plant procedures for adequacy and to review the importance of following approved plant operating procedures with the operations personnel.

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