ML20134D439

Discusses Auxiliary Feedwater Sys.Administrative Limit of Greater than or Equal to 60% Established for Water Level in Condensate Storage Tank.Review of History of Sys Will Be Performed

ML20134D439
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	08/12/1985
From:	Withers B PORTLAND GENERAL ELECTRIC CO.
To:	Butcher E Office of Nuclear Reactor Regulation
References
TAC-60783, NUDOCS 8508190219
Download: ML20134D439 (2)

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Bart D. Weers Vce Presdent August 12, 1985 Trojan Nuclear Plant Docket 50-344 License NPF-1 Director of Nuclear Reactor Regulation ATTN: Mr. E. J. Butcher Jr., Acting Chief Operating Reactors Branch No. 3 Division of Licensing U.S. Nuclear Regulatory Commission Washington DC 20555

Dear Sir:

Auxiliary Feedwater System Pursuant to discussions with members of your staff, an administrative limit of 160 percent has been established for the water level in the condensate storage tank (CST). This minimum level of 60 percent has been incorporated into several Plant operating procedures as a limit below which one auxiliary feedwater pump would be declared inoperable, and the action statement of Technical Specification 3.7.1.2, Auxiliary Feedwater System, would be implemented. Action Statement a of Technical Specification 3.7.1.2 requires that, with one of the two safety-related auxiliary feedwater pumps inoperable, the inoperable pump must be restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or the Plant placed in hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The minimum limit of 60-percent water level in the CST was determined by a Temporary Plant Test. The Plant test started both auxiliary feedwater pumps simultaneously from an automatic initiation signal for various CST water levels and verified that they would both start and continue to run, performing their design functions.

Subsequently, prior to startup, changes were made to the appropriate Plant operating procedures with a 10 CFR 50.59 safety evaluation conducted for those changes. It was determined that operating the Plant at a CST level 160 percent would not require a change to existing Technical Specifica-tions. Administrative controls exist to implement the action of Technical Specification 3.7.1.2 with a CST water level of less than 60 percent.

Although Technical Specification 3.7.1.4 specifies a minimum water level in the CST of 47 percent (196,000 gallons), the action statement of Technical Specification 3.7.1.4 does not require an auxiliary feodwater pump to be inoperable if the level decreases below 47 percent.

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, Ptztland General BechicCompany Mr. E. J. Butcher, Jr.

August 12, 1985 Page 2 An unreviewed safety question was determined to not exist because the probability of occurrence, or the consequences of an accident or malfunc-tion of equipment important to safety previously evaluated in the safety analysis report, was not increased. Raising the CST minimum water level to 60 percent would decrease the probability and the consequences of an acci-dont or malfunction of equipment important to safety. A level of 60 per-cent provides greater assurance that both auxiliary feedwater pumps will automatically start and operate and provides a greater volume of water in the CST for heat removal.

The possibility for an accident or malfunction of a different type than any evaluated previously in the safety analysis report would not be created by an increase in the CST level to 60 percent. A 60-percent water level pro-vides additional conservatism and does not allow for the possibility for an accident or a malfunction of a different type than evaluated previously.

Finally, the margin of safety defined in the basis for any Technical Speci-fication has not been reduced by this increase in CST level. The margin of safety is increased by this change in the limit.

For the above reasons and following discussions with members of your staff, it is not felt necessary to submit a proposed revision to the Trojan Tech-nical Specifications to reflect the new CST level. Administrative controls have been implemented for determining the operability of the auxiliary feedwater pumps in accordance with the Technical Specifications. It is preferable to resolve Plant problems by identifying the root cause and implementing the appropriate modifications instead of by temporary Technical Specification changes.

As long-term corrective action, PGs will perform a detailed review of the design and failure history of the Auxiliary Feedwater System. This study is scheduled to be completed by the end of October. The results of this study will be submitted to the NRC by the end of November with a schedule for any resulting modifications that might occur. It is our intention at this time to eliminate the low-suction pressure trips from the auxiliary feedwater pumps. However, should the study indicate other desirable alternatives, such changes would likely be made.

Sincerely, t

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Bart D. Withers Vice President Nuclear c: Mr. John B. Martin Regional Administrator, Region V U.S. Nuclear Regulatcry Commission Mr. Lynn Frank, Director State of Oregon Department of Energy