ML20004B637

Application for Amend of License DPR-57 to Revise Tech Spec for Instrumentation Which Initiates Disconnection of Offsite Power Sources

ML20004B637
Person / Time
Site:	Hatch
Issue date:	05/21/1981
From:	Beckham J GEORGIA POWER CO.
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20004B638	List: ML20004B637 ML20004B639
References
TAC-10026, TAC-11262, TAC-47044, TAC-47045, TAC-47876, TAC-47877, NUDOCS 8105290212
Download: ML20004B637 (3)

Text

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Avt 3 Greg a ?NH M pe r > 04 576R 26 P C hw 1M5 M r a G+ m 12030J May 21, 1981 GeorgiaPower Power Generation Department U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. C. 20555 mC DOCKET 50-321 OPERATING LICENSE DPR-57 EDWIN I. HATCH NUCLEAR PLANT UNIT 1 EMERGENCY POWER SYSTEMS Gentlemen; Georgia Power Company's letter of July 22, 1977, proposed Technical Specifications on the interaction of onsite and offsite power sources.

Specifically, the letter proposed Technical Specifications for the disconnection from offsite power in the event of loss-of-offsite-powcr or a sustained degraded system voltage at the interconnection to cffsite power.

At the time of our July 22, 1977, submittal, all four bus undervoltage relays for each bus were set to the same value. The voltage and time delay values proposed for the loss of voltage and bus undervoltage conditions related to the combination of voltage tap setting and time delay curve which existed at that time. Subsequent to our submittal, and following several conversations with your consultants, our system protection personnel determined that additional protection against the degraded system voltage condition could be achieved by a revised combination of settings of the bus undervoltage relays. Accordingly, the relay values were changed such that two relays on each bus are now set to the 93 volt tap, time dial 2, and two relays on each bus are set to the 105 volt tap, time dial 5. The values proposed in our earlier submittal are therefore no longer appropriate.

Georgia Power Company therefore amends our submittal of July 22, 1977, by providing revised trip values for the proposed Technical Specifications.

The revised tap settings for the relays provide nearly 10% more margin against a sustained degraded voltage condition while providing protection from spurious disconnection from offsite power as a result of momentary voltage dips on the emergency buses. The basis for the revised values is unchanged. The Plant Review Board and the Safety Review Board have reviewed and approved the proposed changes and have determined that they do not involve an unreviewed safety question.

This amendment to our submittal of July 22, 1977, meets the NRC position stated in item 1 of the attachment to your October 30, 1979, letter, by providing surveillance requirements for a second level of undervoltage protectiom Ple6se note that we have not specified a channel check because the relays' state can be discerned by the presence or absence of alarms which would signify operation of the relays. The attached revised logic diagram replaces the diagram submitted with our July 22, 1977, letter, and clearly shows that operation of any one of the four relays is sufficient to start the diesel / generator for that bus.

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o GeorgiaPower A U. S. Nuclear Regulatory Commission Washington, D. C. 20555 May 21, 1981 Page Two Item 2 of the attachment to your October 30, 1979, letter, discussed actual loading of the diesel generators vs. racking breakers to the test position. The initial preoperational and startup testing of the unit demonstrsted the capability of the diesel / generators to sequence and load as designed. In addition, a monthly test is required by Technical Specifications which loads the diesel / generators for an hour at 50% or greater load. Additional surveillance requirements, including those proposed by our July 22, 1977, letter, demonstrate operability of the common accident signal logic and other associated diesel / generator logic. We believe the existing Technical Specifications, along with those proposed by the July 22, 1977, letter and amended by this submittal, will provide adequate assurance that the emergency -buses will not be tripped spuriously by voltage transients from the starting of large motors. Additional assurance is provided by the observation that no operational difficulty with starting large motors on the emergency buses, or difficulty with operation of the buses has been observed in Unit l's operating history.

J. T. Beckham, Jr. states that he is Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgis Powe: Company, and that to the best of his knowledge nad belief the facts set forth in this letter are true.

GEORGIA POWER COMPANY By: -

J. T. Beckham, M.

Sworn to and subscribed before me this 21st day of May,1981.

Notary Pubhc, Georgia, State at Larce b2 . s uu enmmlednn runirac ont 9n 1% i Notary Public RDB/mb xc: R. F. Rogers, III M. Manry

ATTACMENT 1 WC DOCKET 50-321 OPERATING LICENSE DPR-57 EDWIN I. HATCH NUCLEAR PLANT UNIT 1 PROPOSEt, CHANGES TO TECHNICAL SPECIFICATIONS The amendment to our proposed change to the Technical Specifications of July 22, 1977 would be incorporated as follows:

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