ML20204H414

Submits Addl Data to 860728 Application to Amend License NPF-5,changing Tech Specs Re one-time Extension of Limiting Condition for Operation for Loss of Diesel Generator 2C. Breakdown of Diesel Reliability,Per Reg Guide 1.108 Listed

ML20204H414
Person / Time
Site:	Hatch
Issue date:	07/28/1986
From:	Gucwa L GEORGIA POWER CO.
To:	Muller D Office of Nuclear Reactor Regulation
References
RTR-REGGD-01.108, RTR-REGGD-1.108 0443H, 443H, SL-1056, TAC-62021, NUDOCS 8608080110
Download: ML20204H414 (3)

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Georgia her Company a 33" Piedmont Avenue Atlanta, Georgia 30308 Telephone 404 526-6526 Mailing Address:

Post Office Box 4545 Atlanta, Georgia 30302 M Georgia Power L T. Gucws tm mNm electorem Manager Nuclear Safety and ucensing SL-1056 0443H July 28,1986 Director of Nuclear Reactor Regulation Attention: Mr. D. Muller, Project Director BWR Project Directorate No. 2 Division of Boiling' Water Reactor Licensing U. S. Nuclear Regulatory Commission i

Washington, D. C. 20555 NRC DOCKET 50-366 OPERATING LICENSE NPF-5 EDWIN I. HATCH NUCLEAR PLANT UNIT 2 ADDITIONAL INFORMATION IN SUPPORT OF REQUEST TO REVISE TECHNICAL SPECIFICATIONS ONE-TIME EXTENSION OF LCO TIME FOR LOSS OF 2C DIESEL GENERATOR Gentlemen:

The following additional information is submitted in support of our July 28,1986 request to amend diesel generator Technical Specifications for Plant Hatch Unit 2.

1. Need for Power As 'you are aware, Georgia has been in a prolonged state of drought accompanied by extremely high temperatures. Today is the 26th consecutive day that temperatures have exceeded the 900F mark. The extremely high temperatures have resul ted in Georgia Power Company setting peak power production records over the past several weeks. At the present time, the Southern Electric System is operating with minimal reserve generation.

2. Compensatory Actions In addition to the compensatory action stated in Enclosure 1 to

our July 28, 1986 letter, we will test the remaining two Unit 2 diesels on staggered 3 day intervals as described in Technical Specifications Surveillance Requirement 4. 8.1.1. 2. a . 4.

Additionally, to keep emergency systems available, we will refrain from unnecessary testing.

3. Loss of Offsite Power 4

Plant Hatch has never experienced a total loss of offsite power.

8608080110 860728 9l6

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a Georgia Power d Attention: Mr. D. Muller, Project Director BWR Project Directorate No. 2 Director of Nuclear Reactor Regulation July 28,1986 Page Two

4. Plant Shutdown With Loss of Offsite Power (LOSP)

Given loss of diesel generator 2C, both units can be brought to safe, cold shutdown assuming LOSP coincident with a single failure on Unit 2.

We have analyzed plant shutdown capabilities utilizing only those components supplied by one diesel generator. This assumes that the limiting single failure is one of the remaining Unit 2 diesel generators (either 2A or 1B).

If the 1B diesel is the only available diesel for Unit 2, the essential 600 volt electrical bus associated with the cooldown components to be used must be manually transferred to the 1B diesel generator. This action is not required if 2A diesel is the remaining operable diesel. Hatch Unit 1 shutdown would be accomplished with the 1 A and 1C diesels.

5. Diesel Generator Reliability Plant Hatch personnel have reviewed diesel generator reliability data for the last 2-1/2 years (1/1/84 to 6/30/86) for diesel g w rators 2A, 2C, and 1B (swing diesel).

During this period, the diesels were started a total of 319 times. The composite reliability for all the Unit 2 diesels was greater than 99%. A detailed breakdown for each diesel is presented below:

Diesel # of Starts # of Failures Reliability (%)

i 2A 119 2 98.32 (117/119) l 1B 95 0 100.0 (95/95) 2C 105 1 99.05 (104/105)

TOTAL 31 9 3 99.1 (316/319)

Note: Failures are defined per Regulatory Guide 1.108 and include not only initial start failures but also failures that occur if the diesel fails to run correctly.

700775

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GeorgiaPower d Attention: Mr. D. Muller, Project Director BWR Project Directorate No. 2 Director of Nuclear Reactor Regulation July 28,1986 Page Three Even in the unlikely event of an additional diesel generator failure, Plant Hatch is supplied with eight reliable offsite power lines. To date, Plant Hatch has not experienced a Loss of Offsite Power (LOSP) event.

It is Georgia Power Company's intent to repair diesel generator 2C expeditiously and return it to service as soon as possible.

Sincerely,

$ r 4 ==

L. T. Gucwa REB /hkt c: Mr. J. P. O'Reilly Mr. J. T. Seckham Mr. H. C. hix Dr. J. N. Grace (NRC-Rll)

Senior Resident Inspector 700775