ML19257C614

Responds to IE Bulletin 80-01.Hard-seat Check Valves,Backup Sys & Category I Seismic Classification Precludes Necessity of Design Mods for Prevention of Pneumatic Sys Failure

ML19257C614
Person / Time
Site:	Hatch
Issue date:	01/22/1980
From:	Widner W GEORGIA POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
IEB-80-01, IEB-80-1, NUDOCS 8001290493
Download: ML19257C614 (2)

Text

CecrT3 Pcaer C:mcany e , 2'") Peacwee G? rect Post Ci6ce Box 4545 At!anta, G:crma 30302 Telephone 404 522-CC60 January 22, 1980 m

Power Generation Department Georgia Power United States Nuclear Regulatory Commission -

Office of Inspection and Enforcement

REFERENCE:

Region II - Suite 3100 RII: JP0 101 Marietta Street, NW 50-321/50-366 Atlanta, Georgia 30303 I&E Bulletin 80-01 Attention: Mr. James P. O'Reilly Gentlemen:

The Georgia Power Company hereby submits the following information in response to your letter dated January 11, 1980, concerning I&E Bulletin 80-01, " Operability of ADS Valve Pneumatic Supply".

1. Plant Hatch has installed hard-seat check valves to isolate the ADS accumulator system from the pneumatic supply system. The manufacturers of these piston check valves are Velan on Unit 1 and Edwards on Unit 2. The seats and pistons for these valves are both stellite faced.

2. Periodic leak tests have not been performed on the ADS accumulator check valves at Plant Hatch. Because the check valves are in a qualified system which has redundant air supplies available, no failure mode exists to allow air supply to be lost to the acc umulators.

3. A review of the seismic qualifications of the ADS pneumatic supply system has determined that the system is seismic category I inside primary containment and is seismic category I outside primary containment through the compressor receiver tank. In addition, the Drywell Atmosphere Nitrogen Make-up System and the Instrument Air Supply System intertie into the Drywell Pneumatic System. These two backup systems are seismic category I and are powered by Class IE power supplies.

4. Inoperability of the ADS system, due to pneumatic system failure, is highly unlikely for either unit. The seismic design of the pneumatic system and redundancy described in item 3 assure that the ADS pneumatic system wili remain operable in conditions under which it is required. Although the check valves in question do have hard-seats, therc are at least two additional check valves upstream of the isolation check valve. The probability of the multiple failure of the check valves and the backup systems is low enough to preclude the necessity of any design modifications.

If you have any questions or comments in this regard, please contact my office.

b

)h 32 Very truly yours, W. A. Widner Vice President and General Manager Nuclear Generation RDB/ JAB /mb 8001290 M b. .

G C0fgia PO WCT Lk United States Nuclear Regulatory Commission Office of Inspection and Enforcement January 22, 1980 Page Two xc: Director of the Office of Inspection and Enforcement Director of the Division of Operating Reactors, Office of Nuclear Reactor Regulation .

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