IR 05000338/1991017

Informs That Two Issues Re EDG Design & Operating Practices Identified for Further Review in Eddfi Rept 50-338/91-17 & 50-339/91-17

ML20128G643
Person / Time
Site:	North Anna
Issue date:	02/02/1993
From:	Gibson A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
References
NUDOCS 9302160066
Download: ML20128G643 (3)

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Docket Nos. 50-338, 50-339 License Nos. NPF-4, NPF-7 Virginia Electric and Power Company ATIN: Mr. W. L. Stewart Senior Vice President - Nuclear 5000 Dominion Boulevard Glen Allen, VA 23060 Gentlemen:

SUBJECT: NORTH ANNA ELECTRICAL DISTRIBUTION SYSTEM FUNCTIONAL INSPECTION (EDSF1) ISSUES UNDER REVIEW: BYPASS OF EMERGENCY DIESEL GENERATOR (EDG) AIR START TIMER CIRCUIT AND EDG AUTOMATIC START SURVEILLANCE TEST ACCEPTANCE CRITERIA This is to inform you of our conclusions regarding two issues related to EDG design and operating practices which were identified for further NRC review in EDSFI Report No. 50-338,339/91-1 The first issue was related to your EDG design which provides for bypass of the air start timer circuit in the emergency mode which could result in exhausting all reserve starting air on a failed start attemp For the last 6 to 7 years the NRC has recommended an approach of not exhausting all starting air if the EDG does not start on the first or second attemp It is our understanding that the industry is generally in agreement with this thinking and has been implementing such an approach. Our evaluation has concluded that .

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your design may not provide sufficient time for operations to-react appropriately to an abnormal EDG unit condition. North Anna should consider conserving enough air in the air start receiver tank to allow a minimum of one engine start in the event that the EDG fails to start during the emergency-mode. It is not clear that you have adequately evaluated this design aspec We request you evaluate this design aspect in light of the EDSF1 Report and the current staff and industry practic The second issue was related to EDG automatic start test acceptance criteria  :

which would permit acceptance of an EDG start test when the voltage parameter had reached the acceptance band but was oscillating beyond the band in the observed time perio We can find no basis for accentance of an automatic EDG start test under this condition and we do not believe that the acceptance criteria in your procedure (2-PT-82-2A) mee! the intent of Technical Specification Surveillance requirrment 4.8.1.1.2 C. This criteria is inconsistent with IEEE 387, Standard Criteria for Diesel Generator Units-Applied as Stariby Power Supplics for Nuclear Power Generating Stations, and  ;

Regulatory Guide 1.108, Periodic Testing of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power P'lants. We request that you re-evaluate the acceptability of the above acceptance criteria, j 9302160066 930202 PDR ADOCK 05000338 G PDR

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te request that you address.these issues and provide to us within 60 days of receipt of this letter your conclusions -and anticip'atec' arrective actions where applicable. Should you have any questions.concei .ng this letter, please contact-us.

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Sincerely, e

g Albert F. Gibson,- Director Division of Reactor Safety cc w/o encl:

M. L. Bowling,-Jr., Manager Nuclear Licensing Virginia Electric & Power Company 5000 Dominion Boulevard Glen Allen, VA 23060- ,

- E. Kane, Station Manager North Anna Power Station- ,

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P. O. Box 402-Mineral, VA 23117-Executive Vice President Old Dominion-Electric Cooperative 4201 Dominion Boulevard Glen Allen, VA 23060

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Dr. W. T. Lough .

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Virginia Corporation Commission Division of Energy Regulation--

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Richmond, VA-' 23209 William C. Porter, J County Administrator Louisa County P. O. BoxLl60l '

iLouisa, VA' 23093-Michael W.-Maupin, Es '

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Hunton and Williams P. O. Box'1535 *

Richmond,iVA 23212-(cc w/o encl cont'd --See page~2)

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Virginia Electric and-Power ~3 0 ~ A b22 Compan ;

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Patrick A. O' Hare Office of. th_e Attorney General

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Supreme Court Building 101 North 8th Street-Richmond, VA 23219 C. M. G. Buttery, M.D., M. State Health Commissioner Office of the Commissioner Virginia Department of Health P. O. Box 2448 Richmond, VA 23219 j-bec w/o enc 1:

P. Fredrickson, RII-L. Engle, NRR Document Control Desk NRC-Resident Inspector U.S. Nuclear Regulatory Commission Route 2, Boy '

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