ML18153B222
| ML18153B222 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 02/06/1995 |
| From: | Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 94-175B, NUDOCS 9502090262 | |
| Download: ML18153B222 (2) | |
Text
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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 February 6, 1995 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 Serial No.
NL&P/CGL Docket Nos.
License Nos.
WITHDRAWAL OF APPENDIX R EXEMPTION REQUEST 27 -
UNIT 2 ESGR MANUAL HALON SYSTEM 94-1758 R2" 50-280 50-281 DPR-32 DPR-37 By an April 20, 1994 letter (Serial No.94-175), we transmitted 10CFR50 Appendix R Exemption Request 27 addressing the manually actuated halon system in the Surry Unit 2 Emergency Switchgear Room (ESGR);
Subsequently, we provided supplemental information in an October 27, 1994 letter (Serial No. 94-175A), and a meeting was held with the NRC on November 4, 1994 to discuss the supplemental information.
As a result of the meeting with the NRC, we have further developed and assessed the 1 OCFR50 Appendix R scenario for a Surry Unit 2 ESGR fire in order to evaluate our ability to maintain adequate Main Control Room (MCR)/Unit 1 ESGR cooling.
Specifically, we have investigated the consequences of a three-hour fire (with no suppression) in the Unit 2 ESGR. The fire is assumed to interrupt the power supply to both the Mechanical Equipment Room (MER) 3 and MER 5 chillers resulting in a loss of ventilation/cooling in the MCR/ESGR envelope. Based on these assumptions, a preliminary assessment shows that at the end of three hours the MCR/ESGR envelope will remain at an acceptable temperature.
Furthermore, after three hours, with supplemental cooling provided by one of two MER 1 chillers, an acceptable MCR/ESGR temperature can be maintained for the remainder of the 72-hour Appendix R event. Based on this assessment, the consequences of a three-hour fire (with no suppression) in the Unit 2 ESGR can be shown to be acceptable in that adequate MCR/ESGR cooling could be provided.
In view of these determinations, we are investigating actions required to ensure supplemental cooling by an MER 1 chiller in the event of a Unit 2 ESGR fire. We are also evaluating other options for complying with 1 OCFR50 Appendix R for the Unit 2 ESGR fire scenario.
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9502090262 950206
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Therefore,.._,.,e have decided to withdraw Exemption Request 27, which was previously transmitted for NRC review and approval. The hourly fire watch, which has been put in place in the Unit 2 ESGR, will remain in place until we have completed our evaluation and implemented those actions required to ensure Appendix R compliance. Related to the Unit 2 ESGR three-hour fire scenario, the Surry Appendix R bases (including the Surry Appendix R Report) will be revised, as appropriate.
If you have questions or require further information regarding our withdrawal of Exemption Request 27, please contact us.
Very truly yours, James P. O'Hanlon Senior Vice President - Nuclear cc:
U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, N. W.
Suite 2900 Atlanta, Georgia 30323 Mr. M. W. Branch NRC Senior Resident Inspector Surry Power Station