ML071970183

Proposed Technical Specification Change, Temporary 45-Day and 14-Day Allowed Outage Times to Replace Main Control Room and Emergency Switchgear Room Air Conditioning System Chilled Water Piping Additional Information Backup Cooling..

ML071970183
Person / Time
Site:	Surry
Issue date:	07/13/2007
From:	Gerald Bichof Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
07-0109C
Download: ML071970183 (3)

Text

VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 July 13, 2007 U.S. Nuclear Regulatory Commission Serial No. 07-0 109C Attention: Document Control Desk SPS-LICICGL RO" Washington, D.C. 20555 Docket Nos. 50-280 50-281 License Nos. DPR-32 DPR-37 TIMES REPLACE AIR CONDITIONING SYSTEM CHILLED WATER PIPING ADDITIONAL INFORMATION REGARDING BACKUP COOLING SUPPLY FLOW By letter dated April 5, 2007 (Serial No. 07-0109A), Virginia Electric and Power Company (Dominion) responded to an NRC request for additional information (RAI).

The RAI response was related to an amendment request for Surry Power Station Units 1 and 2 that was transmitted to the NRC on February 26, 2007 (Serial No. 07-0109). The amendment request will permit the use of temporary 45-day and 14-day allowed outage times to facilitate replacement of Main Control Room (MCR) and Emergency Switchgear Room (ESGR) Air Conditioning System chilled water piping.

In the discussion of the Capability of the Backup Cooling Supply, the April 5, 2007 transmittal indicated that performance of a calculation was planned to verify adequate chilled water flow from the backup cooling supply from the Mechanical Equipment Room # I (MER-1) chillers. The transmittal also indicated that it was expected that, with the backup cooling supply in operation, the temperatures would be close to those of normal operation. The April 5, 2007 transmittal identified a commitment to provide the calculation results to the NRC by July 16, 2007. The purpose of this letter is to provide the results of the calculation.

The calculation has been completed to verify the capability of the MER-1 chillers 1-VS-E-3A and 1-VS-E-3B to provide chilled water to the MCR and ESGR air handling units through the existing piping to chilled water loop A and through the valves and hose connections being added to supply chilled water loop C. The calculation shows that one MER-1 chiller can supply approximately 190 gpm to chilled water loop C, which bounds the chilled water loop A configuration. Normal flow to the loop is in the range of

Serial No. 07-0109C Docket Nos. 50-280, 50-281 Page 2 of 3 200 - 230 gpm. Thus, the calculated chilled water flow from an MER-1 chiller is approximately 15% less than the normal flow. With approximately 85% of normal chilled water flow, the MCR and ESGR space temperatures are projected to rise several degrees above normal, but remain well within the design limits for the safety-related equipment housed in the MCR and the ESGR.

If you have any questions or require additional information, please contact Mr. Gary D. Miller at (804) 273-2771.

Very truly yours, Gerald T. Bischof w Vice President - Nuclear Engineering Commitments made in this letter: None.

COMMONWEALTH OF VIRGINIA 1 1

COUNTY OF HENRICO 1 The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Gerald T. Bischof, who is Vice President - Nuclear Engineering, of Virginia Electric and Power Company. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me the /3T day of a k,!! ,2007 My Commission Expires: ,. /I~A 3 /; $!I

Serial No. 07-0109C Docket Nos. 50-280, 50-281 Page 3 of 3 cc: U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 23 T85 Atlanta, Georgia 30303 Mr. E. Riggs NRC Senior Resident Inspector Surry Power Station State Health Commissioner Virginia Department of Health James Madison Building - 7thFloor 109 Governor Street Room 730 Richmond, Virginia 23219 Mr. S. P. Lingam NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 8G9A Rockville, Maryland 20852 Mr. R. A. Jervey NRC Project Manager - North Anna U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 8G9A Rockville, Maryland 20852