ML081020691
| ML081020691 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 04/11/2008 |
| From: | Gerald Bichof Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 08-0152 | |
| Download: ML081020691 (6) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 April 11, 2008 10 CFR 50.90 U. S. Nuclear Regulatory Commission Serial No. 08-0152 ATTN: Document Control Desk NLOS/GDM R2 Washington, D. C. 20555 Docket Nos. 50-280 50-281 License Nos. DPR-32 DPR-37 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 PROPOSED LICENSE AMENDMENT REQUEST INCREASED MAXIMUM SERVICE WATER TEMPERATURE LIMIT REQUEST FOR ADDITIONAL INFORMATION (RAJ)
By letter dated June 25, 2007 (Serial No. 07-0401), Virginia Electric and Power Company (Dominion) requested amendments, in the form of changes to the Technical Specifications (TS) to Facility Operating License Numbers DPR-32 and DPR-37 for Surry Power Station Units 1 and 2, respectively. The proposed change increases the maximum service water temperature limit from 95°F to 100°F. The proposed change is necessary to proactively address observed increases in service water intake temperatures during the past two summers, which have approached the existing TS limit.
In a letter dated March 13, 2008, the NRC staff requested additional information to facilitate their review of the proposed license amendment request. The NRC questions and Dominion's response are provided in the attachment.
The additional information provided herein does not affect the significant hazards consideration determination or environmental assessment that was previously provided in support of the proposed license amendment request.
Serial No. 08-0152 Docket Nos. 50-280/281 Page 2 of 3 If you have any questions or require additional information, please contact Mr. Gary D. Miller at (804) 273-2771.
Sincerely, Gt:!~~g15 Vice President - Nuclear Engineering Commitments made in this letter: None.
Attachment:
Response to NRC Request for Additional Information COMMONWEALTH OF VIRGINIA )
)
COUNTY OF HENRICO )
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 this I / 'h, day of I2;>>uL ,2008.
My Commission Expires: ~Mt; 34 dt;08.
MAR8ARET '0 IENNITT NotCIfY PubIIc.3 5"'1 30 ~
lk~ & .~'JLaZU Commonweottl\ of VIIg1n1o My Commllllon ExpIret Aug 31. 200t Notary Public
Serial No. 08-0152 Docket Nos. 50-280/281 Page 3 of 3 cc: U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 23T85 Atlanta, Georgia 30303 NRC Senior Resident Inspector Surry Power Station State Health Commissioner Virginia Department of Health James Madison Building - t h Floor 109 Governor Street Room 730 Richmond, Virginia 23219 Mr. S. P. Lingam NRC Project Manager - Surry and North Anna U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, Maryland 20852
Serial No. 08-0152 Docket Nos. 50-280 and 281 ATTACHMENT LICENSE AMENDMENT REQUEST TO INCREASE THE MAXIMUM SERVICE WATER TEMPERATURE LIMIT RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION Virginia Electric and Power Company (Dominion)
Surry Power Station Units 1 and 2
Serial No. 08-0152 Docket Nos. 50-280 and 281 Attachment Page 1 of 2 Response to NRC Request for Additional Information Increase in Maximum Service Water Temperature Limit Surry Power Station Units 1 and 2 By letter dated June 25, 2007 (Serial No. 07-0401), Virginia Electric and Power Company (Dominion) requested amendments, in the form of changes to the Technical Specifications (TS) to Facility Operating License Numbers DPR-32 and DPR-37 for Surry Power Station Units 1 and 2, respectively. The proposed change increases the maximum service water temperature limit from 95°F to 100°F. The proposed change is necessary to proactively address observed increases in service water intake temperatures during the past two summers, which have approached the existing TS limit. In a letter dated March 13, 2008, the NRC staff requested additional information to facilitate their review of the proposed license amendment request. Dominion's response to the NRC questions is provided below.
NRC Question No.1 The licensee stated in the license amendment request (Reference 1) and again in the response to RAI 1.a (Reference 2) that the component cooling water heat exchanger (CCHX) outlet temperature was constrained to 120°F and that this is the same temperature that was used in the evaluations with a maximum service water (SW) temperature of 95°F. The NRC staff is unable to verify that 120°F was used as the CCHX outlet temperature for cooling component cooling water system safety-related loads. Please provide the technical basis for the 120°F CCHX outlet temperature being acceptable for all design and licensing basis conditions.
Dominion Response A special test was performed on a CCHX in February 2007 to determine heat exchanger fouling and tubeside differential pressure at various SW flows. This information was used to calculate operability curves for different levels of tube plugging and SW temperatures (up to 101°F).
The existing CCHX calculations (pre-2007) used conservative fouling levels derived from testing in the late 1980's. Since then, the CCHXs have been replaced and a chemical treatment system added to limit fouling on the SW side of the heat exchangers.
Data from the 2007 testing was also used to analyze the required cooldown scenarios (e.g., dual unit shutdown following a LOOP, single unit shutdown with two trains operating, and single unit shutdown with one train operating). The calculations demonstrated that the CCHXs would be capable of meeting cooldown requirements with inlet SW temperature of 101°F for these conditions. For these calculations, the
Serial No. 08-0152 Docket Nos. 50-280 and 281 Attachment Page 2 of2 CCHX outlet temperature was limited to 120°F, consistent with the original Westinghouse functional requirements for balance of plant interface systems.
NRC Question No.2 Updated Final Safety Analysis Report (UFSAR) Section 9.4.1.1.1, "Component Cooling Water System," (Reference 3) states in part: "Each heat exchanger is also capable of removing half of the heat load occurring four hours after a shutdown of one unit under conditions representing the maximum allowable cooldown rate." Is this still accurate with an SWtemperature of 1000F? Please provide the technical basis.
Dominion Response As indicated in the response to Question 1 above, calculations were performed to demonstrate that the CCHXs would be capable of meeting cooldown requirements with an inlet SW temperature of 101°F for the required cooldown scenarios. These calculations demonstrated that the cooling capability of a single CCHX exceeded one half of the projected heat load occurring four hours after a shutdown of one unit under conditions representing the maximum allowable cooldown rate.
NRC Question No.3 The response to RAI 4 (Reference 2) states that ".... for a maximum SW temperature of 100°F, the diesel jacket outlet water temperature will not exceed 200°F. . . ." with no explanation of how this temperature was determined. Please provide the technical basis for the diesel jacket outlet water temperature not exceeding 200°F.
Dominion Response The subject of minimum cooling water supply flow for the jacket cooling system was previously discussed with a diesel field technical representative and documented in a plant calculation. The representative stated that the jacket cooling system (i.e., heat exchanger and pump) is sized to limit the jacket cooling water temperature rise to 1OO°F above the external cooling medium (i.e., SW) temperature. Thus, for a 101°F SW inlet temperature, the jacket cooling water outlet temperature would be approximately 201°F.
Testing of the jacket cooling system was performed, and the results indicated that the available SW cooling flow was greater than that required to limit the jacket cooling water temperature rise to 100°F.
During operation, the jacket cooling water temperature is procedurally controlled within a range of 165°F-185°F by a thermostat in the diesel cooling loop and by the operator using a manual valve on the SW cooling loop. The jacket cooling water high temperature switches are set at 205°F to maintain the maximum operating temperature of the jacket water below the 210°F limit listed in the vendor technical manual.