ML040920128
| ML040920128 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 03/29/2004 |
| From: | Gasser J Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-96-006, NL-04-0452 | |
| Download: ML040920128 (3) | |
Text
JeffreyT. Gasser Vice President Southern Nuclear Operating Company. Inc.
40 Inverness Center Parkway Post Office Box 1295 Birmingham. Alabama 35201 Tel 205.992.7721 Fax 205 992.0403 March 29, 2004 SOUTHERN A COMPANY Energy to Serve Your World' NL-04-0452 Docket Nos.:
50-424 50-425 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant - Units I and 2 Additional Information Concerning GL 96-06, Assurance of Equipment Operability and Containment Integrity During Design Basis Accident Conditions Ladies and Gentlemen:
By letter NL-03-0620 dated March 21, 2003, Southern Nuclear Operating Company (SNC) provided additional information concerning GL 96-06, Assurance of Equipment Operability and Containment Integrity During Design Basis Accident Conditions.
Additional information was requested on February 9, 2004, by Mr. Steve Bloom of the NRC. The requested information is provided in the attachment to this letter.
This letter contains no NRC commitments. If you have any questions, please advise.
Sincerely, T.Gasser JTG/KGL/daj
Enclosures:
Additional Information Concerning GL 96-06 cc:
Southern Nuclear Operating Company Mr. J. B. Beasley, Jr., Executive Vice President Mr. W. F. Kitchens, General Manager - Plant Vogtle Mr. M. Sheibani, Engineering Supervisor - Plant Vogtle RType: CVC7000 U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. C. Gratton, NRR Project Manager - Vogtle Mr. J. Zeiler, Senior Resident Inspector - Vogtle
Attachment to NL-04-0452 Vogtle Electric Generating Plant - Units I and 2 Additional Information Concerning GL 96-06 RAI Additional information was requested on February 9, 2004, by Mr. Steve Bloom of the NRC. The following request was made to complete the GL 96-06 review for Vogtle Electric Generating Plant (VEGP) response (Ref. 1) to Generic Letter (GL) 96-06 Request for Additional Information. Response to this question is provided as follows.
NRC Request The licensee's response to Q12 in the attachment to their letter dated December 2, 2002, indicates that the check valves in the nuclear service cooling water supply lines to the containment cooling units are disassembledfor cleaning and inspection on a 15-year frequency. These check valves are credited in the licensee's analysis to prevent backilow and drain down of the containment air coolers, thereby minimizing the consequences of ivaterhamnmer. The licensee's response does not provide assurance that these check valves wsill remain leak-tight (consistent with accident analysis assumptions) over the life of the plant. A 15-year frequency has not been justifled by any means, and valve disassembly and cleaning does not provide any assurance that the valves are leak-tight. Further, it appears that the licensee's surveillance of these valves does not satisfy in-service testing requirements for check valves that are creditedfor preventing back7lowiv The licensee is requested to provide a complete response to this question such that assurance is provided that these valves will remain leak-tight in accordance with accident analysis assumptions over the life of the plant.
SNC Response The NSCW containment cooler supply check valves are credited in the analyses to prevent backflow and drain down of the containment coolers. The analyses do not assume these check valves will be leak-tight over the life of the plant, instead they assume there will be minimal draining through the supply lines. The volume of water that could leak-by the containment cooler supply check valves is insignificant compared to the drain down volume from the containment cooler outlet lines.
The type and frequency of inspections required for the containment cooler check valves are based on previous inspections and maintenance history. The NSCW pump discharge check valves are in the in-service testing plan. They are tested quarterly to assure both opening and closing. The containment cooler check valves are also in the in-service testing plan. They are tested quarterly to assure opening only.
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Attachment to NL-04-0452 Vogtle Electric Generating Plant - Units I and 2 Additional Information Concerning GL 96-06 RAI Since the water-hammer analysis assumes these containment cooler check valves close, the in-service testing plan will be revised to require these valves be tested to assure closure. Testing of these containment cooler check valves to assure closure will provide assurance that the assumptions in the water-hammer analyses remain valid.
Assurance that the containment cooler check valves are leak-tight is not required since this is not an assumption of the analyses. Therefore, the inspection and testing requirements, including the in-service testing plan, for these check valves and the NSCW pump discharge check valves will provide reasonable assurance that drain down of the NSCW containment cooler supply lines as credited in the accident analyses will not occur.
References
- 1. SNC letter to NRC, LCV-0897-D, Request for Additional Information Concerning GL 96-06, October 28, 1998.
- 2.
SNC letter to NRC, LCV-0897-H, Request for Additional Information Concerning GL 96-06, December 2, 2002.
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