ML091871307
| ML091871307 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 07/06/2009 |
| From: | Price J Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 09-328, GL-08-001 | |
| Download: ML091871307 (7) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 July 6, 2009 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 Serial No:
NLOS/GDM Docket No.:
License No.:
09-328 R2 50-280 DPR-32 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
SURRY POWER STATION UNIT 1 SUPPLEMENTAL RESPONSE TO NRC GENERIC LETTER 2008-01, MANAGING GAS ACCUMULATION IN EMERGENCY CORE COOLING, DECAY HEAT REMOVAL, AND CONTAINMENT SPRAY SYSTEMS The Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01 on January 11, 2008, requesting each licensee to evaluate the licensing basis, design, testing, and corrective action programs for the Emergency Core Cooling Systems (ECCS), Residual Heat Removal (RHR) System, and Containment Spray (CS) System to ensure that gas accumulation is maintained less than the amount that could challenge the operability of those systems and to ensure that appropriate action is taken when conditions adverse to quality are identified.
In an October 14, 2008 letter (Serial No. 08-0013B), Dominion provided the information requested in GL 2008-01 for Surry and North Anna Power Stations.
However, as identified in our May 8, 2008 letter (Serial No. 08-0013A), Dominion provided an alternate schedule for the completion of the walkdowns and evaluations of the inaccessible portions of the ECCS and Spray Systems inside containment. Specifically, Dominion committed to provide this information by July 15, 2009 for Surry Unit 1. The NRC approved the completion schedule in a letter dated July 23, 2008. The attachment to this letter provides the results of the walkdown and evaluations of the inaccessible portion of the ECCS inside containment for Surry Unit 1.
In summary, Dominion has completed the walkdowns and evaluations of the previously inaccessible portions of the applicable systems at Surry Power Station Unit 1 that perform the functions described in GL 2008-01 and has concluded that these systems are operable. Furthermore, the original conclusions documented in Dominion's October 14,2008 response remain valid: 1) the ECCS, RHR and Containment Spray systems at Surry Power Station are in compliance with their TS definitions of operability, i.e.,
capable of performing their intended safety functions, and 2) Surry Power Station is in compliance with 10 CFR 50, Appendix B, Criterion III, V, XI, XVI, and XVII, with respect to the concerns outlined in GL 2008-01 regarding gas accumulation in the applicable systems.
Serial No.09-328 Docket No. 50-280 Page 2 of 3 Please contact Mr. Gary D. Miller at (804) 273-2771 if you have any questions or require additional information.
Sincerely, n Price resident - Nuclear Engineering Commitments made in this letter: None.
Attachment:
Supplemental Response to GL 2008-01, Surry Power Station Unit 1 COMMONWEALTH OF VIRGINIA
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COUNTY OF HENRICO
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The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by J. Alan Price, 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 (P+h day of My Commission Expires:
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U. S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, S.W., Suite 23T85 Atlanta, GA 30303-8931 NRC Senior Resident Inspector Surry Power Station Mr. J. F. Stang, Jr.
NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, MD 20852-2738 Ms. D. N. Wright NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 H4A 11555 Rockville Pike Rockville, MD 20852-2738 Ms. K. R. Cotton NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 16 E15 11555 Rockville Pike Rockville, MD 20852-2738 Serial No.09-328 Docket No. 50-280 Page 3 of 3
ATTACHMENT SUPPLEMENTAL RESPONSE TO GL 2008-01 SURRY POWER STATION UNIT 1 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
Serial No.09-328 Docket No. 50-280
Serial No.09-328 Docket No. 50-280 Attachment Supplemental Response to NRC Generic Letter 2008-01 Surry Power Station Unit 1 This attachment provides Dominion's supplemental response to Generic Letter (GL) 2008-01 for actions that were deferred until the next refueling outage for Surry Unit 1 as requested in a May 8, 2008 letter (Serial No. 08-0013A) and approved by the NRC in a July 23, 2008 letter.
This supplemental response provides the results of the design evaluation reviews conducted during the recent Unit 1 refueling outage associated with walkdowns of previously inaccessible systems.
A. EVALUATION RESULTS
- 1. Design Basis Documents No changes to the licensing or design bases have been identified as a result of the confirmatory inspections and walkdowns performed during the Surry Unit 1 spring refueling outage.
- 2. Confirmatory Walkdowns a) The Low Head Safety Injection (LHSI) pump discharge piping to the Reactor Coolant System (RCS) cold leg piping inside containment was laser scanned, and detailed isometrics were prepared.
A slope report was developed to identify high points in the piping, and each identified high point irregularity of greater than one degree was evaluated for potential gas accumulation.
The evaluation determined that the irregular high points did not exceed previously determined acceptance criteria developed for the LHSI pump discharge piping.
b) Full flow testing and system flow sweeping was performed in accordance with existing station procedures to provide dynamic venting of the system high points both outside and inside containment for each Emergency Core Cooling System (ECCS) piping train.
Static venting was performed at the system piping high points outside of containment in accordance with existing station procedures for each ECCS subsystem piping train upon return to service.
The vented system local high points were previously confirmed to be located correctly.
Ultrasonic testing (UT) was then utilized to confirm the effectiveness of static venting procedures.
- 3. Vent Valves The confirmatory inspection identified four (4) new high point vent valve locations in the LHSI discharge piping to the RCS cold leg piping that would aid operators in more efficiently venting the system inside containment following testing. Vent valves were installed to allow the LHSI discharge piping to the RCS cold leg Page 1 of 3
Serial No.09-328 Docket No. 50-280 Attachment piping to be drained and refilled following testing without the use of dynamic venting.
- 4. Procedures Procedure revisions were completed to incorporate the new vent valves into the station procedure for returning the LHSI discharge piping to the RGS cold legs to service following leak testing of the RGS pressure isolation valves.
In addition, a new administrative procedure was developed to perform confirmatory inspections of unvented high points in the LHSI system.
This procedure will be used to monitor and trend the performance of EGGS systems by providing guidance on gas accumulation indicators and ways to detect and mitigate the accumulation of gas.
- 5. Inspections UT inspections were conducted at nineteen (19) vented high points in the accessible sections of the suction piping to the EGGS pumps and on the LHSI discharge piping to confirm the effectiveness of venting procedures.
UT was performed at each location prior to venting activities and was then re-performed to quantify any possible as-left volume.
The inspections revealed only small volumes of gas at four locations in piping areas not impacted by the dynamic venting procedures.
These high points were successfully vented using the existing vent valves to less than 0.030 ft3 of total system gas volume.
B. DESCRIPTION OF NECESSARY ADDITIONAL CORRECTIVE ACTIONS
- 1. Additional Corrective Actions As noted above, four additional vents valves were installed to allow the LHSI discharge piping to the RGS cold leg to be drained and refilled following testing, and associated procedure revisions were implemented to use the new vent valves.
A new administrative procedure was developed to perform confirmatory inspections of unvented high points in the LHSI system. The procedure will also be used to monitor and trend the performance of EGGS systems by providing guidance on gas accumulation indicators and ways to detect and mitigate the accumulation of gas.
- 2. Corrective Action Updates No additional corrective actions are anticipated beyond those specified in Item B.1 above.
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Serial No.09-328 Docket No. 50-280 Attachment CONCLUSION Dominion has completed the walkdowns and evaluations of the previously inaccessible portions of the applicable systems at Surry Power Station Unit 1 that perform the functions described in GL 2008-01 and has concluded that these systems are operable.
Furthermore, the original conclusions documented in Dominion's October 14, 2008 response remain valid: 1) the ECCS, RHR and Containment Spray systems at Surry Power Station are in compliance with their TS definitions of operability, i.e., capable of performing their intended safety functions, and 2) Surry Power Station is in compliance with 10 CFR 50, Appendix B, Criterion III, V, XI, XVI, and XVII, with respect to the concerns outlined in GL 2008-01 regarding gas accumulation in the applicable systems.
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