NL-07-0121, Examination and Mitigation of Alloy 82/182 Pressurizer Butt Welds

Examination and Mitigation of Alloy 82/182 Pressurizer Butt Welds

ML070310331
Person / Time
Site:	Vogtle, Farley
Issue date:	01/30/2007
From:	Gasser J Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-07-0121
Download: ML070310331 (21)

Text

Jeffrey T. Gasser Southern Nuclear Executive Vice President Operating Company, Inc.

and Chief Nuclear Officer 40 lnverness Center Parkway Post Office Box 1295 Birmingham, Alabama 35201 Tel 205.992.7721 Fax 205.992.6165 SOUTHERN COMPANY A

January 30, 2007 Energy to Serve YourWorld' Docket Nos.: 50-348 50-424 50-364 50-425 U. S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, D. C. 20555-0001 Joseph M. Farley Nuclear Plant Vogtle Electric Generating Plant Examination and Mitigation of Alloy 821182 Pressurizer Butt Welds Ladies and Gentlemen:

In October 2006, while performing examinations of its pressurizer Alloy 821182 butt welds in accordance with MRP-139, a PWR licensee discovered several circumferential indications in its pressurizer surge, safety, and relief nozzles. Because of the potential importance of this issue, Southern Nuclear Operating Company (SNC) hereby notifies the NRC of Joseph M. Farley Nuclear Plant's (FNP) and Vogtle Electric Generating Plant's (VEGP) actions taken or committing to for examination and mitigating activities for Alloy 821182 butt welds on pressurizer spray, surge, safety, and relief nozzles.

Mitigation activities and post-mitigation examinations at FNP-1 and VEGP-2 will be completed prior to December 3 1, 2007. Examination activities at FNP-2 will be completed prior to December 31,2007. Mitigation activities and post-mitigation examinations at VEGP-1 will be completed after December 3 1,2007. Please refer to the enclosures for details on the actions planned or taken for each plant.

SNC will stay apprised of industry actions and recommendations provided in NEI letter, dated January 26, 2007, fiom Marvin S. Fertel to Luis A. Reyes, "Industry Actions Associated with Potential Generic Implications of Wolf Creek Inspection Findings." For VEGP-1, SNC will accelerate the planned mitigation outage, currently scheduled for 2008, if analytical results do not demonstrate that current schedules are adequate.

This letter contains NRC commitments. The NRC will be informed if FNP or VEGP deviates fiom any of the commitments described in this letter.

U. S. Nuclear Regulatory Commission NL-07-0 121 Page 2 Our staff is available to meet with the NRC to discuss the information in this letter.

If you have any questions, please advise.

Sincerely,

~effre~'?. Gasser JTGILPWdaj

Enclosures:

1. Examination and Mitigation Information for FNP-1 & FNP-2

2. Examination and Mitigation Information for VEGP-1 & VEGP-2

3. List of Regulatory Commitments cc: Southern Nuclear Ouerating Comvany Mr. J. R. Johnson, Vice President - Farley Mr. T. E. Tynan, Vice President - Vogtle RType: CFA04.054; CVC7000; LC# 14531 U. S. Nuclear Remlatorv Commission Dr. W. D. Travers, Regional Administrator Ms. K. R. Cotton, NRR Project Manager - Farley Mr. B. K. Singal, NRR Project Manager - Vogtle Mr. C. A. Patterson, Senior Resident Inspector - Farley Mr. G. J. McCoy, Senior Resident Inspector - Vogtle Nuclear Enerw Institute Mr. M. S. Fertel Mr. J. H. Riley

Enclosure 1 Joseph M. Farley Nuclear Plant Examination and Mitigation Information for FNP-I & FNP-2

Enclosure I Joseph M. Farley Nuclear Plant Examination and Mitigation Information for FNP-1 & FNP-2 FNP- 1 Examination and mitigation of pressurizer Alloy 821182 butt welds at Farley Unit 1 have not been completed, but SNC will complete all MRP-139 examination and mitigation activities on these locations during the 1R21 outage which starts in September 2007.

Details concerning Farley Unit 1 examination and mitigation activities are provided in the enclosed table. Additional details can be found in proposed alternative ISI-GEN-ALT-06-03, which was submitted to the NRC by SNC letter NL-06-2768, dated January 3, 2007. Future examinations of pressurizer weld overlays at Farley Unit 1 will be performed in accordance with industry guidance (MRP-139) and NL-06-2768. The results of future inspections or mitigations of pressurizer Alloy 821182 butt weld locations will be reported to the NRC within 60 days of startup fi-om the outage during which they were performed.

In addition to the examination and mitigation actions described above, the process below for monitoring primary system leakage will be used at FNP-1 until all Alloy 821182 butt weld locations on the pressurizer have been mitigated.

1. Monitoring Capabilities and Methods

a. Reactor Coolant System (RCS) Leak Rate Surveillance

.i.. Procedure FNP-1-STP-9.0 performed every 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />

11. Leak measurement is normally performed over 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> period.

iii. Not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after establishment of steady state operation.

b. Online RCS Leak Rate Computer Point

i. Provides online trending ability ii. Trend is viewed during performance of FNP-1-STP-9.0.

c. Containment Radiation Monitors

i. R-1 1 & R-12 containment radiation monitors provide alarm

.. function.

11. Trending is available on plant computer.

iii. Recorded on FNP-1 -STP-9.0 for trending.

d. Containment Cooler Condensate Pot Level Indication and Alarms

i. Indication and alarm function for moisture in containment.

e. Containment Sump Level Indication and Alarms

i. Indication of unexpected leakage in containment.

ii. Recorded on FNP-1-STP-9.0 for trending.

Enclosure 1 Joseph M. Farley Nuclear Plant Examination and Mitigation Information for FNP-1 & FNP-2

2. Action Levels and Responses

a. If any abnormal leakage is detected, then perform an inspection and evaluation to identify and document the leakage path(s), any corrective actions, and the affects of the leakage (Procedure FIW-1-AOP-1 .O, attachments 2 through 5). Generally, 2 0.15 gpm would be considered abnormal.

b. If unidentified leakage is determined to be > 0.25 gpm, then perform an additional FNP- 1-STP-9.0 to confirm the result. If the result is confirmed to be > 0.25 gpm, then request chemistry to collect a manual sample for Iron analysis.

FNP is evaluating the Pressurized Water Reactors Owner Group (PWROG) program (WCAP-16465 & WCAP-16423) regarding standardized RCS leakage monitoring, and anticipates implementation during 2007.

SNC will provide updates to the NRC as necessary regarding any changes to the FNP leakage monitoring program by March 31,2007.

nnnn d ~ m w w w w b

Enclosure 1 Joseph M. Farley Nuclear Plant Examination and Mitigation Information for FNP-1 & FNP-2 Two pressurizer Alloy 821182 butt welds at FNP-2 have been examined per a Performance Demonstration Initiative (PDQ qualified ultrasonic testing (UT) method in accordance with MRP-139. Details concerning the locations examined and the results of completed examinations are provided in the enclosed tables. Future examinations of pressurizer butt welds at FNP-2 will be performed in accordance with industry guidance (MRP-139).

Examination of the four remaining pressurizer Alloy 821182 butt welds at FNP-2 has not been completed, but SNC will complete all MRP-139 required examinations on these locations during the 2R18 outage in April 2007. Mitigation by weld overlay of all six FNP-2 pressurizer nozzles is planned for the 2R20 outage in spring 2010. Details concerning FNP-2 examination and mitigation activities are provided in the enclosed table.

In addition to the examination and mitigation actions described above, the process below for monitoring primary system leakage will be used at FNP-2 until all Alloy 821182 butt weld locations on the pressurizer have been examined per a PDI qualified UT method.

1. Monitoring Capabilities and Methods

a. RCS Leak Rate Surveillance

i. Procedure FNP-2-STP-9.0 performed every 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> ii. Leak measurement is normally performed over 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> period.

iii. Not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after establishment of steady state operation.

b. Online RCS Leak Rate Computer Point

i. Provides online trending ability ii. Trend is viewed during performance of FNP-2-STP-9.0.

c. Containment Radiation Monitors

i. R-1 1 & R-12 containment radiation monitors provide alarm function.

ii. Trending is available on plant computer.

iii. Recorded on FNP-2-STP-9.0 for trending.

d. Containment Cooler Condensate Pot Level Indication and Alarms

i. Indication and alarm function for moisture in containment.

e. Containment Sump Level Indication and Alarms

i. Indication of unexpected leakage in containment.

ii. Recorded on FNP-2-STP-9.0 for trending.

Enclosure 1 Joseph M. Farley Nuclear Plant Examination and Mitigation Information for FNP-1 & FNP-2

2. Action Levels and Responses

a. If any abnormal leakage is detected, then perform an inspection and evaluation to identify and document the leakage path(s), any corrective actions, and the affects of the leakage (Procedure FNP-2-AOP-1.O, attachments 2 through 5). Generally, ? 0.15 gpm would be considered abnormal.

a. If unidentified leakage is determined to be > 0.25 gpm, then perform an additional FNP- 2-STP-9.0 to confirm the result. If the result is c o n f i e d to be > 0.25 gpm, then request chemistry to collect a manual sample for Iron analysis.

FNP is evaluating the PWROG program (WCAP-16465 & WCAP- 16423) regarding standardized RCS leakage monitoring, and anticipates implementation during 2007.

SNC will provide updates to the NRC as necessary regarding any changes to the FNP leakage monitoring program by March 31,2007.

FNP-2 Inspection and Mitigation Information Table Examination and Mitigation Summary for Alloy 821182 Pressurizer Butt Welds Mitigation Nozzle MRP- 139 Volumetric Completed or to be Examination Requirement Met or Completed Comments to be Met Susceptible Function I Designation Material Outage Start Date Outage Designation Description Designation ( M m )

spray (1) (2) (3) & (4) PDI examination acceptable.

APR 1-4205-49DM Alloy 82 I 182 2R17 1012005 2R20 (Spring 2010) Mitigate by weld overlay.

Surge (1) (2) (3)

APR 1-4500-7DM Mitigate by weld overlay Alloy 82 I 182 2R18 0412007 2R20 (Spring 20 10)

Safety 1 (1) (2) (4) Mitigate by weld overlay APR 1-4501-1DM Alloy 82 I 182 2R18 0412007 2R20 (Spring 20 10)

Safety 2 (1) (2) (4) Mitigate by weld overlay APR 1-4502- 1DM Alloy 82 1 182 2R18 2R20 (Spring 20 10)

Safety 3 (1) (2) (4) PDI examination acceptable.

A P R -4503-1

~ DM Alloi 82 / 1.82 2R17 1012005 2R20 (Spring 20 10) Mitigate by weld overlay.

Relief (1) (2) (4) Mitigate by weld overlay APR 1-4504- 1DM Alloy 82 I 182 2R18 0412007 2R20 (Spring 20 10)

(I) Nozzle-to-safe end butter (2) Nozzle-to-safe end weld (3) Thermal sleeve-to-safe end weld (4) Liner weld-to-safe end butter

Enclosure 2 Vogtle Electric Generating Plant Examination and Mitigation Information for VEGP-1 & VEGP-2

Enclosure 2 Vogtle Electric Generating Plant Examination and Mitigation Information for VEGP-1 & VEGP-2 The pressurizer spray nozzle Alloy 82 butt weld at VEGP-1 has been examined per a PDI qualified UT method in accordance with MRP-139. Details concerning the examination are provided in the enclosed table.

Examination of the five remaining pressurizer Alloy 82 butt welds and mitigation activities at VEGP-1 will be completed after December 3 1,2007. Details concerning VEGP-1 examination and mitigation activities are provided in the enclosed table. Future examinations of pressurizer weld overlays at VEGP-1 will be performed in accordance with industry guidance (MRP-139) and an approved NRC alternative. The results of future inspections or mitigations of pressurizer Alloy 82 butt weld locations will be reported to the NRC within 60 days of startup from the outage during which they were performed.

Mitigation by weld overlay of all six VEGP-1 pressurizer nozzles is planned for the 1R14 outage in March 2008. The primary reason that VEGP-1 is not being completed before December 3 1,2007 is because the outage cycle for this unit had only one planned outage between the issuance of MRP-139 in July 2005 and the December 3 1,2007 implementation schedule for pressurizer butt welds. SNC considered it essential to perform a walkdown of the pressurizer cubicle to plan the weld overlay activity, since the design of the top of the Vogtle pressurizer has several significant interferences that must be removed to provide access for the weld overlay tooling and then replaced. The walkdown information permits better planning, a more accurate design package, reduced implementation risk, and lower radiation exposure than performing this activity without the benefit of the walkdown.

The industry examination and evaluation guideline MRP-139, paragraph 6.8.2 states, "Owners who know that their welds cannot be volumetrically examined are not required to perform a best-effort NDE; however, by the time the examination is due, they are required to have a plan to address either the susceptibility of the weld or the inspectability of the weld." Vogtle performed physical profiling of the six pressurizer Alloy 82 butt welds during the 1R12 outage in spring 2005 and determined the three safety nozzles and the relief nozzle cannot be examined in accordance with PDI requirements due to unfavorable geometries that limit examination volume coverage to between 27% and 60%. Vogtle has a plan in place and a vendor contract awarded to make the welds examinable by applying weld overlays during the 1R14 outage in March 2008, which is approximately 10 weeks after the MRP-139 implementation schedule.

Enclosure 2 Vogtle Electric Generating Plant Examination and Mitigation Information for VEGP-1 & VEGP-2 SNC considers the scheduled March 2008 mitigation date acceptable based on the following:

Previous examination results Bare metal visual (BMV) examinations were performed of all six pressurizer Alloy 82 butt welds during the 1R12 and 1R13 outages in 2005 and 2006 with no evidence of leakage. The spray nozzle was examined in accordance with PDI in the 1R12 outage in 2005 and found acceptable. The remaining five Alloy 82 butt weld examinations have been performed under the IS1 Program in accordance with ASME Section XI. Details of the safety nozzles and relief nozzle exams were reported in SNC response to Bulletin 2004-01 by letter NL-04-1150, dated July 26, 2004. The most recent IS1 examinations were in the 1R9 outage (2000) for the safety nozzles and relief nozzle, and in the 1R5 (1995) for the surge nozzle. These were not PDI exam; however, based on physical profile data the anticipated PDI exam coverage for the surge nozzle is near 100%. Therefore, the past IS1 exam on the surge nozzle achieved good examination coverage.

Assessment of original fabrication welds documentation to identify welds that had been reworked SNC participated in a PWR Owners Group Materials Subcommitteeproject (PWROG PA-MSC-0233) to review fabrication details of dissimilar metal welds.

For Vogtle Unit 1, Alloy 82 weld repairs were only identified on the inside diameter of the spray nozzle and the safety #1 nozzle. The spray nozzle was examined in accordance with PDI in 2005, and there were no recordable indications. The safety #1 nozzle had a number of ground outs on the inner diameter which were repaired using Alloy 82 weld filler metal. A postweld heat treatment was performed after the safety #1 nozzle repairs. It is possible that not all in-process weld repairs were documented.

Water chemistry, ex., zinc addition VEGP-1 follows current industry guidelines for primary water chemistry. Strong evidence exists that zinc addition to the primary coolant inhibits the initiation of PWSCC and may also slow the propagation of existing cracks. The VEGP-1 pressurizer surge line has been exposed to approximately 50 ppb-months of zinc chemistry. Zinc was initially added during Cycle 12 (August 2004); however, it was discontinued in October 2005 because of considerations for nuclear fuel.

There are plans to resume zinc addition approximately midway through the current operating cycle at VEGP-1.

Plant age The susceptibility to PWSCC of Alloy 821182 is largely a function of time at temperature when all other variables are constant. Since pressurizers in a PWR operate at saturated conditions, all PWRs that operate at a nominal 2250 psi have a pressurizer operating temperature within a few degrees of 653" F, and can be

Enclosure 2 Vogtle Electric Generating Plant Examination and Mitigation Information for VEGP- 1 & VEGP-2 compared directly based on operating time. Based on industry data (MRP-48) in response to NRC Bulletin 200 1-0 1, the EFPY for VEGP- 1 ranked in the lower third of U.S. PWR operating plants and has less operating time than the plant that observed circumferential flaws in the pressurizer dissimilar metal welds.

Industry safety assessment As a result of the circumferential indications found in October 2006 the industry, through EPRI MRP, reviewed the Alloy 821182 Pipe Butt Weld Safety Assessment (MRP-113) and the Primary System Piping Butt Weld Inspection and Evaluation Guideline (MRP-139). This review was transmitted from EPRI to the NRC by letter MRP 2007-03 dated January 22,2007. The review is contained in the report, entitled "Implications of Wolf Creek Pressurizer Butt Weld Indications Relative to Safety Assessment and Inspection Requirements," attached to the letter. The conclusions from the industry review included:

- MRP-113 and MRP- 139 remain valid.

- Critical flaw sizes are several times larger than the indications observed in October 2006.

- Bare metal visual examinations during that last refueling outage, and improved leak monitoring, ensure a low risk of leaks and an extremely low risk of rupture through the spring 2008.

Details concerning Vogtle Unit 1 examination and mitigation activities are provided in the enclosed table. Future examinations of pressurizer butt welds at Vogtle Unit 1 will be performed in accordance with industry guidance (MRP-139) and proposed alternative ISI-GEN-ALT-06-03, which was submitted to the NRC by SNC letter NL-06-2768, dated January 3,2007.

The process below for monitoring primary system leakage will be used at VEGP-1 until all Alloy 82 butt weld locations on the pressurizer have been mitigated.

1. Monitoring Capabilities and Methods

a. Reactor Coolant System (RCS) Leak Rate Surveillance

.i.. VEGP procedure 14905-1 performed every 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.

11. Leak measurement is normally performed over 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> period.

iii. Not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after establishment of steady state operation.

b. 1-RE-2562A and 1-RE-2562C containment radiation monitors provide alarm function. The alarm setpoint for both monitors is 2 times background level which provides for sensitive indication of RCS leakage.

Operational experience has demonstrated that these alarms will provide indication of RCS leakage before it can be detected via the leak rate surveillance.

c. Containment air cooler condenser flow monitoring system provides indication and alarm function for moisture in containment.

d. Containment sump level indication and alarms provide indication of unexpected leakage in containment.

Enclosure 2 Vogtle Electric Generating Plant Examination and Mitigation Information for VEGP-1 & VEGP-2 Action Levels and Responses

a. If RCS unidentified leakage increases to greater than 0.2 gpm, direct chemistry to analyze 1-RE-2562A filter for iron content.

b. If RCS leakage increases by 0.05 gpm over the 30 day trend, use procedure 14905-1 Attachment 1 to determine the source of the leakage.

c. If the containment air cooler condensate flow rate high condensate flow alarm actuates and a RCS leak is suspected, a RCS leakage calculation is performed.

d. If containment radiation monitors alarm, the RCS leakage procedure 18004-C is performed.

e. If containment sump level alarms and the leakage source is unknown, a RCS leakage calculation is performed.

VEGP is evaluating the Pressurized Water Reactors Owner Group (PWROG) program (WCAP-16465 & WCAP-16423) regarding standardized RCS leakage monitoring, and anticipates implementation during 2007.

In addition, for VEGP-1, SNC will stay apprised of industry actions and recommendations provided in NEI letter, dated January 26,2007, from Marvin S. Fertel to Luis A. Reyes, "Industry Actions Associated with Potential Generic Implications of Wolf Creek Inspection Findings."

SNC will provide updates to the NRC as necessary regarding any changes to the VEGP leakage monitoring program by March 3 1,2007.

Plans for any additional capability which reliably and meaningfully adds to the ability to diagnose primary system leakage, as well as installation schedules as appropriate, will be submitted to the NRC by May 3 1,2007.

VEGP-1 Examination and Mitigation Information Table Examination and Mitigation Summary for Alloy 82 Pressurizer Butt Welds Mitigation Nozzle MRP-139 Volumetric Completed or to be Examination Requirement Met or Completed Comments to be Met Susceptible Function I Designation Material Outage Start Date Outage Designation Description Designation (MMIYYYY) spray (1) (2) (3) & (4) PDI examination acceptable.

11201-V6-002-W21 Alloy 82 1R12 0312005 1R14 (Spring 2008) Mitigate by weld overlay.

Surge (1) (2) & (3) Mitigate by weld overlay.

11201-V6-002-W22 Alloy 82 1R14 0312008 1R14 (Spring 2008)

Safety 1 (1) & (2) Mitigate by weld overlay.

11201-V6-002-W17 Alloy 82 1R14 0312008 1R14 (Spring 2008)

Safety 2 (1) & (2) Mitigate by weld overlay.

11201-V6-002-W18 Alloy 82 1R14 0312008 1R 14 (Spring 2008)

Safety 3 (1) & (2) Mitigate by weld overlay.

11201-V6-002-W19 Alloy 82 1R14 0312008 1R14 (Spring 2008)

Relief (1) & (2) Mitigate by weld overlay.

11201-V6-002-W20 Alloy 82 1R14 0312008 1R14 (Spring 2008)

Nozzle-to-safe end butter Nozzle-to-safe end weld Thermal sleeve-to-safe end weld Liner weld-to-safe end butter

Enclosure 2 Vogtle Electric Generating Plant Examination and Mitigation Information for VEGP-1 & VEGP-2 VEGP 2 Examination and mitigation of pressurizer Alloy 82 butt welds at Vogtle Unit 2 have not been completed, but SNC will complete all MRP-139 examination and mitigation activities on these locations during the 2R12 outage which starts in March 2007. Details concerning Vogtle Unit 2 examination and mitigation activities are provided in the enclosed table. Additional details can be found in proposed alternative ISI-GEN-ALT-06-03, which was submitted to the NRC by SNC letter NL-06-2768, dated January 3, 2007. Future examinations of pressurizer weld overlays at Vogtle Unit 2 will be performed in accordance with industry guidance (MRP-139) and NL-06-2768. The results of future inspections or mitigations of pressurizer Alloy 82 butt weld locations will be reported to the NRC within 60 days of startup from the outage during which they were performed.

In addition to the examination and mitigation actions described above, the process below for monitoring primary system leakage will be used at VEGP-2 until all Alloy 82 butt weld locations on the pressurizer have been mitigated.

Monitoring Capabilities and Methods

a. RCS Leak Rate Surveillance

.i.. VEGP procedure 14905-2 performed every 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.

11. Leak measurement is normally performed over 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> period.

iii. Not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after establishment of steady state operation.

b. 2-RE-2562A and 2-RE-2562C containment radiation monitors provide alarm function. The alarm setpoint for both monitors is 2 times background level which provides for sensitive indication of RCS leakage.

Operational experience has demonstrated that these alarms will provide indication of RCS leakage before it can be detected via the leak rate surveillance.

c. Containment cooler condenser leak alarms provide indication and alarm function for moisture in containment.

d. Containment sump level indication and alarms provide indication of unexpected leakage in containment.

2. Action Levels and Responses

a. If RCS unidentified leakage increases to greater than 0.2 gpm, direct chemistry to analyze 2-RE-2562A filter for iron content.

b. If RCS leakage increases by 0.05 gpm over the 30 day trend, use procedure 14905-2 Attachment 1 to determine the source of the leakage.

c. If containment cooler condenser leak alarms and a RCS leak is suspected, a RCS leakage calculation is performed.

d. If containment radiation monitors alarm, the RCS leakage procedure 18004-C is performed.

e. If containment Sump level alarms and leakage source is unknown, a RCS leakage calculation is performed.

Enclosure 2 Vogtle Electric Generating Plant Examination and Mitigation Information for VEGP-1 & VEGP-2 VEGP is evaluating the PWROG program (WCAP-16465 & WCAP-16423) regarding standardized RCS leakage monitoring, and anticipates implementation during 2007.

SNC will provide updates to the NRC as necessary regarding any changes to the VEGP leakage monitoring program by March 3 1,2007.

VEGP-2 Examination and Mitigation Information Table Examination and Mitigation Summary for Alloy 82 Pressurizer Butt Welds Mitigation Nozzle MRP-139 Volumetric Completed or to be Examination Requirement Met or Completed Comments to be Met Susceptible Function I Designation Material Outage Start Date Outage Description Designation (MMIYYYY) Designation spray (1) (2) (3) & (4) 2R12 Mitigate by weld overlay 2 1201-V6-002-W21 Alloy 82 2R12 0312007 Surge (1) (2) & (3) 2R12 0312007 2R12 Mitigate by weld overlay 2 1201-V6-002-W22 Alloy 82 Safety 1 (1) (2) 2R12 0312007 2R12 Mitigate by weld overlay 21201-V6-002-W17 Alloy 82 Safety 2 (1) & (2) 2R12 0312007 2R12 Mitigate by weld overlay 21201-V6-002-W18 Alloy 82 Safety 3 (1) & (2) 2R12 0312007 2R12 Mitigate by weld overlay 2 1201-V6-002-W19 Alloy 82 Relief (1) & (2) 2R12 0312007 2R12 Mitigate by weld overlay 2 1201-V6-002-W20 Alloy 82 (1) Nozzle-to-safe end butter (2) Nozzle-to-safe end weld (3) Thermal sleeve-to-safe end weld (4) Liner weld-to-safe end butter

Enclosure 3 Joseph M. Farley Nuclear Plant Vogtle Electric Generating Plant List of Regulatory Commitments

Enclosure 3 Joseph M. Farley Nucleat Plant Vogtle Electric Generating Plant List of Regulatory Commitments The following table identifies those actions committed to by Southern Nuclear Operating Company in this document for Farley Nuclear Plant and Vogtle Electric Generating Plant. Any other statements in this submittal are provided for information purposes A d are not considered to be regulatory commitrne&s.

I Scheduled Completion 1 Type Date One-Time I Continuing (If Required) mitigation and post-mitigation examination activities on the End of 1R2 1 Outage pressurizer nozzles by the end of the 1 FNP-2 will perform MRP-139 required 1

examinations on the pressurizer Alloy 821182 butt welds during - the 2R18 1 I / End of 2R18 Outage 1 outage (Spring 2007).

FNP-2 will perform MRP-139 mitigation and post-mitigation examination activities on the X End of 2R20 Outage pressurizer nozzles by the end of the I 2R20 outage (spring 10).

1 VEGP-1 will perform MRP-139 mitigation and post-mitigation examination activities on the X End of 1R14 Outage pressurizer nozzles during the 1R14 I outage (Spring 2008).

For VEGP-1, SNC will accelerate the planned mitigation outage, currently scheduled for 2008, if analytical results December 31,2007 do not demonstrate that current schedules are adequate.

For VEGP-1, plans for any additional capability which reliably and meaningfully adds to the ability to diagnose primary system leakage, as May 3 1,2007 well as installation schedules as appropriate, will be submitted to the NRc.-

VEGP-2 will perform MRP-139 mitigation and post-mitigation examination activities on the X End of 2R12 Outage pressurizer nozzles during the 2R12 outage (Spring 2007).

Enclosure 3 Joseph M. Farley Nuclear Plant Vogtle Electric Generating Plant List of Regulatory Commitments I Scheduled Completion Type Date One-Time 1 Continuing (If Required)

Commitment If a shut down occurs due to excessive primary system unidentified leakage, an if the leakage cannot be confirmed to originate from a source other than the pressurizer nozzles, a bare metal visual examination of Alloy 821182 weld locations on the pressurizer will be Action ICom liance Ongoing until mitigation of pressurizer Alloy 821182 welds performed to determine whether the leakage originated at those locations (FNP & VEGP).

Examinations of pressurizer weld overlays will be performed in accordance with MRP-139 andlor NRC-approved alternatives (FNF&

VEGP).

The results of future inspections or mitigations of pressurizer Alloy 821182 End after two butt weld locations will be reported to consecutive acceptable the NRC within 60 days of startup fiom examinations the outage during which they are

~

Processes described in Enclosures 1 &

2 for monitoring primary system leakage will be used until Alloy 821182 Until mitigated or butt weld locations on the pressurizer examined.

have been mitigated or examined (FNF

& VEGP).

SNC will provide updates to the NRC as necessary regarding any changes to March 3 1,2007 the FNF & VEGP leakage monitoring