ML070440188

Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds Reissuance of January 31, 2007 Letter

ML070440188
Person / Time
Site:	Millstone, Kewaunee, Surry, North Anna
Issue date:	02/12/2007
From:	Funderburk C Dominion Energy Kewaunee, Dominion Nuclear Connecticut, Dominion Resources Services, Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
07-0035A
Download: ML070440188 (21)

Text

b Dominion Resources Services, Inc.

5 0 0 0 Dominion Boulevard, Glcn Allen, VA 23060 Dominion"'

February 12, 2007 U.S. Nuclear Regulatory Commission Serial No.: 07-0035A ATTN: Document Control Desk NL&OS/ETS : RO Washington, DC 20555 Docket Nos.: 50-305 50-3361423 50-3381339 50-2801281 License Nos.: DPR-43 DPR-65lNPF-49 NPF-417 DPR-32/37

-DOlMlNlON ENERGY KEWAUNEE INC. (DEK)

-DOlMlNlON NUCLEAR CONNECTICUT. INC. (DNC)

VlFlGlNlA ELECTRIC AND POWER COMPANY (DOMINION)

KEWAUNEE POWER STATION

-MILLSTONE POWER STATION UNITS 2 AND 3

-NORTH ANNA AND SURRY POWER STATIONS UNITS 1 AND 2 INSPECTION AND MITIGATION OF ALLOY 600/821182 PRESSURIZER BUTT WELDS

-REISSUANCE OF JANUARY 31.2007 LETTER In a January 31, 2007 letter (Serial No. 07-0035), DEK, DNC and Dominion submitted their plans for inspection and mitigation of Alloy 6001821182 pressurizer butt welds. However, due to a pagination error, the electronic submittal is missing the first line of text on the second page of the cover letter. This letter provides a corrected cover letter and the original attachments. No additional commitments are made in this letter.

We are sorry for this inconvenience. If you have any questions or require additional information, please contact Mr. Thomas Shaub at (804) 273-2763.

Very truly yours, L2*-

C. L. Funderburk Dirlector - Nuclear Licensing and Operations Support Dominion Resource Services, Inc. for Dominion Energy Kewaunee, Inc.

Dominion Nuclear Connecticut, Inc.

Virginia Electric and Power Company Attachment Coirrected January 31, 2007 letter with attachments.

Serial No. 07-0035A Docket Nos. 50-305, 50-3361423, 50-3381339, 50-2801281 Page 2 of 3 cc: U. S. Nuclear Regulatory Commission Region I Regional Administrator 475 Allendale Road King of Prussia, PA 19406-1415 U. S. Nuclear Regulatory Commission Region II Regional Administrator Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 231-85 Atlanta, Georgia 30303 U. S. Nuclear Regulatory Commission Region Ill Regional Administrator 2443 Warrenville Road Suite 21 0 Lisle, Illinois 60532-4352 Mr. R. F. Kuntz Project Manager Kewaunee U. S. Nuclear Regulatory Commission, Mail Stop 7D1A One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 Mr. V. Nerses NRC Senior Project Manager Millstone Units 2 and 3 U. S. Nuclear Regulatory Commission, Mail Stop 8 B1 One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 Mr. S. P. Lingam NRC Project Manager North Anna and Surry U. S. Nuclear Regulatory Commission, Mail Stop 8 G9A One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738

Serial No. 07-0035A Docket Nos. 50-305, 50-3361423, 50-3381339, 50-2801281 Page 3 of 3 Mr. S. C. Burton NRC Senior Resident lnspector Kewaunee Power Station Mr. S. M. Schneider NRC Senior Resident lnspector Millstone Power Station Mr. J. T. Reece NRC Senior Resident lnspector North Anna Power Station Mr. N. P. Garrett NRC Senior Resident lnspector Surry Power Station

ATTACHMENT CORRECTED JANUARY 31,2007 LETTER WITH ATTACHMENTS INSPECTION AND MITIGATION OF ALLOY 6001821182 PRESSURIZER BUTT WELDS (SERIAL NO. 07-0035A)

DOMINION ENERGY KEWAUNEE INC. (DEK)

DOMINION NUCLEAR CONNECTICUT, INC. (DNC)

VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)

Dominion Resources Services, Inc.

5000 Dominion Boulevard, Glen Allen, VA 23060 Dominion" January 31, 2007 U.S. Nuclear Regulatory Commission Serial No.: 07-0035 ATTN: Document Control Desk NL&OS/ETS: RO Washington, DC 20555 Docket Nos.: 50-305 50-3361423 50-3381339 50-2801281 License Nos.: DPR-43 DPR-65lNPF-49 N PF-417 DPR-32/37 DOMINION ENERGY KEWAUNEE INC. (DEK)

DOMINION NUCLEAR CONNECTICUT, INC. (DNC)

VIlRGlNlA ELECTRIC AND POWER COMPANY (DOMINION)

KEWAUNEE POWER STATION MILLSTONE POWER STATION UNITS 2 AND 3 NORTH ANNA POWER STATION UNITS 1 AND 2 S!URRY POWER STATION UNITS 1 AND 2 INSPECTION AND MITIGATION OF ALLOY 6001821182 PRESSURIZER BUTT WELDS In October of 2006, while performing inspections 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, DEK, DNC, and Dominion are committing to the following actions taken or planned for inspecting or mitigating Alloy 6001821182 butt welds on pressurizer spray, surge, safety and relief lines.

Tlhe pressurizer spray, surge, safety and relief nozzles at Surry Power Station Units 1 and 2 and Kewaunee Power Station do not have Alloy 6001821182 butt welds. Future inspections of butt welds in pressurizer spray, surge, safety and relief nozzles at Surry and Kewaunee will be performed in accordance with the requirements outlined in 10CFR50.55a implemented through the NRC reviewed and approved inservice inspection plans. The inservice inspection plans are based upon the requirements in th~e1998 Edition through 2000 Addenda of Section XI of the ASME Boiler and Pressure Vessel Code.

The pressurizer at Millstone Power Station Unit 2 (MPS 2) has been replaced with a component that uses materials (i.e., stainless steel nozzle safe ends and weld material) resistant to stress corrosion cracking. This replacement occurred during the Millstone

Serial No. 07-0035 Docket Nos. 50-305, 50-3361423, 50-3381339, 50-2801281 Page 2 of 4 Unit 2 refueling outage (M2-RF-17) in the fall of 2006. Future inspections of butt welds in pressurizer spray, surge, safety and relief nozzles at MPS 2 will be performed in accordance with requirements outlined in 10CFR50.55a implemented through the NRC reviewed and approved inservice inspection plans. The inservice inspection plans are based upon requirements in the 1989 Edition of Section XI of the ASME Boiler and Pressure Vessel Code.

Pressurizer Alloy 600/82/182 butt welds at Millstone Power Station Unit 3 (MPS 3) and North Anna Power Station Units 1 and 2 (NAPS 1 and 2) have been inspected. A weld overlay of one spray nozzle at MPS3 was completed during the last refueling outage.

Details concerning the locations inspected and results are provided in the attachments to this letter. DNC and Dominion intend to complete mitigation activities on these locations during the spring 2007 refueling outages for MPS 3 and NAPS 2 and the fall 2007 refueling outage for NAPS 1. Future inspections of pressurizer butt welds at MPS 3 and NAPS 1 and 2 will be performed as described in the following relief requests:

IF;-2-47 for MPS 3 (Serial No.06-731 dated October 17, 2006) and CMP-022 for NAPS 1 and CMP-023 for NAPS 2 (Serial No. 06-1007, dated January 3, 2007), and subsequent NRC approved revisions to these relief requests. The results of these future inspections or mitigation of pressurizer Alloy 600/82/182 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 inspection and mitigation actions described above, MPS 3 and NAPS 1 and 2 will continue to maintain a heightened sensitivity to primary system leakage until all Alloy 600/82/182 butt weld locations on the pressurizer have been inspected or mitigated on each unit. The procedures/methods used for leak detection are identified in the attachments to this letter.

Prior to the scheduled mitigation activities, if MPS 3 and NAPS 1 and 2 should shut down due to excessive unidentified primary system leakage and if the leakage cannot be confirmed to originate from a source other than the pressurizer, a bare metal visual examination of Alloy 600/82/182 butt weld locations on the pressurizer will be performed to determine whether the leakage originated at those locations.

In light of the planned mitigation schedule, the existing guidance and heightened sensitivity to primary system leakage provide adequate assurance that structural integrity will be maintained and that primary system pressure boundary leakage will be dilscovered in a timely manner.

Consistent with our Commitment Management Program, the NRC will be informed prior to revising the commitment related information contained in this letter regarding intspection and mitigation activities for MPS 3 or NAPS 1 and 2.

Serial No. 07-0035 Docket Nos. 50-305, 50-3361423, 50-3381339, 50-2801281 Page 3 of 4 If you have any questions or require additional information, please contact Mr. Thomas Sliaub at (804) 273-2763.

Very truly yours, D,avidA. Christian Senior Vice President - Nuclear Operations and Chief Nuclear Officer Dlominion Energy Kewaunee, Inc.

Dlominion Nuclear Connecticut, Inc.

Virginia Electric and Power Company Attachments

1. DNC - Millstone Power Station Unit 3 Alloy 821182 Pressurizer Butt Welds

2. Dominion - North Anna Units 1 and 2 Alloy 821182 Pressurizer Butt Welds

3. Commitment Summary cc:: U. S. Nuclear Regulatory Commission Region 1 Regional Administrator 475 Allendale Road King of Prussia, PA 19406-1415 U. S. Nuclear Regulatory Commission Region II Regional Administrator Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 231-85 Atlanta, Georgia 30303 U. S. Nuclear Regulatory Commission Region Ill Regional Administrator 2443 Warrenville Road Suite 21 0 Lisle, Illinois 60532-4352

Serial No. 07-0035 Docket Nos. 50-305, 50-3361423, 50-3381339, 50-2801281 Page 4 of 4 Mr. R. F. Kuntz Project Manager Kewaunee U. S. Nuclear Regulatory Commission, Mail Stop 7D1A One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 Mr. V. Nerses NRC Senior Project Manager Millstone Units 2 and 3 U. S. Nuclear Regulatory Commission, Mail Stop 8 B1 One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 Mr. S. P. Lingam NRC Project Manager North Anna and Surry U. S. Nuclear Regulatory Commission, Mail Stop 8 G9A One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 Mr. S. C. Burton NRC Senior Resident lnspector Kewaunee Power Station Mr. S. M. Schneider NRC Senior Resident lnspector Millstone Power Station Mr. J. T. Reece NRC Senior Resident lnspector North Anna Power Station Mr. N. P. Garrett NRC Senior Resident lnspector Surry Power Station

ATTACHMENT 1 DOCKET NO. 50-423 INSPECTION AND MITIGATION OF ALLOY 821182 PRESSURIZER BUTT WELDS (SERIAL NO. 07-0035)

DOMINION CONNECTICUT NUCLEAR, INC.

MILLSTONE POWER STATION UNIT 3

Serial No. 07-0035 Docket No. 50-423 Attachment 1 Y!!LLSTONE UN!T 5 lnspection and Mitigation Summary for Alloy 6001821182 Pressurizer Butt Welds No credit was taken for MRP- 139 inspection requirements. The examinations performed in M3-R-10 were done to meet the Licensee's commitment to NRC Bulletin 2004-01.

MRP-139 Nozzle Mitigation to Volumetric Inspection be Completed Require~ nent Met ('I Comments Susceptible Function / Outage Completion Outage Material Designation Designation Date Designation Descri~tion Weld No. 03-X- I Allov-., 821182 Fall 2005 M3-R-11 Profile data was taken on the safe end-5551-X-T:14-inch ~ " 1 1 Penetration Spring 2007 to-nozzle weld to determine RCS Safe End-T0- No stress relief inspectability.

Surge Nozzle and adjacent Safe End- Butter weld

~ o - ~ (Weld i ~ eNo.

RCS-SL-FW-4)

Weld No. 03-X- Alloy 821182 Fall 2005 I Essentially 100% coverage for axial 5644-A-T: 6inch Full Penetration Spring 2007 indications was performed with a PDI Safety Nozzle-To- No stress relief UT and RT performed to ensure Safe End Weld at coverage for circumferential indications 81Wzimuth and Butter weld due to the as-found field condition weld adjacent Safe End- crown. The adjacent weld was not To- Pipe (Weld No. examined.

RCS-516-FW-1)

Page ! of 4

Serial No. 07-0035 Docket No. 50-423 Attachment 1 MRP-139 Nozzle I Volumetric Inspection Mitigation to be Completed Comments Susceptible Function I Outage Completion Outage Material Designation Designation Date Designation Description Weld No. 03-X- Alloy 821182 M3-R-10 Fa11 2005 M3-R-11 Essentially 100% coverage for axial 5648-B-T: 6-inch Full Penetration Spring 2007 indications was performed with a PDI Safety Nozzle-To- No stress relief UT and RT performed to ensure Safe End Weld at coverage for circumferential indications 147"zimuth and Butter weld due to the as-found field condition weld adjacent Safe End- crown. The adjacent weld was not To-Pipe (Weld No. examined.

RCS-5 16-FW-3)

Weld No. 03-X- Alloy 821182 M3-R-I 0 Fall 2005 Essentially 100% coverage for axial 5649-C-T: 6-inch Full Penetration Spring 2007 indications was performed with a PDI Safety Nozzle-To- No stress relief UT and RT performed to ensure Safe End Weld at coverage for circumferential indications 212"zimuth and Butter weld due to the as-found field condition weld adjacent Safe End- crown. The adjacent weld was not To-Pipe (Weld No. examined.

RCS-516-FW-5) -

Weld No. 03-X- Alloy 821182 M3-R-10 Fa11 2005 M3-R-11 Essentially 100% coverage for axial 5650-D-T: 6-inch Full Penetration Spring 2007 indications was performed with a PDI Relief Nozzle-To- No stress relief UT and RT performed to ensure Safe End Weld at coverage for circumferential indications 278"zimuth and Butter weld due to the as-found field condition weld adjacent Safe End- crown. The adjacent weld was not To-Pipe (Weld No. examined.

RCS-513-FW-1)

Page 2 of 4

Serial No. 07-0035 Docket No. 50-423 Attachment 1 MR?-! 39 Mitigation to Nozzle I Volumetric lns~ection be Completed I Reauirer ent ' ~ e(')t Comments Susceptible Function 1 Outage Completion Outage Material Designation Designation Date Designation Description Weld No. 03-X- I Allov 821182 I M3-R-10 Fall 2005 Completed Examination of the nozzle to safe end 5641-E-T: 6-inch M3-R-10 weld had no reportable indications with Relief Nozzle-To- No stress relief a PDI UT. The UT examination was Safe End Weld and performed for axial indications only. RT adiacent Safe End- Butter weld was performed to ensure coverage for

~ d - ~(Weld i ~ eNo. circumferential indications due to the RCS-517-FW-12) as-found field condition weld crown.

This examination revealed circumferential indications which led to machining the weld flat and performing an automated UT which achieved 100%

coverage for indications in both directions. Indications, which were evaluated as fabrication flaws (not connected to the ID), were detected and these flaws ran essentially 360 degrees around in the circumferential direction.

The weld and the adjacent weld were weld overlay repaired and a manual PDI baseline UT of the weld overlay was performed with no reportable indications.

(1) No credit was taken for MRP-139 inspection requirements. The examinations performed in M3-R-10 were done to meet the Licensee's commitment to NRC Bulletin 2004-01.

Page 3 nf 4

Serial No. 07-0035 Docket No. 50-423 Attachment 1 RCS Leakage Monitoring Tlhe Millstone Power Station Reactor Coolant System (RCS) Leakage Management Program monitors RCS leakage at a very low threshold. While the Millstone Unit 3 Technical Specifications establish allowable leakage limits, the Millstone Power Station monitoring thresholds are established to ensure that the Technical Specification requirements are not challenged.

RCS leakage monitoring procedure (SP 3601 F.6) is currently performed daily (TS SR 4.4.6.2.1.d requirement is once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> during steady state operation). The leakage rate procedure utilizes an RCS water inventory balance to determine identified and unidentified RCS leakage rate values. This leakage is trended using a database program in accordance with C OP 200.15, RCS Leakage Trending and Investigation.

Action levels in C OP 200.15 are established to identify 1) 9 consecutive leakage rates above the 90 day running average, 2) 2 out of 3 consecutive unidentified leakage rates above the 90 day running average plus two standard deviation value, 3) any single unidentified leakage rate greater than the 90 day running average plus three standard deviations. The trending program provides three-month graphs identifying each action level and the daily RCS leakage values. The requirements for exceeding these action levels include checking various independent indications to confirm a leak, writing a Condition Report (CR), and walkdowns outsidelinside containment.

In addition to a primary system leakage calculation, the containment sump level monitoring and containment gaseouslparticulate radiation monitoring instrumentation are also available for detection of RCS leakage (TS 3.4.6.1). The containment sump in-leakage rate and the radiation monitor readings are logged regularly by Operations and included in the trending database program. This program provides 90 day graphs for containment sump leakage and containment gaseouslparticulate radiation monitoring readings. Operations plots and evaluates the daily TS value against the containment in-leakage 90 day running average and the 7 day average monitor reading. The STA also monitors RCS leakage and sump in-leakage as part of normal daily functions. In addition, real time sump level, sump in-leakage rate, and radiation monitor instrumentation readings are available on the plant computer system for historicalltrending purposes.

Page 4 of 4

ATTACHMENT 2 DOCKET NOS.: 50-3381339 INSPECTION AND MITIGATION OF ALLOY 821182 PRESSURIZER BUTT WELDS (SERIAL NO. 07-0035)

VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2

Serial No. 07-0035 Docket Nos. 50-3381339 Attachment 2 NORTH ANNA UNITS 1 AND 2 InspectionSummary for Alloy 6001821182 Pressurizer Butt Welds North Anna Unit 1 Inspection Outage1 Method PDI Coverage Limitations Encountered Findings Sco~e Date Examined* Used Qualification Obtained Limitation due to proximity of nozzle No Recordable taper to weld for nozzle side access and lndications Surge SW-51 N1-R-17lFall2004 No transition between the nozzle and safe-end which limits search unit contact from the safe-end side of the weld.

Limitation due to proximity of nozzle No Recordable taper to weld for nozzle side access and lndications Safety SW-30 N1-R-17lFall2004 No transition between the nozzle and safe-end which limits search unit contact from the safe-end side of the weld.

Limitation due to proximity of nozzle No Recordable taper to weld for nozzle side access and lndications Safety SW-31 N1-R-17lFall 2004 transition between the nozzle and safe-end which limits search unit contact from the safe-end side of the weld.

Limitation due to proximity of nozzle No Recordable taper to weld for nozzle side access and lndications transition between the nozzle and safe-end which limits search unit contact from the safe-end side of the weld.

Limitation due to proximity of nozzle No Recordable taper to weld for nozzle side access and lndications Relief SW-64 N1-R-17lFall 2004 transition between the nozzle and safe-end which limits search unit contact from the safe-end side of the weld.

0Spray SW-71 N1-R-17lFall 2004

• MRP-139 Volumetric lnspection Requirement Not Met.

Limitation due to proximity of nozzle taper to weld for nozzle side access and transition between the nozzle and safe-end which limits search unit contact from the safe-end side of the weld.

No Recordable lndications Page 1 of 5

Serial No. 07-0035 Docket Nos. 50-3381339 Attachment 2 Mitigation Summary for Alloy 600/82/182 Pressurizer Butt Welds North Anna Unit 1 Mitigation to Nozzle be Completed Comments Outage Material Designation Surge SW-51 I Nozzle-to-safe end weld N1-R-19 Fall 2007 14-inch RCS Safe End Reducer-To-Surge Nozzle Weld and adjacent Pipe-to-Safe End Reducer Weld No. 39 (Pipe ldentifier 14-RC-10-2501R-Q1) 6-inch Safe End-to-Safety Nozzle-Weld and adjacent Elbow-to-Safe End Weld No. 21 (Pipe ldentifier 6-RC-38-1502-Q1)

N1-R-19 Alloy 82/182 Fa11 2007 Full Penetration, Butter weld Butter heat treated with nozzle 6-inch Safe End-to-Safety Nozzle-Weld and adjacent Elbow-to-Safe End Weld No.17 (Pipe ldentifier 6-RC-39-1502-Q1)

Nozzle-to-safe N1-R-19 Alloy 82/182 Safety SW-31 Fall 2007 end weld Full Penetration, Butter weld

( Butter heat treated with nozzle I &inch Safe End-to-Safetv Nozzle-Weldand adiacent Elbow-to-Safe End Weld No.25 (Pipe I ldentifier 6 - ~ ~ - 3 7502-Ql)

-1 Nozzle-to-safe N1-R-19 Alloy 82/182 Safety SW-38 Fall 2007 end weld Full Penetration, Butter weld Butter heat treated with nozzle 6-inch Safe End-to-Relief Nozzle-Weld and adjacent 6x4 Concentric Reducer-to-Safe End Weld No. 30 (Pipe ldentifier 4-RC-34-I502-Ql)

N1-R-19 Alloy 82/182 Fall 2007 Full Penetration, Butter weld I Butter heat treated with nozzle 4-inch Safe End-to-Spray Nozzle-Weld and adjacent Pipe-to-Safe End Weld No. 11 (Pipe ldentifier 4-RC-l5-1502-QIl

-~ ~

N1-R-19 Alloy 82/182 Fall 2007 Full Penetration, Butter weld I Butter heat treated with nozzle Page 2 of 5

Serial No. 07-0035 Docket Nos. 50-3381339 Attachment 2 Nozzle I Mitigation to be Completed Comments Susceptible Function 1 Outage Material Designation Designation Description Nozzle-to-safe N2-R-18 14-inch RCS Safe End Reducer-To-SurgeNozzle Weld and adjacent Pipe-to-Safe End Surge SW-5 Spring 2007 Reducer Weld No. 1 (Pipe Identifier 14-RC-410-2501R-Q1) end weld 6-inch Safe End-to-Safety Nozzle-Weld and adjacent Elbow-to-SafeEnd Weld No. 1 (Pipe

/

ldentifier 6-RC-437-1502-Q11 Nozzle-to-safe N2-R-18 Alloy 82/182 Safety SW-6 spring 2007 end weld Full Penetration, Butter i e l d Butter heat treated with nozzle 6-inch Safe End-to-Safety Nozzle-Weld and adjacent Elbow-to-Safe End Weld No. 1 (Pipe ldentifier 6-RC-438-1502-Q1)

Nozzle-to-safe N2-R-18 Alloy 82/182 Safety SW-9 Spring 2007 end weld Full Penetration, Butter weld I Butter heat treated with nozzle I 1 6-inch Safe End-to-Safetv Nozzle-Weld and adiacent Elbow-to-Safe End Weld No. 1 (Pipe I I Identifier 6-RC-439-1502:~l)

Safety SW-17 Nozzle-to-safe end weld I N2-R-18 Spring 2007 Alloy 82/182 Full Penetration, Butter weld Butter heat treated with nozzle 6-inch Safe End-to-Relief Nozzle-Weld and adjacent 6x4 Concentric Reducer-to-Safe End Weld No. 1 (Pipe ldentifier 4-RC-434-1502-Q1)

Nozzle-to-safe N2-R-18 Alloy 82/182 Relief SW-40 end weld Spring 2007 Full Penetration, Butter weld I Butter heat treated with nozzle I 4-inch Safe End-to-S~ravNozzle-Weld and adiacent Pipe-to-Safe End Weld No. 42 (Pipe I I ldentifier ~-Rc-~I5-1SO~-QI 1 Spray SW-62 Nozzle-to-safe end weld I N2-R-18 "lin 2007 g

Alloy 821182 Full Penetration, Butter weld I Butter heat treated with nozzle Page 4 of 5

Serial No. 07-0035 Docket Nos. 50-3381339 Attachment 2 RCS Leakaae Monitorina Activities The North Anna Reactor Coolant System (RCS) Leakage Management Program monitors RCS leakage at a very low threshold. While the North Anna Technical Specifications specifies that NO pressure boundary leakage is acceptable and that up to 1 gpm is allowed as unidentified leakage, the North Anna monitoring thresholds are established to ensure that the Technical Specification requirements are not challenged.

RCS leakage monitoring procedures (112-PT-52.2152.2A) are currently performed daily (TS SR 3.4.13.1 requirement is once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />). The leakrate procedures utilize an RCS water inventory balance to determine total, identified, and unidentified RCS leakrate values. Action levels within the leakrate procedures are set to identify

1) a slight change to the leakrate baseline or an adverse trend in RCS leakrate, 2) a doubling of the unidentified leakrate above the baseline coincident with a value greater than 0.05 gpm, 3) an increase of 0.20 gpm above the baseline, and 4) any unidentified leakrate above 0.20 gpm. Follow-on actions for exceeding these action levels include walkdowns outsidelinside containment, operations manager on call (OMOC) notification, and/or evaluate implementing the Operational Decision Making process.

In addition, NAPS System Engineering has established monitoring thresholds for unidentified RCS leakage to identify 1) 9 consecutive unidentified leakrates above the 3 month average, 2) 2 out of 3 consecutive unidentified leakrates above the 3 month average plus two standard deviations, and 3) any single unidentified leakrate greater than the 3 month average plus three standard deviations. A Condition Report (CR) is submitted when any monitoring threshold has been crossed.

In addition to primary system leakage calculation, the containment sump level monitoring and containment gaseouslparticulate radiation monitoring instrumentation are also available for detection of RCS leakage (TS 3.4.15). The containment sump inleakage rate and the radiation monitor readings are 1) logged regularly by the Operations and 2) included in a narrative log entry that documents the results of the RCS leakage determination procedure. The STA is required to monitor the containment sump inleakage rate each shift for changes. Sump level, sump inleakage rate, and radiation monitor instrumentation readings are available on the plant computer system, for historicalltrending purposes.

Page 5 of 5

Serial No. 07-0035 Docket Nos. 50-3381339 Attachment 3 ATTACHMENT 3 DOCKET NOS. 50-423,50-3381339 COMMITMENT

SUMMARY

INSPECTION AND MITIGATION OF ALLOY 821182 PRESSURIZER BUTT WELDS (SERIAL NO. 07-0035)

DOMINON NUCLEAR CONNECTICUT, INC.

VIRGINIA ELECTIC AND POWER COMPLANY MILLSTONE UNIT 3 NORTH ANNA UNITS 1 AND 2

Serial No. 07-0035 Docket Nos. 50-3381339 Attachment 3 COMMITMENT

SUMMARY

INSPECTION AND MITIGATION OF ALLOY 821182 PRESSURIZER BUTT WELDS Commitment M3-R-11 6001821182 Pressurizer Butt Welds during - the Spring 2007 spring

- 2007 refueling outage for MPS 3.

Dorninion will complete the mitigation activities described by this letter on the Alloy 600/82/182 Pressurizer Butt Welds durina spring 2007 refueling outage for NAPS 2.

- the 1 N2-R-18 Spring 2007 Dominion will complete the mitigation activities described by this letter on the Alloy X

600/821182 Pressurizer Butt Welds during - the fall 2007 refueling outage for NAPS 1.

In addition to the inspection and mitigation actions described above, MPS-3 and NAPS 1 and 2 will continue to have a heightened sensitivity to primary system leakage until all Alloy 6001821182 butt weld locations on the pressurizer have been inspected or mitigated on each unit.

Prier to the scheduled mitigation activities, if MPIS 3 and NAPS 1 and 2 shut down due to exclessive unidentified primary system leakage and if the leakage cannot be confirmed to originate from a source other than the pressurizer, a bare metal visual examination of Alloy 600/82/182 butt weld locations on the pressurizer will be performed to determine if

-leakage originated at those locations.

the Future inspections of pressurizer butt welds at MPI3 3 and NAPS 1 and 2 will be performed as described in relief requests: IR-2-47 for MPS 3 (Serial No.06-731 dated October 17, 2006) and CMP-022 for NAPS 1 and CMP-023 for NAPS 2 (Serial No. 06-1007, dated January 3, 2007) and subsequent approved revisions by the NRC.

The results of future inspections or mitigation of pressurizer Alloy 6001821182 butt weld loca~tionsat MPS 3 and NAPS 1 and 2 will be reported to the NRC within 60 days of startup from the outage during which they were performed.