ML070600169

Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds

ML070600169
Person / Time
Site:	Oconee
Issue date:	02/22/2007
From:	Brandi Hamilton Duke Energy Carolinas, Duke Energy Corp, Duke Power Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML070600169 (12)

Text

Duke BRUCE H HAMILTON Vice President Energy Oconee Nuclear Station Duke Energy Corporation ONO0 VP / 7800 Rochester Highway Seneca, SC 29672 864 885 3487 864 885 4208 fax February 22, 2007 bhhamilton@duke-energy. com U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.

20555

Subject:

Duke Power Company LLC, d/b/a Duke Energy Carolinas, LLC Oconee Nuclear Station, Units 2, and 3 Dockets Nos. 50-270, and 287 Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds This letter supplements our letter of January 31, 2007 and is in response to our phone conversation with NRC staff on February 14, 2007.

Oconee commits to completing the mitigation of Alloy 600/82/182 Pressurizer Butt Welds as stated in Attachments 3 and 4 of our January 31, 2007 letter for Oconee Units 2 and 3.

We also commit to enhanced leakage detection on Units 2 and 3 until the aforementioned mitigation is complete as follows:

1. Unidentified leakage will be determined daily whenever the unit is in Mode 1, 2, or 3 steady state operations;

2.

If unidentified Reactor Coolant System (RCS) leakage increases 0.1 gallon per minute over the previous daily reading and is sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the unit will take action to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and perform bare metal visual examination of the Alloy 600/82/182 butt weld locations, unless it can be confirmed the increase is not from these pressurizer welds;

3.

If unidentified RCS leakage increases 0.25 gallons per minute above baseline and is sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> the unit will take action to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and.

Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and perform bare metal visual Silr www. duke-energy, corn

U.

S. Nuclear Regulatory Commission February 22, 2007 examination of the Alloy 600/82/182 butt weld locations, unless it can be confirmed the increase is not from these pressurizer welds;

4.

The baseline RCS leakage rate will be determined from data obtained during the first 7 days of steady state operation at 100% after the most recent bare metal visual inspection of pressurizer welds for that unit;

5.

Inspection results of any bare metal visual examinations performed will be provided to the NRC in a written report within 60 days of restart;

6.

These enhanced leakage commitments will be implemented no later than March 1, 2007.

The NRC will be informed if Oconee revises any of the information contained in this letter.

If there are any questions, please contact Reene' Gambrell at (864) 885-3364.

Very truly yours, B.H. Hamilton, Vice President Oconee Nuclear Site Attachment Commitments

U.

S. Nuclear Regulatory Commission February 22, 2007 cc:

Mr.

L.

N. Olshan, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-14 H25 Washington, D.C.

20555 Dr.

W. D. Travers, Regional Administrator U.S. Nuclear Regulatory Commission -

Region II Atlanta Federal Center 61 Forsyth St.,

SW, Suite 23T85 Atlanta, Georgia 30303 Mr.

D.

W. Rich Senior Resident Inspector Oconee Nuclear Station Mr. Henry Porter, Director Division of Radioactive Waste Management Bureau of Land and Waste Management Department of Health & Environmental Control 2600 Bull Street

Columbia, S.C.

29201

U.

S.

Nuclear Regulatory Commission February 22, 2007 bcc:

L.

F. Vaughn R.

L. Gill NRI&A K.

L. Ashe -

MNS R.

D. Hart -

CNS S.

D. Capps P.

E. Mabry J.

A. Patterson P.

A. Wells D.

W. Peltola R.

C. Gamberg D.

V. Deatherage S.

L. Batson D.

B. Coyle K.

R. Redmond R.

V. Gambrell B.

G. Davenport BWOG Working Group ONS Document Management ELL NSRB NEI

U.

S. Nuclear Regulatory Commission February 22, 2007 Attachment Commitments

U.

S. Nuclear Regulatory Commission February 22, 2007 Attachment Commitments Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds The following commitments are contained in this letter.

Action Commitment Completion Date Repair Mitigation of Alloy 600/82/182 Pressurizer Butt Welds as stated in Unit 2 Attachments 3 and 4 of our January 31, 2007 letter for Oconee Units 2 and 2 EOC 22

3.

4/2007 Unit 3 3 EOC 23 10/2007 Procedure Enhanced leakage detection as stated below:

Implementation NLT 3/1/2007, until mitigation completion Unidentified leakage will be determined daily whenever the unit is in Mode 1, 2, or 3 steady state operations; If unidentified Reactor Coolant System (RCS) leakage increases 0.1 gallon per minute over the previous daily reading and is sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the unit will take action to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and perform bare metal visual examination of the Alloy 600/82/182 butt weld locations, unless it can be confirmed the increase is not from these pressurizer welds; If unidentified RCS leakage increases 0.25 gallons per minute above baseline and is 5ustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> the unit will take action to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and perform bare metal visual examination of the Alloy 600/82/182 butt weld locations, unless it can be confirmed the increase is not from these pressurizer welds; The baseline RCS leakage rate will be determined from data obtained during the first 7 days of steady state operation at 100% after the most recent bare metal visual inspection of pressurizer welds for that unit.

Report Inspection results of any bare metal visual examinations performed will be As occurs provided to the NRC in a written report within 60 days of restart.

Letter The NRC will be informed if Oconee revises any of the information As necessary contained in this letter.

BRUCE H HAMILTON Vice President

OrEnergy, Oconee Nuclear Station Duke Energy Corporation ONO1VP / 7800 Rochester Highway Seneca, SC 29672 864 885 3487 864 885 4208 fax bhhamilton@duke-energy. corn February 22, 2007 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.

20555

Subject:

Duke Power Company LLC, d/b/a Duke Energy Carolinas, LLC Oconee Nuclear Station, Units 2, and 3 Dockets Nos.

50-270, and 287 Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds This letter supplements our letter of January 31, 2007 and is in response to our phone conversation with NRC staff on February 14, 2007.

Oconee commits to completing the mitigation of Alloy 600/82/182 Pressurizer Butt Welds as stated in Attachments 3 and 4 of our January 31, 2007 letter for Oconee Units 2 and 3.

We also commit to enhanced leakage detection on Units 2 and 3 until the aforementioned mitigation is complete as follows:

1. Unidentified leakage will be determined daily whenever the unit is in Mode 1, 2, or 3 steady state operations;

2.

If unidentified Reactor Coolant System (RCS) leakage increases 0.1 gallon per minute over the previous daily reading and is sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the unit will take action to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and perform bare metal visual examination of the Alloy 600/82/182 butt weld locations, unless it can be confirmed the increase is not from these pressurizer welds;

3.

If unidentified RCS leakage increases 0.25 gallons per minute above baseline and is sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> the unit will take action to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and.

Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and perform bare metal visual www duke-ener.y. corn

U.

S. Nuclear Regulatory Commission February 22, 2007 examination of the Alloy 600/82/182 butt weld locations, unless it can be confirmed the increase is not from these pressurizer welds;

4.

The baseline RCS leakage rate will be determined from data obtained during the first 7 days of steady state operation at 100% after the most recent bare metal visual inspection of pressurizer welds for that unit;

5.

Inspection results of any bare metal visual examinations performed will be provided to the NRC in a written report within 60 days of restart;

6.

These enhanced leakage commitments will be implemented no later than March 1, 2007.

The NRC will be informed if Oconee revises any of the information contained in this letter.

If there are any questions, please contact Reene' Gambrell at (864) 885-3364.

Very truly yours, B.H. Hamilton, Vice President Oconee Nuclear Site Attachment Commitments

U.

S. Nuclear Regulatory Commission February 22, 2007 cc:

Mr.

L.

N.

Olshan, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-14 H25 Washington, D.C.

20555 Dr. W. D.

Travers, Regional Administrator U.S. Nuclear Regulatory Commission -

Region II Atlanta Federal Center 61 Forsyth St.,

SW, Suite 23T85 Atlanta, Georgia 30303 Mr.

D.

W. Rich Senior Resident Inspector Oconee Nuclear Station Mr.

Henry Porter, Director Division of Radioactive Waste Management Bureau of Land and Waste Management Department of Health & Environmental Control 2600 Bull Street Columbia, S.C.

29201

U.

S. Nuclear Regulatory Commission February 22, 2007 bcc:

L. F. Vaughn R. L. Gill NRI&A K. L. Ashe -

MNS R. D. Hart -

CNS S. D. Capps P. E. Mabry J. A. Patterson P. A. Wells D.

W. Peltola R.

C. Gamberg D.

V. Deatherage S.

L. Batson D.

B. Coyle K.

R. Redmond R.

V. Gambrell B.

G. Davenport BWOG Working Group ONS Document Management ELL NSRB NEI

U.

S.

Nuclear Regulatory Commission February 22, 2007 Attachment Commitments

U.

S.

Nuclear Regulatory Commission February 22, 2007 Attachment Commitments Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds The following commitments are contained in this letter.

Action Commitment Completion Date Repair Mitigation of Alloy 600/82/182 Pressurizer Butt Welds as stated in Unit 2 Attachments 3 and 4 of our January 31, 2007 letter for Oconee Units 2 and 2 EOC 22

3.

4/2007 Unit 3 3 EOC 23 10/2007 Procedure Enhanced leakage detection as stated below:

Implementation NLT 3/1/2007, until mitigation completion Unidentified leakage will be determined daily whenever the unit is in Mode 1, 2, or 3 steady state operations; If unidentified Reactor Coolant System (RCS) leakage increases 0.1 gallon per minute over the previous daily reading and is sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the unit will take action to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and perform bare metal visual examination of the Alloy 600/82/182 butt weld locations, unless it can be confirmed the increase is not from these pressurizer welds; If unidentified RCS leakage increases 0.25 gallons per minute above baseline and is sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> the unit will take action to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and perform bare metal visual examination of the Alloy 600/82/182 butt weld locations, unless it can be confirmed the increase is not from these pressurizer welds; The baseline RCS leakage rate will be determined from data obtained during the first 7 days of steady state operation at 100% after the most recent bare metal visual inspection of pressurizer welds for that unit.

Report Inspection results of any bare metal visual examinations performed will be As occurs provided to the NRC in a written report within 60 days of restart.

Letter The NRC will be informed if Oconee revises any of the information As necessary contained in this letter.