RC-07-0028, Inspection and Mitigation of Alloy 82/182 Pressurizer Butt Welds (C-04-1719) - Supplement

Inspection and Mitigation of Alloy 82/182 Pressurizer Butt Welds (C-04-1719) - Supplement

ML070520146
Person / Time
Site:	Summer
Issue date:	02/19/2007
From:	Archie J South Carolina Electric & Gas Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
C-04-1719, RC-07-0028
Download: ML070520146 (4)

Text

Jeffrey B. Archie Vice President,Nuclear Operations 803.345.4214 February 19, 2007 RC-07-0028 A SCANA COMPANY U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

VIRGIL C. SUMMER NUCLEAR STATION (VCSNS)

DOCKET NO. 50/395 OPERATING LICENSE NO. NPF-12 INSPECTION AND MITIGATION OF ALLOY 82/182 PRESSURIZER BUTT WELDS (C-04-1719) - SUPPLEMENT

Reference:

1. Marvin S. Fertel (NEI) Letter to Luis A. Reyes (NRC), Industry Actions Associated with Potential Generic Implications of Wolf Creek Inspection Findings, January 26, 2007

2. Jeffrey B. Archie Letter to Document Control Desk, Inspection and Mitigation of Alloy 82/182 Pressurizer Butt Welds (C-04-1719), dated January 31, 2007, RC-07-0021 Pursuant to your February 12, 2007 telephone conference call with our Virgil C. Summer Nuclear Station (VCSNS) staff, South Carolina Electric and Gas Co. (SCE&G) submits a supplemental response to reference 2.

In response to your concerns regarding reactor coolant system (RCS) leakage monitoring, VCSNS is performing the following RCS leakage measurements:

• Daily measurement of unidentified leakage.

• Identification of unidentified leakage rates greater than either of the following limits when this increase is maintained for 3 days:

0.25 gpm greater than a baseline value.

The baseline is established as the value obtained following 7 days of full power operation after startup following the last bare metal visual examination of the pressurizer Alloy 82/182 butt weld locations.

0.1 gpm increase between two consecutive daily measurements.

" If unidentified leakage exceeds either limit, identify the source within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or shut down the plant and perform bare metal visual examinations of all pressurizer Alloy 82/182 butt weld locations. Following the initiation of a shutdown, the plant must be in Hot Standby in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

SCE&G I Virgil C.Summer Nuclear Station - P.0. Box 88

• Jenkinsville, South Carolina 29065

• T(803) 345.5209

• www.swana.com Ailo

Document Control Desk Letter C-04-1719 RC-07-0028 Page 2 of 2

• A positive determination that the source of the unidentified leakage did not come from the pressurizer will negate the requirement for shutdown and/or pressurizer Alloy 82/182 butt weld bare metal examination.

• If a quantity of leakage can be assigned to a source other than the pressurizer and that quantity decreases the unidentified leakage below one of the thresholds (0.1 gpm step increase or 0.25 gpm above baseline), this will negate the requirement for shutdown and/or pressurizer Alloy 82/182 butt weld bare metal examination.

" Report results of any bare metal visual inspections to NRC 60 days after plant start up.

In response to your concerns regarding schedule acceleration, VCSNS will accelerate its inspection or mitigation outage, currently scheduled for April 2008, into 2007 if the results of ongoing industry analysis do not demonstrate to the NRC that current schedules are adequate.

In addition, the schedule could be accelerated into 2007 if new information is obtained during upcoming inspections that challenge current assumptions.

Commitments made through this letter are identified in the attachment to this letter and will be in place until the pressurizer Alloy 82/182 butt welds have been successfully inspected and/or mitigated.

SCE&G staff is available to meet with the NRC to discuss any of the information contained in this letter.

Should you have questions, please call Mr. Bruce Thompson at (803) 931-5042.

AJC/JBA/dr

Attachment:

List of Commitments c: K. B. Marsh NRC Resident Inspector S. A. Byrne K. M. Sutton N. S. Cams J. Riley (NEI)

J. H. Hamilton NSRC R. J. White RTS (C-04-1719)

W. D. Travers File (815.02)

R. E. Martin DMS (RC-07-0028)

Document Control Desk Letter Attachment C-04-1719 RC-070028 Page 1 of 2 List of Commitments Alloy 821182 Program Enhancements COMMITTED COMMITMENT TYPE No. COMMITMENT DATE OR ONE-TIME ACTION PROGRAMMATIC "OUTAGE" (Yes/No) ACTION (Yes/No)

Daily measurement of unidentified Until inspection Yes No leakage. and/or mitigation of pressurizer Alloy 82/182 butt welds

2. Identification of unidentified leakage Until inspection Yes No rates greater than either of the and/or mitigation of following limits when this increase is pressurizer Alloy maintained for 3 days: 82/182 butt welds 0.25 gpm greater than a baseline value.

The baseline is established as the value obtained following 7 days of full power operation after startup following the last bare metal visual examination of the pressurizer Alloy 82/182 butt weld locations.

0.1 gpm increase between two consecutive daily measurements.

3. If unidentified leakage exceeds either Until inspection Yes No limit, identify the source within 72 and/or mitigation of hours or shut down the plant and pressurizer Alloy perform bare metal visual 82/182 butt welds examinations of all pressurizer Alloy 82/182 butt weld locations. Following the initiation of a shutdown, the plant must be in Hot Standby in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

4. Results of any bare metal visual Until inspection Yes No inspections will be reported to the and/or mitigation of NRC 60 days after plant start up. pressurizer Alloy 82/182 butt welds

Document Control Desk Letter Attachment C-04-1719 RC-070028 Page 2 of 2 COMMITTED COMMITMENT TYPE No. COMMITMENT DATE OR PROGRAMMATIC "OUTAGE" (Yes-No) ACTION (Yes/No)

5. VCSNS will accelerate its inspection Until inspection Yes No or mitigation outage, currently and/or mitigation of scheduled for April 2008, into 2007 if pressurizer Alloy the results of ongoing industry 82/182 butt welds analysis do not demonstrate to the NRC that current schedules are adequate. In addition, the schedule could be accelerated into 2007 if new information is obtained during upcoming inspections that challenge current assumptions.