ML070590212

Commitment to Perform Enhanced Leak Monitoring Associated with Pressurizer Dissimilar Welds and Reactor Coolant System

ML070590212
Person / Time
Site:	Palo Verde
Issue date:	02/16/2007
From:	Bement R Arizona Public Service Co
To:	Document Control Desk, NRC/NRR/ADRO
References
102-05643-RSB/SAB/RJR
Download: ML070590212 (3)

Text

A subsidiary of Pinnacle West Capital Corporation Palo Verde Nuclear Generating Station Robert S. Bement Vice President Nuclear Operations Tel (623) 393-6116 Fax (623) 393-6077 Mail Station 7602 PO Box 52034 Phoenix, Arizona 85072-2034 102-05643-RSB/SAB/RJR February 16, 2007 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2, and 3 Docket Nos. STN 50-5281529/530 Commitment to Perform Enhanced Leak Monitoring Associated with Pressurizer Dissimilar Welds and Reactor Coolant System This letter documents the commitment made in a telephone call between the NRC and Arizona Public Service Company on February 15, 2007, to perform enhanced reactor coolant system leakage monitoring at PVNGS Units 1, 2 and 3. This new commitment will be implemented by March 1, 2007, as discussed with the NRC, and replaces the previous commitment made in APS letter 102-05640, dated January 31, 2007.Previous Commitment to be superseded:

Revise plant procedures to state that if a shutdown of a unit should occur due to excessive primary system unidentified leakage, and if the leakage cannot be confirmed to originate from a source other than the pressurizer, perform a bare metal visual examination of the Alloy 600/82/182 butt weld locations on the pressurizer to determine whether the leakage originated from those locations.

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak 0 Diablo Canyon

• Palo Verde

• South Texas Project 0 Wolf Creek Aow NRC Document Control Desk Commitment Associated with Pressurizer Dissimilar Welds and Reactor Coolant System Page 2 New Commitment:

Pressurizer Dissimilar Welds and RCS Leak Monitoring RCS LeakReiscto Weld Inspection Date Monitoring RCS Leak Monitoring Action RCS Leak Monitoring Re-inspection Frequency (2)(3) Levels Actions Reporting Frequency Inspect by 12/31/07 Daily while the (1) A 0.1 gpm change from one Once the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Report details of Within every 4 plant is in day to the next, sustained for evaluation period is inspection results of years, until the OR MODES 1-3. (4) 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with at least 0.1 gpm complete, and the any unmitigated weld welds are not confirmed from sources leakrate is still elevated, examination and any removed from Plant is shutdown with other than pressurizer nozzle place the unit in MODE corrective or mitigative service or inspections completed prior to welds. 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and action within 60 days mitigated.

plant operation above 200 MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> of unit restart.degrees F (average RCS (2) A 0.25 gpm above a and perform a bare temperature in Mode 5) after baseline (established using metal visual inspection Report bare metal 12/31/07 RCS leakrate information of unmitigated visual inspection OR collected within 7 days after pressurizer surge, spray, results within 60 days achieving steady state in safety and relief nozzle of the unit restart.Commit to develop contingency MODE 1 operation after the butt welds, and safe end plans to inspect welds prior to most recent bare metal visual butt welds containing 12/31/07 if MRP calculations do examination) sustained for 72 alloy 82/182 material not demonstrate adequate hours with 0.25 gpm not safety. (1) confirmed from sources other than the pressurizer nozzle welds.Notes: 1. This commitment was made for PVNGS Unit 2 in letter 102-05640, dated January 31, 2007, by stating that APS will accelerate the Unit 2 weld overlays currently scheduled for the spring of 2008 if analytical results do not demonstrate that current schedules are adequate or if new information is obtained during upcoming inspections that challenge current assumptions.

2. PVNGS Technical Specification Surveillance Requirement 3.0.2, which allows 1.25 times the interval specified in the Frequency applies to these intervals.

3. As specified in PVNGS Technical Specification 3.4.14, "RCS Operational Leakage," Surveillance Requirement 3.4.14.1, RCS water inventory balance [leak monitoring]

is 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 and applies to this leak monitoring.

This same provision is provided in NUREG-1432 Volume 1, Revision 3.0, "Standard Technical Specifications Combustion Engineering Plants," Specification 3.4.13, "RCS Operational Leakage," Surveillance Requirement 3.4.13.1.4. "Daily" is defined as a frequency of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

NRC Document Control Desk Commitment Associated with Pressurizer Dissimilar Welds and Reactor Coolant System Page 3 If you have any questions, please contact Thomas N. Weber at (623) 393-5764.CDM/SAB/RJR/gt cc: B. S. Mallett M. B. Fields M. T. Markley G. G. Warnick NRC Region IV Regional Administrator NRC NRR Project Manager NRC NRR Project Manager NRC Senior Resident Inspector for PVNGS