ML073461017
| ML073461017 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/12/2007 |
| From: | Schwarz C Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC MD4168, NRR-07-023 | |
| Download: ML073461017 (8) | |
Text
Entergy Nuciear Operations, lnc.
Palisades Nuclear Plant 27780 Blue Star Pderriorial i-iiyhibvay Covert. MI 49043 December 12,2007 CAL No. NRR-07-023 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Palisades Nuclear Plant Docket 50-255 License No. DPR-20 60-Dav Post-Outaqe Report per CAL No. NRR-07-023 Pressurizer Butt Weld Inspection
Dear Sir or Madam:
On March 29,2007, the Nuclear Regulatory Commission (NRC) issued CAL NRR-07-023, "Confirmatory Action Letter - Palisades Nuclear Plant (TAC No. MD4168)," confirming new and revised commitments made on February 27, 2007, by the Nuclear Management Company, LLC (NMC), former license holder for Palisades Nuclear Plant (PNP). The commitments addressed actions that would be taken regarding pressurizer dissimilar metal butt welds containing Alloy 600182/182 material.
The PNP 2007 refueling outage began on September 9, 2007, and the plant was returned to operation on October 21, 2007. During the outage, Entergy Nuclear Operations, Inc. (ENO) conducted inspection of all pressurizer dissimilar metal butt welds containing Alloy 600/82/182 material in accordance with commitments and qualified procedures, Inspections included a combination of bare-metal and volumetric examinations. Thirteen butt weld piping connections containing Alloy 600/82/182 butt welds were examined. Based on the results of the examinations performed, EN0 concluded that all Alloy 600/82/182 pressurizer butt welds that were returned to service, following the 2007 refueling outage, were not degraded, and no wastage of the pressurizer occurred. Enclosure 1 provides the details of the inspection results.
Document Gor~trolDesk Page 2 This letter documents the completion of six commitments. No new commitments have been made, and remaining commitments have not been revised.
Site Vice President Palisades Nuclear Plant Enclosure CC Administrator, Region Ill, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC
ENCLOSURE 7 60-DAY REPORT PER CAL NRR-07-623 PRESSURIZER BUTT WELD INSPECTION RESULTS 8INTRODUCTION On March 29, 2007, the Nuclear Regulatory Commission (NRC) issued CAL NRR-07-023, "Confirmatory Action Letter - Palisades Nuclear Plant (TAC No. MD4168)," confirming new and revised commitments made on February 27,2007, by the Nuclear Management Company, LLC (NMC), former license holder for Palisades Nuclear Plant (PNP). The commitments addressed actions that would be taken regarding pressurizer dissimilar metal butt welds containing Alloy 600/82/182 material.
The PNP 2007 refueling outage began on September 9, 2007, and the plant was returned to operation on October 21, 2007. During the outage, Entergy Nuclear Operations, Inc. (ENO) conducted inspection of all pressurizer dissimilar metal butt welds containing Alloy 600/82/182 material in accordance with commitments and qualified procedures. lnspections included a combination of bare-metal and volumetric examinations. Thirteen butt weld piping connections containing Alloy 600/82/182 butt welds were examined. Based on the results of the examinations performed, E N 0 concluded that all Alloy 6001821182 pressurizer butt welds that were returned to service, following the 2007 refueling outage, were not degraded, and no wastage of the pressurizer occurred.
2.0 DESCRIPTION
OF INSPECTION METHODS Bare metal, direct visual examinations were performed by qualified Consumers Energy personnel using qualified procedures to examine the eight butt-welded level taps, three pressurizer safety valve mounting flange to nozzle welds, spray line safe end welds to elbow and nozzle, and the surge line nozzle to safe end weld that had been mitigated by mechanical stress improvement (MSIP) in 1995.
Performance Demonstration Initiative (PDI) - qualified ultrasonic (UT) examinations were performed by qualified Consumers Energy personnel using qualified procedures. lnspections included examination from the outer diameter (OD) of the spray nozzle safe end welds, and examinations from the inner and outer diameters (ID and OD) of the three Alloy 600 safety valve mounting flanges and nozzle butt welds.
3.0 COMMITMENTS AND RESULTS In February 2007, NMC made a total of eight new and revised commitments for Palisades (referenced as PNP) regarding Alloy 600/82/182 pressurizer butt welds.
The Palisades operating license has since been transferred to ENO. Commitments 1 through 4 apply to non-outage activities and terminate upon completion of the Page 1 of 6
2007 refueling outage. This report completes the requirements of Commitments 5 and 6. Only Commitments 7 and 8 will remain open.
All Alloy 6001821182 pressurizer butt welds were examined during the 2007 refueling outage. There was no evidence of cracking or leakage.
Commitment 1:
NMC will determine unidentified leakage daily whenever the unit is in Mode I , 2, or 3 steady state operations, until the completion of the 2007 refueling outage at PNP.
NMC will implement this commitment no later than March 8, 2007. NMC will notify the NRC in writing, prior to making any changes to this commitment.
Results for Commitment 1 :
On March 7, 2007, Revision 76 of Technical Specification Surveillance Procedure DWO-1, "Operator's DailyMeekly Items, Modes 1, 2, 3, and 4," which incorporated this commitment, was issued. NMC and E N 0 determined unidentified leakage daily as required.
Commitment 1 was fulfilled upon completion of the 2007 refueling outage.
Commitment 2:
If the unidentified Primary Coolant System (PCS) leakage increases 0. I gallons per minute (gprn) 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 />, NNIC 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 a 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, until the completion of the 2007 refueling outage at PNP. NMC will implement this commitment no later than March 8, 2007. NlLlC will notify the NRC in writing, prior to making any changes in this commitment.
Results for Commitment 2:
On March 7, 2007, NMC issued Revision 76 of Technical Specification Surveillance Procedure DWO-1, "Operator's Daily/Weekly Items, Modes 1, 2, 3, and 4," which incorporated this commitment.
Palisades did not enter the conditions that would have required pressurizer butt weld inspection under this commitment.
Commitment 2 was fulfilled upon completion of the 2007 refueling outage.
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If unidentified PCS leakage increases 0.25 gpm above baseline (see item 4) and is sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, NMC 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 a bare metal visual examination of the Alloy 600/8=1/182butt-weld locations, unless it can be confirmed the increase is not from these pressurizer welds, until the completion of the refueling outage at PNP.
NMC will implement this commitment no later than March 8, 2007. NNlC will notify the NRC in writing, prior to making any changes in this commitment.
Results for Commitment 3:
On March 7, 2007, NMC issued Revision 76 of Technical Specification Surveillance Procedure DWO-I, "Operator's DailylWeekly Items, Modes 1, 2, 3, and 4," which incorporated this commitment.
Palisades did not enter the conditions that would have required pressurizer butt weld inspection under this commitment.
Commitment 3 was fulfilled upon completion of the 2007 refueling outage.
Commitment 4:
NMC will determine the baseline PCS leakage rate from data obtained during the first 7 days of steady state operation at approximately 100% power, after the most recent bare metal visual examination of the Alloy 600/82/182 butt-welds, until the completion of the 2007 refueling outage at PNP. NMC will implement this commitment no later than March 8, 2007. NNlC will notify the NRC in writing, prior to making any changes in this commitment.
Results for Commitment 4:
Prior to the 2007 refueling outage, the most recent bare metal visual examination of Alloy 600/82/182 pressurizer butt welds occurred during the 2006 refueling outage.
On March 7, 2007, NMC issued Revision 76 of Technical Specification Surveillance Procedure DWO-I , "Operator's Daily/Weekly Items, Modes 1, 2, 3, and 4," which incorporated a 7-day baseline leakage rate of 0.023 gpm in accordance with this commitment.
Commitment 4 was fulfilled upon completion of the 2007 refueling outage.
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Commitment 5:
NMC will provide inspection results of any bare metal visual examinations performed as a result of these requirements to the NRC in a written report within 60 days of plant restart until the completion of the 2007 refueling outage at PNP. NMC will notify the NRC in writing, prior to making any changes to this commitment.
Results for Commitment 5:
Bare metal visual examinations of all Alloy 600/82/182 pressurizer butt welds were performed during the 2007 refueling outage, although they were not required by Commitments 2 and 3. There was no accumulation of boric acid in the vicinity of the welds.
Commitment 5 is fulfilled upon submittal of this 60-day report.
Commitment 6:
NMC will complete inspections of the pressurizer ANoy 600/82/182 butt-welds at PNP during the 2007 refueling outage per the industry guidance, IVIRP- 139
[Materials Reliability Program: Primary System Piping Butt Weld Inspection and Evaluation Guideline]. NNIC will notify the NRC in writing, prior to making any changes to this Commitment.
Results for Commitment 6:
During the 2007 refueling outage, EN0 conducted PDI-qualified UT examinations of pressurizer spray line welds in accordance with MRP-139 Category D, and pressurizer safety valve flanges and welds in accordance with MRP-139 Category H. EN0 performed qualified bare metal visual examinations of pressurizer level tap welds in accordance with MRP-139 Category J for weldments less than 4-inch nominal pipe size at pressurizer temperatures.
EN0 performed a qualified bare metal visual examination of the pressurizer surge nozzle to safe end weld that was mitigated with Mechanical Stress Improvement (MSIP) in 1995, in accordance with MRP-139 Category C. A separate commitment requires EN0 to perform volumetric examination every two refueling cycles for Alloy 600 welds mitigated by MSIP. PDI-qualified UT examination of the pressurizer surge nozzle to safe end weld was performed during the 2006 refueling outage.
Ail inspections of pressurizer Alloy 6001821182 butt welds have been completed in accordance with MRP-139. All examination results were acceptable.
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Commitment 6 was fulfilled upon completion of the 2007 refueling outage.
Commitment 7:
NMC will inspect the Alloy 600/82/182 pressurizer butt-welds per MRP- 139, on a frequency of at least every four years, until the Alloy 600/82/182 pressurizer butt-welds are mitigated or removed at PNP. NMC will notify the NRC in writing, prior to making any changes to this commitment.
Results for Commitment 7 :
Alloy 6001821182 pressurizer surge line butt welds were mitigated with Mechanical Stress Improvement (MSIP) in 1995. Alloy 6001821182 power operated relief valve line butt welds were removed in 1995. All existing Alloy 6001821182 pressurizer butt welds were examined in accordance with MRP-139 within the last two refueling outages (Spring 2006 and Fa11 2007). The four-year frequency will not be exceeded for any affected weld by the next refueling outage, which is scheduled for Spring 2009.
Commitment 7 is not changed.
Commitment 8:
NMC will provide results of future inspections, including inspections on unmitigated welds and any corrective or mitigative actions taken on the pressurizer surge, spray, safety, or relief nozzle and safe end welds containing Alloy 600/82/182 material, within 60 days of the end of the station refueling outage during which the inspection was performed, until the Alloy 600/82/182 pressurizer buft-welds are mitigated or removed at PNP. NMC will notify the NRC in writing, prior to making any changes to this commitment.
Results for Commitment 8:
Palisades returned to operation from its most recent refueling outage on October 21, 2007. This 60-day report describes inspections and their results for pressurizer surge, spray, safety, and relief nozzle and safe end welds containing Alloy 600/82/182 material. No corrective or mitigative actions were taken during the 2007 refueling outage for these welds.
Commitment 8 is not changed.
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4.0 CONCLUSION
S E N 0 has complied with commitments described in CAL NRR-07-023 for the 2007 PNP refueling outage. Based on the results of the examinations performed during the refueling outage, E N 0 concluded that all Alloy 6001821182 pressurizer butt welds that were returned to service were not degraded.
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