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| | issue date = 04/05/2011 | | | issue date = 04/05/2011 |
| | title = Evaluation Regarding the 2009 Steam Generator Tube Inspections Performed During the 15th Refueling Outage (2R15) | | | title = Evaluation Regarding the 2009 Steam Generator Tube Inspections Performed During the 15th Refueling Outage (2R15) |
| | author name = Wang A B | | | author name = Wang A |
| | author affiliation = NRC/NRR/DORL/LPLIV | | | author affiliation = NRC/NRR/DORL/LPLIV |
| | addressee name = Conway J T | | | addressee name = Conway J |
| | addressee affiliation = Pacific Gas & Electric Co | | | addressee affiliation = Pacific Gas & Electric Co |
| | docket = 05000323 | | | docket = 05000323 |
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| =Text= | | =Text= |
| {{#Wiki_filter:UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555*0001 April 5. 2011 Mr. John T. Conway Senior Vice President | | {{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 April 5. 2011 Mr. John T. Conway Senior Vice President -- Energy Supply and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant 77 Beale Street, Mail Code B32 San Francisco, CA 94105 |
| --Energy Supply and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant 77 Beale Street, Mail Code B32 San Francisco, CA 94105 DIABLO CANYON POWER PLANT, UNIT NO.2 -EVALUATION REGARDING THE 2009 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. ME3995) | | |
| | ==SUBJECT:== |
| | DIABLO CANYON POWER PLANT, UNIT NO.2 - EVALUATION REGARDING THE 2009 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. ME3995) |
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| ==Dear Mr. Conway:== | | ==Dear Mr. Conway:== |
| By letter dated May 5, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 101330269), Pacific Gas and Electric Company (the licensee), submitted information summarizing the results of the 2009 steam generator (SG) tube inspections performed at Diablo Canyon Power Plant (DCPP), Unit No.2. These inspections were performed during the fifteenth refueling outage (2R15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at DCPP, Unit No.2, provided by the licensee in a letter dated November 24,2010 (ADAMS Accession No. ML 103300051). | | |
| The NRC staff has completed its review of these reports and concludes that the licensee provided the information required by the DCPP, Unit No.2, technical specifications. | | By letter dated May 5, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML101330269), Pacific Gas and Electric Company (the licensee), |
| No additional follow-up is required at this time. That staff's review of this report is enclosed. | | submitted information summarizing the results of the 2009 steam generator (SG) tube inspections performed at Diablo Canyon Power Plant (DCPP), Unit No.2. These inspections were performed during the fifteenth refueling outage (2R15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at DCPP, Unit No.2, provided by the licensee in a letter dated November 24,2010 (ADAMS Accession No. ML103300051). |
| | The NRC staff has completed its review of these reports and concludes that the licensee provided the information required by the DCPP, Unit No.2, technical specifications. No additional follow-up is required at this time. That staff's review of this report is enclosed. |
| If you have any questions regarding this matter, please contact me at (301) 415-1445. | | If you have any questions regarding this matter, please contact me at (301) 415-1445. |
| Sincerely, rll n.. \ . \ | | Sincerely, rll n.. \ . \ |
| .. Alan B. Wang, Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-323 | | ~ \J\)6.-~ .. |
| | Alan B. Wang, Projec(~nager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-323 |
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| ==Enclosure:== | | ==Enclosure:== |
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| As stated cc w/encl: Distribution via Listserv | | As stated cc w/encl: Distribution via Listserv |
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| ==SUMMARY== | | ==SUMMARY== |
| OF U.S. NUCLEAR REGULATORY COMMISSION STAFF'S REVIEW 2009 STEAM GENERATOR TUBE INSPECTIONS PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON POWER PLANT, UNIT NO.2 DOCKET NO. 50-323 By letter dated May 5, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 101330269), Pacific Gas and Electric Company (the licensee), submitted information summarizing the results of the 2009 steam generator (SG) tube inspections performed at Diablo Canyon Power Plant (DCPP), Unit No.2. These inspections were performed during the fifteenth refueling outage (2R 15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at DCPP, Unit No.2, provided by the licensee in a letter dated November 24,2010 (ADAMS Accession No. ML 103300051). | | OF U.S. NUCLEAR REGULATORY COMMISSION STAFF'S REVIEW 2009 STEAM GENERATOR TUBE INSPECTIONS PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON POWER PLANT, UNIT NO.2 DOCKET NO. 50-323 By letter dated May 5, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML101330269), Pacific Gas and Electric Company (the licensee), |
| DCPP, Unit No.2, has four Westinghouse Model D54 SGs, each of which contains 4,444 thermally-treated Alloy 690 tubes. Each tube has a nominal outside diameter of 0.75 inches. During SG fabrication, the tubes were hydraulically expanded over the full depth of the tubesheet. | | submitted information summarizing the results of the 2009 steam generator (SG) tube inspections performed at Diablo Canyon Power Plant (DCPP), Unit No.2. These inspections were performed during the fifteenth refueling outage (2R 15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at DCPP, Unit No.2, provided by the licensee in a letter dated November 24,2010 (ADAMS Accession No. ML103300051). |
| The end of each tube is tack-expanded using a urethane plug expansion process. The tubes are arranged on a triangular pitch with 1.144-inch spacing. The tubes in rows 1 through 16 were full-length stress relieved following bending. Eight Type 405 stainless steel support plates, which have broached trefoil-shaped holes, support the vertical section of tubes. In the U-bend section, there are three sets of "V' shaped, rectangular stainless steel (Type 405) anti-vibration bars. The licensee provided the scope, extent, methods, and results of its SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (i.e., tube plugging) taken in response to the inspection findings. | | DCPP, Unit No.2, has four Westinghouse Model D54 SGs, each of which contains 4,444 thermally-treated Alloy 690 tubes. Each tube has a nominal outside diameter of 0.75 inches. During SG fabrication, the tubes were hydraulically expanded over the full depth of the tubesheet. The end of each tube is tack-expanded using a urethane plug expansion process. The tubes are arranged on a triangular pitch with 1.144-inch spacing. The tubes in rows 1 through 16 were full-length stress relieved following bending. Eight Type 405 stainless steel support plates, which have broached trefoil-shaped holes, support the vertical section of tubes. In the U-bend section, there are three sets of "V' shaped, rectangular stainless steel (Type 405) anti-vibration bars. |
| | The licensee provided the scope, extent, methods, and results of its SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (i.e., tube plugging) taken in response to the inspection findings. |
| After reviewing the information provided by the licensee, the NRC staff has the following comments or observations: | | After reviewing the information provided by the licensee, the NRC staff has the following comments or observations: |
| * There are 12 tubes with proximity indication Signals in the U-bend region. The signals were attributed to the proximity of a given tube to another tube. The licensee conducted | | * There are 12 tubes with proximity indication Signals in the U-bend region. The signals were attributed to the proximity of a given tube to another tube. The licensee conducted +Point probe inspections on the 12 tubes and no tube-to-tube contact or wear was associated with these proximity signals. These signals were observed during both the preservice inspection and the 2009 inspections. A potential cause of these Signals is manufacturing tolerances on a tube-to-tube basis (e.g., tolerances on U-bend profile and overall tube height). A tolerance stack-up indicates a reduced gap may occur, but tube-to-tube contact is not possible. Similar conditions have occurred at other plants. |
| +Point probe inspections on the 12 tubes and no tube-to-tube contact or wear was associated with these proximity signals. These signals were observed during both the preservice inspection and the 2009 inspections. | | * During fabrication, 12 tubes were reported to be visibly damaged by a grinding tool. Of these 12 tubes, 3 were plugged with welded plugs at the factory. The Enclosure |
| A potential cause of these Signals is manufacturing tolerances on a tube-to-tube basis (e.g., tolerances on U-bend profile and overall tube height). A tolerance stack-up indicates a reduced gap may occur, but tube-to-tube contact is not possible. | | |
| Similar conditions have occurred at other plants. | | - 2 remaining nine tubes remain inservice and have no indication of degradation, but eight of the nine tubes have ding signals at the visibly damaged area. |
| * During fabrication, 12 tubes were reported to be visibly damaged by a grinding tool. Of these 12 tubes, 3 were plugged with welded plugs at the factory. The Enclosure | | Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the DCPP, Unit No.2, technical specifications. In addition, the NRC staff concludes that there are no technical issues that warrant follow-up actions at this time since the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units. |
| -remaining nine tubes remain inservice and have no indication of degradation, but eight of the nine tubes have ding signals at the visibly damaged area. Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the DCPP, Unit No.2, technical specifications. | | |
| In addition, the NRC staff concludes that there are no technical issues that warrant follow-up actions at this time since the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units. | | April 5, 2011 Mr. John T. Conway Senior Vice President - Energy Supply and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant 77 Beale Street, Mail Code B32 San Francisco, CA 94105 |
| April 5, 2011 Mr. John T. Conway Senior Vice President | | |
| -Energy Supply and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant 77 Beale Street, Mail Code B32 San Francisco, CA 94105 DIABLO CANYON POWER PLANT, UNIT NO.2 -EVALUATION REGARDING THE 2009 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. ME3995) | | ==SUBJECT:== |
| | DIABLO CANYON POWER PLANT, UNIT NO.2 - EVALUATION REGARDING THE 2009 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. ME3995) |
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| ==Dear Mr. Conway:== | | ==Dear Mr. Conway:== |
| By letter dated May 5, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 101330269), Pacific Gas and Electric Company (the licensee), submitted information summarizing the results of the 2009 steam generator (SG) tube inspections performed at Diablo Canyon Power Plant (DCPP), Unit No.2. These inspections were performed during the fifteenth refueling outage (2R15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at DCPP, Unit No.2, provided by the licensee in a letter dated November 24,2010 (ADAMS Accession No. ML 103300051). | | |
| The NRC staff has completed its review of these reports and concludes that the licensee provided the information required by the DCPP, Unit No.2, technical specifications. | | By letter dated May 5, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML101330269), Pacific Gas and Electric Company (the licensee), |
| No additional follow-up is required at this time. That staff's review of this report is enclosed. | | submitted information summarizing the results of the 2009 steam generator (SG) tube inspections performed at Diablo Canyon Power Plant (DCPP), Unit No.2. These inspections were performed during the fifteenth refueling outage (2R15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at DCPP, Unit No.2, provided by the licensee in a letter dated November 24,2010 (ADAMS Accession No. ML103300051). |
| | The NRC staff has completed its review of these reports and concludes that the licensee provided the information required by the DCPP, Unit No.2, technical specifications. No additional follow-up is required at this time. That staff's review of this report is enclosed. |
| If you have any questions regarding this matter, please contact me at (301) 415-1445. | | If you have any questions regarding this matter, please contact me at (301) 415-1445. |
| Sincerely, IRA! Alan B. Wang, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-323 | | Sincerely, IRA! |
| | Alan B. Wang, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-323 |
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| ==Enclosure:== | | ==Enclosure:== |
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| As stated cc w/encl: Distribution via Listserv DISTRIBUTION: | | As stated cc w/encl: Distribution via Listserv DISTRIBUTION: |
| PUBLIC RidsNrrDorlLpl4 Resource RidsRgn4MailCenter Resource LPLIV Reading RidsNrrLAJBu rkhardt Resource KKarwoski, NRRIDCIICSGB RidsAcrsAcnw | | PUBLIC RidsNrrDorlLpl4 Resource RidsRgn4MailCenter Resource LPLIV Reading RidsNrrLAJBu rkhardt Resource KKarwoski, NRRIDCIICSGB RidsAcrsAcnw_MailCTR Resource RidsNrrPMDiabloCanyon Resource AObodoako, NRR/DCI/CSGB RidsNrrOciCsgb Resource RidsOgcRp Resource ADAMS Accession No. ML110940269 *Memo dated OFFICE NRR/DORLlLPL4/PM RLlLPL4/PM RLlLPL4/LA JPolickoski (AWang for) 4/5/11 NRR/DCI/CSGB/BC NRR/OORLlLPL4/PM RTaylor* AWang 3/9/11 4/5/11}} |
| _ MailCTR Resource RidsNrrPMDiabloCanyon Resource AObodoako, NRR/DCI/CSGB RidsNrrOciCsgb Resource RidsOgcRp Resource ADAMS Accession No. ML110940269
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| *Memo dated OFFICE NRR/DORLlLPL4/PM RLlLPL4/PM | |
| ----JPolickoski (AWang for) 4/5/11 NRR/DCI/CSGB/BC RTaylor* 3/9/11 RLlLPL4/LA NRR/OORLlLPL4/PM AWang 4/5/11}}
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Category:Letter
MONTHYEARML24260A1222024-09-14014 September 2024 14 Sept 2024 Ltr - California Coastal Commission to Pg&E, Incomplete Consistency Certification for Requested Nuclear Regulatory Commission License Renewal for Diablo Canyon Power Plant DCL-24-087, License Renewal - Historic and Cultural Resources Reference Documents (Redacted)2024-09-12012 September 2024 License Renewal - Historic and Cultural Resources Reference Documents (Redacted) ML24262A2462024-09-11011 September 2024 10 CFR 2.206 - Diablo Canyon Units 1 and 2 Seismic - Petitioner Response to Acknowledgement Letter - DCL-24-083, CFR Part 21 Notification: Commercially Dedicated Snubber Valve Not Properly Heat Treated2024-09-0909 September 2024 CFR Part 21 Notification: Commercially Dedicated Snubber Valve Not Properly Heat Treated DCL-24-078, Pre-Notice of Disbursement from Decommissioning Trust2024-09-0303 September 2024 Pre-Notice of Disbursement from Decommissioning Trust DCL-24-082, Decommissioning Draft Biological Assessment and Draft Essential Fish Habitat Assessment2024-08-28028 August 2024 Decommissioning Draft Biological Assessment and Draft Essential Fish Habitat Assessment ML24205A0662024-08-27027 August 2024 OEDO-24-00083 - 10 CFR 2.206 - Ack Letter - Diablo Canyon Units 1 and 2 Seismic Core Damage Frequency - IR 05000275/20243012024-08-26026 August 2024 NRC Examination Report 05000275/2024301; 05000323/2024301 IR 05000275/20240052024-08-22022 August 2024 Updated Inspection Plan for Diablo Canyon Power Plant, Units 1 and 2 (Report 05000275/2024005 and 05000323/2024005) DCL-24-077, Responses to NRC Requests for Additional Information on Diablo Canyon Power License Renewal Application Severe Accident2024-08-15015 August 2024 Responses to NRC Requests for Additional Information on Diablo Canyon Power License Renewal Application Severe Accident DCL-24-075, Response to Request for Additional Information for License Amendment Request 23-02, Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power React2024-08-0808 August 2024 Response to Request for Additional Information for License Amendment Request 23-02, Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power React IR 05000275/20240022024-08-0606 August 2024 Integrated Inspection Report 05000275/2024002 and 05000323/2024002 DCL-24-070, License Amendment Request 24-03 Revision to Technical Specification 5.5.16 for Permanent Extension of Type a and Type C Leak Rate Test Frequencies2024-07-31031 July 2024 License Amendment Request 24-03 Revision to Technical Specification 5.5.16 for Permanent Extension of Type a and Type C Leak Rate Test Frequencies DCL-24-071, Core Operating Limits Report for Unit 2 Cycle 252024-07-22022 July 2024 Core Operating Limits Report for Unit 2 Cycle 25 DCL-2024-523, Submittal of Report on Discharge Self-Monitoring2024-07-18018 July 2024 Submittal of Report on Discharge Self-Monitoring ML24187A1352024-07-16016 July 2024 Letter to Paula Gerfen - Diablo Canyon Units 1 and 2 - Summary of June 2024 Audit Related to the License Renewal Application Severe Accident Mitigation Alternatives Review IR 05000275/20240142024-07-11011 July 2024 Age-Related Degradation Inspection Report 05000275/2024014 and 05000323/2024014 IR 05000275/20244012024-07-0808 July 2024 Security Baseline Inspection Report 05000275/2024401 and 05000323/2024401 (Full Report) IR 05000323/20240112024-07-0303 July 2024 License Renewal Phase Report 05000323/2024011 DCL-2024-527, Sea Turtle Stranding Report (Loggerhead Sea Turtle) Diablo Canyon Power Plant2024-07-0101 July 2024 Sea Turtle Stranding Report (Loggerhead Sea Turtle) Diablo Canyon Power Plant DCL-24-066, Request to Extend the Nrg Approval of Alternative for Use of Full Structural Weld Overlay, REP-RHR-SWOL2024-06-27027 June 2024 Request to Extend the Nrg Approval of Alternative for Use of Full Structural Weld Overlay, REP-RHR-SWOL ML24155A2182024-06-18018 June 2024 OEDO-23-00350-NRR - (LTR-23-0228-1) - Closure Letter - 10 CFR 2.206 Petition from Mothers for Peace and Friends of the Earth Regarding Diablo Canyon ML24129A1762024-06-14014 June 2024 National Historic Preservation Act Section 106 Consultation – Results of Identification and Evaluation (Docket Number: 72-026) ML24200A2052024-06-0707 June 2024 Fws to NRC, List of Threatened and Endangered Species That May Occur in Your Proposed Project Location or May Be Affected by Your Proposed Project for Diablo Canyon License Renewal ML24099A2192024-05-29029 May 2024 Issuance of Amendment Nos. 245 and 247 Revision to TSs to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b ML24117A0132024-05-20020 May 2024 Letter to Paula Gerfen-Diablo Canyon Units 1 and 2-Regulatory Audit Regarding Severe Accident Mitigation Alternatives for the License Renewal Application DCL-24-054, LCO 3.0.3 Completion Time Limits2024-05-17017 May 2024 LCO 3.0.3 Completion Time Limits DCL-24-052, Responses to NRC Requests for Additional Information on the Diablo Canyon Power Plant License Renewal Application Environmental Report2024-05-16016 May 2024 Responses to NRC Requests for Additional Information on the Diablo Canyon Power Plant License Renewal Application Environmental Report DCL-24-051, One Hundred Eighty Day Steam Generator Report for Twenty-Fourth Refueling Outage2024-05-0808 May 2024 One Hundred Eighty Day Steam Generator Report for Twenty-Fourth Refueling Outage ML24127A2042024-05-0202 May 2024 02May2024 Ltr - California Coastal Commission to Pg&E, Coastal Development Permit Needed for Pg&E’S Proposed Relicensing of Diablo Canyon Nuclear Power Plant DCL-24-047, 2023 Annual Non-radiological Environmental Operating Report2024-05-0101 May 2024 2023 Annual Non-radiological Environmental Operating Report DCL-24-049, 2023 Annual Radiological Environmental Operating Report2024-05-0101 May 2024 2023 Annual Radiological Environmental Operating Report L-24-004, Independent Spent Fuel Storage Installation - Responses to NRC Requests for Additional Information on the Diablo Canyon Independent Spent Fuel Storage Installation License Renewal Application (Cac/Epid 001028/L-2022-RNW-0007)2024-04-30030 April 2024 Independent Spent Fuel Storage Installation - Responses to NRC Requests for Additional Information on the Diablo Canyon Independent Spent Fuel Storage Installation License Renewal Application (Cac/Epid 001028/L-2022-RNW-0007) DCL-24-048, O CFR 50.59 and 1 O CFR 72.48 Summary Report for the Period of January 1, 2022, Through December 31, 20232024-04-30030 April 2024 O CFR 50.59 and 1 O CFR 72.48 Summary Report for the Period of January 1, 2022, Through December 31, 2023 DCL-24-027, 2023 Annual Radioactive Effluent Release Report2024-04-28028 April 2024 2023 Annual Radioactive Effluent Release Report DCL-24-045, Annual Report of Occupational Radiation Exposure for 20232024-04-24024 April 2024 Annual Report of Occupational Radiation Exposure for 2023 IR 05000275/20240012024-04-23023 April 2024 Integrated Inspection Report 05000275/2024001 and 05000323/2024001 ML24114A2032024-04-22022 April 2024 Request for Information for EP Program and Performance Indicator Verification Inspection (Wolf Creek Nuclear Generating Station) Inspection Report 05000482/2024003 ML24106A2882024-04-18018 April 2024 License Renewal Application Environmental Review RCIs and RAIs ML24106A2892024-04-18018 April 2024 Letter to Paula Gerfen - Diablo Canyon Units 1 and 2 - Summary of March 2024 Audit Regarding the Environmental Review of the License Renewal Application DCL-24-042, Response to NRC Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations2024-04-17017 April 2024 Response to NRC Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations ML24108A1122024-04-15015 April 2024 License Amendment Request 24-02 Request for Approval of DCPP Early Warning System to Meet 10 CFR 73.55(i)(2) and 10 CFR 73.55(e)(9)(vi)(A) DCL-24-022, Notification of Changes to Decommissioning Schedule2024-04-0202 April 2024 Notification of Changes to Decommissioning Schedule DCL-24-023, Revised Certification of Permanent Cessation of Power Operations2024-04-0202 April 2024 Revised Certification of Permanent Cessation of Power Operations DCL-24-031, Decommissioning Funding Report2024-03-27027 March 2024 Decommissioning Funding Report DCL-24-032, 2024 Annual Statement of Insurance for Pacific Gas and Electric Company’S Diablo Canyon Power Plant2024-03-27027 March 2024 2024 Annual Statement of Insurance for Pacific Gas and Electric Company’S Diablo Canyon Power Plant ML24082A2592024-03-25025 March 2024 Notice of Enforcement Discretion for Diablo Canyon Power Plant, Unit 2 (EPID L-2024-LLD-0002) - March 25, 2024 ML24081A0462024-03-22022 March 2024 Audit Summary in Support of the License Amendment Request to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b DCL-24-028, Request for Enforcement Discretion Regarding Compliance with Technical Specification 3.0.3, Limiting Condition for Operation Applicability2024-03-21021 March 2024 Request for Enforcement Discretion Regarding Compliance with Technical Specification 3.0.3, Limiting Condition for Operation Applicability ML24081A4052024-03-21021 March 2024 Request for Enforcement Discretion Regarding Compliance with Technical Specification 3.0.3, Limiting Condition for Operation Applicability 2024-09-09
[Table view] Category:Report
MONTHYEARML24129A1762024-06-14014 June 2024 National Historic Preservation Act Section 106 Consultation – Results of Identification and Evaluation (Docket Number: 72-026) DCL-24-051, One Hundred Eighty Day Steam Generator Report for Twenty-Fourth Refueling Outage2024-05-0808 May 2024 One Hundred Eighty Day Steam Generator Report for Twenty-Fourth Refueling Outage DCL-24-048, O CFR 50.59 and 1 O CFR 72.48 Summary Report for the Period of January 1, 2022, Through December 31, 20232024-04-30030 April 2024 O CFR 50.59 and 1 O CFR 72.48 Summary Report for the Period of January 1, 2022, Through December 31, 2023 ML23307A1622023-11-0303 November 2023 OIG-24-A-01 Inspector Generals Assessment of the Most Serious Management and Performance Challenges Facing the U.S. Nuclear Regulatory Commission in Fiscal Year 2024 ML23130A0052023-06-27027 June 2023 Report to Congress Regarding Diablo Canyon ML22108A2892022-05-0303 May 2022 Enclosure - Response to Representative Carbajal Regarding OIG Report on Diablo ML22108A1662022-05-0303 May 2022 Enclosure 1 - Assessment Event Inquiry Into the Nuclear Regulatory Commission Oversight of the Auxiliary Feedwater System at Diablo Canyon Nuclear L-22-003, Independent Spent Fuel Storage Installation - License Renewal Application for the Diablo Canyon Independent Spent Fuel Storage Installation2022-03-0909 March 2022 Independent Spent Fuel Storage Installation - License Renewal Application for the Diablo Canyon Independent Spent Fuel Storage Installation DCL-21-071, Federally Listed Species Affects Determination Memorandum2021-10-14014 October 2021 Federally Listed Species Affects Determination Memorandum ML21188A0362021-07-0707 July 2021 Draft PG&E Letter DCL-21-046 - Diablo Canyon Unit 1: Emergency License Amendment Request 21-05, Revision to Technical Specification 3.7.8, Auxiliary Saltwater (Asw) System ML21076A6142021-03-17017 March 2021 NRC Examination Report 05000275/2021301 and 05000323/2021301 ML20353A3972020-12-18018 December 2020 NRC Response to Public Comment Regarding Spent Fuel Canister Drop from 2019 Regcon DCL-20-102, Nuclear Material Transaction Report for New Fuel2020-12-0909 December 2020 Nuclear Material Transaction Report for New Fuel ML20335A0132020-11-30030 November 2020 NRC Response to Public Watchdogs November 2 ML20328A3012020-11-23023 November 2020 NERC Reliability Standards for the Bulk Electric System of North America Updated July 20, 2020 (Cgnp Public Comments on Diablo Canyon Nuclear Power Plant, Units 1 and 2 - Pre-submittal Meeting of 11/24/2020) ML20239A9562020-08-26026 August 2020 Evaluation of the Potential Piping Degradation Safety Concern on the Auxiliary Feedwater System at Diablo Canyon Unit 1 DCL-19-054, Submittal of Acceptance Report Following the Installation of Structural Weld Overlay, REP-RHR-SWOL for Unit 12019-07-0101 July 2019 Submittal of Acceptance Report Following the Installation of Structural Weld Overlay, REP-RHR-SWOL for Unit 1 ML18254A0402019-01-22022 January 2019 Staff Review of Seismic Probabilistic Risk Assessment Associated with Reevaluated Seismic Hazard Implementation of the Near Term Task Force Recommendation 2.1: Seismic DCL-18-050, Evaluation Documents in Support of Structural Weld Overlay, REP-RHR-SWOL, Unit 22018-09-11011 September 2018 Evaluation Documents in Support of Structural Weld Overlay, REP-RHR-SWOL, Unit 2 IR 05000275/20180052018-08-31031 August 2018 Updated Inspection Plan for Diablo Canyon Power Plant, Units 1 and 2 (Report 05000275/2018005 and 05000323/2018005) DCL-18-058, Flaw Evaluation of Unit 2, ASME Code Class 2 Charging Pump Discharge Lines: Welds WIC-45A and RB-46-72018-08-0808 August 2018 Flaw Evaluation of Unit 2, ASME Code Class 2 Charging Pump Discharge Lines: Welds WIC-45A and RB-46-7 DCL-18-027, Seismic Probabilistic Risk Assessment for the Diablo Canyon Power Plant, Units 1 & 2 - Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1: Seismic of the Near-Term Task Force Review of Insight2018-04-24024 April 2018 Seismic Probabilistic Risk Assessment for the Diablo Canyon Power Plant, Units 1 & 2 - Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1: Seismic of the Near-Term Task Force Review of Insights ML17024A2072017-12-18018 December 2017 Staff Assessment of Response to 10 CFR 50.54(F) Information Request Flood-Causing Mechanism Reevaluation ML17341A0652017-11-30030 November 2017 Technical Evaluation Report Diablo Canyon Nuclear Power Plant Tsunami Hazard Reevaluation Review ML17334A1052017-11-29029 November 2017 Reactor Coolant System Pressure and Temperature Limits Report ML17229B6172017-08-17017 August 2017 Flaw Evaluation of Residual Heat Removal Suction Weld Joint DCL-17-064, Plant Focused Evaluation Report for External Flooding2017-07-19019 July 2017 Plant Focused Evaluation Report for External Flooding DCL-17-049, Flaw Evaluation of Unit 2 Residual Heat Removal Suction Weld Joint2017-05-18018 May 2017 Flaw Evaluation of Unit 2 Residual Heat Removal Suction Weld Joint DCL-16-117, Reactor Coolant System Pressure and Temperature Limits Report, Revision 152016-11-10010 November 2016 Reactor Coolant System Pressure and Temperature Limits Report, Revision 15 ML16314C6912016-11-0909 November 2016 Enclosure, Statement of the Problem Concerning PWR Primary Coolant System Pipe Rupture DCL-16-124, Implementation of Alternative Source Term Summary of Dose Analyses and Results Revision 52016-11-0909 November 2016 Implementation of Alternative Source Term Summary of Dose Analyses and Results Revision 5 ML16314B0822016-11-0909 November 2016 Criteria for Protection Against Dynamic Effects Associated with a Postulated Rupture of Piping ML16287A7552016-10-0606 October 2016 Technical Assessment Implementation of Alternative Source Terms Summary of Dose Analyses and Results Revision 4 ML16215A1092016-08-0202 August 2016 OEDO-16-00436 - Supplemental Information from Mr. Lochbaum 10 CFR 2.206 Petition on Apparent Violation of 10 CFR 50.9 at Diablo Canyon Nuclear Power Plant ML16169A2652016-05-18018 May 2016 Technical Report, Implementation of Alternative Source Terms Summary of Dose Analysis and Results, Revision 3 ML16146A0952016-04-21021 April 2016 54006-CALC-01, Diablo Canyon Power Plant: Evaluation of Risk Significance of Permanent ILRT Extension. ML16238A1042016-03-31031 March 2016 15-0681-RTM-001, Revision 0, System Level Requirements Traceability Matrix (Rtm). DCL-16-081, 15-0681-RTM-001, Revision 0, System Level Requirements Traceability Matrix (Rtm).2016-03-31031 March 2016 15-0681-RTM-001, Revision 0, System Level Requirements Traceability Matrix (Rtm). ML16019A2242016-02-0101 February 2016 Record of Review, Dispositions to Diablo Canyon Nuclear Plant, Units 1 and 2, Internal Events, Internal Flooding, Seismic, and Fire PRA Facts and Observations ML16061A4642016-01-15015 January 2016 Revision 3 to 993754-11-861-NP, V&V Design Phase Summary Report Ppsi ML16061A4682016-01-15015 January 2016 9Revision 1 to 93754-12-862-NP, V&V Implementation Phase Summary Report PPSII-IV DCL-16-020, Diablo Canyon, Units 1 and 2 - 9Revision 1 to 93754-12-862-NP, V&V Implementation Phase Summary Report PPSII-IV2016-01-15015 January 2016 Diablo Canyon, Units 1 and 2 - 9Revision 1 to 93754-12-862-NP, V&V Implementation Phase Summary Report PPSII-IV DCL-16-020, Diablo Canyon, Units 1 and 2 - Revision 3 to 993754-11-861-NP, V&V Design Phase Summary Report Ppsi2016-01-15015 January 2016 Diablo Canyon, Units 1 and 2 - Revision 3 to 993754-11-861-NP, V&V Design Phase Summary Report Ppsi ML16061A4592016-01-14014 January 2016 Revision 3 to 993754-11-854-1-NP, Protection Set I, Factory Acceptance Test Report DCL-16-020, Diablo Canyon, Units 1 and 2 - Revision 3 to 993754-11-854-1-NP, Protection Set I, Factory Acceptance Test Report2016-01-14014 January 2016 Diablo Canyon, Units 1 and 2 - Revision 3 to 993754-11-854-1-NP, Protection Set I, Factory Acceptance Test Report ML16048A2072015-12-15015 December 2015 Once Through Cooling ML16048A2152015-12-15015 December 2015 Fleet Vehicle-Asset List ML16004A3542015-12-11011 December 2015 Response to NRC Request for Additional Information Regarding License Amendment Request 15-03, Application of Alternative Source Terms Summary of Dose Analysis & Results, Revision 1 DCL-15-134, ISFSI - Submits 2014 Annual Commitment Change Summary Report2015-11-0505 November 2015 ISFSI - Submits 2014 Annual Commitment Change Summary Report DCL-15-102, 10 CFR 71.95 Report Regarding Energy Solutions' Model 8-120B Shipping Cask2015-08-24024 August 2015 10 CFR 71.95 Report Regarding Energy Solutions' Model 8-120B Shipping Cask 2024-06-14
[Table view] Category:Miscellaneous
MONTHYEARML24129A1762024-06-14014 June 2024 National Historic Preservation Act Section 106 Consultation – Results of Identification and Evaluation (Docket Number: 72-026) DCL-24-048, O CFR 50.59 and 1 O CFR 72.48 Summary Report for the Period of January 1, 2022, Through December 31, 20232024-04-30030 April 2024 O CFR 50.59 and 1 O CFR 72.48 Summary Report for the Period of January 1, 2022, Through December 31, 2023 ML23130A0052023-06-27027 June 2023 Report to Congress Regarding Diablo Canyon ML22108A2892022-05-0303 May 2022 Enclosure - Response to Representative Carbajal Regarding OIG Report on Diablo ML22108A1662022-05-0303 May 2022 Enclosure 1 - Assessment Event Inquiry Into the Nuclear Regulatory Commission Oversight of the Auxiliary Feedwater System at Diablo Canyon Nuclear DCL-21-071, Federally Listed Species Affects Determination Memorandum2021-10-14014 October 2021 Federally Listed Species Affects Determination Memorandum ML21188A0362021-07-0707 July 2021 Draft PG&E Letter DCL-21-046 - Diablo Canyon Unit 1: Emergency License Amendment Request 21-05, Revision to Technical Specification 3.7.8, Auxiliary Saltwater (Asw) System DCL-20-102, Nuclear Material Transaction Report for New Fuel2020-12-0909 December 2020 Nuclear Material Transaction Report for New Fuel ML20335A0132020-11-30030 November 2020 NRC Response to Public Watchdogs November 2 ML20328A3012020-11-23023 November 2020 NERC Reliability Standards for the Bulk Electric System of North America Updated July 20, 2020 (Cgnp Public Comments on Diablo Canyon Nuclear Power Plant, Units 1 and 2 - Pre-submittal Meeting of 11/24/2020) ML18254A0402019-01-22022 January 2019 Staff Review of Seismic Probabilistic Risk Assessment Associated with Reevaluated Seismic Hazard Implementation of the Near Term Task Force Recommendation 2.1: Seismic IR 05000275/20180052018-08-31031 August 2018 Updated Inspection Plan for Diablo Canyon Power Plant, Units 1 and 2 (Report 05000275/2018005 and 05000323/2018005) ML17024A2072017-12-18018 December 2017 Staff Assessment of Response to 10 CFR 50.54(F) Information Request Flood-Causing Mechanism Reevaluation DCL-16-117, Reactor Coolant System Pressure and Temperature Limits Report, Revision 152016-11-10010 November 2016 Reactor Coolant System Pressure and Temperature Limits Report, Revision 15 ML16215A1092016-08-0202 August 2016 OEDO-16-00436 - Supplemental Information from Mr. Lochbaum 10 CFR 2.206 Petition on Apparent Violation of 10 CFR 50.9 at Diablo Canyon Nuclear Power Plant ML16019A2242016-02-0101 February 2016 Record of Review, Dispositions to Diablo Canyon Nuclear Plant, Units 1 and 2, Internal Events, Internal Flooding, Seismic, and Fire PRA Facts and Observations ML16048A2152015-12-15015 December 2015 Fleet Vehicle-Asset List ML16048A2072015-12-15015 December 2015 Once Through Cooling DCL-15-102, 10 CFR 71.95 Report Regarding Energy Solutions' Model 8-120B Shipping Cask2015-08-24024 August 2015 10 CFR 71.95 Report Regarding Energy Solutions' Model 8-120B Shipping Cask ML15231A5712015-07-28028 July 2015 Holtec Information Bulletin (HIB) No. 67 (Rev. 0), VCT Restraint Strap Weld Failure ML15160A2612015-07-0101 July 2015 Letter to NMFS Notice of Intent to Reinitiate Scoping Process for Diablo Canyon Power Plant Units 1 and 2 License Renewal Application ML16048A2042015-06-30030 June 2015 Notice of Intent, General Permit to Discharge Storm Water ML16048A2132015-06-22022 June 2015 Permit Renewal No. 49-1 ML15355A2972015-05-31031 May 2015 DCPP Fsaru R22 File a Drawings - Combined - (Redacted) ML15355A0792015-05-31031 May 2015 DCPP Fsaru R22 File B Drawings - Combined (Redacted) RIS 2014-07, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 2 of 52014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 2 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 3 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 4 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 5 of 5 ML14189A5432014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 5 of 5 ML14189A5372014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 4 of 5 ML14189A5332014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 3 of 5 ML14189A5312014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 2 of 5 ML14189A5002014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 1 of 5 RIS 2014-07, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 5 of 52014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 5 of 5 RIS 2014-07, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 4 of 52014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 4 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 5 of 5 RIS 2014-07, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 3 of 52014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 3 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 4 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 5 of 5 RIS 2014-07, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 1 of 52014-06-19019 June 2014 Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 1 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 2 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 3 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 4 of 5, Regulatory Issue Summary (RIS) 2014-07, Enhancements to the Vendor Inspection Program- Vendor Information Request. Part 5 of 5 DCL-14-030, Diablo, Units 1 and 2 - Report of 10 CFR 50.59, Changes, Tests and Experiments, for the Period of January 1, 2012 Through December 31, 20132014-04-17017 April 2014 Diablo, Units 1 and 2 - Report of 10 CFR 50.59, Changes, Tests and Experiments, for the Period of January 1, 2012 Through December 31, 2013 DCL-14-021, Reactor Coolant System Pressure and Temperature Limits Report for Units 1 and 22014-03-25025 March 2014 Reactor Coolant System Pressure and Temperature Limits Report for Units 1 and 2 ML13364A1922014-02-0303 February 2014 Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-12-049 (Mitigation Strategies) DCL-13-094, and Humboldt Bay Power Plant, 10 CFR 71.95 Reports Regarding Energysolutions' Model 8-120B Shipping Cask2013-09-30030 September 2013 and Humboldt Bay Power Plant, 10 CFR 71.95 Reports Regarding Energysolutions' Model 8-120B Shipping Cask DCL-12-080, Nonroutine Report of Planned Disturbance of Archaeological Site SLO-22012-08-21021 August 2012 Nonroutine Report of Planned Disturbance of Archaeological Site SLO-2 DCL-12-050, Diablo Canyon, Units 1 and 2, Attachment 16 to DCL-12-050, PGE-12-52 Np, Westinghouse Input to Diablo Canyon Digital Process Protection System Replacement Uncertainty Calculations Summary Lar.2012-06-0606 June 2012 Diablo Canyon, Units 1 and 2, Attachment 16 to DCL-12-050, PGE-12-52 Np, Westinghouse Input to Diablo Canyon Digital Process Protection System Replacement Uncertainty Calculations Summary Lar. ML12170A8402012-06-0606 June 2012 Attachment 16 to DCL-12-050, PGE-12-52 Np, Westinghouse Input to Diablo Canyon Digital Process Protection System Replacement Uncertainty Calculations Summary Lar. DCL-12-023, Third Interval Snubber Program, Revision 12012-02-28028 February 2012 Third Interval Snubber Program, Revision 1 DCL-11-136, Annual Update to the DCPP License Renewal Application and License Renewal Application Amendment Number 452011-12-21021 December 2011 Annual Update to the DCPP License Renewal Application and License Renewal Application Amendment Number 45 DCL-11-073, Diablo Canyon, Unit 2 - Core Operating Limits Report for Cycle 172011-06-18018 June 2011 Diablo Canyon, Unit 2 - Core Operating Limits Report for Cycle 17 ML1116803532011-06-18018 June 2011 Core Operating Limits Report for Cycle 17 ML1109402692011-04-0505 April 2011 Evaluation Regarding the 2009 Steam Generator Tube Inspections Performed During the 15th Refueling Outage (2R15) DCL-10-158, CFR 54.21(b) Annual Update to the DCPP License Renewal Application and Amendment No. 342010-12-29029 December 2010 CFR 54.21(b) Annual Update to the DCPP License Renewal Application and Amendment No. 34 DCL-10-081, Diablo Canyon, Units 1 and 2, Backup 60M Tower Data File, Calendar Year 2008, Part 2 of 52010-08-0202 August 2010 Diablo Canyon, Units 1 and 2, Backup 60M Tower Data File, Calendar Year 2008, Part 2 of 5 ML1025803172010-08-0202 August 2010 2009 Meteorological Data 2024-06-14
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 April 5. 2011 Mr. John T. Conway Senior Vice President -- Energy Supply and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant 77 Beale Street, Mail Code B32 San Francisco, CA 94105
SUBJECT:
DIABLO CANYON POWER PLANT, UNIT NO.2 - EVALUATION REGARDING THE 2009 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. ME3995)
Dear Mr. Conway:
By letter dated May 5, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML101330269), Pacific Gas and Electric Company (the licensee),
submitted information summarizing the results of the 2009 steam generator (SG) tube inspections performed at Diablo Canyon Power Plant (DCPP), Unit No.2. These inspections were performed during the fifteenth refueling outage (2R15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at DCPP, Unit No.2, provided by the licensee in a letter dated November 24,2010 (ADAMS Accession No. ML103300051).
The NRC staff has completed its review of these reports and concludes that the licensee provided the information required by the DCPP, Unit No.2, technical specifications. No additional follow-up is required at this time. That staff's review of this report is enclosed.
If you have any questions regarding this matter, please contact me at (301) 415-1445.
Sincerely, rll n.. \ . \
~ \J\)6.-~ ..
Alan B. Wang, Projec(~nager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-323
Enclosure:
As stated cc w/encl: Distribution via Listserv
SUMMARY
OF U.S. NUCLEAR REGULATORY COMMISSION STAFF'S REVIEW 2009 STEAM GENERATOR TUBE INSPECTIONS PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON POWER PLANT, UNIT NO.2 DOCKET NO. 50-323 By letter dated May 5, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML101330269), Pacific Gas and Electric Company (the licensee),
submitted information summarizing the results of the 2009 steam generator (SG) tube inspections performed at Diablo Canyon Power Plant (DCPP), Unit No.2. These inspections were performed during the fifteenth refueling outage (2R 15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at DCPP, Unit No.2, provided by the licensee in a letter dated November 24,2010 (ADAMS Accession No. ML103300051).
DCPP, Unit No.2, has four Westinghouse Model D54 SGs, each of which contains 4,444 thermally-treated Alloy 690 tubes. Each tube has a nominal outside diameter of 0.75 inches. During SG fabrication, the tubes were hydraulically expanded over the full depth of the tubesheet. The end of each tube is tack-expanded using a urethane plug expansion process. The tubes are arranged on a triangular pitch with 1.144-inch spacing. The tubes in rows 1 through 16 were full-length stress relieved following bending. Eight Type 405 stainless steel support plates, which have broached trefoil-shaped holes, support the vertical section of tubes. In the U-bend section, there are three sets of "V' shaped, rectangular stainless steel (Type 405) anti-vibration bars.
The licensee provided the scope, extent, methods, and results of its SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (i.e., tube plugging) taken in response to the inspection findings.
After reviewing the information provided by the licensee, the NRC staff has the following comments or observations:
- There are 12 tubes with proximity indication Signals in the U-bend region. The signals were attributed to the proximity of a given tube to another tube. The licensee conducted +Point probe inspections on the 12 tubes and no tube-to-tube contact or wear was associated with these proximity signals. These signals were observed during both the preservice inspection and the 2009 inspections. A potential cause of these Signals is manufacturing tolerances on a tube-to-tube basis (e.g., tolerances on U-bend profile and overall tube height). A tolerance stack-up indicates a reduced gap may occur, but tube-to-tube contact is not possible. Similar conditions have occurred at other plants.
- During fabrication, 12 tubes were reported to be visibly damaged by a grinding tool. Of these 12 tubes, 3 were plugged with welded plugs at the factory. The Enclosure
- 2 remaining nine tubes remain inservice and have no indication of degradation, but eight of the nine tubes have ding signals at the visibly damaged area.
Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the DCPP, Unit No.2, technical specifications. In addition, the NRC staff concludes that there are no technical issues that warrant follow-up actions at this time since the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units.
April 5, 2011 Mr. John T. Conway Senior Vice President - Energy Supply and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant 77 Beale Street, Mail Code B32 San Francisco, CA 94105
SUBJECT:
DIABLO CANYON POWER PLANT, UNIT NO.2 - EVALUATION REGARDING THE 2009 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. ME3995)
Dear Mr. Conway:
By letter dated May 5, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML101330269), Pacific Gas and Electric Company (the licensee),
submitted information summarizing the results of the 2009 steam generator (SG) tube inspections performed at Diablo Canyon Power Plant (DCPP), Unit No.2. These inspections were performed during the fifteenth refueling outage (2R15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at DCPP, Unit No.2, provided by the licensee in a letter dated November 24,2010 (ADAMS Accession No. ML103300051).
The NRC staff has completed its review of these reports and concludes that the licensee provided the information required by the DCPP, Unit No.2, technical specifications. No additional follow-up is required at this time. That staff's review of this report is enclosed.
If you have any questions regarding this matter, please contact me at (301) 415-1445.
Sincerely, IRA!
Alan B. Wang, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-323
Enclosure:
As stated cc w/encl: Distribution via Listserv DISTRIBUTION:
PUBLIC RidsNrrDorlLpl4 Resource RidsRgn4MailCenter Resource LPLIV Reading RidsNrrLAJBu rkhardt Resource KKarwoski, NRRIDCIICSGB RidsAcrsAcnw_MailCTR Resource RidsNrrPMDiabloCanyon Resource AObodoako, NRR/DCI/CSGB RidsNrrOciCsgb Resource RidsOgcRp Resource ADAMS Accession No. ML110940269 *Memo dated OFFICE NRR/DORLlLPL4/PM RLlLPL4/PM RLlLPL4/LA JPolickoski (AWang for) 4/5/11 NRR/DCI/CSGB/BC NRR/OORLlLPL4/PM RTaylor* AWang 3/9/11 4/5/11