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Category:Meeting Summary
MONTHYEARML24009A0552024-01-24024 January 2024 Summary of January 8, 2024, Presubmittal Meeting Between the U.S. Nuclear Regulatory Commission and Constellation Energy Generation, LLC, Regarding Removal of the Power Distribution Monitoring System from Technical Specifications ML24018A1772024-01-19019 January 2024 Summary of August 30, 2023, Presubmittal Meeting Between the U.S. Nuclear Regulatory Commission and Constellation Energy Generation, LLC, Regarding Relaxation of Inspection Requirements for the Head Penetration P-75 Flaw ML23363A0942024-01-0303 January 2024 Summary of October 4, 2023, Pre Submittal Meeting Between the U.S. NRC and Constellation Energy Generation, LLC, Regarding Revising Technical Specification 3.7.9. Ultimate Heat Sink (UHS) ML23362A0042024-01-0202 January 2024 Documentation of Cancelled September 1, 2023, Presubmittal Meeting Between the NRC and Constellation Energy Generation, LLC, Regarding 6-Month Extension of Certain Reactor Pressure Vessel Weld Inspections ML23352A3822023-12-19019 December 2023 Summary of December 11, 2023, Presubmittal Meeting Between the U.S. Nuclear Regulatory Commission and Constellation Energy Generation, LLC, Regarding Deletion of Technical Specification 5.6.5.b.5 ML23320A2472023-11-17017 November 2023 Constellation - Summary of November 14, 2023, Public Pre-Application Meeting with Constellation Energy Generation, LLC on Adoption of TSTF-591 ML23263B1062023-09-22022 September 2023 R. E. Ginna Nuclear Power Plant - Constellation - Pre-Application Amse 9/18/2023 Meeting Summary ML23164A2112023-06-14014 June 2023 Summary of the June 1, 2023, Public Outreach to Discuss the NRC 2022 End-of-Cycle Plant Performance Assessment of Braidwood Station, Units 1 and 2; and Byron Station, Units 1 and 2 ML23129A0202023-05-30030 May 2023 Summary of March 22, 2023, Closed Meeting with Constellation Energy Generation, LLC, to Discuss a Future License Amendment Request That Allows Byron Station and Braidwood Station to Utilize a New Citicality Analysis for the Spent Fuel Pools ML23055A0352023-03-24024 March 2023 Summary of February 23, 2023, with Constellation Energy Generation, LLC on Proposed Changes to Emergency Plans to Revise Emergency Action Levels ML23033A6662023-02-0909 February 2023 Summary of Public Meeting with Constellation Energy Generation, LLC (Constellation) to Discuss Its Request for Alternatives for Certain Steam Generator Weld Inspections for Calvert Cliffs 1 & 2, Byron 1 & 2, Braidwood 1 & 2, and Ginna ML22264A1992022-11-14014 November 2022 Summary of August 22, 2022, Meeting Between the U.S. Nuclear Regulatory Commission and Constellation Energy Generation, LLC, Regarding Performance Monitoring of Steam Generator Welds (Epids L-2022-LRR-0074, 0076, 0079, 0091, 0092, 0093 and ML22305A5992022-11-10010 November 2022 Summary of Closed Presubmittal Meeting Between the U. S. Nuclear Regulatory Commission and Constellation Energy Generation, LLC, Regarding Transition to Framatome Fuel ML22159A2232022-06-0909 June 2022 Summary of the June 2, 2022, Public Outreach to Discuss the NRC 2021 End of Cycle Plant Performance Assessment of Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2 ML22115A2122022-05-12012 May 2022 Summary of April 11, 2022, Meeting Between the U.S. NRC and Constellation Energy Generation, LLC, Regarding a Future Amendment to Place One High Burnup Lead Test Assembly Into the Byron, Unit 2, Reactor ML22111A2852022-05-0909 May 2022 Summary of April 4, 2022, Meeting Between the U.S. NRC and Constellation Energy Generation, LLC, Regarding Performance Monitoring of Pressurizer Welds (EPIDs L-2022-LLR-0035/36) ML22111A3362022-05-0909 May 2022 Summary of April 7, 2022, Meeting Between the NRC and Constellation Energy Generation, LLC, Regarding Performance Monitoring of Pressurizer Welds (Epids L-2022-LRR-0035 and 0036) ML21330A0722021-12-0303 December 2021 Summary of November 17, 2021, Meeting with Exelon Generation Company, LLC, Related to a Future License Amendment to Remove License Condition 2.C.(12)(d) for Braidwood Station, Unit 2 ML21333A1532021-11-30030 November 2021 Summary of November 16, 2021, Meeting with Exelon Generation Company, LLC Regarding a Planned Request for an Alternative to Extend the Inservice Inspection Interval ML21237A0412021-08-30030 August 2021 Summary of the July 27, 2021, Meeting with Exelon Generation Company, LLC Regarding a Planned Request to Use Case OMN-28, ML21176A0822021-07-0606 July 2021 June 15, 2021, Summary of Meeting with Exelon Generation Company, LLC Vessel Nozzle Repair Related to a Planned Request for an Alternative Related to Reactor Pressure ML21139A1852021-06-22022 June 2021 Summary of Meeting with Exelon Generation Company, LLC Regarding Its Requested Alternative to Eliminate Certain Documentation Requirements for the Replacement of Pressure Retaining Bolting ML21167A2152021-06-16016 June 2021 June 8, 2021, Summary of the Public Outreach to Discuss the NRC 2020 End-Of-Cycle Plant Performance Assessment of Braidwood Station, Units 1 and 2; and Byron Station, Units 1 and 2 ML21147A4262021-06-0303 June 2021 Summary of May 12, 2021, Meeting with Exelon Generation Company, Llc, Related to a Planned License Amendment to Modify the Ultimate Heat Sink Technical Specifications ML21033A6582021-02-0404 February 2021 Summary of October 13, 2020, Presubmittal Meeting Between the U. S. Nuclear Regulatory Commission and Exelon Generation Company, LLC Regarding Post Shutdown Emergency Plan Staffing to Support the Planned Early Closures ML21011A2822021-01-21021 January 2021 Summary of January 6, 2021, Presubmittal Meeting Between the NRC and Exelon Generation Company, LLC Regarding Licensing Activities to Support the Planned Early Closures of Byron, Unit Nos. 1 and 2 and Dresden, Units 2 and 3 ML20351A2832020-12-18018 December 2020 Summary of Meeting with Exelon Generation Company, LLC Regarding a Planned Request for an Exemption to Reduce the Frequency of Updates to Its Inservice Testing and Inspection Programs ML20342A3522020-12-10010 December 2020 Summary of November 13, 2020, Meeting with Exelon Generation Company, LLC Regarding a Planned Request for an Alterantive to Certain Documentation Requirements for the Replacement of Pressure Retaining Bolting (EPID-L-2020-LRM-0102) ML20323A0332020-12-0101 December 2020 Summary of November 4, 2020, Meeting with Exelon Generation Company, LLC Regarding a Planned Request for an Alternative to Reduce the Frequency of Updates to Its Inservice Testing and Inspection Programs ML20280A2482020-10-0707 October 2020 Summary of September 22, 2020, Presubmittal Meeting Between the NRC and Exelon Generation Company LLC Regarding Licensing Activities to Support the Planned Early Closures of Byron, Units 1 and 2 and Dresden, Units 2 and 3 ML20171A3812020-08-12012 August 2020 (COVID-19) Presubmittal Meeting Summary - Byron Unit 2 LAR - One-Time Extension of Steam Generator Tube Inspections ML20218A5302020-08-0505 August 2020 July 14, 2020, Summary of the Public Webinar to Discuss the NRC 2019 End-of-Cycle Plant Performance Assessment of Braidwood Station, Units 1 and 2; and Byron Station, Units 1 and 2 ML20181A0002020-06-29029 June 2020 Summary of 6/24/20 Meeting with Exelon Generation Company, LLC Regarding Planned Request for Alternative to Supplemental Valve Position Indication Testing Requirements for Braidwood, Calvert Cliffs, Clinton, Limerick, Nine Mile, Peach Botto ML19326A3152019-12-0303 December 2019 Summary of November 18, 2019, Meeting with Exelon Generation Company, LLC Regarding a Planned Request for an Alternative to Supplemental Valve Position Indication Testing Requirements ML19326C3582019-12-0303 December 2019 Summary of November 20, 2019, Meeting with Exelon Generation Company, LLC Regarding a Planned Request to Revise the Quality Assurance Program ML19162A0272019-06-21021 June 2019 Summary of June 4, 2019, Meeting with Exelon Generation Company, LLC Regarding a Planned Request to Extend the Test Interval for Safety Relief Valves ML20108F0902019-04-20020 April 2019 April 15, 2020, Meeting Summary with Exelon Generation Company, LLC Regarding Planned Request to Defer Submittal of Owner'S Activity Report (Braidwood 2,Byron 2,Calvert Cliffs 1, LaSalle 1, Limerick 1, Nine Mile Point 2, Quad 2, R. E. Ginna ML19036A8832019-02-0707 February 2019 Summary of Meeting with Exelon Generation Company, LLC Regarding a Planned Request to Use ASME Code Case N-879 ML18354B1712019-01-0202 January 2019 Summary of December 19, 2018, Meeting with Exelon Generation Company, LLC Regarding the Use of Boiling Water Reactor Vessel and Internals Project Guidelines ML18325A1712018-11-28028 November 2018 Summary of Meeting with Exelon Generation Company, LLC Regarding Planned Fleet License Amendment Request to Revise Technical Specifications for High Radiation Areas ML18297A1722018-10-26026 October 2018 Summary of Meeting with Exelon Generation Company, LLC Regarding Planned License Amendment Request to Adopt TSTF-427 ML18225A3042018-08-16016 August 2018 Summary of August 8, 2018, Meeting with Exelon Generation Company, LLC, on a Future Relief Request to Extend the Post Peening Follow-Up Inspections for Certain Reactor Pressure Vessel Head Penetrations ML18135A0222018-05-14014 May 2018 Summary of the May 10th, 2018, Public Open House Regarding Braidwood Nuclear Power Station ML18120A1772018-05-0101 May 2018 Summary of Meeting with Exelon Generation Company, LLC Regarding Draft Guidance for Emergency Response Organization Staffing ML18113A7052018-04-23023 April 2018 Summary of Open House to Discuss the 2017 End-of-Cycle Plant Performance Assessment of Byron Station ML18113A6592018-04-23023 April 2018 Summary of Open House to Discuss the 2017 End-of-Cycle Plant Performance Assessment of Palisades Nuclear Plant ML18065A8362018-03-0707 March 2018 Summary of February 27, 2018, Meeting with Exelon Generation Company, LLC Planned Fleet License Amendment Request to Relocate Staff Qualification Requirements from TSs to the Quality Assurance Topical Report ML18058A5232018-03-0101 March 2018 Summary of February 26, 2018, Meeting with Exelon Generation Company, LLC Regarding Proposed Alternative to the Main Steam Isolation Valve Testing Requirements ML18018B4432018-01-25025 January 2018 Summary of December 17, 2017, Closed Meeting with Exelon Generation Company, LLC, Regarding Tvel Lead Test Assemblies to Be Placed in the Braidwood Reactor (EPID 000976/05000456/L-2017-LRM and 000976/05000457/L-2017-LRM-0047 ML17347B1022017-12-14014 December 2017 Summary of Meeting with Exelon Generation Company, LLC on Its Planned Fleet License Amendment Request to Revise the Minimum Staffing Requirements for Emergency Response 2024-01-03
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 12, 2017 LICENSEE: Exelon Generation Company, LLC FACILITIES: Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2
SUBJECT:
SUMMARY
OF DECEMBER 5, 2016, MEETING WITH EXELON GENERATION COMPANY LLC TO DISCUSS PROPOSED SUBMITTAL RELATED TO REACTOR PRESSURE VESSEL NOZZLE INSPECTIONS On December 5, 2016, the U.S. Nuclear Regulatory Commission (NRC) staff conducted a Category 1 public meeting with Exelon Generation Company, LLC (Exelon, the licensee) at NRC Headquarters, 11555 Rockville Pike, One White Flint North, Rockville, Maryland. The purpose of the meeting was to discuss Exelon's proposal to submit a request for relief from various inspection requirements and frequencies associated with the pressure vessel head penetration nozzles (RPVHPNs) as a result of ultra-high pressure (UHP) cavitation peening. contains a list of attendees. The licensee's presentation is available in the Agencywide Documents Access and Management System (ADAMS) under Accession No. ML16334A445.
BACKGROUND:
Pressurized-water reactor plants have experienced primary water stress corrosion cracking (PWSCC) in Alloy 82/182 dissimilar metal butt welds (DMWs), Alloy 600 reactor RPVHPNs, and associated Alloy 82/182 J-groove welds. Circumferential and axial cracks have been found in these components in several U.S. and international nuclear power plants, challenging the leak-tightness and structural integrity of the subject components. As a result of PWSCC, the NRC requires augmented inspections for these DMWs, RPVHPNs, and associated J-groove welds.
For the unpeened nozzles and welds at issue, current regulatory requirements establish inspection periodicities and modalities (techniques) as required by Section 50.55a to Title 10 of the Code of Federal Regulations (10 CFR). These requirements are intended to ensure the probability of PWSCC crack growth to a through wall flaw size is sufficiently low to provide adequate assurance of structural integrity.
Byron and Braidwood units applied an UHP cavitation peening process, which uses submerged UHP water jets to treat the surfaces of reactor vessel components susceptible to PWSCC. The intent being rather than allowing random fractures to develop on a component's surface, this cavitation peening would create compressive stresses on the surface of the material in a controlled manner, which is intended to mitigate initiation of PWSCC.
The NRC staff has determined that the application of peening, as described in "Materials Reliability Program: Topical Report for Primary Water Stress Corrosion Cracking Mitigation by Surface Stress Improvement, Revision 3 (MRP-335R3, or the MRP) (ADAMS Accession No. ML 166055A215), is not in conflict with any aspect of the American Society of Mechanical
Engineers (ASME) Code, Sections Ill and XI, or NRC regulations. The MRP uses a series of deterministic and probabilistic calculations to quantify the relationship among peening, inspection frequency and modality, and through wall cracking probability.
The NRC staff notes that relief from the ASME Code and NRC regulations is not required to perform peening on DMWs or RPVHPNs. The staff further notes that the peening application as described in MRP [materials reliability program]-335R3 is distinctly different than peening for the purpose of distortion control as described in the ASME Code, Section Ill. Each nuclear power plant may apply peening to components and evaluate its acceptability in accordance with the requirements of 10 CFR 50.59, "Changes, Tests, and Experiments." However, the ability of a licensee to self-evaluate the acceptability of peening plant components does not extend to the modification (i.e., relaxation) of current inspection requirements of peened components.
The MRP proposes to apply peening as a mitigation method to prevent PWSCC from occurring at DMWs in primary loop piping, RPVHPNs, and associated J-groove welds that are fabricated from nickel-based Alloy 600/82/182 material. As part of peening, the MRP proposes to relax the current inspection requirements for the peened DMWs and RPVHPNs. MRP-335R3 contains the technical basis for peening application, including affected components, peening processes, performance criteria, analyses, and alternative inspection requirements.
In a letter dated August 24, 2016 (ADAMS Accession No. ML16208A485), the NRC found that MRP-335R3 is acceptable for referencing in licensing applications for nuclear power plants to the extent specified and under the limitations delineated in the MRP and the approved final safety evaluation.
DISCUSSION:
A video was shown by the licensee to demonstrate the peening process used in support of PWSCC mitigation for the Byron/Braidwood facilities. The licensee indicated that future submittals will be provided requesting relief from performing the follow-up inspections currently required at the first and second refueling outage after peening, as well as the inspections in the next 10-year interval. The basis for this request was discussed. The expanded scope of the coverage area peened, combined with some conservative assumptions made have provided what the licensee has identified as extensive margins. The licensee cited the rigor or technical review and extent of the margins as support for relief from follow-up inspections.
The licensee discussed the applicability of this request to Byron, Unit 2, as some nozzles could not be tested due to leakage. The licensee indicated the mitigation method, the pending mitigation activities, and the intended scope of the submittal. It was discussed that information on components would be needed to support that request. Additionally, the licensee addressed the use of a different x-ray diffraction methodology which was indicated to provide more accurate and repeatable results in support of required stress measurements. The NRC staff indicated that the licensee should provide a summary of the methodology, including controlling inputs and assumptions, as well as the results. The licensee identified where the verification and validation was performed. The NRC staff indicated an interest in the technique generally and suggested submittal of information by the associated industry group. For use in the proposed requests, the staff would be looking for a discussion on the process for reportability and repeatability.
The discussion included peening parameters margins, which focused on the extent of coverage, depth of compression, and post-peening stress accuracy. NRC comments included ensuring a discussion is included on thermal sleeves and centering tabs. The NRC staff indicated an interest in the licensee providing full drawings in support of the stress accuracy analysis and in seeing a discussion addressing whether thermal sleeves were included in the mock-up and whether weld residual stresses were impacted by the centering tabs.
Part of the deterministic justification for the proposed request for relief rests on the results of the crack growth analysis. An industry paper was discussed which the licensee has identified as additional support to the results of the deterministic crack growth analysis performed using an unapproved method (UAM). The licensee indicates that the industry paper provides sufficient conservatism to support the extension of the inspection interval even if credit for peening was not taken or approved. The NRC staff indicated concerns with the application of the UAM as there are concerns with defense in depth, the presumption of no crack initiation, and whether the analyses is appropriately bounding for the use proposed. Additionally, no applicable operating experience has been identified. The staff notes that the use of an UAM could significantly affect the review time for the request.
Overall, the NRC staff indicated that all margins being credited should be explicitly identified, along with any associated process or inspection uncertainties; and for any required coverage with small margins additional information should be provided. For the total margins, the staff indicated an interest in seeing the total margin represented as a percentage of the total area.
The staff summarized that, in general, details should be provided regarding the peening process applied, testing of components, quality control of applicable processes, analyses, inspections, and testing, stress measurement uncertainties, essential variables and input values, as well as performance criteria. No commitments or regulatory decisions were made by the NRC staff during the meeting.
Sincerely,
'~Irl)/iJ.>
S. Wiebe, Senior Project Manager
/ Plant Licensing Branch Ill
" Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-456, STN 50-457, STN 50-454 and STN 50-455
Enclosure:
List of Attendees cc w/encl: Ms. Ruth Thomas 354 Woodland Drive Columbus, NC 28722 Distribution via Listserv
Attendees U.S. Nuclear Regulatory Commission Public Meeting with Exelon Concerning PWSCC Mitigation Inspection Frequency December 5, 2016 U.S. NUCLEAR REGULATORY COMMISSION Ali Rezai Roger Kalikian Stephen Cumbridge John Tsao Jay Collins Margaret Audrain Eva Brown EXELON GENERATION COMPANY LLC Jessica Krejcie Bernie Rudell Ben Youman Brad Lanka Darren Gardner Enclosure
ML17009A067 NRC-001 *via e-mail OFFICE LPLlll/PM LPLlll/PM LPLlll/LA LPLlll/BC NAME EBrown* JWiebe SRohrer DWrona DATE 12/19/13 1/11/17 1/10/17 1/12/17