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MONTHYEAR2CAN111101, Use of Alternate ASME Code Case N-770-1 Baseline Examination Request for Alternative ANO2-ISI-0072011-11-30030 November 2011 Use of Alternate ASME Code Case N-770-1 Baseline Examination Request for Alternative ANO2-ISI-007 Project stage: Request ML1200303682012-01-0303 January 2012 Acceptance Review Email, Relief Request ANO2-ISI-007, Alternative to Use ASME Code Case N-770-1 Baseline Examination, Fourth 10-Year Inservice Inspection Interval Project stage: Acceptance Review ML1205410892012-02-23023 February 2012 Email, Request for Additional Information, Request to Use of Alternate ASME Code Case N-770-1 Baseline Examination, Request for Alternative ANO2-ISI-007, Project stage: RAI 2CAN051202, Additional Information Related to Request for Alternative ANO2-ISI-007 Code Case N-770-1 Baseline Examination2012-05-21021 May 2012 Additional Information Related to Request for Alternative ANO2-ISI-007 Code Case N-770-1 Baseline Examination Project stage: Request ML12241A2962012-08-28028 August 2012 RAI for the Request to Use of Alternate ASME Code Case N-770-1 Baseline Examination, Request for Alternative ANO2-ISI-007 Project stage: RAI 2CAN091205, Response to Second Request for Additional Information, Request for Alternative ANO2-ISI-007 Code Case N-770-1 Baseline Examination2012-09-10010 September 2012 Response to Second Request for Additional Information, Request for Alternative ANO2-ISI-007 Code Case N-770-1 Baseline Examination Project stage: Request ML12306A2912012-11-0101 November 2012 Transmittal Email and WCAP-17128-NP, Revision 1, Flaw Evaluation of CE Design RCP Suction and Discharge Nozzle Dissimilar Metal Welds, Phase III Study, May 2010 Project stage: Other ML12319A3672012-11-27027 November 2012 Relief Request ANO2-ISI-007, Alternative to Use ASME Code Case N-770-1 Baseline Examination, Fourth 10-Year Inservice Inspection Interval Project stage: Other ML12314A0602012-12-11011 December 2012 Request for Withholding Information from Public Disclosure, Affidavit Dated 9/4/2012, Executed by Marcos Legaspi Herrera of Structural Integrity Associates, Inc. Re Second RAI Response Project stage: RAI ML12314A0492012-12-11011 December 2012 Request for Withholding Information from Public Disclosure, Affidavit Dated 8/16/12, Executed by J. Gresham of Westinghouse Electric Company LLC, Re CN-MRCDA-12-27 Project stage: Withholding Request Acceptance ML13113A2182013-04-23023 April 2013 Technical Letter Report, PNNL Evaluation and Modeling of Licensee'S Alternative for Volumetric Inspection of Dissimilar Metal Butt Welds at Arkansas Nuclear One Project stage: Other 2012-12-11
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Category:Report
MONTHYEAR1CAN062304, Supplement Related to License Amendment Request to Remove Technical Specification Condition Allowing Two Reactor Coolant Pump Operation2023-06-29029 June 2023 Supplement Related to License Amendment Request to Remove Technical Specification Condition Allowing Two Reactor Coolant Pump Operation ML23180A1082023-06-20020 June 2023 ANO Unit 1 SAR Amendment 31, TRM, TS Bases, 10 CFR 50.59 Report, and Commitment Change Summary Report 1CAN062302, Enclosure 2: ANO-1 SAR Amendment 31 - Redacted Version2023-06-20020 June 2023 Enclosure 2: ANO-1 SAR Amendment 31 - Redacted Version ML23088A2172022-12-31031 December 2022 Relief Request for Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 46 - Technical Report, ANP-4023NP, Revision 0, December 2022 2CAN022202, Requests for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fourth 10-Year Interval, Second and Third Periods2022-02-24024 February 2022 Requests for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fourth 10-Year Interval, Second and Third Periods 0CAN102102, Units 1 and 210 CFR 50.71(e) Report Revision 20 of the ANO Fire Hazards Analysis2021-10-0606 October 2021 Units 1 and 210 CFR 50.71(e) Report Revision 20 of the ANO Fire Hazards Analysis CNRO-2021-00023, Entergy Operations, Inc. - Supplement to CNRO-2021-00002, Basis for Concluding the Terms of Confirmatory Order EA-17-132/EA-17-153 Are Complete, Element L2021-10-0606 October 2021 Entergy Operations, Inc. - Supplement to CNRO-2021-00002, Basis for Concluding the Terms of Confirmatory Order EA-17-132/EA-17-153 Are Complete, Element L ML21272A3032021-09-30030 September 2021 Technology Inclusive Content of Application Project (Ticap) for Non-Light Water Reactors Westinghouse Evinci; Micro-Reactor Tabletop Exercise Report ML21237A0512021-08-25025 August 2021 Follow-on Risk Informed Performance Based Implementation Guidance Needed for Advanced Non-Light Water Reactors ML21081A1922021-06-30030 June 2021 Enclosure - USNRC-CNSC Joint Report Concerning X-Energy's Reactor Pressure Vessel Construction Code Assessment 2CAN062103, Request for Alternative ANO2-PT-003 End-of-Interval System Leakage Test for Extended Reactor Coolant Pressure Boundary Piping - Fifth Interval2021-06-29029 June 2021 Request for Alternative ANO2-PT-003 End-of-Interval System Leakage Test for Extended Reactor Coolant Pressure Boundary Piping - Fifth Interval 0CAN052102, Annual 10 CFR 50.46 Report for Calendar Year 2020 Emergency Core Cooling System Evaluation Changes2021-05-10010 May 2021 Annual 10 CFR 50.46 Report for Calendar Year 2020 Emergency Core Cooling System Evaluation Changes ML21272A3382021-04-0101 April 2021 Technology Inclusive Content of Application Project (Ticap) for Non-Light Water Reactors Versatile Test Reactor Ticap Tabletop Exercise Report ML21090A0332021-03-31031 March 2021 Historical Context and Perspective on Allowable Stresses and Design Parameters in ASME Section III, Division 5, Subsection Hb, Subpart B (ANL/AMD-21/1) ML21083A1362021-03-23023 March 2021 Completed Activities ML21083A1422021-03-22022 March 2021 Strategy 4 ML21083A1402021-03-22022 March 2021 Strategy 2 ML21083A1412021-03-22022 March 2021 Strategy 3 ML21083A1442021-03-22022 March 2021 Strategy 6 ML21083A1382021-03-22022 March 2021 Rulemaking ML21083A1432021-03-22022 March 2021 Strategy 5 ML21083A1372021-03-22022 March 2021 NEIMA Reporting ML21083A1392021-03-22022 March 2021 Strategy 1 ML21014A2672021-01-14014 January 2021 Preapplication Engagement to Optimize Application Reviews January 12 Version - Copy 1CAN032001, Supplemental Information Related to License Amendment Request to Revise Loss of Voltage Relay Allowable Values2020-03-19019 March 2020 Supplemental Information Related to License Amendment Request to Revise Loss of Voltage Relay Allowable Values 0CAN121901, Summary of Lost Specimens Investigation Report2019-12-0303 December 2019 Summary of Lost Specimens Investigation Report ML18215A1782018-06-30030 June 2018 WCAP-18169-NP, Rev 1, Arkansas Nuclear One Unit 2 Heatup and Cooldown Limit Curves for Normal Operation. ML17214A0292018-02-12012 February 2018 Staff Assessment of Flooding Focused Evaluation (CAC Nos. MF9809 and MF9810) ML17291A0092017-10-26026 October 2017 Staff Assessment Regarding Program Plan for Aging Management for Reactor Vessel Internals (CAC No. MF8155; EPID L-2016-LRO-0001) ML17236A1792017-08-22022 August 2017 Arkansas, Units 1 and 2, ANO Emergency Plan On-Shift Staffing Analysis Report, Revision 2 0CAN081703, Document 51-9257562-001, Revision 1, Arkansas Nuclear One Hfe - High Frequency Confirmation Report2017-08-16016 August 2017 Document 51-9257562-001, Revision 1, Arkansas Nuclear One Hfe - High Frequency Confirmation Report ML17167A0832017-06-28028 June 2017 Arkansas Nuclear One, Unit 2 - Review of Commitment Submittal for License Renewal Regarding Nickel-Based Alloy Aging Management Program Plan (CAC No. MF8154) 0CAN061701, Transmittal of 10 CFR 50.71(e) Report, Revision 17 of the ANO Fire Hazards Analysis2017-06-0707 June 2017 Transmittal of 10 CFR 50.71(e) Report, Revision 17 of the ANO Fire Hazards Analysis 0CAN051704, Engineering Report No. CALC-ANOC-CS-14-00017, Rev 0, 2017 Focused Evaluation for External Flooding at Arkansas Nuclear One.2017-03-13013 March 2017 Engineering Report No. CALC-ANOC-CS-14-00017, Rev 0, 2017 Focused Evaluation for External Flooding at Arkansas Nuclear One. 2CAN011703, Submittal of Additional Protocol Report2017-01-26026 January 2017 Submittal of Additional Protocol Report ML17024A0362016-12-31031 December 2016 Operating Data Report for 2016 0CAN121602, Mitigating Strategies Assessment (MSA) Report for the New Seismic Hazard Information Per Nuclear Energy Institute (NEI) 12-06, Appendix H, Revision 2, H.4.3 Path 32016-12-30030 December 2016 Mitigating Strategies Assessment (MSA) Report for the New Seismic Hazard Information Per Nuclear Energy Institute (NEI) 12-06, Appendix H, Revision 2, H.4.3 Path 3 ML17003A2902016-12-20020 December 2016 Areva, Inc. - Engineering Information Record - Arkansas Nuclear One HFE-High Frequency Confirmation Report ML16365A0272016-10-31031 October 2016 ANP-3486NP, Revision 0, MRP-227-A Applicant/Licensee Action Item 6 Analysis for Arkansas Nuclear One Unit 1 (ANO-1). ML16293A5842016-09-30030 September 2016 WCAP-18166-NP, Revision 0, Analysis of Capsule 284 from the Entergy Operations, Inc. Arkansas Nuclear One, Unit 2 Reactor Vessel Radiation Surveillance Program. 1CAN091601, Submittal of Initial Examination Completion of Post-Examination Analysis2016-09-0101 September 2016 Submittal of Initial Examination Completion of Post-Examination Analysis ML16202A1672016-07-0505 July 2016 Report 1500227.401, PWR Internals Aging Management Program Plan. ML16147A3242016-05-31031 May 2016 ANP-3417NP, Rev. 1, MRP-227-A Applicant/Licensee Action Item #7 Analysis for Arkansas Nuclear One, Unit 1. ML16004A1792015-12-31031 December 2015 Attachment 2, ANP-3418NP, Revision 0, Arkansas Nuclear One Unit 1 Reactor Vessel Internals License Renewal Scope and MRP-189, Revision 1 Comparison (MRP-227-A Action Item 2) Licensing Report. (Non-Proprietary) ML15278A0242015-09-28028 September 2015 Attachment 2, Areva Document ANP-3417NP, Revision 0, MRP-227-A Applicant / Licensee Action Item No. 7 Analysis for Arkansas Nuclear One, Unit 1 (Non-Proprietary), Attachment 3, Affidavit, and Attachment 4, List of Commitments ML15099A1522015-04-16016 April 2015 Review of Spring 2014 Steam Generator Tube Inspection Report, Inspection During Refueling Outage 2R23 ML15071A0552015-03-31031 March 2015 ANP-3300Q2NP, Revision 0, Response to Request for Additional Information on Reactor Coolant System Pressure/Temperature and Low Temperature Overpressure Protection System Limits to 54 EFPY for Arkansas Nuclear One, Unit 1. ML15086A0242015-03-25025 March 2015 ANP-3300Q3NP, Revision 0 to Response to Request for Additional Information on Reactor Coolant System Pressure/Temperature and Low Temperature Overpressure Protection System Limits to 54 EFPY for Arkansas Nuclear One, Unit 1 (Non-Proprietary ML15043A1032015-02-10010 February 2015 Areva Document ANP-3383NP, Response to Request for Additional Information for the Reactor Pressure Vessel Internals Aging Management Program Plan for Arkansas Nuclear One Unit 1 ML15041A0742015-02-0606 February 2015 ANP-3300Q1NP, Rev. 0, Response to Request for Additional Information on Reactor Coolant System Pressure/Temperature and Low Temperature Overpressure Protection System Limits to 54 EFPY for Arkansas Nuclear One, Unit 1, Attachment 2 to 1CAN0 2023-06-29
[Table view] Category:Technical
MONTHYEAR1CAN062304, Supplement Related to License Amendment Request to Remove Technical Specification Condition Allowing Two Reactor Coolant Pump Operation2023-06-29029 June 2023 Supplement Related to License Amendment Request to Remove Technical Specification Condition Allowing Two Reactor Coolant Pump Operation ML23180A1082023-06-20020 June 2023 ANO Unit 1 SAR Amendment 31, TRM, TS Bases, 10 CFR 50.59 Report, and Commitment Change Summary Report 1CAN062302, Enclosure 2: ANO-1 SAR Amendment 31 - Redacted Version2023-06-20020 June 2023 Enclosure 2: ANO-1 SAR Amendment 31 - Redacted Version ML23088A2172022-12-31031 December 2022 Relief Request for Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 46 - Technical Report, ANP-4023NP, Revision 0, December 2022 2CAN022202, Requests for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fourth 10-Year Interval, Second and Third Periods2022-02-24024 February 2022 Requests for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fourth 10-Year Interval, Second and Third Periods 0CAN102102, Units 1 and 210 CFR 50.71(e) Report Revision 20 of the ANO Fire Hazards Analysis2021-10-0606 October 2021 Units 1 and 210 CFR 50.71(e) Report Revision 20 of the ANO Fire Hazards Analysis ML21272A3032021-09-30030 September 2021 Technology Inclusive Content of Application Project (Ticap) for Non-Light Water Reactors Westinghouse Evinci; Micro-Reactor Tabletop Exercise Report ML21237A0512021-08-25025 August 2021 Follow-on Risk Informed Performance Based Implementation Guidance Needed for Advanced Non-Light Water Reactors ML21081A1922021-06-30030 June 2021 Enclosure - USNRC-CNSC Joint Report Concerning X-Energy's Reactor Pressure Vessel Construction Code Assessment 2CAN062103, Request for Alternative ANO2-PT-003 End-of-Interval System Leakage Test for Extended Reactor Coolant Pressure Boundary Piping - Fifth Interval2021-06-29029 June 2021 Request for Alternative ANO2-PT-003 End-of-Interval System Leakage Test for Extended Reactor Coolant Pressure Boundary Piping - Fifth Interval ML21272A3382021-04-0101 April 2021 Technology Inclusive Content of Application Project (Ticap) for Non-Light Water Reactors Versatile Test Reactor Ticap Tabletop Exercise Report ML21090A0332021-03-31031 March 2021 Historical Context and Perspective on Allowable Stresses and Design Parameters in ASME Section III, Division 5, Subsection Hb, Subpart B (ANL/AMD-21/1) ML18215A1782018-06-30030 June 2018 WCAP-18169-NP, Rev 1, Arkansas Nuclear One Unit 2 Heatup and Cooldown Limit Curves for Normal Operation. ML17236A1792017-08-22022 August 2017 Arkansas, Units 1 and 2, ANO Emergency Plan On-Shift Staffing Analysis Report, Revision 2 0CAN081703, Document 51-9257562-001, Revision 1, Arkansas Nuclear One Hfe - High Frequency Confirmation Report2017-08-16016 August 2017 Document 51-9257562-001, Revision 1, Arkansas Nuclear One Hfe - High Frequency Confirmation Report 0CAN061701, Transmittal of 10 CFR 50.71(e) Report, Revision 17 of the ANO Fire Hazards Analysis2017-06-0707 June 2017 Transmittal of 10 CFR 50.71(e) Report, Revision 17 of the ANO Fire Hazards Analysis 0CAN051704, Engineering Report No. CALC-ANOC-CS-14-00017, Rev 0, 2017 Focused Evaluation for External Flooding at Arkansas Nuclear One.2017-03-13013 March 2017 Engineering Report No. CALC-ANOC-CS-14-00017, Rev 0, 2017 Focused Evaluation for External Flooding at Arkansas Nuclear One. ML16365A0272016-10-31031 October 2016 ANP-3486NP, Revision 0, MRP-227-A Applicant/Licensee Action Item 6 Analysis for Arkansas Nuclear One Unit 1 (ANO-1). ML16293A5842016-09-30030 September 2016 WCAP-18166-NP, Revision 0, Analysis of Capsule 284 from the Entergy Operations, Inc. Arkansas Nuclear One, Unit 2 Reactor Vessel Radiation Surveillance Program. ML16202A1672016-07-0505 July 2016 Report 1500227.401, PWR Internals Aging Management Program Plan. ML16004A1792015-12-31031 December 2015 Attachment 2, ANP-3418NP, Revision 0, Arkansas Nuclear One Unit 1 Reactor Vessel Internals License Renewal Scope and MRP-189, Revision 1 Comparison (MRP-227-A Action Item 2) Licensing Report. (Non-Proprietary) ML15278A0242015-09-28028 September 2015 Attachment 2, Areva Document ANP-3417NP, Revision 0, MRP-227-A Applicant / Licensee Action Item No. 7 Analysis for Arkansas Nuclear One, Unit 1 (Non-Proprietary), Attachment 3, Affidavit, and Attachment 4, List of Commitments ML15071A0552015-03-31031 March 2015 ANP-3300Q2NP, Revision 0, Response to Request for Additional Information on Reactor Coolant System Pressure/Temperature and Low Temperature Overpressure Protection System Limits to 54 EFPY for Arkansas Nuclear One, Unit 1. ML15041A0742015-02-0606 February 2015 ANP-3300Q1NP, Rev. 0, Response to Request for Additional Information on Reactor Coolant System Pressure/Temperature and Low Temperature Overpressure Protection System Limits to 54 EFPY for Arkansas Nuclear One, Unit 1, Attachment 2 to 1CAN0 ML14330A2502014-11-30030 November 2014 Attachment 4 to 1CAN111401, ANP-3300, Revision 1, Pressure-Temperature Limits at 54 Efpy. ML14241A2412014-06-30030 June 2014 ANP-3300, Arkansas Nuclear One (ANO) Unit 1 Pressure-Temperature Limits at 54 EFPY, Attachment 4 ML14139A3812014-05-14014 May 2014 CALC-ANO2-CS-12-00002, Revision 1, Flooding Walkdown Report for Resolution of Fukushima Near Term Task Force Recommendation 2.3, Attachment 2 to 0CAN051402 ML14139A3802014-05-14014 May 2014 CALC-ANO1-CS-12-00003, Revision 1, Flooding Walkdown Report for Resolution of Fukushima Near Term Task Force Recommendation 2.3, Attachment 1 to 0CAN051402 1CAN051401, Time-Limited Aging Analysis Regarding Reactor Vessel Internals Loss of Ductility for Arkansas Nuclear One, Unit 1 at 60 Years Arkansas Nuclear One Unit 12014-05-0606 May 2014 Time-Limited Aging Analysis Regarding Reactor Vessel Internals Loss of Ductility for Arkansas Nuclear One, Unit 1 at 60 Years Arkansas Nuclear One Unit 1 ML14141A5552014-05-0101 May 2014 Attachment 1 to 1CAN051403 PWR Internals Aging Management Program Plan ML14007A4592014-02-25025 February 2014 Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-12-049 (Mitigation Strategies) ML14045A1562014-02-20020 February 2014 Mega-Tech Services, LLC Technical Evaluation Report Regarding the Overall Integrated Plan for Arkansas Nuclear One, Units 1 and 2, TAC Nos.: MF0942 and MF0943 1CAN091301, Updated Seismic Walkdown Report2013-09-30030 September 2013 Updated Seismic Walkdown Report ML13213A2702013-07-22022 July 2013 Stator Drop Root Cause Evaluation Report CR-ANO-C-2013-00888, Rev. 0, Unit 1 Main Turbine Generator Stator. ML13113A2182013-04-23023 April 2013 Technical Letter Report, PNNL Evaluation and Modeling of Licensee'S Alternative for Volumetric Inspection of Dissimilar Metal Butt Welds at Arkansas Nuclear One ML12334A0092012-11-19019 November 2012 CALC-ANO1-CS-12-00003, Flooding Walkdown Submittal Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Flooding, Attachment 1 to 1CAN111202 ML12334A0072012-11-19019 November 2012 CALC-ANO2-CS-12-00002, Rev. 0, Arkansas Nuclear One Unit 2 Flooding Walkdown Submittal Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Flooding. ML12342A0522012-11-16016 November 2012 Arkansas, Unit 2, Attachment 1 - Engineering Report CALC-ANO2-CS-12-00001, Rev. 0, Seismic Walkdown Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, and Attach. 2, List of Regulatory Commitments, Cover - 1CAN111201, Engineering Report CALC-ANO1-CS-12-00002, Rev. 0, Seismic Walkdown Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Pages 1 Through 3312012-11-16016 November 2012 Engineering Report CALC-ANO1-CS-12-00002, Rev. 0, Seismic Walkdown Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Pages 1 Through 331 2CAN111201, Arkansas, Unit 2, Attachment 1 - Engineering Report CALC-ANO2-CS-12-00001, Rev. 0, Seismic Walkdown Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Page 364 of 533 Through End2012-11-16016 November 2012 Arkansas, Unit 2, Attachment 1 - Engineering Report CALC-ANO2-CS-12-00001, Rev. 0, Seismic Walkdown Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Page 364 of 533 Through End ML12342A2202012-11-16016 November 2012 Engineering Report CALC-ANO1-CS-12-00002, Rev. 0, Seismic Walkdown Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Pages 1 Through 331 1CAN111201, Engineering Report CALC-ANO1-CS-12-00002, Rev. 0, Seismic Walkdown Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Pages 332 Through 5602012-11-16016 November 2012 Engineering Report CALC-ANO1-CS-12-00002, Rev. 0, Seismic Walkdown Report for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Pages 332 Through 560 ML1200903102012-01-0909 January 2012 Email Apparent Cause Evaluation Report, Final ACE for Tube to Tube Wear ML0832603222008-11-12012 November 2008 Letter to Elmo E. Collins from FEMA, Region IV, Denton, Texas Dated 11-12-2008 Subj: ANO Radiological EP Final Report for ANO ML0821900132008-08-0707 August 2008 Monthly Operating Reports Second Quarter 2008 2CAN040801, Summary of Design and Analyses of Weld Overlays for Hot Leg Nozzle Dissimilar Metal Welds for Alloy 600 Mitigation at ANO-22008-04-0202 April 2008 Summary of Design and Analyses of Weld Overlays for Hot Leg Nozzle Dissimilar Metal Welds for Alloy 600 Mitigation at ANO-2 ML0713703522007-05-0808 May 2007 Stress Analysis Summary Report, Pressurizer and Reactor Coolant Hot Leg Weld Overlays ML0710002572007-03-26026 March 2007 Attachment 5 - HI-2063601, Holtec Licensing Report for ANO Unit 2 Partial Rerack, (non-propriety) ML0622204422006-08-10010 August 2006 Holtec Report HI-2022867 Spent Fuel Pool Racks Modifications with Poison Material Inserts in ANO Unit 1 for Entergy. ML0522303712005-08-0808 August 2005 Attachment 2, HI-2043262NP, Rev 0 - Part 50 Criticality Analysis of the MPC-32 for ANO Unit 2, Holtec Project No: 1104, Report Class Safety Related 2023-06-29
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TECHNICAL LETTER REPORT EVALUATION OF LICENSEES ALTERNATIVE TO 10 CFR 50.55A(G)(6)(II)(F) FOR LIMITATIONS TO VOLUMETRIC EXAMINATIONS OF DISSIMILAR METAL WELDS ENTERGY OPERATIONS, INC.
ARKANSAS NUCLEAR ONE, UNIT 2 - DOCKET NUMBER: 50-368 BACKGROUND By letter dated November 11, 2011, and with subsequent information in letters dated April 13, May 21, and September 10, 2012, the licensee, Entergy Operations, Inc., submitted an alternative to the examination requirements of Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(6)(ii)(F) which, in part, requires licensees implement American Society of Mechanical Engineers Boiler and Pressure Vessel (ASME) Code Case N-770-1, Alternative Examination Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities. The CFR requirements include a baseline ultrasonic examination to be performed on each full penetration piping butt weld in the reactor coolant pressure boundary welded with Alloy 82/182 materials. Ultrasonic examination requirements are listed in ASME Code Section XI and ASME Code Case N-770-1, as modified by CFR.
The licensee submitted an alternative to volumetric examination coverage requirements for multiple dissimilar metal welds (DMW) at Arkansas Nuclear One, Unit 2 (ANO-2). The alternative applies only to limited coverage on circumferential scans (for detection of axially-oriented cracking), as full coverage was obtained on axial scans. The NRC requested that Pacific Northwest National Laboratory (PNNL) evaluate the licensees alternative with respect to claimed coverage and ultrasonic technique capabilities as applied to two reactor coolant pump (RCP)-to-primary loop piping welds identified as Weld 09-008 and Weld 10-014. The evaluation included theoretical modeling of the sound beams based on actual phased-array design parameters and component geometrical information provided by the licensee. It should be noted that currently modeled sound field extents and densities represent only isotropic material, i.e., actual grain sizes and structures, velocity ranges, and other material variables that will affect sound beam attenuation, re-direction, and signal-to-noise values have not been applied, and in some cases, are presently unknown.
Another consideration is the potential for inconsistent transducer coupling. This variable is not addressed in the current modeling software, as both CIVA1 and UltraVision1 tend to set perfect contact between the probe and the examined component. However, the actual component outside diameter (OD) weld surfaces, from where the manual phased-array examinations were performed, would typically possess varied waviness around the circumference of the pipe, as the weld crowns would have been manually ground or blended smooth during the time of 1
CIVA and UltraVision are trademarked acoustic modeling and phased array operating software of CEA and ZETEC, respectively.
fabrication. Depending on the extent of surface irregularities that exist, intermittent and unpredictable losses of ultrasonic transducer coupling may affect transmitted sound beam coherence. This can be more pronounced with phased-array probes, as the array is generally required to be adequately coupled over the entire primary axis in order for wave-fronts emitted from individual elements to constructively interfere to produce proper beam steering and focusing. In addition, the licensee stated that probe wedges with flat contact surfaces were used for these examinations, which could also contribute to coupling inconsistencies in wavy regions, or if the probe were to rock during circumferential scans on the component.
Based on the physical limitations described above, the models should be viewed as a best-case representation only.
As requested, PNNL performed individual assessments for each of the subject welds. These are provided in the following sections of this report.
EVALUATION Weld 09-008 Weld 09-008 is a full penetration DMW on the RCP discharge nozzle joining the carbon steel, inside diameter (ID) clad primary piping to a cast austenitic stainless steel (CASS) safe end.
The safe end is welded directly to the RCP pump housing. An idealized cross-sectional depiction of Weld 09-008 is shown as Figure 1. Note that this drawing shows a very flat OD surface in cross-sectional profile. Because the OD surface features of a ground weld crown can vary circumferentially, and no information could be obtained from the licensee to depict actual field conditions, PNNL modeled Weld 09-008 with this same perfectly flat OD surface.
Figure 1 Idealized Cross Section of RCP Weld 09-008 The licensee also submitted a volumetric coverage sketch, showing calculated beam plots for claimed circumferential scan coverage. This is shown as Figure 2, and a legend has been included to depict volumetric weld coverage. The licensees sketch indicates that inner one-third coverage could only be obtained in the buttering and portions of the weld nearest the fusion zones. The licensee further shows that coverage in the outer two-thirds of the weld is similar. However, a large center portion of the weld is shown as not examined, due primarily to OD surface features. The licensee has estimated volumetric coverage as being approximately 73.8%, which includes the inner one-third of the ID-clad carbon steel piping, but no coverage on the CASS safe end.
Figure e 2 Licensee e Calculated d Volumetric Coverage fo or Weld 09-00 08 PNNL mo odeled the ultrasonic u beeam on this weld, w given actual a probee parameterss and the idealizedd drawing submitted by the licensee.. As shown in Figure 3, the PNNL UT U coverage e plot does not exactly mattch the licensees sketch h. There are e several rea asons for this discrepanccy.
The PNN NL model contained idea al OD surface features, resulting r in volumetric v cooverage in thhe center off the weld; and based on n the array matrix m designn dimensionss, an area of o limited coverage e results nea ar the OD of the weld (6 6 decibel [dB B] or less is shown in ligght red). The e PNNL mo odel is base ed on theorettical 6 dB sound s beam extremity lim mits; that is, volumetric coverage e with soundd field density from a com mbination off all steered beams, equal to, or grea ater than, 6 dB has been n depicted as a light greenn in the figurre. The licen nsees coverrage sketch (Figure 2) 2 is more co onservative than t the PNNNL model, but b there are individual beam b densityy profile isssues that sh hould be disccussed.
Figure 3 PNNL Modeled -6 dB Coverage The phased array was operated with focal laws defined to produce steered beams from 0 to 80 degrees, at one-degree increments, each focused at approximately 122 mm of metal path after exiting the probe. This focal length is beyond the ID surface for steered beams less than around 20 degrees, and only produces 6 dB field densities at the ID for beams at approximately 20-25 degrees. In a similar manner, steered beams above about 65-70 degrees will not produce useful beam profiles for detecting flaws near the ID because they are focused at too short a metal path length (6 dB sound field limits produced by the array are shown in Figure 4).
Therefore, the model predicts that all sound beams above approximately 30 degrees to have less than 6 dB beam intensities near the ID of the weld. The 6 dB value represents a point where field intensity is diminished by 50% of the initial maximum; every 6 dB is an additional 50% reduction; for example, 12 dB is 4 times lower than initial sound energy. The model is a best-case scenario; that is, no material attenuation or backscattered noise from coarse grains in the weld is included. These factors, as well as other potential coupling issues described above, will typically lower the amplitudes of reflected energies from flaws, resulting in decreased signal-to-noise ratio (S/N), and making flaw detection significantly more challenging.
Figure 4 - Sound Beam Intensity Profiles for 20-80 Degree Beams Weld 10-014 Weld 10-014 is a full penetration DMW on the RCP suction nozzle joining the carbon steel, ID clad primary piping to a CASS safe end. The safe end is welded directly to the RCP pump housing. An idealized cross-sectional depiction of Weld 10-014 is shown as Figure 5. This weld varies from the discharge DMW 09-008 by an OD taper between the ferritic elbow to the CASS safe end, as shown in the figure.
Figure 5 Idealized Cross Section for Weld 10-014 As with previous Weld 09-008, the licensee submitted sketches showing areas of inner one-third, outer two-thirds, and no volumetric coverage obtained for Weld 10-014. One such sketch is provided as Figure 6. The licensee estimated combined circumferential scan coverage to be approximately 84.1% of the required volume, with the area of no coverage shown to be an ID-to-OD region of the weld nearest the CASS fusion zone. Note that the licensee did not take credit for electronically skewing the UT beam down into the weld ID region, although focal laws for a 10-degree lateral skew were used. As shown in the figure, the primary reason for limited coverage is the OD taper.
Figuree 6 Licensee e Calculated d Volumetric Coverage fo or Weld 10-01 14 PNNL alsso modeled Weld 10-014; beam covverage resullts are shown in Figure 7. 7 Sound fie eld 6 dB limmits were again used, bu ut in this case, due to the e OD taper anda slightly increased i w wall thicknesss, an area off less than 6 dB is also o shown on the ID of the weld that do oes not agre ee with the licensees l sttated coveraage. In fact, in order for the lower an ngles (20-25 5 degrees, similar to o the previouus weld) to extend e to the eir maximumm 6 dB lengtth, electronicc lateral ske ewing was requ uired. While focal laws were w producced to laterallly skew the beam by 10 0 degrees doown into the weld w ID, the actual arrayy matrix would only produce an apprroximate 4-d degree skew.
This is beecause onlyy two elemen nts exist in th he passive direction d of th he array. Ho owever, the 4-degree laateral skew was w helpful to extend the sound bea ams as modeled. Figure es 8 and 9 depict d
end and side views of o the sound fields; the ende view of the t sound fie eld is the cro oss-sectionaal view. No ote that the overall o sound field sufferrs from poorr densities inn the steered d beams abo ove about 30 degrees, similar to thatt modeled fo or Weld 09-008.
Figure 7 PNNL Modeled 6 dB Coverage Figure 8 End View of PNNL Modeled Aggregate Sound Field Figure 9 Sound Field Intensity Profiles for 20-80 Degrees on Weld 10-014 Flaw Detection and Optimized ID Impingement Based on the sound fields described above, it is shown that only certain lower (20-30 degrees projected) angles produce focused energies, at or above 6 dB, at the ID surface of these welds. Flaw detection in austenitic weld materials is complicated, but is generally believed to require a corner-trapped, or crack-face, specular response to be back-scattered to the detecting probe with sufficient energy to yield a minimum 2:1 S/N. This amplitude is affected by several factors, including material acoustic properties, and impedance mismatching and orientation of the flaw, with respect to the impinging sound beam. When attempting to detect axially-oriented, ID surfacing-breaking planar flaws, there is a theoretical optimum range of ID impingement angles that should be designed into the transducer/wedge combination. The desired impingement angle should be below a critical value (above which sound would not impact the ID surface) and can be calculated by the following:
OD sin ( ) = sin ( ) (1)
ID where: is the ID impingement angle, is the initial refracted angle from the probe on the OD surface, and OD/ID is the ratio of the outside-to-inside pipe diameters.
A graphical depiction of this relationship is shown as Figure 10. According to the industrys Performance Demonstration Initiative (PDI) generic DMW ultrasonic procedure 10 (PDI-UT-10),
the optimum ID impingement angle () for detecting PWSCC on the subject welds is in the range of 55-60 degrees, vis--vis, the transmitted refracted angle () should be in the range of 42-45 degrees.
Figure 10 Representation of Solution for ID Impingement Angle CONCLUSIONS With respect to volumetric coverage extent, and a few minor differences, ultrasonic ray trace drawings provided by the licensee are in general agreement with PNNL modeling results.
However, there are several key observations provided by the theoretical model that could impact the quality of the subject examinations. When one considers the optimum range of impingement angles for flaw detection in ANO-2 RCP discharge and suction Welds09-008 and 10-014, and the best-case theoretical sound field intensities modeled by PNNL, it would seem that insufficient acoustic energy at the correct angles (42-45 degrees) is being generated by the phased-array probe and focal laws used for detecting axially-oriented PWSCC. This would be especially true for shallow cracks, on the order of 20-30% through-wall and smaller. Further, the model predicts that only angles below about 25-degrees appear to provide adequate
( 6 dB) sound fields to facilitate detection. It is presently unclear how well these lower transmitted angles, and resultant impingement angles, will perform on ID surface-breaking flaws.