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| | number = ML17062A552 | | | number = ML17062A552 |
| | issue date = 03/09/2017 | | | issue date = 03/09/2017 |
| | title = Oyster Creek 2016 E EMRV Failure Slides for Regulatory Conference Meeting Notice for 03/09/17 | | | title = E EMRV Failure Slides for Regulatory Conference Meeting Notice for 03/09/17 |
| | author name = | | | author name = |
| | author affiliation = Exelon Generation Co, LLC | | | author affiliation = Exelon Generation Co, LLC |
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| {{#Wiki_filter:Regulatory ConferenceOyster Creek Generating StationElectromatic Relief Valve (EMRV)Preliminary White FindingMarch 9, 2017 Exelon Representatives*Chris MudrickSenior VP Operations*Garey StathesSite Vice President | | {{#Wiki_filter:Regulatory Conference Oyster Creek Generating Station Electromatic Relief Valve (EMRV) |
| *Michael GillinPlant Manager | | Preliminary White Finding March 9, 2017 |
| *Scot GreenleeSenior VP Engineering | | |
| *James BarstowDirector, Licensing | | Exelon Representatives |
| *Greg KruegerDirector, Risk Management | | * Chris Mudrick Senior VP Operations |
| *David BidwellJensen Hughes, PRA Analyst1 Agenda*PurposeGarey Stathes, Site Vice President*BackgroundMike Gillin, Plant Manager | | * Garey Stathes Site Vice President |
| *Common CauseGreg Krueger, Risk Management Director *Recommendations Jim Barstow, Licensing Director | | * Michael Gillin Plant Manager |
| *Closing RemarksChris Mudrick, Sr. VP Operations2 PurposeTo provide a comprehensive overview of the event (degradation of one EMRV) and establish a common understanding of the following factors that should influence the final significance of the Regulatory Finding:*Causal analysis of the single EMRV degradation*Corrective actions taken by Exelon | | * Scot Greenlee Senior VP Engineering |
| *NRC application of the guidance in RASP Handbook | | * James Barstow Director, Licensing |
| *Reasonable estimates of the potential risk impact of the performance deficiency (both qualitative and quantitative)3 Preliminary White Finding *Inspection Report 05000219/2016004 (EA-16-241)*Violation of Technical Specification 6.8.1, "Procedures and Programs" and TS 3.4.B (inoperable > allowed outage time)*Failure to follow EMRV reassembly instructions, causing 'E' EMRV to be incorrectly reassembled *Finding of low to moderate safety significance | | * Greg Krueger Director, Risk Management |
| *Human performance cross-cutting aspect in Procedure Adherence*NRC preliminary evaluation concluded increase in core damage frequency (CDF) related to failure of 'E' EMRV is greater than Green4 Causal Product Investigation Conclusions*One of five EMRVs found failed due to a maintenance technician error in reassembly of the valve actuator *The other four valves were correctly assembled (with star washers installed) and tested satisfactory *Conditions typically associated with shared common cause, including organizational factors, were not present5Inattention to detail resulted in washers not being installed on one EMRV Unique Defenses to Prevent Common CauseQualitative factors applied to the EMRV actuator rebuild and modification that should be considered in an SDP case:-Specific just-in-time training -Oversight and observations | | * David Bidwell Jensen Hughes, PRA Analyst 1 |
| -Industry subject matter experts | | |
| -Original equipment manufacturer representative consultation-Human performance briefings | | Agenda |
| -Quality Assurance modification inspections | | * Purpose Garey Stathes, Site Vice President |
| -Procedure revisions6Numerous actions were taken as barriers to prevent common cause effects Potential Consequences of Undervaluing Causal Factors when Quantifying RiskExelon requests that the following potential consequences of undervaluing causal factors be considered when quantifying risk: *Applying full conditional Common Cause Factor (CCF) probability establishes an upper bound and does not reflect a graded approach | | * Background Mike Gillin, Plant Manager |
| -warranted in this case *RASP Handbook guidance represents a bounding application of common cause, which dominates the risk significance result *SDP practices that overestimate risk significance can cause undue effort (on both sides) not commensurate with safety significance 7Results should not be driven by limitations of models, methods, databases Sensitivities -CCF Increase vs. CDF 8*CCF probability changes from 3 chances in 100,000 to 9 chances in 1,000*Green-White threshold at about 100X increase in CCF | | * Common Cause Greg Krueger, Risk Management Director |
| *The base value is more representative of "true" risk given that there was no extent of condition and many barriers applied*Demonstrates extreme nature of applying full RASP CCF increaseCCF IncreaseCCF ProbabilityChange in CDFBase value3.05E-057.00E-075X1.53E-047.30E-0710X3.05E-047.60E-0720X6.11E-048.30E-0750X1.53E-031.02E-06100X3.05E-031.35E-06Full RASP(233X)9.17E-032.67E-06 Increasing CCF Probability vs. Risk Significance 90.00E+005.00E-071.00E-061.50E-062.00E-062.50E-063.00E-0615102050100233Total CDF [Internal + Fire]Factor Increase in EMRV CCF TermFull RASP NRC should strive to represent "true risk" and should not apply the full RASP CCF increase unless warranted by the extent of condition and lack of barriers associated with the causeBASE Current SDP Common Cause Choices101.Nominal impact of common cause*Base value for CCF remains unchanged2.Full impact of common cause*Large numeric impact from increased common cause*No credit for actual extent of condition | | * Recommendations Jim Barstow, Licensing Director |
| *No credit for defenses employed*Explore sensitivities of graded approach to increasing common cause*Credit the actual extent of condition and defenses employed *Arrive at a reasonable estimate of potential risk impact of deficiencyWhat it Should beCurrent Application of CCF Align Safety Significance with the Facts*Increasing common cause "potential" (by factor of 233) does not reflect the true nature of the particular deficiency in question *Full CCF increase has a disproportionate impact on risk significance, particularly given EMRV success criteria (2 of 5 EMRVs) for dominant PRA model sequences*It is not anticipated that this case would be considered as a common cause event when processed in the industry database (NUREG/CR-6268)11Application of common cause in an SDP calculation should be tempered by known extent of condition and defenses employed RecommendationsShort Term*Credit unique defenses employed and actual extent of condition to address EMRV common cause *Treatment of CCF probability should be a graded application in this case as opposed to the full RASP increaseLong Term*Factor-in actual extent of condition and barriers in SDP cases *Institute a graded approach for increasing CCF probability | | * Closing Remarks Chris Mudrick, Sr. VP Operations 2 |
| *Revise the RASP Handbook guidance to reflect these changes | | |
| *Create inspection guidance for evaluating/crediting CCF defenses*Promote pre-emptive industry use of defenses for common cause12 Closing Remarks*Health and safety of the public is best served by showing the true risk of an event*NRC has the flexibility to do this under existing guidance | | Purpose To provide a comprehensive overview of the event (degradation of one EMRV) and establish a common understanding of the following factors that should influence the final significance of the Regulatory Finding: |
| *Following the RASP Handbook without looking at actual extent of condition and existing barriers is not in keeping with good regulatory principles13 | | * Causal analysis of the single EMRV degradation |
| }} | | * Corrective actions taken by Exelon |
| | * NRC application of the guidance in RASP Handbook |
| | * Reasonable estimates of the potential risk impact of the performance deficiency (both qualitative and quantitative) 3 |
| | |
| | Preliminary White Finding |
| | * Inspection Report 05000219/2016004 (EA-16-241) |
| | * Violation of Technical Specification 6.8.1, Procedures and Programs and TS 3.4.B (inoperable > allowed outage time) |
| | * Failure to follow EMRV reassembly instructions, causing E EMRV to be incorrectly reassembled |
| | * Finding of low to moderate safety significance |
| | * Human performance cross-cutting aspect in Procedure Adherence |
| | * NRC preliminary evaluation concluded increase in core damage frequency (CDF) related to failure of E EMRV is greater than Green 4 |
| | |
| | Causal Product Investigation Conclusions |
| | * One of five EMRVs found failed due to a maintenance technician error in reassembly of the valve actuator |
| | * The other four valves were correctly assembled (with star washers installed) and tested satisfactory |
| | * Conditions typically associated with shared common cause, including organizational factors, were not present Inattention to detail resulted in washers not being installed on one EMRV 5 |
| | |
| | Unique Defenses to Prevent Common Cause Qualitative factors applied to the EMRV actuator rebuild and modification that should be considered in an SDP case: |
| | - Specific just-in-time training |
| | - Oversight and observations |
| | - Industry subject matter experts |
| | - Original equipment manufacturer representative consultation |
| | - Human performance briefings |
| | - Quality Assurance modification inspections Numerous |
| | - Procedure revisionsactions were taken as barriers to prevent common cause effects 6 |
| | |
| | Potential Consequences of Undervaluing Causal Factors when Quantifying Risk Exelon requests that the following potential consequences of undervaluing causal factors be considered when quantifying risk: |
| | * Applying full conditional Common Cause Factor (CCF) probability establishes an upper bound and does not reflect a graded approach |
| | - warranted in this case |
| | * RASP Handbook guidance represents a bounding application of common cause, which dominates the risk significance result |
| | * SDP practices that overestimate risk significance can cause undue effort (on both sides) not commensurate with safety significance Results should not be driven by limitations of models, methods, databases 7 |
| | |
| | Sensitivities - CCF Increase vs. CDF CCF CCF Increase Change in CDF Probability Base value 3.05E-05 7.00E-07 5X 1.53E-04 7.30E-07 10X 3.05E-04 7.60E-07 20X 6.11E-04 8.30E-07 50X 1.53E-03 1.02E-06 100X 3.05E-03 1.35E-06 Full RASP(233X) 9.17E-03 2.67E-06 |
| | * CCF probability changes from 3 chances in 100,000 to 9 chances in 1,000 |
| | * Green-White threshold at about 100X increase in CCF |
| | * The base value is more representative of true risk given that there was no extent of condition and many barriers applied |
| | * Demonstrates extreme nature of applying full RASP CCF increase 8 |
| | |
| | Increasing CCF Probability vs. Risk Significance 3.00E-06 2.50E-06 Full RASP Total CDF [Internal + Fire] |
| | 2.00E-06 1.50E-06 1.00E-06 5.00E-07 0.00E+00 1 |
| | 5 10 BAS 20 E 50 100 233 Factor Increase in EMRV CCF Term NRC should strive to represent true risk and should not apply the full RASP CCF increase unless warranted by the extent of condition and lack of barriers associated with the cause 9 |
| | |
| | Current SDP Common Cause Choices Current Application of CCF |
| | : 1. Nominal impact of common cause |
| | * Base value for CCF remains unchanged |
| | : 2. Full impact of common cause |
| | * Large numeric impact from increased common cause |
| | * No credit for actual extent of condition |
| | * No credit for defenses employed What it Should be |
| | * Explore sensitivities of graded approach to increasing common cause |
| | * Credit the actual extent of condition and defenses employed |
| | * Arrive at a reasonable estimate of potential risk impact of deficiency 10 |
| | |
| | Align Safety Significance with the Facts |
| | * Increasing common cause potential (by factor of 233) does not reflect the true nature of the particular deficiency in question |
| | * Full CCF increase has a disproportionate impact on risk significance, particularly given EMRV success criteria (2 of 5 EMRVs) for dominant PRA model sequences |
| | * It is not anticipated that this case would be considered as a common cause event when processed in the industry database (NUREG/CR-6268) |
| | Application of common cause in an SDP calculation should be tempered by known extent of condition and defenses employed 11 |
| | |
| | Recommendations Short Term |
| | * Credit unique defenses employed and actual extent of condition to address EMRV common cause |
| | * Treatment of CCF probability should be a graded application in this case as opposed to the full RASP increase Long Term |
| | * Factor-in actual extent of condition and barriers in SDP cases |
| | * Institute a graded approach for increasing CCF probability |
| | * Revise the RASP Handbook guidance to reflect these changes |
| | * Create inspection guidance for evaluating/crediting CCF defenses |
| | * Promote pre-emptive industry use of defenses for common 12 cause |
| | |
| | Closing Remarks |
| | * Health and safety of the public is best served by showing the true risk of an event |
| | * NRC has the flexibility to do this under existing guidance |
| | * Following the RASP Handbook without looking at actual extent of condition and existing barriers is not in keeping with good regulatory principles 13}} |
|
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Category:Meeting Briefing Package/Handouts
MONTHYEARML19269B6892019-10-0303 October 2019 NEIMA Section 108 Public Meeting Slides - Oyster Creek - October 3, 2019 ML18347B3142018-12-19019 December 2018 Bwrvip/Asme Relief Request Discussion December 19, 2018 ML18334A2162018-11-30030 November 2018 Presentation Slides: Exelon BWR MSIV (Boiling-Water Reactor - Main Steam Isolation Valve) Leakage Optimization for NRC Pre-Submittal Meeting of December 6, 2018 ML18319A1272018-11-19019 November 2018 Slides for 11/19/18 Public Meeting - Exelon Fleet LAR for Common Language for TS 5.7 High Radiation Areas ML18225A1752018-08-15015 August 2018 Decommissioning License Transfer Application NRC Pre-Submittal Meeting ML18201A2372018-07-17017 July 2018 Slides 7/17/2018 PSDAR Meeting ML18201A2842018-07-17017 July 2018 PSDAR Public Meeting the NRC Review Process ML18201A3072018-07-17017 July 2018 Post Shutdown Decommissioning Activities Report (PSDAR) Public Meeting Presentation ML18054B3592018-02-27027 February 2018 Slide: NRC Pre-Submittal Meeting for Exelon Fleet LAR to Relocate TS Unit Staff Qualification ANSI Requirements to the QATR, February 27, 2018, Profile Info: Submitted by Frank Mascitelli ML17142A2382017-05-25025 May 2017 OEDO-17-00280 - Briefing Package for Drop-In Visit on June 9, 2017, by Senior Management of Exelon Generation Company, LLC with Chairman Svinicki, Commissioner Baran, and Commissioner Burns ML17062A5522017-03-0909 March 2017 E EMRV Failure Slides for Regulatory Conference Meeting Notice for 03/09/17 ML16314E4812016-11-14014 November 2016 Part 37 Applicability to Reactor Vessels and Associated Structures, Systems, and Components While in Safstor Awaiting Active Decommissioning Activities - November 14, 2016 ML16092A1402016-04-0606 April 2016 4/6/16, Meeting Slide for Pre-Submittal Meeting with NRC Regarding Oyster Creek Decommissioning Post-Shutdown Emergency Plan License Amendment Request ML16075A3292016-03-16016 March 2016 OEDO-16-00165 - Briefing Package for Drop-In Visit on March 23, 2016, by Senior Management of Exelon Generation Company, LLC with the NRC Executive Director for Operations ML15265A3592015-09-21021 September 2015 NRC Oyster Creek Decommissioning Pre-Submittal Meeting Slides 09-21-15 ML15118A8042015-05-0505 May 2015 Webinar 2015 Slides Presentation ML15265A3742015-02-21021 February 2015 NRC Pre-Submittal Meeting 09-21-15 - Decommissioning Submittal List ML12173A1322012-06-21021 June 2012 Summary of Public Meeting with Exelon Generation Company, LLC Regarding Items of Public Interest Related to Oyster Creek Nuclear Generating Station ML12110A3402012-04-19019 April 2012 Annual Assessment Meeting - 2011 ROP-NRC Slides ML1208701402012-03-27027 March 2012 Licensee Slides for Exelon Fleet Pre-Submittal Public Meeting 4-10-12 Licensed Operator Eligibility Requirements LAR ML1012300492010-05-0303 May 2010 Slides for the Oyster Creek Annual Assessment Public Meeting ML0934102382009-12-0404 December 2009 Meeting Presentation, ACRS Meeting with the U.S. Nuclear Regulator Commission ML0928701922009-10-0909 October 2009 FEMA Public Meeting at Oyster Creek Slides, October 2009 ML0919803632009-08-20020 August 2009 Summary of Licensing Counterparts Meeting with Exelon Generation Company, to Discuss Licensing Practices and Processes ML0919801452009-06-17017 June 2009 NRC Discussions with Nj DEP Engineers ML0919605452009-06-17017 June 2009 10/01/2008 Senior Management Briefing Oyster Creek License Renewal Regulatory Footprint, to Describe Current Regulatory Footprint, Additional Options & Actions, and Gov'T & Public Outreach Needs ML0919605462009-06-17017 June 2009 10/01/2008 Senior Management Briefing Oyster Creek License Renewal Regulatory Footprint, Working Discussion of Issues and Options in Response to RA Questions ML0919605472009-06-17017 June 2009 10/01/2008 Senior Management Briefing Oyster Creek License Renewal Regulatory Footprint, Working Discussion of Issues and Options in Response to RA Questions ML0919605572009-06-17017 June 2009 10/01/2008 Senior Management Briefing Oyster Creek License Renewal Regulatory Footprint, to Describe Current Regulatory Footprint, Additional Options & Actions, and Gov'T & Public Outreach Needs ML0919605582009-06-17017 June 2009 10/01/2008 Senior Management Briefing Oyster Creek License Renewal Regulatory Footprint, to Describe Current Regulatory Footprint, Additional Options & Actions, and Gov'T & Public Outreach Needs ML0919605592009-06-17017 June 2009 09/23/2008 DRS Management Briefing Oyster Creek License Renewal Regulatory Footprint, Working Discussion of Issues and Options in Response to RA Questions on a Lr Regulatory Foodprint ML0919605602009-06-17017 June 2009 09/23/2008 DRS Management Briefing Oyster Creek License Renewal Regulatory Footprint, Working Discussion of Issues and Options, in Response to RA Questions ML0919805202009-06-17017 June 2009 Brief for Ora Oyster Creek Commitment Inspection Results and Related Issues ML0916802102009-05-28028 May 2009 Oc Aam Public Feedback Form, 05/28/2009, 2008 Annual Assessment Meeting ML0913205742009-05-12012 May 2009 Meeting Slides, Oyster Creek Annual Assessment Meeting 2008 Reactor Oversight Process ML0912702392009-05-0404 May 2009 Calvert County Sheriff- Special Operations Team ML0912406092009-04-23023 April 2009 Meeting, Slides, New Jersey State Police Response to Hostile Action at Nuclear Power Plants, National Radiological Emergency Preparedness Conference ML0919801442008-12-22022 December 2008 Brief for Ora Oyster Creek Commitment Inspection Results and Related Issues with Handwritten Notes ML0919801392008-12-22022 December 2008 Brief for Ora Oyster Creek Commitment Inspection Results and Related Issues ML0919801402008-12-22022 December 2008 Brief for Ora Oyster Creek Commitment Inspection Results and Related Issues ML0919801422008-12-22022 December 2008 Brief for Ora Oyster Creek Commitment Inspection Results and Related Issues ML0919801432008-12-22022 December 2008 Brief for Ora Oyster Creek Commitment Inspection Results and Related Issues ML0812007842008-06-0202 June 2008 Meeting Slides, Nrc/Exelon Licensing Counterparts Meeting. ML0810606002008-04-15015 April 2008 Meeting Slides, NRC Annual Performance Assessment of Oyster Creek 2007 Reactor Oversight Program. ML0715204362007-05-23023 May 2007 Feedback Forms, List of Attendees, & Final Slides from the Oyster Creek 2007 Annual Assessment Meeting (Aam) ML0634206092006-11-0404 November 2006 Powerpoint: Oyster Creek 1R21 Outage Startup PORC Update on Drywell Shell Inspections November 4, 2006 (PA) ML0622301292006-07-12012 July 2006 Powerpoint Presentation Associated with Oyster Creek Draft EIS Public Meetings ML0610003702006-04-10010 April 2006 NRC Slides for Annual Assessment Public Meeting with Amergen Reference CY2005 Oyster Creek Station Performance ML0509800822005-04-0808 April 2005 05/12/2005 - Oyster Creek Annual Assessment Meeting Slides for Meeting with Amergen ML0430302762004-09-27027 September 2004 Attendance List for Oyster Creek EDG Cooling Fan Regulatory Conference 2019-10-03
[Table view] Category:Slides and Viewgraphs
MONTHYEARML19269B6892019-10-0303 October 2019 NEIMA Section 108 Public Meeting Slides - Oyster Creek - October 3, 2019 ML18347B3142018-12-19019 December 2018 Bwrvip/Asme Relief Request Discussion December 19, 2018 ML18334A2162018-11-30030 November 2018 Presentation Slides: Exelon BWR MSIV (Boiling-Water Reactor - Main Steam Isolation Valve) Leakage Optimization for NRC Pre-Submittal Meeting of December 6, 2018 ML18319A1272018-11-19019 November 2018 Slides for 11/19/18 Public Meeting - Exelon Fleet LAR for Common Language for TS 5.7 High Radiation Areas ML18226A0022018-08-14014 August 2018 Holtec Revised Slides for NRC LTA Pre-Submittal Meeting (Oyster Creek Nuclear Generating Station) ML18201A2372018-07-17017 July 2018 Slides 7/17/2018 PSDAR Meeting ML18054B3592018-02-27027 February 2018 Slide: NRC Pre-Submittal Meeting for Exelon Fleet LAR to Relocate TS Unit Staff Qualification ANSI Requirements to the QATR, February 27, 2018, Profile Info: Submitted by Frank Mascitelli ML17062A5522017-03-0909 March 2017 E EMRV Failure Slides for Regulatory Conference Meeting Notice for 03/09/17 ML16314E4812016-11-14014 November 2016 Part 37 Applicability to Reactor Vessels and Associated Structures, Systems, and Components While in Safstor Awaiting Active Decommissioning Activities - November 14, 2016 ML16092A1402016-04-0606 April 2016 4/6/16, Meeting Slide for Pre-Submittal Meeting with NRC Regarding Oyster Creek Decommissioning Post-Shutdown Emergency Plan License Amendment Request ML15265A3592015-09-21021 September 2015 NRC Oyster Creek Decommissioning Pre-Submittal Meeting Slides 09-21-15 ML15153A1372015-05-28028 May 2015 Aam - NRC Slide Presentation May 28 2015 ML15118A8042015-05-0505 May 2015 Webinar 2015 Slides Presentation ML15265A3742015-02-21021 February 2015 NRC Pre-Submittal Meeting 09-21-15 - Decommissioning Submittal List ML12173A1322012-06-21021 June 2012 Summary of Public Meeting with Exelon Generation Company, LLC Regarding Items of Public Interest Related to Oyster Creek Nuclear Generating Station ML12159A3522012-06-0606 June 2012 June 6 2012 Public Meeting - NRC Slides ML12159A3582012-06-0606 June 2012 Public Meeting, 6/6/12 - Slides - EPA Role in NPPs - Debonis ML12110A3402012-04-19019 April 2012 Annual Assessment Meeting - 2011 ROP-NRC Slides ML1208701402012-03-27027 March 2012 Licensee Slides for Exelon Fleet Pre-Submittal Public Meeting 4-10-12 Licensed Operator Eligibility Requirements LAR ML1115201902011-05-26026 May 2011 Assessment Meeting - NRC Slides ML1012300492010-05-0303 May 2010 Slides for the Oyster Creek Annual Assessment Public Meeting ML0934102382009-12-0404 December 2009 Meeting Presentation, ACRS Meeting with the U.S. Nuclear Regulator Commission ML0929400522009-10-22022 October 2009 Meeting Power Uprate Meeting Slides ML0929407012009-10-21021 October 2009 Slides for October 22, 2009, Public Meeting, Buried Piping Experience ML0928701922009-10-0909 October 2009 FEMA Public Meeting at Oyster Creek Slides, October 2009 ML0913206522009-05-13013 May 2009 Annual Assessment Meeting, Slides for May 28, 2009 Public Meeting ML0913205742009-05-12012 May 2009 Meeting Slides, Oyster Creek Annual Assessment Meeting 2008 Reactor Oversight Process ML0912702392009-05-0404 May 2009 Calvert County Sheriff- Special Operations Team ML0912406092009-04-23023 April 2009 Meeting, Slides, New Jersey State Police Response to Hostile Action at Nuclear Power Plants, National Radiological Emergency Preparedness Conference ML0812007842008-06-0202 June 2008 Meeting Slides, Nrc/Exelon Licensing Counterparts Meeting. ML0810606002008-04-15015 April 2008 Meeting Slides, NRC Annual Performance Assessment of Oyster Creek 2007 Reactor Oversight Program. ML0802501172008-01-15015 January 2008 1/15/2008 Slides from Drop-in Visit Exelon/Amergen ML0715204362007-05-23023 May 2007 Feedback Forms, List of Attendees, & Final Slides from the Oyster Creek 2007 Annual Assessment Meeting (Aam) ML0716601022007-03-20020 March 2007 Slides to Counterparts Meeting with Exelon to Discuss Current and Planned Licensing Activities and Process - Correction ML0726804132006-12-31031 December 2006 Katz, B., and R. Puentes, May 2006, Prosperity at Risk: Toward a Competitive New Jersey, the Brookings Institute ML0634206092006-11-0404 November 2006 Powerpoint: Oyster Creek 1R21 Outage Startup PORC Update on Drywell Shell Inspections November 4, 2006 (PA) ML0634206282006-10-24024 October 2006 E-MAIL: (PA) Fwd: Slides ML0622301292006-07-12012 July 2006 Powerpoint Presentation Associated with Oyster Creek Draft EIS Public Meetings ML0610003702006-04-10010 April 2006 NRC Slides for Annual Assessment Public Meeting with Amergen Reference CY2005 Oyster Creek Station Performance ML0534003822005-11-0101 November 2005 Environmental Scoping Meeting Oyster Creek Nuclear Generating Station, U.S. Nuclear Regulatory Commission and National Environmental Policy Act, November 1, 2005 ML0534003912005-11-0101 November 2005 the NRC: Who We Are and What We Do and How We Regulate ML0514001792005-05-12012 May 2005 NRC Slides for Annual Assessment Meeting with Amergen Regarding Oyster Creek Station ML0509800822005-04-0808 April 2005 05/12/2005 - Oyster Creek Annual Assessment Meeting Slides for Meeting with Amergen ML0430302502004-09-27027 September 2004 Slides for Oyster Creek EDG Regulatory Conference from Amergen ML0726803592003-12-31031 December 2003 Private Property and the Common Good, Anonymous, 2003, Powerpoint Presentation ML0323000332003-07-30030 July 2003 Exelon Nuclear State of the Fleet Presentation ML0310405012003-03-28028 March 2003 Notice of Meeting Slides Annual Assessment of Safety Performance of Oyster Creek Station 2019-10-03
[Table view] |
Text
Regulatory Conference Oyster Creek Generating Station Electromatic Relief Valve (EMRV)
Preliminary White Finding March 9, 2017
Exelon Representatives
- Chris Mudrick Senior VP Operations
- Garey Stathes Site Vice President
- Michael Gillin Plant Manager
- Scot Greenlee Senior VP Engineering
- Greg Krueger Director, Risk Management
- David Bidwell Jensen Hughes, PRA Analyst 1
Agenda
- Purpose Garey Stathes, Site Vice President
- Background Mike Gillin, Plant Manager
- Common Cause Greg Krueger, Risk Management Director
- Recommendations Jim Barstow, Licensing Director
- Closing Remarks Chris Mudrick, Sr. VP Operations 2
Purpose To provide a comprehensive overview of the event (degradation of one EMRV) and establish a common understanding of the following factors that should influence the final significance of the Regulatory Finding:
- Causal analysis of the single EMRV degradation
- Corrective actions taken by Exelon
- NRC application of the guidance in RASP Handbook
- Reasonable estimates of the potential risk impact of the performance deficiency (both qualitative and quantitative) 3
Preliminary White Finding
- Failure to follow EMRV reassembly instructions, causing E EMRV to be incorrectly reassembled
- Finding of low to moderate safety significance
- Human performance cross-cutting aspect in Procedure Adherence
- NRC preliminary evaluation concluded increase in core damage frequency (CDF) related to failure of E EMRV is greater than Green 4
Causal Product Investigation Conclusions
- One of five EMRVs found failed due to a maintenance technician error in reassembly of the valve actuator
- The other four valves were correctly assembled (with star washers installed) and tested satisfactory
- Conditions typically associated with shared common cause, including organizational factors, were not present Inattention to detail resulted in washers not being installed on one EMRV 5
Unique Defenses to Prevent Common Cause Qualitative factors applied to the EMRV actuator rebuild and modification that should be considered in an SDP case:
- Specific just-in-time training
- Oversight and observations
- Industry subject matter experts
- Original equipment manufacturer representative consultation
- Human performance briefings
- Quality Assurance modification inspections Numerous
- Procedure revisionsactions were taken as barriers to prevent common cause effects 6
Potential Consequences of Undervaluing Causal Factors when Quantifying Risk Exelon requests that the following potential consequences of undervaluing causal factors be considered when quantifying risk:
- Applying full conditional Common Cause Factor (CCF) probability establishes an upper bound and does not reflect a graded approach
- warranted in this case
- RASP Handbook guidance represents a bounding application of common cause, which dominates the risk significance result
- SDP practices that overestimate risk significance can cause undue effort (on both sides) not commensurate with safety significance Results should not be driven by limitations of models, methods, databases 7
Sensitivities - CCF Increase vs. CDF CCF CCF Increase Change in CDF Probability Base value 3.05E-05 7.00E-07 5X 1.53E-04 7.30E-07 10X 3.05E-04 7.60E-07 20X 6.11E-04 8.30E-07 50X 1.53E-03 1.02E-06 100X 3.05E-03 1.35E-06 Full RASP(233X) 9.17E-03 2.67E-06
- CCF probability changes from 3 chances in 100,000 to 9 chances in 1,000
- Green-White threshold at about 100X increase in CCF
- The base value is more representative of true risk given that there was no extent of condition and many barriers applied
- Demonstrates extreme nature of applying full RASP CCF increase 8
Increasing CCF Probability vs. Risk Significance 3.00E-06 2.50E-06 Full RASP Total CDF [Internal + Fire]
2.00E-06 1.50E-06 1.00E-06 5.00E-07 0.00E+00 1
5 10 BAS 20 E 50 100 233 Factor Increase in EMRV CCF Term NRC should strive to represent true risk and should not apply the full RASP CCF increase unless warranted by the extent of condition and lack of barriers associated with the cause 9
Current SDP Common Cause Choices Current Application of CCF
- 1. Nominal impact of common cause
- Base value for CCF remains unchanged
- 2. Full impact of common cause
- Large numeric impact from increased common cause
- No credit for actual extent of condition
- No credit for defenses employed What it Should be
- Explore sensitivities of graded approach to increasing common cause
- Credit the actual extent of condition and defenses employed
- Arrive at a reasonable estimate of potential risk impact of deficiency 10
Align Safety Significance with the Facts
- Increasing common cause potential (by factor of 233) does not reflect the true nature of the particular deficiency in question
- Full CCF increase has a disproportionate impact on risk significance, particularly given EMRV success criteria (2 of 5 EMRVs) for dominant PRA model sequences
- It is not anticipated that this case would be considered as a common cause event when processed in the industry database (NUREG/CR-6268)
Application of common cause in an SDP calculation should be tempered by known extent of condition and defenses employed 11
Recommendations Short Term
- Credit unique defenses employed and actual extent of condition to address EMRV common cause
- Treatment of CCF probability should be a graded application in this case as opposed to the full RASP increase Long Term
- Factor-in actual extent of condition and barriers in SDP cases
- Institute a graded approach for increasing CCF probability
- Revise the RASP Handbook guidance to reflect these changes
- Create inspection guidance for evaluating/crediting CCF defenses
- Promote pre-emptive industry use of defenses for common 12 cause
Closing Remarks
- Health and safety of the public is best served by showing the true risk of an event
- NRC has the flexibility to do this under existing guidance
- Following the RASP Handbook without looking at actual extent of condition and existing barriers is not in keeping with good regulatory principles 13