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{{#Wiki_filter:Second License Amendment Request for the Unit 3 Train B Diesel GeneratorPalo Verde Nuclear Generating StationDecember 29, 2016 Agenda*Background*Regulatory Commitments*Event Investigation*Risk Assessment*Second License Amendment Request*Conclusions2 First License Amendment Request (LAR)*One-time Technical Specification (TS) Change to Allow a 21 day Completion Time In Response to Failure of Unit 3 B Train DG on December 15, 2016-Extension of 11 days needed to collect/analyze data and continue repair -Deterministic justification based upon BTP 8-8-Risk insights provided to support change -NRC commitments made in LAR-NRC Amendment 199 issued on December 23, 20163 Regulatory Commitments*Commitments documented in NRC Amendment #199 include but are not limited to:-Three, 2 MW portable DGs staged, tested and hooked-up to Unit 3 FLEX 4.16KV connections-Diesel driven FLEX Steam Generator make-up pump staged in Unit 3-Suspension of discretionary maintenance on SBOGs, Switchyard, Safety Systems-Establish protected equipment controls for Train A equipment, SBOGs, portable equipment-Commitments monitored and tracked by OPS-Dedicated personnel4 Palo Verde AC Power System5 Palo Verde AC Power System6 Event Investigation*Partnerships established with MPR, Goltens, Structural Integrity, EPRI, and the Cooper-Bessemer Owners Group*Evidence of high cycle fatigue on master connecting rod*Second major failure of 3B DG (9R)*1986 event created localized misalignment7 Operating Experience (OE)*Cooper-Bessemer KSV-20 OE -1986 -Palo Verde 3B DG connecting rod (9R) failure during unit startup testing program-1989 -South Texas Project DG 22 connecting rod failure during a surveillance test -2003 -South Texas Project DG 22 connecting rod failure during a surveillance test (one-time LAR using a two-phased approach to extend allowable outage time to 113 days)-2016 -Palo Verde 3B DG connecting rod (9R) failure during a surveillance test8 DIRECT CAUSE OF FAILURE*High cycle fatigue failure of the master connecting rod ligament which surrounds the lower part of the articulating rod pin. 9 Event Investigation10Master Rod Fracture Surface ROOT CAUSE OF FAILUREFLAW + STRESS = FATIGUE POTENTIAL FLAWSSTRESS1. Residualtensile within master connecting rod bore due to machining process changeMis-Alignment2. Fretting 3. "Undersized" OversizedBearing following 1987 repair. 11 12 3A/3B COMPARITIVE EVALUATION*Evaluating Wide Array of Data*Relevant Data-Vibration -Engine Analysis-Line Bore Data-Work History-Event History13 3A/3B COMPARITIVE EVALUATION*Unit 3 "B" Emergency Diesel Generator experienced a catastrophic failure that induced crankshaft mis-alignment which increased the stress profile within the engine*Unit 3 "A" engine has not had a catastrophic failure*Unit 3 "A" engine vibration displacement data is consistently less and has significantly less variability*Unit 3 "A" Master connecting rods are original  equipment (i.e. Pre machining change)14 Engineering ConclusionThere is no common cause mode of failure to Unit 3 "A" Emergency Diesel Generator due to the unique aspects of the Unit 3 "B" Diesel Generator root cause.15 Risk Assessment*PRA models for-Internal Events-Internal Flood-Internal Fire-Seismic*Other hazards screened out16 PRA Model and Risk-Informed Application Model History Pre-2010201020112012201320142015201617Internal Events CEOG peer review & numerous risk-informed TS changesTSTF-425 Surveillance Frequency Control Program approved2ndfire PRA peer reviewTSTF-505 submittedInternal Flood peer reviewRisk-informed 7-day inverter TS approvedSeismic PRA peer review1stfire PRA peer reviewInternal Events self-assessment per RG 1.200 App BAll Unit 3Mods Comp  
{{#Wiki_filter:Second License Amendment Request for the Unit 3 Train B Diesel GeneratorPalo Verde Nuclear Generating Station December 29, 2016 Agenda*Background
& all ASME PRA Std SRs Met to CC IIExternal Hazards Screening peer review Risk Assessment*Palo Verde PRA Aspects-Six 100% capacity SG makeup pumps all supplied by onsite power sources-Only one of these powered by B DG if loss of offsite power-RCP seal LOCAs negligible -ECCS significance minimal in loss of offsite power events-No Pressurizer power-operated relief valves-Very low internal events CDF and LERF -consistent with STP and Millstone 3-Only shared systems in PRA are SBOGs and firewater-Dedicated fire department staff and equipment-Risk significant FLEX connections outside of unit-Did not need to implement NFPA-805 to address multiple spurious operations18 PRA Model Credited Changes *Revised emergency operating procedures and night order to direct timely use of firewater to auxiliary feedwatercross-tie in total loss of feedwaterevent -validated in simulator-Additional dedicated auxiliary operator added to each shift to implement cross-tie*Post continuous fire watch in fire zone FCCOR2 (120' Corridor Building)*Establish new transient combustible and hot work exclusion zones and conduct shiftlyinspections-Fire zones FCCOR2 (120' Corridor Building) and FCCOR2A (120' Corridor Riser Shaft)-Fire zones FCTB04 (upper level only, non-class DC Equipment, [FCTB04-TRAN1])-Fire zone FC86A (train A Seismic Gap, make part of train A Electrical Protected Equipment)-Fire zone FCTB100 zone ZT1G (SW corner, south half of 100' Turbine between columns TA and TC)19 Risk Assessment*Defense-in-Depth Evaluation-Unavailability does not reduce the amount of available equipment to a level below that necessary to mitigate a design basis accident*Safety Margin Evaluation-No significant reduction in margin of safety*Regulatory Guide 1.200, Revision 2 compliant*Regulatory Guide 1.177, Revision 1 compliant*Regulatory Guide 1.174, Revision 2 compliant20 Second License Amendment Request*Requesting a extension of TS 3.8.1 Condition B.4 Completion Time to complete the DG Repairs*Request on Emergency Basis*Risk-informed LAR*Carrying forward the Commitments made in Deterministic LAR*To be submitted Friday, December 30*Request approval by early Thursday morning 21 Conclusions*Direct cause of the 3B DG failure has been determined*No common mode failure applicability to 3A DG*Continue to have diverse and redundant sources of AC power and steam generator makeup*PRA risk acceptable in accordance with Regulatory Guides 1.174 and 1.177*No significant hazards consideration criteria satisfied22 Questions?}}
*Regulatory Commitments
*Event Investigation
*Risk Assessment
*Second License Amendment Request
*Conclusions 2
First License Amendment Request (LAR)
*One-time Technical Specification (TS) Change to Allow a 21 day Completion Time In Response to Failure of Unit 3 B Train DG on December 15,  
 
2016-Extension of 11 days needed to collect/analyze data and continue repair  
-Deterministic justification based upon BTP 8-8
-Risk insights provided to support change  
-NRC commitments made in LAR
-NRC Amendment 199 issued on December 23, 2016 3
Regulatory Commitments
*Commitments documented in NRC Amendment #199 include but are not limited  
 
to:-Three, 2 MW portable DGs staged, tested and hooked-up to Unit 3 FLEX 4.16KV connections
-Diesel driven FLEX Steam Generator make-up pump staged in Unit 3
-Suspension of discretionary maintenance on SBOGs, Switchyard, Safety Systems
-Establish protected equipment controls for Train A equipment, SBOGs, portable equipment
-Commitments monitored and tracked by OPS
-Dedicated personnel 4
Palo Verde AC Power System 5
Palo Verde AC Power System 6
Event Investigation
*Partnerships established with MPR, Goltens, Structural Integrity, EPRI, and the Cooper-
 
Bessemer Owners Group
*Evidence of high cycle fatigue on master connecting rod
*Second major failure of 3B DG (9R)
*1986 event created localized misalignment 7
Operating Experience (OE)
*Cooper-Bessemer KSV-20 OE  
-1986 -Palo Verde 3B DG connecting rod (9R) failure during unit startup testing program
-1989 -South Texas Project DG 22 connecting rod failure during a surveillance test  
-2003 -South Texas Project DG 22 connecting rod failure during a surveillance test (one-time LAR using a two-phased approach to extend allowable outage time to 113 days)
-2016 -Palo Verde 3B DG connecting rod (9R) failure during a surveillance test 8
DIRECT CAUSE OF FAILURE
*High cycle fatigue failure of the master  
 
connecting rod  
 
ligament which  
 
surrounds the lower part of  
 
the articulating  
 
rod pin.
9 Event Investigation 10Master Rod Fracture Surface ROOT CAUSE OF FAILUREFLAW + STRESS = FATIGUE POTENTIAL FLAWSSTRESS1. Residualtensile within master connecting rod bore due to machining process changeMis-Alignment2. Fretting 3. "Undersized" OversizedBearing following 1987 repair.
11 12 3A/3B COMPARITIVE EVALUATION
*Evaluating Wide Array of Data
*Relevant Data
-Vibration  
-Engine Analysis
-Line Bore Data
-Work History
-Event History 13 3A/3B COMPARITIVE EVALUATION
*Unit 3 "B" Emergency Diesel Generator experienced a catastrophic failure that induced crankshaft mis-alignment which increased the stress profile within the engine
*Unit 3 "A" engine has not had a catastrophic failure*Unit 3 "A" engine vibration displacement data is consistently less and has significantly less variability
*Unit 3 "A" Master connecting rods are original  equipment (i.e. Pre machining change) 14 Engineering Conclusion There is no common cause mode of failure to Unit 3 "A" Emergency Diesel Generator due to the unique aspects of the Unit 3 "B" Diesel Generator root cause.
15 Risk Assessment
*PRA models for
-Internal Events
-Internal Flood
-Internal Fire
-Seismic*Other hazards screened out 16 PRA Model and Risk-Informed Application Model History Pre-2010201020112012201320142015201617Internal Events CEOG peer review & numerous risk-informed TS changesTSTF-425 Surveillance Frequency Control Program approved 2ndfire PRA peer reviewTSTF-505 submittedInternal Flood peer reviewRisk-informed 7-day inverter TS approvedSeismic PRA peer review 1stfire PRA peer reviewInternal Events self-assessment per RG 1.200 App B All Unit 3 Mods Comp  
& all ASME PRA Std SRs Met to CC IIExternal Hazards Screening peer review Risk Assessment
*Palo Verde PRA Aspects
-Six 100% capacity SG makeup pumps all supplied by onsite power sources
-Only one of these powered by B DG if loss of offsite power
-RCP seal LOCAs negligible -ECCS significance minimal in loss of offsite power events
-No Pressurizer power-operated relief valves
-Very low internal events CDF and LERF -consistent with STP and Millstone 3
-Only shared systems in PRA are SBOGs and firewater
-Dedicated fire department staff and equipment
-Risk significant FLEX connections outside of unit
-Did not need to implement NFPA-805 to address multiple spurious operations 18 PRA Model Credited Changes  
*Revised emergency operating procedures and night order to direct timely use of firewater to auxiliary feedwatercross-tie in total loss of feedwaterevent -validated in  
 
simulator
-Additional dedicated auxiliary operator added to each shift to implement cross-tie
*Post continuous fire watch in fire zone FCCOR2 (120' Corridor Building)
*Establish new transient combustible and hot work exclusion zones and conduct shiftlyinspections
-Fire zones FCCOR2 (120' Corridor Building) and FCCOR2A (120' Corridor Riser Shaft)
-Fire zones FCTB04 (upper level only, non-class DC Equipment, [FCTB04-TRAN1])
-Fire zone FC86A (train A Seismic Gap, make part of train A Electrical Protected Equipment)
-Fire zone FCTB100 zone ZT1G (SW corner, south half of 100' Turbine between columns TA and TC) 19 Risk Assessment
*Defense-in-Depth Evaluation
-Unavailability does not reduce the amount of available equipment to a level below that necessary to mitigate a design basis accident
*Safety Margin Evaluation
-No significant reduction in margin of safety
*Regulatory Guide 1.200, Revision 2 compliant
*Regulatory Guide 1.177, Revision 1 compliant
*Regulatory Guide 1.174, Revision 2 compliant 20 Second License Amendment Request
*Requesting a extension of TS 3.8.1 Condition B.4 Completion Time to complete the DG Repairs*Request on Emergency Basis
*Risk-informed LAR
*Carrying forward the Commitments made in Deterministic LAR
*To be submitted Friday, December 30
*Request approval by early Thursday morning 21 Conclusions
*Direct cause of the 3B DG failure has been determined
*No common mode failure applicability to 3A DG*Continue to have diverse and redundant sources of AC power and steam generator makeup*PRA risk acceptable in accordance with Regulatory Guides 1.174 and 1.177
*No significant hazards consideration criteria satisfied 22 Questions?}}

Revision as of 00:20, 30 June 2018

Palo Verde, Enclosure 2 - APS Meeting Slides
ML17003A033
Person / Time
Site: Palo Verde Arizona Public Service icon.png
Issue date: 12/29/2016
From:
Arizona Public Service Co
To:
Office of Nuclear Reactor Regulation
Watford M
References
CAC MF9019
Download: ML17003A033 (23)
v • d • e


Text

Second License Amendment Request for the Unit 3 Train B Diesel GeneratorPalo Verde Nuclear Generating Station December 29, 2016 Agenda*Background

  • Regulatory Commitments
  • Event Investigation
  • Risk Assessment
  • Second License Amendment Request
  • Conclusions 2

First License Amendment Request (LAR)

  • One-time Technical Specification (TS) Change to Allow a 21 day Completion Time In Response to Failure of Unit 3 B Train DG on December 15,

2016-Extension of 11 days needed to collect/analyze data and continue repair

-Deterministic justification based upon BTP 8-8

-Risk insights provided to support change

-NRC commitments made in LAR

-NRC Amendment 199 issued on December 23, 2016 3

Regulatory Commitments

  • Commitments documented in NRC Amendment #199 include but are not limited

to:-Three, 2 MW portable DGs staged, tested and hooked-up to Unit 3 FLEX 4.16KV connections

-Diesel driven FLEX Steam Generator make-up pump staged in Unit 3

-Suspension of discretionary maintenance on SBOGs, Switchyard, Safety Systems

-Establish protected equipment controls for Train A equipment, SBOGs, portable equipment

-Commitments monitored and tracked by OPS

-Dedicated personnel 4

Palo Verde AC Power System 5

Palo Verde AC Power System 6

Event Investigation

  • Partnerships established with MPR, Goltens, Structural Integrity, EPRI, and the Cooper-

Bessemer Owners Group

  • Evidence of high cycle fatigue on master connecting rod
  • Second major failure of 3B DG (9R)
  • 1986 event created localized misalignment 7

Operating Experience (OE)

  • Cooper-Bessemer KSV-20 OE

-1986 -Palo Verde 3B DG connecting rod (9R) failure during unit startup testing program

-1989 -South Texas Project DG 22 connecting rod failure during a surveillance test

-2003 -South Texas Project DG 22 connecting rod failure during a surveillance test (one-time LAR using a two-phased approach to extend allowable outage time to 113 days)

-2016 -Palo Verde 3B DG connecting rod (9R) failure during a surveillance test 8

DIRECT CAUSE OF FAILURE

  • High cycle fatigue failure of the master

connecting rod

ligament which

surrounds the lower part of

the articulating

rod pin.

9 Event Investigation 10Master Rod Fracture Surface ROOT CAUSE OF FAILUREFLAW + STRESS = FATIGUE POTENTIAL FLAWSSTRESS1. Residualtensile within master connecting rod bore due to machining process changeMis-Alignment2. Fretting 3. "Undersized" OversizedBearing following 1987 repair.

11 12 3A/3B COMPARITIVE EVALUATION

  • Evaluating Wide Array of Data
  • Relevant Data

-Vibration

-Engine Analysis

-Line Bore Data

-Work History

-Event History 13 3A/3B COMPARITIVE EVALUATION

  • Unit 3 "B" Emergency Diesel Generator experienced a catastrophic failure that induced crankshaft mis-alignment which increased the stress profile within the engine
  • Unit 3 "A" engine has not had a catastrophic failure*Unit 3 "A" engine vibration displacement data is consistently less and has significantly less variability
  • Unit 3 "A" Master connecting rods are original equipment (i.e. Pre machining change) 14 Engineering Conclusion There is no common cause mode of failure to Unit 3 "A" Emergency Diesel Generator due to the unique aspects of the Unit 3 "B" Diesel Generator root cause.

15 Risk Assessment

  • PRA models for

-Internal Events

-Internal Flood

-Internal Fire

-Seismic*Other hazards screened out 16 PRA Model and Risk-Informed Application Model History Pre-2010201020112012201320142015201617Internal Events CEOG peer review & numerous risk-informed TS changesTSTF-425 Surveillance Frequency Control Program approved 2ndfire PRA peer reviewTSTF-505 submittedInternal Flood peer reviewRisk-informed 7-day inverter TS approvedSeismic PRA peer review 1stfire PRA peer reviewInternal Events self-assessment per RG 1.200 App B All Unit 3 Mods Comp

& all ASME PRA Std SRs Met to CC IIExternal Hazards Screening peer review Risk Assessment

  • Palo Verde PRA Aspects

-Six 100% capacity SG makeup pumps all supplied by onsite power sources

-Only one of these powered by B DG if loss of offsite power

-RCP seal LOCAs negligible -ECCS significance minimal in loss of offsite power events

-No Pressurizer power-operated relief valves

-Very low internal events CDF and LERF -consistent with STP and Millstone 3

-Only shared systems in PRA are SBOGs and firewater

-Dedicated fire department staff and equipment

-Risk significant FLEX connections outside of unit

-Did not need to implement NFPA-805 to address multiple spurious operations 18 PRA Model Credited Changes

  • Revised emergency operating procedures and night order to direct timely use of firewater to auxiliary feedwatercross-tie in total loss of feedwaterevent -validated in

simulator

-Additional dedicated auxiliary operator added to each shift to implement cross-tie

  • Establish new transient combustible and hot work exclusion zones and conduct shiftlyinspections

-Fire zones FCCOR2 (120' Corridor Building) and FCCOR2A (120' Corridor Riser Shaft)

-Fire zones FCTB04 (upper level only, non-class DC Equipment, [FCTB04-TRAN1])

-Fire zone FC86A (train A Seismic Gap, make part of train A Electrical Protected Equipment)

-Fire zone FCTB100 zone ZT1G (SW corner, south half of 100' Turbine between columns TA and TC) 19 Risk Assessment

  • Defense-in-Depth Evaluation

-Unavailability does not reduce the amount of available equipment to a level below that necessary to mitigate a design basis accident

  • Safety Margin Evaluation

-No significant reduction in margin of safety

  • Regulatory Guide 1.200, Revision 2 compliant
  • Regulatory Guide 1.177, Revision 1 compliant
  • Regulatory Guide 1.174, Revision 2 compliant 20 Second License Amendment Request
  • Requesting a extension of TS 3.8.1 Condition B.4 Completion Time to complete the DG Repairs*Request on Emergency Basis
  • Risk-informed LAR
  • Carrying forward the Commitments made in Deterministic LAR
  • To be submitted Friday, December 30
  • Request approval by early Thursday morning 21 Conclusions
  • Direct cause of the 3B DG failure has been determined
  • No common mode failure applicability to 3A DG*Continue to have diverse and redundant sources of AC power and steam generator makeup*PRA risk acceptable in accordance with Regulatory Guides 1.174 and 1.177
  • No significant hazards consideration criteria satisfied 22 Questions?
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