ML19046A390

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01/23/2019 Presentation Binder
ML19046A390
Person / Time
Issue date: 01/23/2019
From: Kenneth Hamburger
Office of Nuclear Regulatory Research
To:
Kenneth Hamburger 415-2022
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PRE-GI-018 Update, January 23, 2019 1Generic Issue (GI) Program Status for PRE-GI-018 Related to High Energy Arcing Faults involving AluminumKenneth HamburgerJanuary 23, 2019 PRE-GI-018 Update, January 23, 2019 2Safety & Security

  • Please keep visitor badges visible while on NRC propert y*First floor access okay without escort
  • Anywhere else requires NRC escort
  • Fire and emergencies
  • Follow NRC staff/security direction PRE-GI-018 Update, January 23, 2019 3*Meeting transcribed
  • Please identify yourself when speaking (every time)
  • Please speak into the microphones
  • Webinar participation
  • Facilitated
  • Keep the meeting on schedule and on topic
  • Public commentsMeeting Logistics PRE-GI-018 Update, January 23, 2019 1High Energy Arcing Faults Involving Aluminum Meeting ObjectivesMark Henry Salley, P.E.Branch ChiefOffice of Nuclear Regulatory ResearchJanuary 23, 2019 PRE-GI-018 Update, January 23, 2019 2Objectives
  • Communication
  • PRE-GI-018 status update
  • Confirmatory testing to

-dat e-Share some early observations from September 2018 medium

-voltage tests

  • Next series of confirmatory tests

-Planning stages

-Target date late summer/early fall 2019

  • Draft NRC/EPRI Working Group charter
  • Open discussion

-Thoughts, ideas, and suggestions PRE-GI-018 Update, January 23, 2019 1Generic Issue (GI) Program Status for PRE-GI-018 Related to High Energy Arcing Faults involving AluminumStan GardockiGI Program ManagerOffice of Nuclear Regulatory ResearchJanuary 23, 2019 PRE-GI-018 Update, January 23, 2019 2ScreeningAssessment ImplementationIssue exits program when issue fails to meet screening criteria, for example:

  • Referred to other regulatory process for action
  • Referred for additional long

-term researchIssue submitted to GI ProgramGI Program Three StagesOr closed when licensees' actions completed and verified PRE-GI-018 Update, January 23, 2019 3

PRE-GI-018 Update, January 23, 2019 4PRE-GI-018 Activities To

-Date*March 4, 2016

-NRR performed a safety review and determined no immediate actions required (ML16064A250

)*May 6 , 2016 -RES submitted into the GI Program (ML16126A096

)*May 17, 2016 -GI Program Staff initial screening complete, recommended forming review board (GIRP) (ML16132A415

)*July 15, 2017

-GIRP issued screening report that determined the seven screening criteria were met, recommended proceed to assessment stage (ML16349A027

)*August 22, 2018

-GIRP issued assessment plan (ML18172A185

)

PRE-GI-018 Update, January 23, 2019 5*GIRP will issue an Assessment Report to determine whether the issue should continue to next stage, regulatory office implementation (ROI)

  • If yes, then a transition team is formed, issue moves

out of RES into appropriate regulatory office, NRR

  • NRR determines the necessary regulatory actions

(example: issue appropriate generic communications)

  • Based upon potential regulatory requirements (if

applicable), licensees may have to take actions

  • Based on potential regulatory actions, NRR will

determine if public meeting will be held PRE-GI-018 Next Steps PRE-GI-018 Update, January 23, 2019 6Assessment Plan TimelinePIRT ExerciseCommunication PlanPublic WorkshopInformation Notice 2017

-04Phase I TestPhase II Test Small ScalePhase II Test Large Scale for Al HEAFEPRI/NRC ZOI Working GroupPilot Plant SelectionPilot Plant StudyRisk/Safety Determination Complete Assessment

-GI SubmittalNRR immediate safety assessmentInitial screening report issuedGIRP members appointedGIRP screening report issuedAssessment report issued01/01/201606/30/201612/28/201606/27/201712/25/201706/24/201812/22/201806/21/201912/19/201906/17/2020 PRE-GI-018 Update, January 23, 2019 1High Energy Arcing Faults (HEAF) AL Phase II Confirmatory Testing Preliminary ObservationsNicholas MellyOffice of Nuclear Regulatory ResearchDivision of Risk Analysis January 23, 2019 PRE-GI-018 Update, January 23, 2019 2*Provide an overview of the High Energy Arcing Fault (HEAF) confirmatory testing performed for PRE-GI-018*Discuss preliminary insights and project goals

  • Discuss future testing parameters, schedule and

milestones Purpose PRE-GI-018 Update, January 23, 2019 3*Public Comment Period-OECD/NEA P hase I members for comment on June 30, 2017

-Federal Register notice (82 FR 36006) published on August 2, 2017

-Public comment period closed September 1, 2017Phase II Draft Test Plan PRE-GI-018 Update, January 23, 2019 4*Official Public Comment Period

-Federal Register notice (82 FR 36006) published on August 2, 2017

-Public comment period closed September 1, 2017*5 comments from NEI

  • 32 comments from OECD

-29 Additional comments received from EPRI on January 12, 2018-28 Additional comments received from NEI on May 17, 2018

-4 Additional comments received from industry technical expert on May 17, 2018*98 comments received in total

-International and U.S. Industry*All comments dispositioned and publically released

-ML18233A469Phase II Draft Test Plan PRE-GI-018 Update, January 23, 2019 5HEAF Phase II Test Structure

-Enclosures Enclosure Testing Aluminum Bus Bars Copper Bus Bars 6900 Volt 480 Volt 6900 Volt 25kA 15kA 35kA 25kA 4s 2-2 35 kA 480 Volt 25 kA 15kA 25kA 4s 2-5 4s 2-8 4s 2-9 4s 2-11 4s 2-12 4s 2-14 4s 2-17 4s 2-20 2s 2-22 4s 2-23 2s 2-1 2s 2-4 2s 2-7 2s 2-10 4s 2-24 X

  • X *8s 2-6 8s 2-3 2s 2-13 8s 2-15 2s 2-16 8s 2-18 4s 2-21 2s 2-19LegendOECD/NEA HEAF Phase 2 Tests US NRC Specific Spplemental Testing driven by Generic Issue Aluminum HEAF Program Uncommitted tests to explore unanticipated results/enhance repetition if necessary
  • PRE-GI-018 Update, January 23, 2019 6Measurement Limitations
  • Melting point of Inconel approximately 2,400

°F (1,325°C)*No measurement locations beyond 3 ft. BeforeAfter PRE-GI-018 Update, January 23, 2019 7Phase II Improvements Tungsten Slug Calorimeter q"total 25 mmT(o C)ThermocoupleStructuralInsulationBoardInsulationMetalCylinder

  • Durable for high incident heat fluxes in direct arc plume environment
  • Calcium Silicate insulating board PRE-GI-018 Update, January 23, 2019 8Phase One (I) Pressure Electromagnetic Interference (EMI)
  • EMI tends to be most severe during large changes in current, voltage, and arc activity, and these are the same periods where large changes are expected in enclosure pressure*Positive and negative pressure peaks occur at the onset of the arc, and are of similar magnitude*New techniques have been

developed for Phase II of testing PRE-GI-018 Update, January 23, 2019 9Pressure Phase Two (II)

  • Strain-gauge type sensor
  • Dynisco Pressure Transducer PT150

-50*Quartz type gauge

  • Fiber Optic Cabling
  • Omega PX-329 PRE-GI-018 Update, January 23, 2019 10*Non-intrusive temperature measurement

-Using video as test data

  • Visualization through smoke*Speed -rapid event
  • Dynamic temperature range

-Ambient to >2000 o C*Compromises

-Resolution

-field of view-Speed -Temperature Range (Dynamic Range)Infrared(IR) Camera Capabilities PRE-GI-018 Update, January 23, 2019 11*Phase I Camera Capabilities

-High Speed Recording

-Limited Temperature Range

-High Resolution

  • Phase II Camera Capabilities

-Greater Temperature Range

-Higher Resolution IR Camera Improvements PRE-GI-018 Update, January 23, 2019 12*Phase II of testing will use an isolated data acquisition system with an independent power supply

  • Redundant systems will be available

for possible arc shorting consequences

  • 72 channels Data Collection PRE-GI-018 Update, January 23, 2019 13Test Setup PRE-GI-018 Update, January 23, 2019 14Phase II InstrumentationThermalCapacitance Slug(Tungsten)

PRE-GI-018 Update, January 23, 2019 15Sandia Camera Angles PRE-GI-018 Update, January 23, 2019 16Weights and Measures PRE-GI-018 Update, January 23, 2019 17Phase II HEAF TestingMedium Voltage Equipment

  • Single compartment GE Magne

-blast M-36 metal clad switchgear containing aluminum busbar PRE-GI-018 Update, January 23, 2019 18Phase II HEAF TestingPre Test Arrangement 24 PRE-GI-018 Update, January 23, 2019 19Phase II HEAF TestingShorting Wire PRE-GI-018 Update, January 23, 2019 20Phase II HEAF TestingPost Test Observations 2-19 2-22 2-21 2-242s, 25kA2s, 35kA4s, 35kA4s, 25kA PRE-GI-018 Update, January 23, 2019 21Phase II HEAF TestingPost Test Observations 2-22 2-21 2-19 2-24 PRE-GI-018 Update, January 23, 2019 22Tungsten Thermocouple Damage State/ Survivability BeforeAfter PRE-GI-018 Update, January 23, 2019 23Plate ThermocoupleDamage State/ Survivability PRE-GI-018 Update, January 23, 2019 24ASTM F1959 ThermocoupleDamage State/Survivability BeforeAfter PRE-GI-018 Update, January 23, 2019 25HEAF Deposition PRE-GI-018 Update, January 23, 2019 26Metal Ejecta PRE-GI-018 Update, January 23, 2019 27*IPC Standard IPC

-TM-650 https://www.ipc.org/TM/2.6.3.3b.pdf

  • NIST Tech Note https://nvlpubs.nist.gov/nistpubs/TechnicalNotes/NIST.TN.1985.pdfNew Measurement for Future TestsCloud Particulate Conductivity PRE-GI-018 Update, January 23, 2019 28HEAF Phase IINext Test SeriesEnclosure Testing Aluminum Bus Bars Copper Bus Bars 6900 Volt 480 Volt 6900 Volt 25kA 15kA 35kA 25kA 4s 2-2 35 kA 480 Volt 25 kA 15kA 25kA 4s 2-5 4s 2-8 4s 2-9 4s 2-11 4s 2-12 4s 2-14 4s 2-17 4s 2-20 2s 2-22 4s 2-23 2s 2-1 2s 2-4 2s 2-7 2s 2-10 4s 2-24 X
  • X *8s 2-6 8s 2-3 2s 2-13 8s 2-15 2s 2-16 8s 2-18 4s 2-21 2s 2-19LegendOECD/NEA HEAF Phase 2 Tests US NRC Specific Spplemental Testing driven by Generic Issue

Aluminum HEAF Program Uncommitted tests to explore unanticipated results/enhance repetition if necessary

  • PRE-GI-018 Update, January 23, 2019 29HEAF Phase IINext Test SeriesLegendOECD/NEA HEAF Phase 2 TestsUS NRC Specific Spplemental Testing driven by Generic Issue Aluminum HEAF Program Uncommitted tests to explore unanticipated results/enhance repetition if necessary
  • Aluminum Bus Steel Enclosure Copper BusAluminum Enclosure Aluminum BusAluminum Enclosure Copper BusSteel Enclosure4s 2-262s 2-25 2s 2-274s 2-284s 2-304s 2-322s 2-31Bus Duct Testing 4160 Volt /25 kA 2s 2-295s 2-33*5s 2-34*

PRE-GI-018 Update, January 23, 2019 30NRC/OECD Phase II Actions

  • Public Comment Period Closes................................................ September 2, 2017
  • OECD Comment Period...................................... August 31 / September 15, 2017
  • OECD HEAF Meeting................................................................. October 12, 2017
  • HEAF Workshop ......................................................................... April 18-19, 2018*OECD HEAF Meeting....................................................................... April 23, 2018
  • Comment Resolution ....................................................................... May 11, 2018
  • Final Test Plan..........................................................................September 1, 2018
  • Signed International Agreement .............................--------Spring 2019
  • International Equipment Delivery.........................................................Spring 2019
  • Initial Test Series............................................................... September 10

-14, 2018*Second Series of Tests (To correspond w/ International OECD Meeting)........................ Spring

-May 2019*Remaining Tests......................................................................... 2019/ 2020/ 2021(Completed)(Completed)(Completed)(Completed)(Target)(Completed)(Completed)(Completed)(Target)(Completed)(Target)

PRE-GI-018 Update, January 23, 2019 1High Energy Arcing Faults (HEAF) AL Future Planning and Equipment SelectionGabriel Taylor & KennMillerOffice of Nuclear Regulatory ResearchJanuary 23, 2019 PRE-GI-018 Update, January 23, 2019 2*Communicate NRC planned equipment types for testing

  • Solicit feedback from stakeholdersPurpose PRE-GI-018 Update, January 23, 2019 3HEAF Phase II -PERFORMEDSeptember testsEnclosure Testing Aluminum Bus Bars Copper Bus Bars 6900 Volt 480 Volt 6900 Volt 25kA 15kA 35kA 25kA 4s 2-2 35 kA 480 Volt 25 kA 15kA 25kA 4s 2-5 4s 2-8 4s 2-9 4s 2-11 4s 2-12 4s 2-14 4s 2-17 4s 2-20 2s 2-22 4s 2-23 2s 2-1 2s 2-4 2s 2-7 2s 2-10 4s 2-24 X
  • X *8s 2-6 8s 2-3 2s 2-13 8s 2-15 2s 2-16 8s 2-18 4s 2-21 2s 2-19LegendOECD/NEA HEAF Phase 2 Tests US NRC Specific Spplemental Testing driven by Generic Issue Aluminum HEAF Program Uncommitted tests to explore unanticipated results/enhance repetition if necessary
  • PRE-GI-018 Update, January 23, 2019 4HEAF Phase II -PLANNEDLow VoltageEnclosure Testing Aluminum Bus Bars Copper Bus Bars 6900 Volt 480 Volt 6900 Volt 25kA 15kA 35kA 25kA 4s 2-2 35 kA 480 Volt 25 kA 15kA 25kA 4s 2-5 4s 2-8 4s 2-9 4s 2-11 4s 2-12 4s 2-14 4s 2-17 4s 2-20 2s 2-22 4s 2-23 2s 2-1 2s 2-4 2s 2-7 2s 2-10 4s 2-24 X
  • X *8s 2-6 8s 2-3 2s 2-13 8s 2-15 2s 2-16 8s 2-18 4s 2-21 2s 2-19LegendOECD/NEA HEAF Phase 2 Tests US NRC Specific Spplemental Testing driven by Generic Issue Aluminum HEAF Program Uncommitted tests to explore unanticipated results/enhance repetition if necessary
  • PRE-GI-018 Update, January 23, 2019 5*Westinghouse DS switchgear
  • GE AK Series
  • 1600A or 2000A frame size
  • 42kA to 65kA interrupting capacityLow Voltage EnclosuresAluminum Bus PRE-GI-018 Update, January 23, 2019 6HEAF Phase II -PLANNEDMV Bus DuctsAluminum Bus Steel Enclosure Copper BusAluminum Enclosure Aluminum BusAluminum Enclosure Copper BusSteel Enclosure4s 2-262s 2-25 2s 2-274s 2-284s 2-304s 2-322s 2-31Bus Duct Testing 4160 Volt /25 kA 2s 2-295s*5s*LegendOECD/NEA HEAF Phase 2 TestsUS NRC Specific Spplemental Testing driven by Generic Issue

Aluminum HEAF Program Uncommitted tests to explore unanticipated results/enhance repetition if necessary

  • PRE-GI-018 Update, January 23, 2019 7*Non-segregated phase bus duct
  • 1200 -2000A rated*31.5 -63kA withstand
  • IEEE C37.23
  • Stabilize arc location

-Gap at arc location?

-Epoxy insulation?MV Bus DuctsGeneral Characteristics PRE-GI-018 Update, January 23, 2019 8*Enclosure-11 gauge aluminum housing

  • Conductor-ASTM B236*Other design considerations?MV Bus DuctsAluminum Components PRE-GI-018 Update, January 23, 2019 9*Working with EPRI and KEMA to implement decrement curve

-6.9kV metal

-clad switchgear

-Requires new contract

-Laboratory analysis & verificationDecrement Curve PRE-GI-018 Update, January 23, 2019 10*Continued focus on aluminum

  • Equipment donations welcome
  • Decrement curve

-Implementation slow due to contracting process-Industry support could expedite thisSummary PRE-GI-018 Update, January 23, 2019 1High Energy Arcing Faults NRC-EPRI Working Group CharterMark Henry Salley, P.E.Branch ChiefOffice of Nuclear Regulatory ResearchJanuary 23, 2019 PRE-GI-018 Update, January 23, 2019 2Mission Statement

  • To improve understanding of risk from electrical arcing fault hazards in nuclear power plants (NPPs

).

PRE-GI-018 Update, January 23, 2019 3*Better understand key factors contributing to:

-Occurrence

-Severity*Advance HEAF fire PRA modeling-Based on experimental data, operating experience, and engineering judgement

-Ignition frequency-Zone of influence (ZOI)

  • Analyze plant impact and risk implications

-What can go wrong?

-How likely is it?

-What are the consequences?Goals PRE-GI-018 Update, January 23, 2019 4Ken Fleischer (Fleischer Consultants)Dane Lovelace (Jensen Hughes)

Shannon Lovvern(TVA)Tom Short (EPRI)

Marko Randelovic/

Ashley Lindeman(EPRI)Working Group MembersJS Hyslop (NRC)

Nicholas Melly (NRC)KennMiller (NRC)Gabriel Taylor (NRC

)Chris LaFleur (SNL)Project ManagersKelli Voelsing(EPRI)Mark Henry Salley (NRC)Project SponsorsTina Taylor (EPRI)Michael Cheok (NRC)

PRE-GI-018 Update, January 23, 2019 5*Improved risk models

-Frequency and binning

-Zone of influence

-Pilot plants

  • Updated guidance
  • Communication with stakeholdersDeliverables PRE-GI-018 Update, January 23, 2019 6*Aluminum HEAF Generic Issue

-Zone of influence

-Physical/thermal damage

-Effects of products of combustion cloud

  • OECD/NEA Testing

-Additional test data (primarily copper)

  • NRC/EPRI Working Group

-Develop realistic models

-International OECD/NEA peer review

  • Improve NUREG/CR

-6850 Appendix M

-Improve FAQ 0035 Bus Duct Guidance for HEAFsNRC Priorities The following 5 slides were presented by: Victoria K Anderson Technical Advisor Risk and Technical Services Nuclear Energy Institute HEAF Aluminum Pre-GI*Decisions regarding a Generic Issue are designed to be risk-informedCDFHEAF Al= CDF(HEAF Al) -CDF(HEAF Baseline)

HEAF Aluminum Pre-GI*Past Generic Issues were dispositioned according to changes*Likely the case for this pre

-GI*Decisions based on could result in inappropriate decisions

  • A single fire PRA

assessment without realistic assessment of the -

frequencies and consequences, will lead to inaccurate assessmentsMost Fire PRA CDF(HEAF Baseline) results found in green region HEAF Aluminum Pre GIDecisions bas ed on could result in industry

-wide assessment that

majority of plants, i.e.:-Assumption Al is always present -HEAF Al is always more

energetic-HEAF Al always increases

CCDP -HEAF AI based on the

worst case fire scenario applies to all plantsNeed to consider whether these points are testing or CCDP estimationPotentially erroneous conclusion without considering full spectrum of plant configurations HEAF Aluminum Pre-GI*information

  • ar e*-informed approach, high decision making impact
  • Resolution of the issue requires better realism in assessment AND in resolution of pre-GI*Assuming a one

-waste resources

  • Crediting realistic HEAF Al impacts, protections against feeding HEAF, critical**Most plants may not require action
  • tests and OE
  • gaps*

data and OEorder

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.comHigh Energy Arcing Fault (HEAF)Technical Considerations for Understanding RiskKelli VoelsingRSM Program ManagerNRC Public MeetingJanuary 23, 2019

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 2Assuming the worst caseInvasive surgery to remove the malignancyPoisonous chemotherapy with damaging side-effectsRisks and sickness from radiation therapyLocation/sizeType of CancerStageGenetic MarkersTargeted therapies on the marketOther treatments supporting quality of lifeNot all cancers, and not all arcing faults, are the same

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 3Current Bin 16 Treatment in NUREG/CR

-6850 (1011989)Current Bin 16 treatment applies one probability and one ZOI to all eventsC-178AC-178A P 1 P 1 P 1-Al?P 1-Al?

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 4Examples of Differentiating Factors in Arcing Fault EventsEnergy -Medium Voltage or Low VoltageLocation -potentially affecting safety significant equipmentSSC -Switchgear, Motor Control Center, Isophase/Non

-segbus ductSource of fault -Breaker-side or load

-sideElectrical configuration -e.g., "Unit-connected*" and protection schemeMaterial -Presence and location of aluminumOperational issues

-Cleanliness, maintenance, human performance* Plant electrical system design found in fossil and nuclear plants that do not employ a generator breaker that can isolate the energy source (main generator) from the fault during generator coast

-down as the voltage collapses

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 5Elements of HEAF Working Group CharterTo improve understanding of risk from electrical arcing fault hazards in nuclear power plants (NPPs) 1.Improved risk models

-supported by all available information (e.g., testing, data, OE, expert engineering judgement) Realistic representation of frequencyof events represented in Bin 16Appropriate modeling of various zones of influence (ZOI) for events included in Bin 16 2.Risk to NPPs

-Evaluation of potential increase in risk of actual plants considering impact of frequency and ZOI work as well as

-built, as-operated plant 3.Updated guidance

-Enhanced fidelity and realism for modeling arcing fault events in Fire PRA 4.Communication with stakeholders

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 6Early Insights Related to "Frequency Work"Limited data

-Total population in Bin 16 from 1964

-2017 is 28 events

-Includes a wide variety of equipment

-Data includes arcing flash/blast events (at least 10) and HEAF events

-Data includes events with and without post

-event fire and damage

-With only 28 events, creating multiple sub

-bins of 0-1 events makes it difficult to break down further and retain statistically useful informationWithin Bin 16 there are useful insights about the which events occur under which conditions

-Medium Voltage (MV) SSCs

-84% of the Bin 16 events that were "damaging" occurred in MV equipment

-Low Voltage (LV) SSCs

-Only 2 damaging events occurred in LV equipment. In both cases, there was insufficient energy to trip the protection features. This prolonged the event, but there is no indication of a HEAF, and the "damage" term was related to post-event fire, not the HEAF

-Of the events with external damage, 7 out of 11 were in buses (isophase/non

-segbuses) that are less likely to impact safety

-significant equipment based on plant configuration

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 7Early Insights Related to "ZOI Work"Limited data

-Fragility of SSCs versus contact with the by-product-Current ZOI used for Bin 16 is based on a SONGS event (Appendix M).

-Small scale nor large scale test results on HEAF by

-product characterization are not availableSignificant useful insights about the which events occur under which conditions

-Al 2 O 3is an excellent insulator material with very low conductivity

-In most conditions Al oxidizes to

Al 2 O 3 very rapidly

-Presence of Al 2 O 3white dust may not cause failure

-The arc travels away from the source.

Cable trays are not likely to be located directly in front/back of switchgear cabinets.

-Bus ducts likely have a downward directed conical ZOI when not constrained by barriers (e.g., floor)

-Arc flash and arc blast events have negligent ZOIs

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 8Early Insights on Plant Risk"Average" plant risk is an elusive concept

-A review of all units in the US shows that ~70% of plants are NOT susceptible to a long-duration generator fed fault on the safety related bus (i.e. do not have the "unit connected" design).

-Even when long

-duration generator fed faults can occur the following factors must be consideredVoltage will decay rapidly as the generator spins downPresence or absence of Al, proximity to fault locationEquipment in the ZOI

-It is not rare to have aluminum in bus ducts (isophase and non

-seg) due to weight/costRisk is depending on SSCs within the ZOIThis is generally a low contributor to risk in most plant fire PRAs

-outside/non

-safety related equipment is impacted

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 9Test ConsiderationsBreaker initiated versus switchgear initiated faults

-OE shows that the frequency is for these is different.

-Breaker-side initiated faults may not be able to persist long enough to impact Al with high energy

-Consequences may be differentData for evaluating "damage"

-Target selection to assure results are representative of plant equipment

-Actual location and data collection to assess impact on operation

-OE does not suggest large

-scale deposition of by

-products and damage outside the cubicle

-Clarity on what conductivity/material is being measured is requiredRepresentative conditions that can lead to longer durations for the 4

-second and 8

-second faults

-MV -Generator wind

-down voltage curve for decay of voltage during spin down

-LV -Not enough energy to trip the protection scheme

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 10Refined Bin 16 Treatment in Supplemental NUREG/CR-6850 (1011989) GuidanceAll arcing fault events are not the same

-Risk should consider probability of various event types and associated ZOIsC-178AC-178A P 1 P 2 P 3 P 4

© 2019 Electric Power Research Institute, Inc. All rights reserved.www.epri.com 11Together-Shaping the Future of Electricity PRE-GI-018 Update, January 23, 2019 1High Energy Arcing Faults Involving Aluminum Closing RemarksMichael FranovichDivision DirectorOffice of Nuclear Reactor RegulationJanuary 23, 2019 PRE-GI-018 Update, January 23, 2019 2Closing Remarks

  • Thank you*Transparency, public involvement, and clear communication
  • Realistic assessment of the hazard
  • Risk-Informed Resolution
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