Post-Fukushima Severe Accident Management Update Kim, Hyeong Taek KHNP- Central Research Institute July KINS Safety Analysis Symposium

1 Introduction 2 Post-Fukushima Facilities Improvement 3 Severe Accident Management Update 4 Severe Accident Response Team 5 Summary 2

Introduction US and Canada SAM update  Organized and combined effort based on NRC/CNSC recommendation Owners Group : CANDU-OG, PWR-OG Supporting Organization – NEI, EPRI Focused on SAM update Korea SAM update  Programmed and regulatory effort based on NSSC inspection / Stress Test Focused on Hardware Improvement Needs more focus on validation of Enhanced SAMG/ EDMG and implementing organization 3

Post-Fukushima Facilities Improvement Emergency Alternative Facility OP(2012) Enhanced SAMG(2012) Plant-specific Severe Accident Analysis, Integral SAMG/EDMG (2017 ~ 2019) Innovative Power Reactor Accident Management guidelines (2025~ 2030) Passive Mitigating System PAFWS, PECCS,PCCS PAR, innovative System (2025~ 2030) CFVS/ECSBS, PAR Mobile Generator(N+1) Mobile Pump(HP) (2017 ~ 2019) CFVS PAR 4.16KV Mobile Generator Mobile Fire Pump (2013) 4

Post-Fukushima Facilities Improvement  Improved Facilities(2014) Containment Performance : CFVS, Flooding from External Sources Hydrogen mitigation: PAR, Hydrogen Monitor Long term Cooling : Injection by External Sources and Fire Pump Extended SBO Prevention from External Hazard : Mobile Generator 5

Severe Accident Management Update 6

 EPRI TBR 1992 Candidate High-Level Actions and Their Effects considering RCS/Containment Damage Conditions Special Consideration(External Cooling of RPV/RCS), steam inerting Physics of Accident Progression 7

Severe Accident Management Update  EPRI TBR 2012 Considered RCS + Containment + SFP + Aux/ Fuel Building Damage Conditions Injection into or Flood the Containment from External Source Injection into SFP/ Spray the SFP Physics of Accident Progression includes IVR Experiment/ SFP Fuel Damage, and Symptoms. 8

Severe Accident Management Update  WOG SAMG First Addendum 2001 Added feedback during plant-specific SAMG development [28 items(feedback/review)] Ex) To prevent the Creep rupture of SG tube, SG depressurization as an emergency control room guide is prohibited unless depressurization was performed in EOP phase. 9

Severe Accident Management Update  WOG SAMG 2 nd Addendum 2012 Added guidance on the use alternative water sources. Discussed the failure of containment penetrations and the impact on the event sequence. Incorporated spent fuel pool challenges into the SAMG structure and added strategies/guidance to address those challenges Updated information regarding natural circulation in the primary system. Updated information regarding ex-vessel steam explosions. Added guidance on the use of portable equipment. Updated information regarding containment venting. Miscellaneous/editorial improvements and corrections. 10

Severe Accident Management Update  Enhanced PWROG SAMG to be released in Dec 2014 WOG, CEOG, BWOG prepare Combined SAMG by Dec 2014 NRC questionnaires 11

Severe Accident Management Update  CANDU Owners Group Instrument and Equipment Survivability Multi-Unit Event Update of SAMG and Technical Basis Shutdown and Low power State Update of SAMG and Technical Basis Habitability Assessment Following a severe Accident Containment Integrity : Emergency water Make-up, Aerosol Behavior, Hydrogen Management, IVR Irradiated Fuel Bay/Spent Fuel Bay Behavior 12

Severe Accident Management Update  Enhanced K-SAMG with SDLP status ISSUES – CFVS Operation with Habitability and Exposed Dose / PAR – LPSD PSA insight – Plant Operational State – SFP phenomena More information to be released in WOG meeting( ) Feedback from Korean Expert Opinions 13

Severe Accident Management Update  Enhanced K-SAMG with SDLP states Current Status – E-01 at Low Power, CET 649 ℃ + Failure of Recovery of Core & RCS Heat Removal – E-02 at Shutdown, CET 649 ℃ or Core Damage expected by Containment Radiation Level(CA-08) – C-01 CET ℃ – 0.5 mSv/Hr(30min) or 5 mSv/Hr(2min) – Containment Pressure 189.8cmH ₂ O(g) – Hydrogen Concentration 5% – SFP water Level 86% – M01 ~ M07 mitigation : Similar with Full Power SAMG with – SFP recovery strategy 14

Severe Accident Response Team Special Experts for each NSSS Supplier type are needed ( WH, FRA, OPR1000, APR, CANDU) ~ 3 person per type  Training & Drill  SAMG Update & Maintenance  Analysis and SAMG Implementation under SA situation Integral SAM Facility Maintenance and Operation Team  SAM Facilities periodic maintenance & test  SAM facilities operation under SA situation Advisory Expert Group for SAM 15

Summary  The First Phase Post-Fukushima Facilities Improvement, Severe Accident Management Update will be completed in  Severe Accident Response manpower will be strengthen.  Severe Accident Analysis for operating plant is expected due to new regulation. 16