FLEX Mitigation Strategies Overview (Rec 4.2) Fukushima Regulatory Response Workshop April 5, 2012

Overview  Background  FLEX Objectives  Relationship to Tier 1 Activities  FLEX Mitigation Strategies  Site Assessment Process  Status & Steps Forward  Q&A 2

Background  Accident at Fukushima Dai-ichi involved a beyond design basis earthquake and tsunami  Order requires licensees to develop “Mitigation Strategies For Beyond Design Basis External Events” – Recommendation adopted from industry “FLEX” proposal, in lieu of enhanced B.5.b 3

What is FLEX? Provide means to prevent fuel damage (core and SFP) while maintaining containment integrity in beyond design basis external event conditions involving: Extended Loss of AC Power Loss of Ultimate Heat Sink Objective: Establish an essentially indefinite coping capability by relying upon installed equipment, onsite portable equipment, and pre-staged offsite resources 4

Diverse & Flexible Coping Capability (FLEX) Protection of Plant Equipment Prevention of Fuel Damage Design Basis External Events SBO Coping Capability SAMGs Emergency Plans Design Basis External Events SBO Coping Capability SAMGs Emergency Plans Increased Defense-in- Depth Diverse & Flexible Coping Strategy (FLEX) Emergency Response CurrentCurrent plus FLEX 5

What does FLEX address? Prevention of fuel damage SAMGs address fuel damage state At power conditions vs outage conditions Highest heat load Outage conditions Short duration Many different plant configurations Equipment will be available to deploy for outages 6

Guidance Document Status  Revision A3 is out for comment  Revision A4 will be distributed April 12  Industry concurrence will be sought to submit to NRC for review  Submit Revision B to NRC end of April  Review through series of public meetings in May  Issue guidance for industry use August 31 7

Relationship to Other Tier 1 Activities 8

FLEX Mitigation Strategies  Provide diverse, flexible means to prevent fuel damage (core and SFP) while maintaining containment function  Employs a three phase approach: 1.Initially cope by relying on installed plant equipment, 2.Transition from installed plant equipment to onsite FLEX equipment, 3.Obtain additional capability and redundancy from offsite equipment until power, water, and coolant injection systems are restored or commissioned. 9

Implementation Guide Framework 10

Step 1 – Baseline Coping Capability  Establish a baseline coping capability for Extended Loss of AC Power (ELAP) and Loss of Ultimate Heat Sink (LUHS)  Address all three phases of coping. Will require: – Enhanced procedures/guidelines – Implementing design changes – Procurement of equipment – Contract for provision of offsite resources 11

Step 2 – External Event “Stress Tests”  Process for identifying potentially applicable hazards: – Extreme seismic events, – Extreme external flooding, – Extreme storms such as hurricanes, high winds, and tornadoes, – Extreme snow, ice, and cold, and – Extreme heat.  Where applicable, each site addresses: – Protection of FLEX equipment, – Deployment of FLEX equipment, – Procedural interfaces, and – Utilization of offsite resources. 12

Step 3 – Implementation Plan and Programmatic Controls  Provision of at least N+1 sets of portable onsite equipment stored reasonably protected from applicable external events  Procedures and guidance to support deployment and implementation  Programmatic controls addressing: – Quality attributes – Equipment design – Maintenance and testing – Training – Staffing 13

Status & Steps Forward  Fourth revision of guidance nearly complete for broad industry review  Goal: Draft guidance document to NRC by the end of April  NRC interactions to refine guidance for endorsement in Interim Staff Guidance (ISG)  NRC ISG issued for public comment in July  Industry workshop during public ISG comment period  NRC ISG endorsing final NEI guidance document issued by August 31,

QUESTIONS? 15