Fukushima Response Timeline: March 11: Event occurred March 18: INPO IER 11-1 issued (April 15) March 23: NRC TI 2515/183 issued (May 13) April 25: INPO IER 11-2 issued (September 20) April 19: NRC TI 2515/184 issued (June 30) May 11: NRC Bulletin 2011-01 issued (July 11) June 8: NEI The Way Forward issued July 12: NRC NTTF issued August 1: INPO IER 11-4 issued (January 28) August 1: INPO Equipment Survey issued (November 4)
Fukushima Response Timeline September 1: INPO IER 11-1 Supplement issued (March) September 9: NRC SECY-11-0124 issued, SRM issued October 18 October 3: NRC SECY-11-0137 issued, SRM issued November 8 December 14: NRC holds first public, issue specific meetings on SECY-11-0137 January 18-19:NRC holds second public issue specific meetings and presents draft 50.54(f) letter with enclosures March 9: 50.54(f) letter and enclosures and Orders issued to the Licensee for Tier I NTTF’s
Fukushima Response NRC Near Term Task Force (NTTF) Recommendations (12) Clarifying The Regulatory Framework (1) Ensuring Protection (2) Enhancing Mitigation (5) Strengthening Emergency Preparedness (3) Improving the Efficiency of NRC Programs (1)
Fukushima Response NTTF Impact NTTF 2.1 Flood and Seismic 50.54(f) letter to licensee New flood analysis beyond design basis Seismic currently following GI 199 NTTF 2.3 Walkdowns 50.54(f) letter to licensee Walk down the site for all external design basis events: flood; seismic, other external events NTTF 4.1 SBO Rule making
Fukushima Response NTTF Impact NTTF 4.2 By order Additional pumps and related equipment FLEX approach NTTF 5.1 Harden Vents By order BWR Mark I & II only Filtration system not in order NTTF 7.1 Spent Fuel Pool Instrumentation By order Level only Primary and backup Control Room or Alternate Shutdown monitoring Qualifications
Fukushima Response NTTF Impact NTTF 8 EDMG EOP SAMG integration Rule making NTTF 9.3 Emergency Preparedness Staffing 50.54(f) letter to licensee Extension of the EP Rule Staffing impact to multiple Unit plant sites Communication guidance
Station Blackout Definition 10CFR50.2 Definition The complete loss of alternating current (ac) electric power to the essential and nonessential switchgear buses in a nuclear power plant. Station blackout does not include the loss of available buses fed by station batteries through inverters or by alternate ac sources as defined, nor does it assume a concurrent single failure or design basis accident.
Alternate AC Sources An alternating current (ac) power source that is available to and located at or nearby a nuclear power plant and meets the following requirements: Is connectable to but not normally connected to the offsite or onsite emergency ac power systems; Has minimum potential for common mode failure with offsite power or the onsite emergency ac power sources; Is available in a timely manner after the onset of station blackout; and Has sufficient capacity and reliability for operation of all systems required for coping with station blackout and for the time required to bring and maintain the plant in safe shutdown (non-design basis accident)
Current NRC Rule 10CFR 50.63 Loss of all alternating current power (a) Requirements. (1) Each light-water-cooled nuclear power plant licensed to operate must be able to withstand for a specified duration and recover from a station blackout as defined in § 50.2. The specified station blackout duration shall be based on the following factors: (i) The redundancy of the onsite emergency ac power sources; (ii) The reliability of the onsite emergency ac power sources; (iii) The expected frequency of loss of offsite power; and (iv) The probable time needed to restore offsite power.
Current NRC Rule (cont’d) (2) The reactor core and associated coolant, control, and protection systems, including station batteries and any other necessary support systems, must provide sufficient capacity and capability to ensure that the core is cooled and appropriate containment integrity is maintained in the event of a station blackout for the specified duration. The capability for coping with a station blackout of specified duration shall be determined by an appropriate coping analysis. Licensees are expected to have the baseline assumptions, analyses, and related information used in their coping evaluations available for NRC review.
Regulatory Guide 1.155 Reg. Guide 1.155, Station Blackout Specifies a method acceptable to the NRC staff for complying with 10CFR50.63 Twenty four pages of detailed guidance EDG Target Reliability Levels Restoration of Offsite Power Ability to Cope with a Station Blackout Quality Assurance Guidance for Non-Safety Systems and Equipment
NUMARC 87-00 Guidelines and Methodologies for Implementing the Nuclear Management an Resources Council (NUMARC) Station Blackout Initiatives Three Hundred Pages of Detailed Guidance, Examples, Topical Reports, and Questions & Answers Endorsed by Reg. Guide 1.155 as Acceptable Guidance for Compliance to 10CFR50.63 Contains Detail Beyond Reg. Guide 1.155
Typical Results Plant Specific SBO Coping Analyses Produced Specifies How Long You Have to Cope Without AC Power Typically 4 or 8 hours Specifies How Coping is Achieved Batteries, alternate ac power, RCS leak rates, water sources, pumps, instrumentation & control, etc. Requires Containment Isolation Typically Addresses Pre- Hurricane Preparations for Coastal Plants Excludes Concurrent Design Basis Events Assumes Restoration of at Least One Source of Offsite or Onsite AC Power is Successful Before the Coping Period Ends
Typical Limitations Beyond SBO Coping Battery Depletion Water Sources Run Out – CST Inventory RCS Inventory Losses - PWR RCP Seal Leakage BWR Suppression Pool Heat-up & Saturation Emergency Lighting Battery Packs Deplete Increasing Manual Actions for Available Personnel as SBO Time Increases
Beyond SBO Coping Strategies Medium Size Generators to Re-Energize Battery Chargers Emergency Engine Driven Pumps to Replenish Water Sources – CST Make-up Medium Size Generators and Pumps to Restore RCP Seal Injection RCP Shutdown Seal Package Designs to Limit Leakage BWR Hardened Wetwell Venting Systems and Suppression Pool Make-up with Cool Water Helmet Mounted LED Lights for Personnel or Longer Lasting LED Emergency Lights Pre-Plan and Pre-Stage More Emergency Equipment to Make Manual Actions Easier and Train More Personnel to Use it
What is FLEX? Response to NRC Mitigating Strategies Order (EA 12- 049) Provides a diverse and flexible means to prevent fuel damage while maintaining containment function in beyond design basis external event conditions resulting in an: Extended Loss of AC Power, and Loss of Normal Access to the Ultimate Heat Sink Objective: Establish an essentially indefinite coping capability by relying upon installed equipment, onsite portable equipment, and pre-staged offsite resources 17
Diverse & Flexible Coping Capability (FLEX) 18 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 CopingStrategy (FLEX) Emergency Response CurrentCurrent plus FLEX
FLEX Mitigation Strategies FLEX employs a three phase approach: Phase 1 - Initially cope by relying on installed plant equipment, Phase 2 - Transition from installed plant equipment to onsite FLEX equipment, Phase 3 - Obtain additional capability and redundancy from offsite equipment until power, water, and coolant injection systems are restored or commissioned. Diverse and flexible to enable deployment of the strategies for a range of initiating events and plant conditions 20
Representative High-level Example (BWR) Phase 1 Initial Coping Capability Use RCIC for RPV makeup from suppression pool Rely on DC Power for key instrumentation and controls Phase 2/3 Extended Coping Capability Charge battery to maintain DC power Use Reliable Hardened Vent for containment heat removal Provide extended RPV makeup with portable pump 21
Representative High-level Example (PWR) Phase 1 Initial Coping Capability Turbine-driven AFW for SG makeup from Condensate Storage Tank Rely on DC Power for key instrumentation and controls Phase 2/3 Extended Coping Capability Charge battery to maintain DC power Provide extended SG makeup with portable pump Provide RCS makeup with portable pump, as needed 22
NRC Advance Notice of Rule Making Rule Making Objectives What specific objectives should the SBO rule be designed to achieve? How should actions taken in the NTTF 4.2 be used? What regulatory approach to SBO mitigation that follows the conceptual approach outlined in NTTF 4.1? How can regulatory action in NTTF 8.0 be best integrated with SBO? How can regulatory action in NTTF 5.1 be best integrated with SBO? How can regulatory action in NTTF 7.1 be best integrated with SBO?
NRC Advance Notice of Rule Making Relationship between 10CFR 50.63 and the new SBO rule Keep existing rule and supplement with scenarios that go beyond the existing rule. Integrate existing rule with new requirements into a new rule for SBO. Supersede the existing SBO rule with an enveloping rule. Comments have been submitted, ACRS meeting to be held. Ball in NRC court.