FUKUSHIMA RESPONSEGeorge Attarian1/21/2013

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

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Diverse & Flexible Coping Capability (FLEX)

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Protection ofPlant Equipment

Prevention ofFuel 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)

EmergencyResponse

Current Current plus FLEX

Tier 1 FLEX Approach

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Extended Station Blackout Coping

sufficient to allow initiation of FLEX

(Tier1)Mitigation of

Loss of Ultimate Heat Sink

(Other Items inSECY11-0137)

Mitigation of Large Fires & Explosions (Security Related)

(Tier 1)

Mitigation of Beyond Design Seismic Event

(Tier 1)

Mitigation of Other Beyond Design Bases External Events

(Tier 1 Support)

Mitigation of Beyond Design Basis Flooding

(Tier 1)

Mitigation of Loss of

Spent Fuel Pool Cooling,

includes Diverse Instrumentation

(Tier 1)

Diverse & Flexible Mitigation

CapabilitiesIncluding

Maintenance/Guidelines/Training/Protection

PLUS

Additional Support Equipment from other

plants and Regional Support Centers

Seismic &FloodingWalk-downs(Tier 1)

Process for Identifying & Assessing Impact of New Information(Tier 3)

EPCommunications & Multi-Unit Staffing(Tier 1)

Reliable & Accessible

BWR Containment Hardened

Vents(Tier 1)

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

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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

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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

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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.