beyond design basis events lessons learned from fukushima

BEYOND DESIGN BASIS EVENTSLessons Learned from Fukushima

David HallSevere Accident Management

Farley Nuclear Plant

Governor’s Preparedness ConferenceApril 2014

Fukushima background

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Fukushima background

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Fukushima background

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LESSON LEARNED

Beyond Design Basis Events can occur

It can happen here

• Ft. Calhoun -- flooding of plant– 2011 flood inundation

• North Anna -- seismic event– 2011 Loss of offsite power

• Brown’s Ferry -- tornado– 2011 loss of offsite power

• Surry -- tornado– 2011 tornado in switching station

• Oyster Creek -- hurricane– 2012 loss of offsite power

• Cooper -- flood– 2011

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Resulting Damage - Fukushima

• Loss of emergency diesel generators• Extended loss of all AC power• Overheating of nuclear fuel• Hydrogen explosions• Ultimate loss of all six units

LESSON LEARNED

WE MUST BE PREPARED

KEY OBJECTIVES• Keep fuel in the reactor vessel

cool• Keep fuel in the spent fuel pool

cool• Protect containment

Regulatory ResponseOrder to Modifying Licenses With Regard to Requirements For Mitigation Strategies For Beyond Design Basis External Events

December 2016

Industry Response to Fukushima

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FLEX• NEI 12-06 (Diverse and Flexible coping

strategies (FLEX) Implementation Guide) endorsed by the NRC Aug 2012

• Provides a diverse and flexible means to prevent fuel damage while maintaining containment function in beyond design basis external event

FLEX ObjectiveEstablish an essentially indefinite coping capability by relying upon installed equipment, onsite portable equipment, and pre-staged offsite resources

Three-Phase Approach• Following the event and prior to the time when

portable equipment can be deployed, the plant must be able to maintain the key safety functions using installed equipment (Phase 1)

• With adequate time and staffing, on-site portable equipment is deployed (Phase 2)

• After 24 hours, off-site equipment can be deployed to sustain key safety functions indefinitely (Phase 3)

On-Site Support• On-site resources must be sufficient to cope for

the first 24 hours• Each site is required to have N+1 sets of FLEX

equipment on-site to respond to the event– Other sites become a source of FLEX

equipment for an effected site in such an event

– Regional Response Center established to supply FLEX equipment to effected site

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Regional Response Centers

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Regional Response Center (RRC) Locations1000 mile radius / 20 hours by truck

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Major Routes from Memphis

SAFER NEI Meeting

Regional Response Centers

– The RRC will deliver the first piece of specified equipment to the effected site’s staging area within 24 hours of being notified

– Delivery will be by air or ground depending on the distance of the site from the RRC

– Equipment technicians will accompany the equipment to the site to assist with set up and deployment

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AL / FL / GA AgenciesState & County EMA’s potential involvement• supporting movement of equipment

• providing escorts• providing security• provide live traffic/ weather updates• provide interstate coordination and hand-offs

• road clearing• assisting travel of site emergency responders

Homeland Security and FEMA

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CLOSING THOUGHTS

• Beyond Design Basis Events can and do happen!• While focus must remain strong on PREVENTION;

we must implement actions to improve response capabilities and minimize challenges should an event occur!

Fukushima OE - Comprehensive BDB event response guidance was not developed in advance, equipment was not pre-staged and readiness maintained, and personnel were not sufficiently trained to deal with Beyond Design Events – this significantly impacted event response

BEYOND DESIGN BASIS EVENTSLessons Learned from Fukushima

David HallSevere Accident Management

Farley Nuclear Plant