NRC: What are the Lessons Learned from Fukushima?

What are the Lessons Learned from Fukushima?

After the Fukushima accident, a task force of senior NRC staff reviewed the circumstances of the event to determine what lessons could be learned. In July 2011, the task force provided recommendations to enhance U.S. reactor safety, and these became the foundation of the NRC's post-Fukushima activities. The Commission then approved a three-tiered prioritization of the recommendations as summarized below (note that Recommendation 1 is being addressed outside of the three tiers).

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• Tier 1 Activities
• Tier 2 Activities
• Tier 3 Activities

Tier 1 Activities

Activity	Brief Description	NRC Addressing by…
Mitigation Strategies	To enhance the capability to maintain plant safety during a prolonged loss of electrical power.	Order
Containment Venting System	To provide a reliable hardened containment vent system for boiling water reactors (BWRs) with Mark I or Mark II containment designs.	Order
Spent Fuel Pool Instrumentation	To provide a reliable wide-range indication of water level in spent fuel storage pools.	Order
Seismic Reevaluations	To reanalyze potential seismic effects using present-day information to determine if safety upgrades are needed.	Request for Information
Flooding Hazard Reevaluations	To reanalyze potential flooding effects using present-day information to determine if safety upgrades are needed.	Request for Information
Seismic and Flooding Walkdowns	To inspect existing plant protection features against seismic and flooding events, and correct any degraded conditions	Request for Information
Emergency Preparedness – Staffing and Communications	To assess staffing needs and communications capabilities to effectively respond to an event affecting multiple reactors at a site.	Request for Information
Station Blackout Mitigation Strategies	To enhance the capability to maintain plant safety during a prolonged loss of electrical power.	Rulemaking
Onsite Emergency Response Capabilities	To strengthen and integrate different types of emergency procedures and capabilities at plants.	Rulemaking
Filtration and Confinement Strategies	To evaluate potential strategies that may further confine or filter radioactive material if core damage occurs	Rulemaking

Tier 2 Activities

Activity	Brief Description	NRC Addressing by…
Spent Fuel Pool Makeup Capability	To provide a reliable means of adding extra water to spent fuel pools	Order [consolidated into Mitigation Strategies] See COMSECY-13-0002 and its associated approval for details
Emergency Preparedness	To address three aspects of Emergency Preparedness for multi-reactor and loss of power events: Training and exercises (drills) Equipment, facilities, and related resources Multi-unit dose assessment capability	Order [aspects (1) and (2) consolidated into Mitigation Strategies] NRC-endorsed industry initiative [to address aspect (3)] See COMSECY-13-0010 and its associated approval for details
"Other" External Hazard Reevaluations	To reanalyze the potential effects of external hazards other than seismic and flooding events (which are being addressed under Tier 1).	Request for Information [planned]

Tier 3 Activities

Plans for addressing each of these activities are available in Enclosure 3 to SECY-12-0095

Activity	Brief Description	NRC Addressing by…
Periodic Confirmation of External Hazards	To ensure external hazards, such as seismic and flooding effects, are periodically reanalyzed during the lifetime of a plant.	Rulemaking [planned]
Seismically-Induced Fires and Floods	To evaluate potential enhancements to the capability to prevent or mitigate seismically‑induced fires and floods.	Longer-term evaluation
Venting Systems for Other Containment Designs	To evaluate the need for enhancements to venting systems in containment designs other than Mark I and II (which are addressed under Tier 1).	Longer-term evaluation
Hydrogen Control	To evaluate the need for enhancements to hydrogen control and mitigation measures inside containment or other plant buildings.	Longer-term evaluation
Emergency Preparedness	To evaluate additional enhancements to Emergency Preparedness (EP) programs that go beyond the Tier 1 and Tier 2 EP-related activities.	Longer-term evaluation
Emergency Response Data System (ERDS) Capability	To enhance the capabilities of the Emergency Response Data System (ERDS)	Longer-term evaluation
Decision-making, Radiation Monitoring, and Public Education	To evaluate the need for enhancements to Emergency Preparedness programs in the areas of decision-making, radiation monitoring, and education.	Longer-term evaluation
Reactor Oversight Process (ROP) Updates	To modify the Reactor Oversight Process to reflect any changes to the NRC's regulatory framework (which is being pursued under a separate activity).	Dependent on Regulatory Framework activity
Training on Severe Accidents	To enhance training of NRC staff on severe accidents and related procedures.	Dependent on outcome of Onsite Emergency Response Capabilities (Tier 1)
Emergency Planning Zone	To evaluate whether the basis for the size of the emergency planning zone needs to be modified.	Longer-term evaluation
Potassium Iodide (KI)	To evaluate the need to modify existing programs for the pre-staging of potassium iodide.	Longer-term evaluation
Expedited Transfer of Spent Fuel to Dry Cask Storage	To evaluate the merits of expediting the transfer of spent nuclear fuel from storage pools to dry cask storage.	See this staff memo to the Commission and staff requirements memorandum for more details
Reactor and Containment Instrumentation	To evaluate potential enhancements for instrumentation in the reactor and containment that can withstand severe accident conditions.	Longer-term evaluation