United States Nuclear Regulatory Commission - Protecting People and the Environment
Home > Nuclear Reactors > Operating Reactors > Operational Experience > Japan Lessons Learned > What are the Lessons Learned from Fukushima?

What are the Lessons Learned from Fukushima? (ARCHIVED)

Note: This is an archived web page. For the most up-to-date information, see the new Post-Fukushima Safety Enhancements page.

Lessons Learned Logo 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).

Post Fukushima Safety

Printable Version

Tier 1 Activities

Activity Brief Description NRC Addressing by…
Mitigation Strategies
a brown circle outline with a brown, rectangle on and off switch in the middle of the circle with the swith in the On position and the words On and Off		 To enhance the capability to maintain plant safety during a prolonged loss of electrical power. Order
Containment Venting System
a brown outline of a domed nuclear reactor building with a white square representing a reactor and a connected vent stack with a white dotted line arrow going up the vent stack		 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
a brown circle with a 3 sided rectangle with short end top open in the center; inside the rectangle are 3 horizontal arrows pointing from the right to left side with the lower arrow having 6 vertical bars or lines tight together extending down to the bottom short end of the rectangle		 To provide a reliable wide-range indication of water level in spent fuel storage pools. Order
Seismic Reevaluations
a brown circle with a graph representation in the center		 To reanalyze potential seismic effects using present-day information to determine if safety upgrades are needed. Request for Information
Flooding Hazard Reevaluations
a brown circle with brown water covering the lower half of the circle
To reanalyze potential flooding effects using present-day information to determine if safety upgrades are needed. Request for Information
Seismic and Flooding Walkdowns
a brown circle outline with a brown shape of a man wearing a hard hat, holding a flashlight and walking down stairs		 To inspect existing plant protection features against seismic and flooding events, and correct any degraded conditions Request for Information
Emergency Preparedness – Staffing and Communications
a brown bell image with two curved lines on either side, signifying the bell is ringing		 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
a brown circle outline with a brown, rectangle on and off switch in the middle of the circle with the swith in the On position and the words On and Off		 To enhance the capability to maintain plant safety during a prolonged loss of electrical power. Rulemaking
Onsite Emergency Response Capabilities
a drawn image of a brown loose-leaf binder page with two paragraphs of simulated written information each with a large check mark to the left of each paragraph.		 To strengthen and integrate different types of emergency procedures and capabilities at plants. Rulemaking
Filtration and Confinement Strategies
a brown outline of a domed nuclear reactor building with a white square representing a reactor and a connected vent stack with a white dotted line arrow going up the vent stack		 To evaluate potential strategies that may further confine or filter radioactive material if core damage occurs Rulemaking

To top of page

Post Fukushima Tier 2, Tier 3 and Non-Tiered Activities

In October 2015, the NRC staff developed an overall approach and specific project plans to resolve the remaining non-Tier 1 Near Term Task Force (NTTF) recommendations, as well as other activities with a direct nexus to Fukushima, by the end of 2016. The staff's evaluation considered existing requirements and voluntary measures, the overall risk posed by the issue, and insights gained during work on the Tier 1 activities, to determine if a recommendation would provide a substantial safety improvement if implemented. For the majority of the remaining recommendations, the staff's evaluation determined that the NRC's existing regulatory framework and requirements are adequate and that no further regulatory action or analysis is needed. Through this effort, all non-Tier 1 recommendations have been resolved. See Resolution of Post Fukushima Tier 2, Tier 3, and Non Tiered Activities for a discussion on how each non-Tier 1 recommendations have been addressed.

To top of page

Page Last Reviewed/Updated Friday, January 04, 2019