The U.S. Congress asked the National Academy of Sciences to examine the causes of the March 11, 2011, accident at the Fukushima Daiichi nuclear plant and identify lessons learned for the United States. NRC (2014) contains the first part of this examination; the present report, which contains the second and final part, focuses on three issues: (1) lessons learned from the accident for nuclear plant security, (2) lessons learned for spent fuel storage, and (3) reevaluation of conclusions from previous Academies studies on spent fuel storage. Brief descriptions of key selected recommendations are provided in this Synopsis. Additional details are provided in the Summary and individual chapters.
Lessons Learned from the Accident for Nuclear Plant Security. Nuclear plant operators and their regulators should upgrade and/or protect nuclear plant security infrastructure and systems and train security personnel to cope with extreme external events and severe accidents. Such upgrades should include independent, redundant, and protected power sources dedicated to plant security systems that will continue to function independently if safety systems are damaged; diverse and flexible approaches for coping with and reconstituting plant security infrastructure, systems, and staffing during and following extreme external events and severe accidents; and training of security personnel on the use of these approaches.
Lessons Learned from the Fukushima Daiichi Accident for Spent Fuel Storage. The U.S. nuclear industry and its regulator should give additional attention to improving the ability of plant operators to measure real-time
conditions in spent fuel pools and maintain adequate cooling of stored spent fuel during severe accidents and terrorist attacks. These improvements should include hardened and redundant physical surveillance systems (e.g., cameras), radiation monitors, pool temperature monitors, pool water-level monitors, and means to deliver pool makeup water or sprays even when physical access to the pools is limited by facility damage or high radiation levels.
Reevaluation of Conclusions from Previous National Academy of Sciences Studies on Spent Fuel Storage. The present report provides a reevaluation of the findings and recommendations from NRC (2004, 2006). Two key recommendations emerged from this reevaluation concerning the application of risk assessment to security applications: (1) the U.S. nuclear industry and the U.S. Nuclear Regulatory Commission should strengthen their capabilities for identifying, evaluating, and managing the risks from terrorist attacks and (2) the U.S. Nuclear Regulatory Commission should sponsor a spent fuel storage security risk assessment for U.S. nuclear plants.
The Academies also examined the U.S. Nuclear Regulatory Commission’s Spent Fuel Pool Study (USNRC, 2014a) and Expedited Transfer Regulatory Analysis (USNRC, 2013) to assess their responsiveness to the recommendations in NRC (2004, 2006). One recommendation emerged from this examination: the U.S. Nuclear Regulatory Commission should perform a spent fuel storage risk assessment to elucidate the risks and potential benefits of expedited transfer of spent fuel from pools to dry casks. This risk assessment should address accident and sabotage risks for both pool and dry storage.