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Pages 3-14

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From page 3...
... Explosion of the released hydrogen damaged three reactor buildings and impeded onsite emergency response efforts. At the time of the Fukushima Daiichi accident, the Blue Ribbon Commission on America's Nuclear Future was completing an assessment of options for managing spent nuclear fuel and high-level radioactive waste in the United States (BRC, 2012)
From page 4...
... Subgroups of the committee visited two nuclear plants in the United States that are similar in design to the Fukushima Daiichi plant to learn about their designs and operations. S.1 CAUSES OF THE FUKUSHIMA DAIICHI ACCIDENT (Study Charge 1)
From page 5...
... Flooding of critical plant equipment resulted in the extended loss of onsite AC and DC power with the consequent loss of reactor monitoring, control, and cooling functions in multiple units. Three reactors sustained severe core damage (Units 1, 2, and 3)
From page 6...
... and long duration. S.2 LESSONS LEARNED FOR THE UNITED STATES (Study Charges 3 and 4)
From page 7...
... RECOMMENDATION 5.1A: As the nuclear industry and its regula tor implement the actions referenced in Finding 5.1, they should give specific attention to improving plant systems in order to enable effective responses to beyond-design-basis events, including, when necessary, developing and implementing ad hoc responses2 to deal with unan ticipated complexities. Attention to availability, reliability, redundancy, and diversity of plant systems and equipment is specifically needed for • DC power for instrumentation and safety system control; • Tools for estimating real-time plant status during loss of power; • Decay-heat removal and reactor depressurization and contain ment venting systems and protocols; • Instrumentation for monitoring critical thermodynamic param eters in reactors, containments, and spent fuel pools; 2  Theterm "ad hoc" refers to responses that are not planned and trained on in advance but rather are developed on the spot.
From page 8...
... Strengthening and better integrating emergency procedures, extensive damage mitigation guidelines, and severe accident manage ment guidelines, in particular for • Coping with the complete loss of AC and DC power for extended periods, • Depressurizing reactor pressure vessels and venting contain ments when DC power and installed plant air supplies (i.e., compressed air and gas) are unavailable, • Injecting low-pressure water when plant power is unavailable, • Transitioning between reactor pressure vessel depressurization and low-pressure water injection while maintaining sufficient water levels to protect the core from damage, • Preventing and mitigating the effects of large hydrogen explo sions on cooling systems and containments, and • Maintaining cold shutdown in reactors that are undergoing maintenance outages when critical safety systems have been disabled.
From page 9...
... events -- can produce severe accidents at nuclear plants that damage reactor cores and stored spent fuel. Such accidents can result in the generation and combustion of hydro gen within the plant and release of radioactive material to the offsite environment.
From page 10...
... Nuclear Regulatory Commission carry out the actions in Recom mendation 5.2A, they should pay particular attention to the risks from beyond-design-basis events that have the potential to affect large geo graphic regions and multiple nuclear plants. These include earthquakes, tsunamis and other geographically extensive floods, and geomagnetic disturbances.
From page 11...
... S.2.5 Examine Offsite Emergency Response Capabilities and Make Necessary Improvements Emergency response to the Fukushima Daiichi accident was greatly inhibited by the widespread and severe destruction caused by the March 11, 2011, earthquake and tsunami. Japan is known to be well prepared for natural hazards; however, the earthquake and tsunami caused devastation on a scale beyond what was expected and prepared for.
From page 12...
... RECOMMENDATION 6.2A: The nuclear industry and organiza tions with emergency management responsibilities in the United States should assess their preparedness for severe nuclear accidents associated with offsite regional-scale disasters. Emergency response plans, includ ing plans for communicating with affected populations, should be revised or supplemented as necessary to ensure that there are scalable and effective strategies, well-trained personnel, and adequate resources for responding to long-duration accident and/or disaster scenarios involving • Widespread loss of offsite electrical power and severe damage to other critical offsite infrastructure, for example, communications, transportation, and emergency response infrastructure; • Lack of real-time information about conditions at nuclear plants, particularly with respect to releases of radioactive material from reactors and/or spent fuel pools; and • Dispersion of radioactive materials beyond the 10-mile emer gency planning zones for nuclear plants that could result in doses exceeding one or more of the protective action guidelines.
From page 13...
... FINDING 7.1: While the Government of Japan acknowledged the need for a strong nuclear safety culture prior to the Fukushima Daiichi acci dent, TEPCO and its nuclear regulators were deficient in establishing, implementing, and maintaining such a culture. Examinations of the Japanese nuclear regulatory system following the Fukushima Daiichi accident concluded that regulatory agencies were not independent and were subject to regulatory capture.6 FINDING 7.2: The establishment, implementation, maintenance, and communication of a nuclear safety culture in the United States are priorities for the U.S.
From page 14...
... nuclear power industry must maintain and continu ously monitor a strong nuclear safety culture in all of their safety-related activities. Additionally, the leadership of the U.S.


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