NRC task force recommends steps to avoid a Fukushima type disaster

The U.S. Nuclear Regulatory Commission’s Japan Task Force today proposed sweeping changes to federal regulations to better protect nuclear reactors and the public from the type of disasters experienced at the Fukushima reactors this spring in Japan.

The NRC’s Japan Task Force was charged with proposing improvements in light of the loss of power, core melts and spent fuel pool fires at Fukushima Daiichi reactors following the tsunami and earthquake there in the spring.

While declaring that “a sequence of events like the Fukushima accident is unlikely to occur in the United States” and that plants can be operated safely, the Task Force also recognized that “an accident involving core damage and uncontrolled release of radioactivity to the environment, even one without significant health consequences, is inherently unacceptable,” the NRC said in a press release.

The recommendations, which the NRC will now consider, cover everything from loss of power, earthquakes, flooding, and spent fuel pools to venting and emergency preparedness. The task force also recommended additional study of some issues.

Saying “everything was on the table” for review, Charles Miller, an NRC veteran who was about to retire when tapped to lead the review team, said the task force looked at four areas: ensuring protection, enhancing accident mitigation, strengthening emergency preparedness and improving the efficiency of NRC programs.

A report from the NRC is due in six months, following a July 19 presentation to the NRC from the task force and a July 28 task force public meeting. Task force members will also appear Aug. 17 before the Advisory Committee on Reactor Safeguards.

Recommendations include:

  • Requiring plants to reevaluate and upgrade as necessary their design-basis seismic and flooding protection of structures, systems and components for each operating reactor and reconfirm that design basis every 10 years;
  • Strengthening Station Black Out mitigation capability for existing and new reactors for design-basis and beyond-design-basis natural events – such as floods, hurricanes, earthquakes, tornadoes or tsunamis – with a rule to set minimum coping time without offsite or onsite AC power at 8 hours;
  • Establishing equipment, procedures and training to keep the core and spent fuel pool cool at least 72 hours; and pre-planning and pre-staging offsite resources to be delivered to the site to support uninterrupted core and pool cooling and coolant system and containment integrity as needed;
  • Requiring that facility emergency plans address prolonged station blackouts and events involving multiple reactors;
  • Requiring additional instrumentation and seismically protected systems to provide additional cooling water to spent fuel pools if necessary; and requiring at least one system of electrical power to operate spent fuel pool instrumentation and pumps at all times.
  • Requiring reliable hardened vent designs in boiling water reactors with Mark I and Mark II containments (similar to those in Japan);
  • Strengthening and integrating onsite emergency response capabilities such as emergency operating procedures, severe accident management guidelines and extensive damage mitigation guidelines;
  • Identifying, as part of the longer term review, insights about hydrogen control and mitigation inside containment or in other buildings as more is learned about the Fukushima accident;
  • Evaluating, as part of the longer term review, potential enhancements to prevent or mitigate seismically induced fires or floods;
  • Pursuing, as part of the longer term review, additional emergency preparedness topics related to Station Black Out and multiunit events;
  • Pursuing, as part of the longer term review, emergency preparedness topics on decision making, radiation monitoring and public education;
  • Strengthened regulatory oversight of plant safety performance – the NRC’s Reactor Oversight Process by which plants are monitored on a daily basis – by focusing more attention on defense-in-depth requirements.


 

 
 

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