Staff of the US Nuclear Regulatory Commission have published a proposed schedule to implement the 12 post-Fukushima recommendations that it issued in July 2011 for US nuclear power plants.
As of mid-October, the research gathered by the Near-Term Task Force remains preliminary and subject to consideration by NRC commissioners. The schedule generally proposes issuing an order for the most urgent actions in March 2012, and requiring compliance from station operators in about six months.
First, the document points out that nothing from its research requires immediate action to counter an imminent threat to public health and safety.
Second, the task force identifies actions for which sufficient resources exist and should be carried out 'without unnecessary delay'. These Tier 1 actions include:
- seismic and flood hazard reevaluations
- seismic and flood walkdowns
- strengthening station blackout (SBO) mitigation capability to 8 hours for loss of all power, and 72 hours for core and spent fuel pool cooling
- improving emergency equipment to strengthen SBO mitigation capability
- installing reliable hardened vents for all Mark I and Mark II containments
- installing spent fuel pool instrumentation that can withstand design-basis natural phenomena for key parameters
- strengthening emergency and accident management guidelines (schedule: rule to be developed by 2015)
- improving emergency preparedness staffing and communications for SBO and multiunit events.
Most of these items had been recommended previously; new additions to the new report are the inclusion of hardened vents for Mark II containment and spent fuel pool instrumentation.
Third, this report proposed other potential safety issues coming out of Fukushima Daiichi and public consultation that were worthy of further consideration (irrespective of priority) by July 2012. These issues are:
- filtration of containment vents
- instrumentation for seismic monitoring
- basis of emergency planning zone size
- prestaging of potassium iodide beyond 10 miles
- transfer of spent fuel to dry cask storage
- loss of ultimate heat sink.
Fourth, it ranks two actions as lower priority depending on technical assessment, the resolution of the higher-priority actions or extra resources. The first of these is installing spent fuel pool makeup capability (installing safety-related AC power for the makeup system; assign one emergency onsite power train to SFP makeup and instrumentation install seismically-qualified means of pool water spray). The second of these is other emergency preparedness regulatory actions (guidance on performing multiunit dose assessment; periodic training for multiunit/prolonged SBO scenarios; ensure emergency equipment is sufficient for multiunit and prolonged SBO situations).
The task force proposes issuing a rule on spent fuel makeup capability in 2015, and on emergency preparedness in mid-2012.
The lowest-priority actions require further NRC study or other work before they could begin. There is no proposed schedule attached, although the commission is due to report back in July 2012. These items include:
- ten-year confirmation of seismic and flooding hazards
- potential enhancements to the capability to prevent or mitigate seismically-induced fires and floods
- reliable hardened vents for other containment designs
- hydrogen control and mitigation inside containment or in other buildings
- emergency preparedness enhancements for prolonged SBO and multiunit events
- emergency response data system capability
- emergency planning topics for decisionmaking, radiation monitoring and public education
- reactor oversight process modifications to reflect the recommended defence-in-depth framework
- staff training on severe accidents and resident inspector training on severe accident management guidelines.
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