US regulators request natural phenomena response data

The US nuclear regulatory commission (NRC) has asked the owners of nuclear fuel facilities to provide more information on how they respond to natural phenomena. The commission said that apart from the need for this information, it is otherwise satisfied  that "little or no further action" is needed to apply the lessons learned from the Fukushima accident.

NRC executive director for operations Mark Sartorius set out a staff evaluation of the applicability of lessons learned from the Fukushima Daiichi accident to facilities other than power plants in a paper to commissioners dated 6 June. The assessment covers licensed facilities other than nuclear power plants across eight general areas, including spent fuel storage and transportation, fuel facilities, radioactive material users, licensed irradiators, low-level waste disposal facilities, uranium recovery facilities, plants undergoing decommissioning and non-power reactors (research and test reactors, or RTRs).

According to the filing, the NRC staff's overall conclusion is that existing regulatory processes provide for adequate protection of public health and safety across all eight areas. Nevertheless, the NRC has called for further assessments at fuel facilities and non-power reactors "to ensure that Fukushima lessons are properly learned".

For fuel facilities, the ongoing work will look at safety assessments and the supporting documentation with respect to the treatment of natural phenomena hazards such as earthquakes, flooding and high winds caused by hurricanes or tornadoes. To that end, the NRC has now issued a generic letter to all fuel cycle facilities asking them to provide further information so that it can validate plants' compliance with their licensing basis for such hazards, and to allow it to determine whether or not further regulatory action is required.

The continuing work for non-power reactors focuses on the three US RTRs that have thermal power ratings higher than 2 MW, for which further assessments will be carried out to determine whether regulatory actions are needed "to mitigate certain beyond-design-basis external events".

For the three reactors concerned - the Massachusetts Institute of Technology's MITR, the National Institute of Standards and Technology's NBSR, and the University of Missouri at Columbia's MURR - NRC staff will perform additional assessments regarding the reactors’ capabilities to prevent or mitigate loss of coolant accidents as a result of beyond-design-basis natural phenomena. The NRC assessments will be carried out by staff with expertise in seismology, hydrology, structural analysis, and RTR design and operation.

"For the majority of regulated facilities discussed in this paper, NRC staff has determined that no other analysis or regulatory action is needed based on its review of the lessons learned from the Fukushima Daiichi accident. If responses to the fuel facility generic letter or the further assessments of the three highest-powered RTRs cause NRC staff to determine that additional regulatory actions are needed to address Fukushima lessons learned, then staff will interact with stakeholders and, as appropriate, engage the Commission," the paper concludes.

Researched and written
by World Nuclear News