NRC Staff: No Safety Benefit in Moving Used Fuel Out of Storage Pools
Oct. 9, 2013—The NRC staff is recommending not pursuing expedited transfer of used fuel from reactor storage pools to dry cask storage systems, concluding that doing so “would neither provide a substantial increase in the overall protection of public health and safety nor sufficient safety benefit to warrant the expected implementation costs.”
Presenting the draft results of its Fukushima lessons-learned generic regulatory analysis on whether used fuel older than five years should be moved out of U.S. reactor storage pools, agency staff told the NRC’s Advisory Committee on Reactor Safeguards last week it believes no further regulatory action is necessary and recommended closing out the associated Tier 3 activity.
In conducting the regulatory analysis on the agency’s post-Fukushima task force recommendation, the staff said it considered the “broad history” of NRC oversight of used fuel storage, domestic and international used fuel pool operating experience, and past and recent pool safety studies.
The most recent of these is the NRC’s June 2013 draft “Consequence Study of a Beyond-Design-Basis Earthquake Affecting the Spent Fuel Pool for a U.S. Mark I Boiling Water Reactor.” The study found that the used fuel pools for the specific reactor studied could withstand a hypothetical earthquake more severe than the one that struck Fukushima Daiichi’s Mark I reactors in March 2011 and concluded that reducing the fuel loading density in storage pools would be of minimal value. The staff said the results of the study, which confirms that used fuel pools adequately protect public health and safety, “contributed to the resolution of this issue.”
The staff evaluation also looked at the July 2007 earthquake in Japan and the August 2011 earthquake in Virginia. None of the 20 reactors in Japan that felt the 2007 quake or the North Anna reactor in Virginia suffered any damage or loss of water from the used fuel pools.
Steven Kraft, NEI’s senior technical adviser, noted how the robustness of used fuel pool design ensures the safety of stored fuel even in extreme conditions. “The storage pools at Fukushima survived the fourth-largest earthquake in recorded history, hydrogen explosions that blew off the roofs of three of the reactor buildings and the debris resulting from those explosions. All accounts from Japan tell us that the fuel in those pools survived with minimal if any damage,” Kraft said.
Apart from storage pool design, the staff also noted in its evaluation the post-Fukushima enhancements in pool safety currently being implemented in response to the NRC orders for reliable used fuel pool instrumentation and for mitigating strategies for beyond-design-basis events.
At the Oct. 2 ACRS meeting, the NRC staff said the commission likely will be briefed on the spent fuel pool study and regulatory analysis by the end of the year.