Full Title: Lessons Learned About Spent Fuel Pools From the Fukushima Accident
Author(s): Herschel Specter
Publisher(s): N/A
Publication Date: December 1, 2013
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Description (excerpt):
The National Academy of Sciences (NAS) Committee on Lessons Learned from the Fukushima Accident has a task to examine the risks associated with drained spent fuel pools. The NAS examined this subject about ten years ago, prior to the accident at Fukushima. The earlier NAS committee examined a concept where about 80% of the spent fuel would be removed from the spent fuel pools and placed into dry casks on an accelerated basis. The remaining 20 % of the spent fuel, the hottest spent fuel, would be kept in the pool, but in a more open array. The safety of the 80 % of the spent fuel that would end up in dry casks is not in question here, but the safety of the other hottest 20% of the spent fuel is. Twenty percent of a spent fuel pool could mean as much as 7 megacuries of cesium 137. By comparison, large areas of land were contaminated when the Chernobyl accident released about 2 megacuries of cesium 137. It was claimed that this remaining 20% of the spent fuel might be safe because the fuel assemblies would be arranged in a more open array which could be air cooled if the pool water were drained.
The author of this report participated in the deliberations of this earlier NAS spent fuel pool effort and provided written and oral testimony. This report provides per- sonal recollections of some of the unclassified portions of this earlier NAS effort. In some instances these recollections are supplemented by further insights gained after the earlier NAS effort was concluded.
A major portion of the previous NAS committee deliberations was devoted to reviewing the adequacy of dry casks. This subject is not covered in this submittal. Where events during the Fukushima accident are related to a better understanding of spent fuel pool risks, the text is printed in red.
The earlier NAS spent fuel committee did not support the concept of transferring about 80% of the spent fuel into dry casks on an accelerated basis. It is the author’s view that the events at Fukushima reinforce this earlier NAS conclusion. Further, lessons learned from the Fukushima accident and further safety improvements implemented since the Fukushima accident indicate that terrorist acts are even less likely to be successful than thought before.