In the Fiscal Year 2004 Energy and Water Development Conference Report, the U.S. Congress asked the National Academies to provide independent scientific and technical advice on the safety and security1 of commercial spent nuclear fuel storage in the United States, specifically with respect to the following four charges:
Potential safety and security risks of spent nuclear fuel presently stored in cooling pools at commercial reactor sites.
Safety and security advantages, if any, of dry cask storage versus wet pool storage at these reactor sites.
Potential safety and security advantages, if any, of dry cask storage using various single-, dual-, and multi-purpose cask designs.
The risks of terrorist attacks on these materials and the risk these materials might be used to construct a radiological dispersal device.
Congress requested that the National Academies produce a classified report that addresses these charges within 6 months and also provide an unclassified summary for unlimited public distribution. The first request was fulfilled in July 2004. This report fulfills the second request.
Spent nuclear fuel is stored at commercial nuclear power plant sites in two configurations:
In water-filled pools, referred to as spent fuel pools.
In dry casks that are designed either for storage (single-purpose casks) or both storage and transportation (dual-purpose casks). There are two basic cask designs: bare-fuel casks and canister-based casks, which can be licensed for either single- or dual-purpose use, depending on their design.
Spent fuel pools are currently in use at all 65 sites with operating commercial nuclear power reactors, at 8 sites where commercial power reactors have been shut down, and at one site not associated with an operating or shutdown power reactor. Dry-cask storage facilities have been established at 28 operating, shutdown, or decommissioned power plants. The nuclear industry projects that up to three or four nuclear power plants will reach full capacity in their spent fuel pools each year for at least the next 17 years.
The congressional request for this study was prompted by conflicting public claims about the safety and security of commercial spent nuclear fuel storage at nuclear power plants. Some analysts have argued that the dense packing of spent fuel in cooling pools at nuclear power plants does not allow a sufficient safety margin in the event of a loss-of-pool-coolant event from an accident or terrorist attack. They assert that such events could result in the release of large quantities of radioactive material to the environment If the zirconium cladding of the spent fuel overheats and ignites. To reduce the potential for such fires, these