Comments on Fuel Crud as a Safety and Operational Factor of Independent Spent Fuel Storage Installations (ISFSI)

摘要

The independent spent fuel storage installation (ISFSI) will be designed to provide a controlled water pool environment for spent nuclear fuel during some part of the time span between its reactor pool residence and its reprocessing or ultimate disposal. It is the purpose of this report to review some of the current characterization of fuel deposited crud, and to indicate a few facets of the crud phenomenon which could conceivably impact operations and safety considerations of ISFSI. Following a review of observations of fuel crud amount, distribution, structure, elemental and chemical compound composition, there is a discussion of various factors affecting the importance of fuel crud to ISFSI. A brief review is given of factors affecting fuel crud formation, deposition and removal; some of the reported radioactivity characteristics of fuel crud are summarized and several simple indices are utilized to identify potentially significant parent elements and activation produce nuclides which could be involved in fuel crud; a comparison is made of the radioactivity inventories assignable to fuel crud and the fuel, respectively, with an indication of the importance of the post-reactor discharge time to fuel crud nuclide significance. On the basis of the conceivable ISFSI radioactivity inventory derived from fuel crud and the ability to manage the crud material, the public safety implications of fuel crud in the ISFSI environment are regarded as minimal. (ERA citation 04:018102)