Criticality and thermal analyses of separated actinides in transmutation.

摘要

Curium and americium pose special problems in the chemical preparation of spent nuclear fuel for transmutation. Once separated from the other minor actinides, the isotopes can lead to nuclear fission with the subsequent release of a large amount of radiation. A neutron criticality code was used to determine the effective neutron multiplication factor for varying quantities of curium and americium oxide held within spherical or cylindrical containers. These geometries were investigated both in air and in water. Recommendations are made on the maximum amount of curium and americium oxide that can be safely stored or handled before encountering nuclear criticality.; Several isotopes of curium and americium also generate a significant amount of heat by radioactive decay. If kilogram quantities are stored in a container, for example, the material may heat to an equilibrium temperature that exceeds its melting temperature. The heat generation of curium and americium present even more restriction on the mass of that can safely be contained in one location. Heat generation was analyzed to determine safe quantities for handling and storage.