Abstract: Method and apparatus for minimizing diversion of radioactive samples from a nuclear fuel sampling system. The apparatus includes a sampler for drawing a radioactive sample from a remote vessel containing nuclear fuel. The sampler is located within a shielding enclosure that has solid walls for preventing direct physical access to the sampler. A tray is located in the wall of the enclosure and is used for translating a sample vessel in and out of the enclosure. The apparatus further includes a time lock escapement that periodically immobilizes the tray for a period of time sufficient to minimize diversion of the radioactive samples.

Abstract: Apparatus for preventing the diversion of plutonium in nuclear fuel reprocessing plants. The apparatus includes various piping arrangements which prevent plutonium in a liquid state from being drawn out of a nuclear fuel reprocessing cell through conduits which are normally accessible to the operators of the facility.

Abstract: A storage module or rack is disclosed for storage of nuclear fuel assemblies in a water-filled pool comprising an array of storage tubes arranged in a checkerboard pattern and attached to one another along their corners. Each tube thus forms a storage cell for a fuel assembly and the spaces between each four adjacent tubes form intermediate fuel assembly storage cells. The storage tubes are formed with spaced double walls between which is contained a layer of neutron absorbing material to assure that the array of stored fuel assemblies remains subcritical. Provision is made for free circulation of water through the storage cells to extract heat from the stored assemblies. The storage module maximizes the number of fuel assemblies that can be stored in a given space while minimizing the material used in its construction.