DEVELOPMENT OF VERIFICATION TECHNIQUES FOR FRESH MOX FUEL ASSEMBLIES AT LWR-MOX RECYCLE REACTORS

There are large quantities of plutonium in fresh plutonium mixed oxide (MOX) assemblies, and it is necessary to apply effective safeguards and material control for the next-generation MOX fuel cycle. An important part of the cycle is the transfer of the assemblies from the fabrication facility to the reactor sites and the subsequent storage of the assemblies underwater in the reactor spent fuel storage pool prior to use. There needs to be effective verification that the plutonium mass remains intact during the transfer and subsequently in the underwater storage location. The passive neutron collar has been used at the fabrication plants for the plutonium verification, and more recently, the under water coincidence counter (UWCC) has been developed for the NDA verification in the water pool. This paper describes a new NDA approach to verify the plutonium content of the fresh MOX fuel in the underwater storage rack without the necessity to move the MOX fuel assemblies.