High Precision Hot Cell Dissolution Protocol for Irradiated Mixed Oxide Fuels

The United States Department of Energy (DOE) Fissile Materials Disposition Program (FMDP) is pursuing the disposal of surplus weapons-usable plutonium via reactor irradiation using the plutonium as the fissile constituent of a mixed uranium and plutonium (MOX) fuel. Lead test assemblies (LTA) have been irradiated for approximately 36 months in Duke Energy’s Catawba- 1 nuclear power plant (NPP). Per the MOX fuel qualification plan, destructive post-irradiation examinations (PIE) are to be performed on second cycle rods (irradiated to an average burn-up of approximately 45 GWd/MTHM). The Radiochemical Analysis Group (RAG) at Oak Ridge National Laboratory has performed some of the detailed destructive post-irradiation examinations (PIE) on selected segments from four of the MOX fuel rods. The analytical process involves quantitative dissolution of designated fuel segments in a shielded hot cell for high precision measurements of select fission products and actinide isotopes employing isotope dilution mass spectrometry (IDMS) among other analyses. The hot cell dissolution protocol to include the collection and subsequent alkaline fusion digestion of the fuel’s acid resistant metallic particulates will be presented