Preparation of Zirconia for Transmutation Targets using Modified Direct Denitration

摘要

A modified direct denitration (MDD) process developed at the Oak Ridge National Laboratory (ORNL) to produce uranium trioxide (UO_3) powder for nuclear fuel pellets was adapted to prepare two zirconia material types for proposed usage in once-through-and-then-out americium/curium minor actinide transmutation targets. The zirconia materials had previously been prepared using sol-gel and solid state processes.rnThe objective of the test program is to develop prefabricated zirconia-based inert matrix material pellets that can be infiltrated with separated minor actinides from spent nuclear fuel in a recycling process. The infiltrated pellets would then be dried, thermally processed to convert the minor actinides to oxides, and loaded and sealed into reactor rods for processing. Zirconia-based ceramic materials have demonstrated durability during irradiation and provide a final rock-like material for cooling and disposal after the minor actinides have been reduced to desired activity levels. The transmutation targets would be suitable for use in a wide variety of irradiation systems including both thermal and fast neutron spectrum reactors.