The feasibility of employing inert matrix ceramic fuels in a Russian light water reactor

This study presents a version of Water–Water Energy Reactor (WWER) type fuel elements made using inert matrix fuels (IMFs) whose oxide fissile particulates are densely placed throughout a highly heat-conductive metal matrix consisting of silumin (cermet fuels). In these WWER-type fuel elements with cermet fuel, the fuel is bonded to cladding in a metallurgic way. It possesses some special features allowing the fuel to be used for both steady-state and load following operation modes. The study presents the results of the analytic study of the two variants of cermet fuel based on UO2 and UO2 + ThO2. The use of burnable poisons Er2O3 and Gd2O3 was considered. Characteristics of WWER with UO2 + ThO2 cermet fuel has been compared with those for conventional ceramic uranium dioxide fuel. In-pile testing of UO2 cermet fuel elements was carried out successfully up to a burnup of ≅60 MW d kg−1 of U. Results of stress calculations have shown fuel element cladding stability for operation in the load following mode.