COMPARISON OF SPARK PLASMA SINTERING AND CONVENTIONAL SINTERING OF UO_2 AND UO_2-COMPOSITE FUEL PELLETS

摘要

An in-depth comparison of the influence of processing conditions on induced microstructural features and thermo-mechanical properties of UO_2 and UO_2-SiC composite fuel pellets produced by spark plasma sintering (SPS) and conventional pressureless sintering, also referred to as oxidative sintering, is presented. In the conventional sintering process a maximum temperature of 1700°C and hold time of 4 hours are required to consolidate UO_2 powder into pellets with relative density of 96%. On the other hand, in SPS localized heat and uniaxial pressure are applied to consolidate powders to 96% relative density at temperatures as low as 1050°C and processing time as low as 0.5 min. SPS also offers additional benefits of being able to produce pellets to desired shape and size with controlled grain size. Using SPS technique we have fabricated UO_2-SiC composites which have not been possible to sinter using conventional techniques. This document presents a summary of these results and high lights the benefits of using SPS.