PROCESSING OF INERT SIC MATRIX WITH TRISO COATED FUEL BY LIQUID PHASE SINTERING

摘要

SiC is a promising material for nuclear applications especially due to its outstanding properties of excellent high temperature strength, high thermal conductivity and exceptional low-activation against neutron irradiation. It is proposed to replace the current uranium oxide fuel pellets for light water reactors with the ceramic micro-encapsulated uranium compacted within SiC inert matrix. In this study, nanostructured SiC fabricated by liquid phase sintering of SiC nanopowder was proposed as a dense inert SiC matrix for compact-packing of surrogate TRISO fuel particles. Sintering additives like Y_2O_3 and Al_2O_3 were used in addition to SiC nanopowder in the amount of 6 wt%. The powder mixture without the fuel particles was sintered by hot-pressing at 1750-1900 °C under 10 MPa to investigate the influences of sintering temperature on density and compression strength in inert SiC matrix itself. Based on the condition for densfied SiC matrix formation without the fuel particles under as a low sintering temperature as possible, pellets including 40 vol% TRISO particles were sintered at hot-pressing and characterized by microstructural observation and evaluation of thermal conductivity.