Sintering and FEA Simulation of Oxide Fuel Pellet Containing Lumped Gd_2O_3

摘要

In order to study the feasibility of the self-shieldedburnable absorber fuel, the fabrication process ofburnable absorber fuel pellet containing lumped Gd_2O_3was demonstrated by the sintering of drip cast Gd_2O_3particles or press-and-sintered Gd_2O_3 compact embeddedin the surrogate oxide matrix of yttrium stabilizedzirconia (YSZ) . The relative densities of the particle orcompact were controlled to understand the effect on themicrostructures of sintered composite pellet. Theshrinkage mismatch resulted in the formation of gaps orinterfacial cracks between the Gd_2O_3 and the YSZ matrix.The interfacial stress originated from the shrinkagemismatch was estimated by using a finite element analysisto simulate the sintering behavior of the composite oxidepellet containing Gd_2O_3 particles or compacts. Thedensification and shrinkage correlations of constituentmaterials were obtained by high temperature dilatometry.The calculated stress at the interface was used todetermine the threshold stress for the development ofcracks by comparing with the experimental results. Fromthe finite element analysis simulation, the processingconditions for the elimination of the interfacial cracks dueto the shrinkage mismatch in the composite burnableabsorber fuel pellet were established.