|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Advanced Characterization and Modeling of Nuclear Fuels: Microstructure, Thermo-physical Properties
||Microstructural Characterization of the Porous Pyrocarbon Buffer Layer in TRISO Fuel Particles
||Claire Griesbach, Tyler Gerczak, Kumar Sridharan, Yongfeng Zhang, Ramathasan Thevamaran
|On-Site Speaker (Planned)
Tristructural isotropic (TRISO) nuclear fuel particles are a robust high temperature fuel architecture; however, failure occurs in rare cases—commonly beginning in the porous pyrocarbon buffer layer nearest the uranium kernel. Understanding the buffer-initiated failure mechanisms requires characterization of the buffer porosity and mechanical properties, which have been relatively unexplored to date. We perform slice-and-view experiments using a dual-beam FIB-SEM to produce 3D reconstructions of the buffer microstructure. Volumes of ~15<sup>3</sup> μm<sup>3</sup> are analyzed at several regions within the buffer layer and on multiple near-representative surrogate particles to investigate the spatial and particle-to-particle variability of the pore structure. We find that the average porosity is significantly lower than the commonly used 50% theoretical density estimate, and the porosity varies along the radial direction. Characterization of the buffer microstructure, along with mechanical properties obtained by nanoindentation testing, will inform multiscale models designed to predict the failure of TRISO particles under irradiation.
||Characterization, Nuclear Materials, Mechanical Properties