The behavior of a generic TRISO particle under two extreme conditions was simulated with BISON to help X-energy explore experiment options. The first extreme condition simulated was of a high fast neutron fluence at normal particle power. BISON material models have a limit on fluence value used during calculations. BISON code was modified to disable these limits to compare two high fluence simulation with and without value limits on material models. The results showed when the two solutions diverged at the high fluence limit. As the two simulations provided two different results, more data at high fluence for higher burnups is needed to improve models. The second extreme condition was of high particle power with typical proportional fast neutron fluence. Particle powers of 350, 500, and 750 mW were simulated with BISON. The results showed SiC layers were in compression for these short periods of elevated power levels when slowly ramped up to power. The buffer layer compressed from thermal expansion of hotter kernels. This helped protect outer layers from high stresses due to kernel thermal expansion.
