2017 | AFC ACCOMPLISHMENTS 155 U-Zr (DP11, DP81-1, DP81-2) U-Pu-Zr (T179, Dp16) Parameter Mean Std. Mean Std. Diffusion Coefficient Multiplier [-] ηα 48.5 30.6 51.2 27.9 ηδ 8.52 5.28 8.47 5.76 ηβ 54.7 29.8 47.5 28.2 ηγ 55.4 28.6 12.2 7.62 Transitional Temperatures [K] A-B 944.3 14.1 943.4 9.86 C-D 986.9 9.25 1030 31.7 Remaining Model Error RMS Error 0.078 0.007 0.101 0.012 would have been impractical with the previous approach. Inclusion of expert judgement to the calibration process by weighting the error metric has been shown to accurately describe the phase transition temperatures and thermal conductivities. Furthermore, the statistical approach provides a better understanding of standard variations in the model and presents a path forward for reducing model errors, such as missing dependence of porosity changes to the fuel’s thermal conductivity model. Progressive calibration completed to date has supported the development of a more advanced, better informed model calibration capability for improving the model’s predictive capability.The final calibration of BISON capability with state aware parameters and predictive maturity index including the gas release model is in progress. Figure 2. Current results from staged Bayesian calibration approach of diffusion coefficients along with transition temperatures for U-Zr and U-Pu-Zr metallic fuels.