Use of Different Reactor Physics Models and CADIS Accelerated MCNP to Yield a 1 MeV Silicon Equivalent Flux for Neutron Damage

Here, we develop and explore hybrid simulation techniques to expedite pre-test analysis of experimental designs for radiation hardness assurance testing efforts. Specifically, we focus on neutron displacement damage (NDD) testing, governed by American Society of Testing and Materials (ASTM) Standard Practice E722, which characterizes test facility neutron sources in terms of 1 MeV silicon equivalents. In doing so, we develop and compare a methodology for creating damage metrics for any materials using Evaluated Nuclear Data File (ENDF) libraries. Moreover, simple unit cell models were created and demonstrated to provide reasonable estimates for 1 MeV silicon equivalents flux comparable to the full core model of the training, research, isotopes, general atomics (TRIGA) nuclear reactor at the University of Utah. Criticality eigenvalue calculations in the full core were converted to fixed source problems by aliasing a deterministic solution of the same model. This approach the enabled acceleration of models and the application of consistent adjoint driven importance sampling (CADIS) variance reduction techniques, enabling Monte Carlo computational speedups of 10–100-fold with excellent statistics in the sample target area, paving the way for the application of the UUTR in highly efficient parameter studies for NDD testing.