Safer nuclear energy promises a reliable, carbon-free power resource capable of meeting the nation’s and the world’s energy needs. One of the critical safety parameters in a nuclear power plant is the peak material temperature. Prediction of the peak temperature involves accurate computation of thermal hydraulics with large eddy simulations (LES). This project focuses on validation and cross-verification of three thermal hydraulics LES codes with benchmark experiment MATiS and data from ANL’s MAX facility (a fluid dynamics test facility). The outcomes of this project will improve state-of-the-art computational simulation capabilities and will advance an international engagement in support of the safe, secure, and peaceful use of nuclear energy.