Safer nuclear energy power promises to become a reliable, carbon‐free resource capable of meeting our nation’s and the world’s energy needs. Numerical simulation has been an intrinsic part of nuclear engineering research, design, and licensing of existing and proposed conventional nuclear power plants. Nuclear modeling and simulation tools available today, however, are mostly low dimensional, empirically based, valid for conditions close to the original experiments, and in many cases incremental improvements on decades‐old legacy codes. The development, deployment, verification, and validation of higher‐fidelity computational capabilities for analyzing, modeling, simulating, and predicting complex thermo‐fluid phenomena will help advance nuclear power capabilities by resolving technical, cost, and safety issues.

The Center for Exascale Simulation for Advanced Reactors (CESAR), one of the three codesign centers funded by DOE, aims to address these challenges by developing a coupled, next generation nuclear reactor core simulation tool capable of efficient execution on exascale computing platforms. This project supports the mission of CESAR with large petascale level simulations needed to address the limitations of current methods and address the potential scaling to larger machines. The resulting improved state‐of‐the art simulation code will aid advancements in nuclear engineering and nuclear energy.