Generating clean, safe nuclear power is essential to meet the world’s growing energy needs. Fischer’s team is performing highly accurate computations that allow them to analyze, model, simulate, and predict complex thermo-fluid phenomena and, ultimately, produce economical, safe nuclear power.

Two critical safety parameters in nuclear power plants are maintaining the peak material temperature and monitoring pressure drops in coolant flow. Predicting peak temperature and pressure drop requires accurately computing thermal mixing governed by thermal conduction and convection in a coolant flow over a complex geometry. Higher-fidelity advanced thermal hydraulics (TH) codes help simulate nuclear systems with well-defined and validated prediction capabilities, allowing researchers to explore points in the parameter space outside the existing database. These simulations can also model the flow and heat transfer phenomena in next-generation nuclear reactors.

The Nuclear Energy Advanced Modeling and Simulation (NEAMS) program is developing simulation capabilities to leverage leadership class computing facilities in the design of advanced nuclear reactors. Its Advanced Fuel Cycle Initiative (AFCI) is examining a closed nuclear fuel cycle based on a new generation of fast neutron reactors designed to safely manage spent nuclear fuel. A central component of that project provides large eddy simulations (LES) and Reynolds-averaged Navier-Stokes (RANS) simulations to study turbulent coolant flow and associated heat transfer.

The TH behavior of multi-pin subassemblies with wire-wrap and grid spacers was identified by Argonne’s reactor designers as a problem of primary interest that has most of the experimental data available for validation and therefore was chosen as a key areas for this multi-year effort.