This continued INCITE project will push the boundaries of thermal hydraulic (TH) modeling in the spectral element code Nek5000 for co-design and validation, and serve as the focus of the current and future cross-verification activities for several international collaborations. As part of the Nuclear Energy Advanced Simulation (NEAMS) effort, Argonne researchers will conduct TH simulations to validate benchmarks for PANDA, the large-scale thermal hydraulics test facility in Switzerland, and continue computational fluid dynamics (CFD) simulations for Nuclear Reactor Safety workshops and their benchmarks.

In collaboration with Atomic Energy and Alternative Energies Commission (CEA), and Japan Atomic Energy Agency (JAEA), we will study the validation experiment PLAJEST. This triple-jet TH mixing experiment provides a unique opportunity to validate conjugate heat transfer simulation techniques for a variety of flow conditions in thermal stripping phenomena.

As a part of NEAMS’ International Nuclear Energy Research Initiative (I-NERI), collaboration with the Nuclear Research Group (NRG) in Petten, Netherlands, calls for an exchange of high-fidelity CFD data between Argonne and NRG to verify the TH codes used by both institutions. This exchange of data will cover rod bundles previously simulated at Argonne, and pebble-bed reactors simulated by the NRG group. The immediate goal of this collaboration is to conduct a series of validation studies for simplified configurations currently designed at NRG that will require up to 200 million grid points and long time-averaging runs.

In collaboration with the U.S.-based, nuclear energy technology company TerraPower, the team will conduct numerical simulations of wire-wrapped rod bundles to quantify the effect of thermal expansion, which had not been considered previously. TerraPower will provide suitably deformed rod-bundle configurations based on its evaluation of thermal expansion. The effect and impact of the deformation due to thermal expansion will be evaluated using the Nek5000 code. Predicting thermal performance of such components is vital to the evaluation of overall reactor performance and safety, which could lead to a viable, carbon-free, energy production technology.