High-fidelity Numerical Simulation of Wire-wrapped Fuel Assemblies

PI Aleksandr Obabko, Argonne National Laboratory

Recent interest in advanced fuel cycles and reactor fuel recycling has led to renewed interest in the development of liquid-metal-cooled fast reactors in the United States. Several private companies have expressed interest in this technology, with a focus on cores with longer life. The prediction of thermal performance in fuel assemblies is vital for evaluating overall reactor performance and safety, particularly as the assembly ages. In particular, deformations driven by thermal expansion and radiation damage is increasingly important as reactor designs look to longer assembly lifetimes. As assemblies deform, traditional heuristic modeling becomes less suitable for evaluating the thermal-hydraulic performance of a given assembly due complex flow patterns that may be introduced.

This project has the goal of validating higher fidelity tools to provide accurate predictions of the flow field and heat transfer in wire-wrapped fuel assemblies, typical of sodium fast reactor designs. The data obtained with these simulations will be instrumental in further improving lower –fidelity models and understanding the flow physics in this complex geometry. The present current work will carry out large eddy simulations of wire-wrapped fuel assemblies typical of liquid metal reactors with Nek5000 code for international benchmarks and fluid-induced vibration cases.

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