Case Study: Oak Ridge National Laboratory advances HFIR fuel conversion safety with COMSOL Multiphysics

Oak Ridge National Laboratory advances HFIR fuel conversion with Comsol, targeting 100 MW operation and 19.75% LEU fuel

Oak Ridge National Laboratory (ORNL) faced the complex challenge of converting its High Flux Isotope Reactor (HFIR) from highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel. This conversion, mandated by the Global Threat Reduction Initiative, required ensuring the reactor's performance, operational efficiency, and safety would be preserved despite the new fuel's different nuclear and thermal properties. Researchers at ORNL turned to multiphysics simulation from Comsol to model the impact of this fuel change.

Using Comsol Multiphysics software, ORNL implemented a fully-coupled fluid-structure interaction (FSI) model to analyze coolant flow and predict deflections in the reactor's unique involute fuel plates. This solution provided accurate and stable simulations that were successfully validated against previous experimental data. The Comsol models gave researchers the confidence to design and optimize the new LEU core, providing a critical tool for the safety analysis required for regulatory approval of the conversion.

Oak Ridge National Laboratory