Development of multiphysics coupling system for nuclear fuel rod with COMSOL and RMC

Coupling fuel performance and neutronics can help improve the prediction accuracy of fuel rod behavior, which is important for fuel design and performance evaluation. A fuel rod multiphysics coupled system was developed with multiphysics software COMSOL and 3D Monte Carlo neutron transport code RMC. The fuel performance analysis module was built on top of COMSOL with the ability to simulate the fuel behavior in two-dimensional axisymmetric (2D-RZ) or three-dimensional (3D) mode. RMC was innovatively wrapped as a component of COMSOL to communicate with the fuel performance analysis module. The data transferring and the coupling process was maintained using COMSOL's functionality. Two-way coupling was achieved by mapping power distribution and fast neutron flux fields from RMC to COMSOL and the temperature and coolant density fields from COMSOL to RMC. A fuel rod pin lattice was modeled to demonstrate the coupling. Results show that the calculated power and temperature distributions are reasonable. Considering the flexibility of the coupled system, it can be applied to the performance evaluation of new fuel design.

Automated summary

Coupling fuel performance and neutronics can enhance the accuracy of predicting fuel rod behavior, which is crucial for fuel design and performance evaluation. A fuel rod multiphysics coupled system was developed using COMSOL and RMC, enabling the simulation of fuel behavior in 2D-RZ or 3D mode. By wrapping RMC as a component of COMSOL, two-way coupling was achieved through data transfer and communication. Model validation of a fuel rod pin lattice demonstrated reasonable power and temperature distributions. The flexibility of the coupled system makes it applicable for evaluating the performance of new fuel designs.