Investigation on the modeling capability of ALPHA code for fuel rod deformation

•A complex geometry supported MOC ray-tracing toolkit and a MOC-EX solver is implemented.•The mesh mapping technique is applied to perform the deformed problem with MOC-EX solver, including inclining, C-shaped bowing and swelling.•Sensitivity studies are performed on discretization parameters of MOC calculation, which demonstrate a high-level accuracy can be archived in deformed problem. Fuel pin cells/assemblies deformations are observed phenomena, which can cause reactivity feedback. To model the deformed geometry and considering the geometry modeling flexibility of method of characteristic (MOC), a complex geometry supported MOC ray-tracing toolkit is implemented on ALPHA (Advanced Lattice Physics code based on Heterogeneous Architecture), which employs the MOC with the axial flux expansion (MOC-EX) to perform 3D problem. Three different types of deformed geometry are calculated to investigate the capability of performing the neutronic simulation of the fuel rod deformation. The numerical results of the ALPHA code show a good agreement with the results of OpenMC, which indicate that the ALPHA code based on the MOC-EX method and complex geometry toolkit are capable to deal with the fuel rod deformation.