Three-dimensional refined burnup characteristics analysis of Helical Cruciform Fuel

• A burnup region division method for 3D HCF was proposed and the burnup characteristic analysis was conducted by OpenMC code. • Neutron flux , power density and nuclides densities of HCF were calculated. • HCF is more economic than cylinder fuel. • The burnup analysis method is applicable to any specially shaped fuel, that is foundation for IFD and safety analysis. The Helical Cruciform Fuel (HCF) is an advanced Innovative Fuel Design (IFD) that present greater challenges for three-dimensional(3D) refined burnup characteristic analysis. A burnup region division method for HCF was proposed and the burnup characteristic analysis was conducted using OpenMC code. 3D refined distribution of thermal and fast neutron flux and power density, isotope densities of typical nuclides at different positions of HCF were calculated. The influences of twist pitch, axial enrichment, and boundary conditions were studied. Meanwhile, burnup characteristic on HCF and cylindrical fuel was compared with the same material and volume. The results show that, the chain reaction of HCF can last longer, and has obvious economic advantages than cylinder fuel. Unlike cylindrical fuel, the circumferential distribution of neutron physical variables for HCF is inhomogeneous and becomes more pronounced with burnup. The proposed analysis method is applicable to any specially shaped fuel and effectively predicts the neutron physical properties during burnup, forming the foundation for IFD and safety analysis.