中子扩散三维非均匀变分节块法及平源加速方法研究

As a foundation of three-dimensional whole-core heterogeneous transport calculation, a 3D heterogeneous variational nodal method is proposed, which employs iso-parametric finite elements within each node and piecewise constants along nodal interfaces to explicitly describe the pin-resolved heterogeneous geometry. This means full elimination of the homogenization approximation. Meanwhile, the flat source acceleration method is proposed accordingly to reduce the computational costs. Numerical results show that the method is accurate and the flat source region acceleration method can effectively decrease the memory storage and computational time without degrading the accuracy.