Study of numerical computation methods for neutron transport equation based on unstructured-meshes

For the numerical solutions of the neutron transport equation based on unstructured-meshes, four types of new methods were developed including the spherical harmonics (P_n) finite element method, the discrete ordinates (S_n) finite element method, the triangle transmission probability method, and the triangle nodal method. The precision of the finite element methods is the highest. The P_n method avoids the ray effect in the S_n method. The S_n method can treat void boundary condition easily. The CPU time of the transmission probability method based on triangle meshes is the least. The nodal S_n method has less CPU time and better precision. The numerical computation was conducted with the present four new methods for some benchmark problems. The results show that the precision of the four new methods is high.