Numerical qualification of the GSP

\nThe simplified P3 (SP3) method is an important way to implement the pin-by-pin neutron transport calculation of the core. This method has the high accuracy but costs twice the computing time of the diffusion method. Recently, the Generalized SPN (GSPN) theory has been developed, and the ad hoc SPN theory is resolved through rigorous theoretical derivation. GSP3(0) theory is the 3rd order and the 0th layer of GSPN theory. Compared with GSP3(0) theory, the SP3 theory with Marshak boundary condition is regarded as the traditional SP3 theory. The equations of the two theories are the same while the interface and the boundary conditions are different. Based on the GSP3(0) theory and the traditional SP3 theory, transport calculation codes have been developed using the analytical function expansion nodal (AFEN) method. The numerical results show that both of the two SP3 theories are more accurate than the diffusion theory, and the GSP3(0) theory can further improve the accuracy of the pin power calculation compared to the traditional SP3 theory.\n