In the calculation of neutron transport problems with spatially localized source or largely void region, the discrete ordinate method (SN) suffers from ray effects, which cause computational inaccuracies. The first collision source method is often used to alleviate the ray effect to improve the reliability of results. However, this method requires the calculation of the uncollided neutron flux. Generally, which is typically achieved through ray tracing technology based on the grid center method or the grid corner average method, destroying the ...
