SP3 solution versus diffusion solution in nodal codes – which improvement can be expected

A detailed analysis of the differences between the diffusion and the SP3 method is given. The analysis is based on one dimensional analytical solutions for the one and two group diffusion and SP3 method. Different cases from a benchmark core configuration are analyzed with the help of the one dimensional analytical solutions. It is shown that only a limited part of the gain achievable due to the use of the SP3 approximation will be seen in nodal calculations.