A Galerkin approach to the boundary element-response matrix method for the multigroup neutron diffusion equations

The boundary element method (BEM) is a natural candidate for the evaluation of the fuel assembly response matrix (RM) coefficients in reactor core neutron flux calculations. A BEM technique based on the application of the Galerkin method is presented, which allows for a fast and accurate computation of the RM elements. The resulting coupled BEM-RM method for 2D multigroup diffusion problems turns out to be very accurate and with a computational efficiency not too distant from that of finite element or nodal methods.