3D LAMBDA-MODES OF THE NEUTRON-DIFFUSION EQUATION

The paper deals with the calculation of the 3D harmonic lambda modes i n a B.W.R. reactor. An algorithm to calculate the harmonic lambda mode s corresponding to the steady state two-group 3D neutron-diffusion equ ation is presented. The algorithm uses subspace iteration method techn iques combined with convergence acceleration based on variational prin ciples. The methodology has been tested on two benchmark problems, and applied to obtain the 3D modes of the Cofrentes Nuclear Power Plant.