A scheme for the evaluation of λ-modes of a neutron diffusion equation

The static multiplication eigenvalue problem over a nuclear reactor is considered in multi-group diffusion theory with a finite difference approximation. An alternative scheme is suggested for the evaluation of higher harmonics where one works in terms of fission sources rather than the group fluxes leading to a reduction in problem size. The scheme is tested for simple cases. The situations arising in more complex problems are briefly discussed. (author)