A New Variational Method for Pulsed-Neutron and Diffusion-Length Problems in Nonmultiplying Assemblies

A variational method particularly suitable for the pulsed-neutron problem was suggested by Ahmed et al.; in this method, one needed the exact solution of the eigenvalue equation for two values of the buckling. In the modification we suggest, no solution of the eigenvalue equation is required; however, compared to the earlier method our results are a little less accurate. A similar variational method has also been developed for the case of neutron diffusion. As examples, we have studied the decay of a neutron pulse and neutron diffusion in beryllium and beryllium oxide blocks.