A Method for Predicting the Penetration and Slowing Down of Neutrons in Reactor Shields

A new approach is presented in the formulation of removal-diffusion theory. The removal cross section is redefined and the slowing down between the multigroup diffusion equations is treated with a complete energy-transfer matrix rather than in an age theory approximation. The method, based on the new approach, contains an adjustable parameter. Examples of neutron spectra and thermal flux penetrations are given in a number of differing shield configurations, and the results compare favorably with experiments and Moments-Method calculations.