Some aspects of thermal neutron diffusion in non-uniform temperature moderator

Abstract

The effect of non-uniform temperature on the Maxwellian distribution of thermal neutrons in a non-capturing moderator has been studied, using the heavy gaseous moderator approach. The results indicate that for typical temperature gradients in power reactors, the neutron temperature follows the moderator temperature with a negligible distortion of the spectrum, and that at the boundary between regions of different temperature, perturbations are restricted to a few centimeters.