The effect of a cylindrical channel on neutron diffusion

Abstract

Voids in the core of a reactor affect the neutron leakage significantly and it is important to allow for this leakage when calculating a critical mass. It is also often of interest to know how empty channels affect the manner in which neutrons diffuse out of the core. The effect of a single hollow cylindrical channel is considered herein. Expressions are derived for the neutron leakage along a channel through the centre of the reactor and for the additional losses in the vicinity of the channel arising from the presence of the channel. The way the form of the flux distribution along the channel affects the applicability of diffusion formulae is considered.