Coolant contamination in gas-cooled reactors due to neutronic sputtering

Abstract

The transport of activated material beyond the bio-shields of nuclear reactors creates a gamma radiation field that poses a risk to operating, maintenance and inspection personnel. This makes the presence of activated material in the primary heat transfer system a critical safety and environmental concern. Neutron sputtering, a phenomenon that occurs when energetic neutrons collide with structural material and cause atoms to be ejected from the surface adjacent to cooling channels or tubes, is the primary mechanism in gas-cooled reactors that contributes to the inventory of activated material within the loops. The idea behind the work is centered on the evaluation of the recoil ranges of the daughter nuclei, therefore the study aims to investigate the physics behind the phenomenology considered in order to develop a suitable method to obtain quantitative results that can be used in the design of gas-cooled nuclear reactors.