The effect of the different parameters on the infinite multiplication factor of Gas-Cooled Fast Reactors

One of the Gen IV reactor concepts is the Gas-Cooled Fast Reactor, the design of which contains a lot of improvements compared to the nowadays operating nuclear reactors; not only regarding the coolant, but the fuel assembly is also different from that of conventional ones. Hence the ceramic fuel design and the helium coolant, it is important to understand the effects of the different parameters, e.g. what the rhenium layer, which is applied on the inner surface of the cladding, may cause. During different examinations of the test reactor ALLEGRO it was investigated how certain geometry and material parameters influence the infinite multiplication factor and thus the reactivity.