Delayed neutron effectiveness in a fluidized bed fission reactor

In a fluidized bed of fuel particles suspended by gas a considerable spatial redistribution of delayed neutron precursors occurs due to mixing processes. 00 the basis of a simple reactor model the reactivity effect of precursor redistribution is analyzed. This analysis is performed for both the limit case of ideal mixing and the general case of finite precursor diffusion length. It is shown that k-infinity and the ratio between precursor diffusion length and neutron diffusion length are the relevant parameters determining the reactivity effect and the effectiveness of the delayed neutrons.