Radial fine flux distribution in AGR-type clusters of fuel pins

The thermal neutron fine flux distribution in AGR-type fuel elements is investigated for different fuel densities in teh cluster, by using Dy-foils. The relative error of the measurements (one standard deviation) is 1.8%-3%. The experimentally derived variation of the thermal neutron flux from the cluster towards its center is compared with that calculated by using simple culster models and one-group diffusion theory.