APOLLO2 calculations of RBMK lattices

The purpose of this study is to investigate the use of erbium as burnable poison in RBMK reactors. The neutronic code APOLLO2 has been used and a comparison with the Monte-Carlo code TRIPOLI2 has been made. The first chapter briefly presents the RBMK characteristics, the second chapter deals with the neutronic behaviour of a fuel assembly in an infinite lattice which is an important step in the modelling process. The third chapter presents the analysis of the use of erbium in typical elements of the RBMK lattice. A good agreement is obtained between the 2 codes except in the draining situations. Erbium appears to reduce the positive reactivity effect of the draining configuration. (A.C.)