Reactor physics of plutonium disposition in PWR and FR

In the frame of the AIDA/MOX programme between France and Russia, the disposition of plutonium in reactors was studied. The AIDA/MOX programme covers different areas, among which are the neutronic consequences of loading reactors with weapons-grade plutonium. The neutron physics aspects are described in order to improve the plutonium degradation and the plutonium consumption in a fast reactor and in a thermal reactor. The weapons-grade plutonium disposition is efficient when using standard reactors. FR may be used due to their larger velocity of consumption. Special designs can improve the Pu consumption by increasing the Pu content or removing the uranium support. Using minor actinides in the fuel also improves the reprocessing resistance. (author)