Using (Np, Am) Fractions of Minor Actinides for ²³⁸Pu Production in a VVER-Type Reactor

The results of research of using the Np and Am fractions of minor actinides for large-scale production of plutonium with an isotope composition suitable for utilization in radioisotope thermoelectric generators (RTG) of spacecraft and in cardiac pacemakers are presented. An irradiation device for plutonium production is considered, which is a standard fuel assembly (FA) of the VVER-1000 reactor, in the fuel elements of which the enriched uranium dioxide is replaced by a mixture of neptunium dioxide NpO₂ with americium dioxide AmO₂. It is shown that, when a central (Np, Am) FA is surrounded by a layer of natural or radiogenic lead, it becomes possible to obtain a production rate of plutonium suitable for RTGs at the level of 2.7–3.3 kg/yr.