Modelling of the cumulative behaviour of Caesium and Strontium activities in nuclear fuel

The nuclear fuel of the operating RBMK-1500 type reactor at Ignalina nuclear power plant is a potential source of accumulated activity which can enter the surrounding environment. Due to the fact, that the high radiotoxic nuclear fuel fission products 90Sr and 137Cs are most important radioactive pollutants, this study is concentrated on the quantitative and qualitative investigation of the cumulative behaviour of all strontium and caesium isotopes during burn-up and cooling time of the nuclear fuel. An investigation is performed on the basis of modelling results, which are important for the risk assessment of environmental contamination and for the interpretation of the results of direct field measurements. (orig.)