Fission products and actinides in spent graphite masonry of the reactors at the Siberian chemical combine

The characteristic feature of the investigations performed was the wide-sca le and representative selection of samples of graphite masonry from reactor s and the comprehensive analysis of their radioactive contamination. An analysis of a large number of samples made it possible to construct a de tailed picture of the contamination. The role of incidents in the formation of the contamination of graphite by individual radionuclides was determine d. The distribution of the radionuclides in the masonry was studied. Correl ations between the content of different radionuclides were investigated. Schemes for estimating the store of radionuclides in graphite masonry were constructed on the basis of the distribution of the radionuclides of differ ent origin. In the approximate schemes the masonry was represented as a col lection of cells. The store of a radionuclide was determined by summing its content in individual cells, which were divided into several categories ac cording to their degree of contamination. The estimates of the store of radionuclides in the masonry differed strongl y from the predicted values. The store of fission products and actinides wa s approximately ten times smaller than previously assumed; this could subst antially simplify the disassembly and choice of utilization technology.