The characteristic feature of the investigations performed was the wide-scale and representative selection of samples of graphite masonry from reactors and the comprehensive analysis of their radioactive contamination. An analysis of a large number of samples made it possible to construct a detailed picture of the contamination. The role of incidents in the formation of the contamination of graphite by individual radionuclides was determined. The distribution of the radionuclides in the masonry was studied. Correlations 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 different origin. In the approximate schemes the masonry was represented as a collection of cells. The store of a radionuclide was determined by summing its content in individual cells, which were divided into several categories according to their degree of contamination.
The estimates of the store of radionuclides in the masonry differed strongly from the predicted values. The store of fission products and actinides was approximately ten times smaller than previously assumed; this could substantially simplify the disassembly and choice of utilization technology. 2 figures, 10 tables, 3 references.