ABSTRACT
The analysis of different physical models describing the cooling of the active zone in the accident ChAPP block required a large amount of detailed estimations and calculations, demanded the physical modelling of cooling processes and special experiments in the accident block, after which the scheme of convective filtering cooling of the ChAPP accident block was accepted as the base model. Subsequent analysis showed that the filtration cooling model of the pile-up completely explains all the phenomena taking place in the reactor after the accident. The behaviour of the pile-up was influenced by melting and evaporation processes of materials volatile at the temperature level in the active zone of the reactor at the beginning of the accident. When the temperature increases, the pile-up should be loosened artificially, otherwise, as the results of modelling show, nature can take care of it itself. The new results obtained were unexpected, since similar problems were never considered in technical applications.
