Thermal and mechanical cutting of concrete and steel

Various thermal and mechanical processes for dismantling radioactive large components and concrete structures were investigated in order to determine the optimal handling conditions and their respective efficiency. For the thermal processes, the separation of heavy concrete and steel components by means of oxygen lances, powder cutting, ocyacetylene cutting, and plasma cutting processes were tested. In order to gain the necessary data for designing filtering equipment with regard to use in nuclear power stations, the amount of dust deposition and particle size distribution for these thermal processes were measured. The largest particle size proportion occurs for a particle size of ca. 0.3 μm. For the mechanical processes, stationary saws were used. Due to the large dimensions of the components which are to be found in a nuclear installation, it is not possible to use such saws for the initial dismantling. These saws can be used for both low-alloy and austenitic types of steel, and for separating materials not containing iron. In order to compare the efficiency of the saws with that of the thermal processes, to some extent the same test pieces were used that were used for the thermal tests. The advantage of the saw technique in comparison to the thermal separation processes lies in that next to no gas or dust contamination can become released. Also, the amount of shavings produced (secondary waste) is low. Furthermore, some of the saws can be used under remote control