Results of the experimental campaign on contaminated metal components parameters and suggestions for safely NPP component dismantling

This paper concerns the dismantling activities of Caorso NPP (BWR, Boiling Water Reactor, 870 MWe, built in the 70s and fully operating in the period 1981–1986). The said plant was shut down on 1987, following Italy's poll that abrogated nuclear power use based on U235 fission. The considered activities involved an experimental campaign using plasma torch and oxyacetylene arc metal cutting processes, and regarding no radioactive materials–pipes and plates exposed to the reactor coolant steam. The performed analyses of by use contaminated components below the free release level (1 × 10 4 Bq/m 2), not yet considering radioactivity, allowed an accurate estimation of the chemical and physical characteristics of the produced aerosol. The adopted operative conditions concerning the cut procedures are firstly described. The emissions composition and technical parameters such as cutting time and cutting rate vs. pipe diameter or plate thickness are reported. The results highlight the kind of trouble that can emerge in the cutting processes, in particular focusing on a comparison of the effects of the two cutting processes and the chemical composition of dusts collected by filtering the gaseous emission. The achievable chances connected to the adopted filtration methods are then revealed, and the obtained parameters related with the production of volatile and solid residuals for cut are reported. Some suggestions follow, finally, for a safely NPP components disassembling.