Radioactivity release and dust production during the cutting of the primary circuit of a nuclear power plant. The case of E. Fermi NPP

This paper concerns the cutting operations and spread of radioactive contamination during the dismantling of a nuclear metal component, carried on with thermal cutting. Our analysis relates to E. Fermi nuclear power plant (Trino Vercellese, Italy), a Pressurized Water Reactor, which had an electrical power of 272MWe, and was in operation from 1965 to 1987. The plant included four primary loops and a pressurizer, each loop equipped with a circulation pump and a steam generator. The criteria for choosing between all the cutting technologies available for dismantling a nuclear component are considered, as well as the methodology allowing the characterization of the primary system. Some cutting scenarios are proposed, with a calculation methodology to evaluate the amount of material involved in main components segmentation. Afterwards, exposition risks are highlighted and the possibility of safely cutting this system is pointed out.