ARC reactor: A preliminary tritium environmental impact study

Abstract

The fusion pilot power plant ARC is a conceptual design of a D–T Tokamak under investigation at the Massachusetts Institute of Technology. Special attention is paid on the radiological hazard, which until now has been translated in the reduction of materials activation. Indeed, one of ARC main goals is to be fast deployable in any US site: thus, the radiological risk associated to its presence must be minimized, both for the population and the environment. Tritium is one of the main sources of radiological hazard in ARC and it is almost ubiquitous: it is found in the vacuum chamber, in the blanket, in structural materials and in tritium processing and storing components. In this work, a safety analysis is proposed to quantify the radioactivity release following an accidental scenario. Tritium inventories in the main components are estimated starting from the preliminary design of the FLiBe circuit. The source term is quantified assuming the occurrence of a severe accident damaging key components. Afterward, the environmental impact and the doses to the most exposed individuals are evaluated through suitable population doses codes, and ARC compliance with safety limits is assessed.