Recent developments in environmental aspects of D-~3He fuelled fusion devices

摘要

The stress on fusion safety has stimulated worldwide research in the late 1980s for fuel cycles other than D-T. With advanced cycles, such as D-D, D-~3He, p-~(11)B, and~3He-~3He, it is not necessary to breed and fuel large amounts of tritium. The D-~3He fuel cycle in particular is not completely aneutronic due to the side D-D reactions. Neutron wall loadings, however, can be kept low (by orders of magnitude) compared to D-T fuelled plants with the same output power, eliminating the need for replacing the first wall and shielding components during the entire plant lifetime. Other attractive safety characteristics include low activity and decay heat levels, low-level waste, and low releasable radioactive inventory from credible accidents. There is a growing international effort to alleviate the environmental impact of fusion and to support the most recent trend in radwaste management that suggests replacing the geological disposal option with more environmentally attractive scenarios, such as recycling and clearance. We took the initiative to apply these approaches to existing D-~3He conceptual designs: the ARIES-III power plant and the Candor experiment. Furthermore, a comparison between the radiological aspect of the D-~3He and D-T fuel cycles was assessed and showed notable differences. This report documents the comparative assessment and supports the safety argument in favour of the D-~3He fuel cycle.