Abstract
There is no practical external source of tritium for fusion energy development beyond ITER and all subsequent fusion systems have to breed their own tritium. To ensure tritium self-sufficiency, the calculated achievable tritium breeding ratio (TBR) should be equal to or greater than the required TBR. The potential of achieving tritium self-sufficiency depends on many system physics and technology parameters. Interactive physics and technology R&D programs should be implemented to determine the potential of realizing those physics and technology options and parameters that have large effects on attaining a realistic “window” for tritium self-sufficiency. The ranges of plasma and technology conditions that need to be met, in order to ensure tritium self-sufficiency, are identified.