Enhanced tritium production in fusion-fission hybrids for the external consumption

While the future fusion power plants (FPP) will consume and breed tritium for their own use, an essential amounts of tritium will be needed additionally from external sources for the FPPs initial start-ups in the commissioning periods and after technical interruptions that result in plasma operation shutdowns and the following a year-scale recovery time. Up-to-date predictive estimates of the start-up T-inventories for a single FPP give the values comparable with the commercial tritium resources currently available in the world nuclear industry or even exceed those. The neutron rich fusion-fission hybrid reactors (FFHR) with subcritical blankets controlled by a fusion neutron source are generally considered as possible producers of several product types as nuclear fuel for fission systems, energy and neutrons for waste burning. In this study, the hybrids are regarded as multifunctional systems acting also as tritium breeders. Some intrinsic properties and distinctive features of such systems are noted with emphasis on the nuclear performance variation during the operation periods. It is shown that a tritium surplus of a few kilograms per year may be produced even in a FFHR with a modest ( 50-100 MW) fusion driven neutron source during 3-4 operation years. Such productivity exceeds essentially the tritium production rate of about 0.2 kg/year at a typical commercial CANDU heavy water nuclear reactor.