Investigations of neutronics of some (D,T)-driven experimental thorium hybrid blankets with actinide multipliers

An experimental fusion-fission hybrid research facility, known as LOTUS and located at the Swiss Federal Institute of Technology (EPFL), is nearing completion. The first series of experiments are likely to commence in early 1984. A whole series of neutronic investigations are already underway to assess the feasibility of experimentally testing various blanket concepts. The following analysis centers around the use of actinide wastes as multiplier for blankets with thorium oxide fuel. The multipliers considered are UO₂, AmO₂, and CmO₂. The limited size of the experimental cavity coupled with the bulky, sealed 14 MeV (D, T)-neutron generator recommends the setting up of blankets in slab geometry. The analysis encompasses the corresponding confinement geometry configurations also for the sake of perspective. It is found that the neutronic performance of thorium oxide hybrid blankets improves radically both from the standpoint of fissile fuel production and energy multiplication in the presence of transplutonium actinides. It is also reported that the specific activities of tritium and²³³Pa are adequate for good counting statistics.