Feasibility of a multi-purpose demonstration neutron source based on a compact superconducting spherical tokamak

Tokamak neutron sources would allow near term applications of fusion such as fusion–fission hybrid reactors, elimination of nuclear wastes, production of radio-isotopes for nuclear medicine, material testing and tritium production. The generation of neutrons with fusion plasmas does not require energetic efficiency; thus, nowadays tokamak technologies would be sufficient for such purposes. This paper presents some key technical details of a compact (∼1.8m3 of plasma) superconducting spherical tokamak neutron source (STNS), which aims to demonstrate the capabilities of such a device for the different possible applications already mentioned. The T-11 transport model was implemented in ASTRA for 1.5D simulations of heat and particle transport in the STNS core plasma. According to the model predictions, total neutron production rates of the order of ∼1015s−1 and ∼1013s−1 can be achieved with deuterium/tritium and deuterium/deuterium respectively, with 9MW of heating power, 1.4T of toroidal magnetic field and 1.5MA of plasma current. Engineering estimates indicate that such scenario could be maintained during ∼20s and repeated every ∼5min. The viability of most of tokamak neutron source applications could be demonstrated with a few of these cycles and around ∼100 cycles would be required in the worst cases.