This drawing shows a plan view of the Pot. The Pot is a stainless steel (SUS316) cylindrical vessel with ellipsoidal heads. The reactor core comprises 84 vertical, hexagonal logs surrounding a central hexagon which contains the control rods. The logs are made up of graphite slabs. Fuelsalt flows upward through the slots between these slabs. The logs are the moderator which must be replaced every four years.
The core is encircled by a radial reflector. The radial reflector consists of 36 graphite wedges. Each pair of wedges is connected on their outer periphery by a shield segment. The shield segments, outlined in blue, contain pockets filled with boron carbide powder. This shield reduces the neutron flux at the wall by about a factor of 100. This means we can be confident that we will be able to recycle the Pot vessel many times. However, in our costing, we assume the entire Can is replaced every four years.
Everything fits together like a 3-D jigsaw puzzle. This makes the Pot easy to assemble and disassemble. More importantly, it allows each log to expand and contract independently. This is required to allow the logs to respond both to differences in temperature and differences in neutron flux.
Both MCNP and Serpent models of ThorCon have been created to calculate the neutron energy spectra and flux distribution through time. Both are full 3-D models of the entire Can silo. These models have been used to determine the design’s initial fuel requirements, stability, control rod worth, moderator and reflector life, fuel addition schedule, build up of fission products and trifluorides, production of U-233 through time, and the decay heat curves. According to both models, the baseline ThorCon operating on nabe and denatured uranium meets all our requirements. The models also show that ThorCon can operate on a wide range of fuels including reactor grade plutonium.