In the ThorCon system, no complex repairs nor fuelsalt processing are attempted at the plant. Up to 50 ThorCon plants are supported by a Centralized Recycling Facility (CRF). Normally, Cans are changed out every four years and the fuelsalt is reprocessed every eight years. When the Cans or fuelsalt need replacing, they are shipped to the CRF in a special purpose Canship. The problems of disassembly, decontamination and waste handling are shifted from the plant to this facility.
After a used Can has cooled in its silo for nearly four years, the Can can be safely lifted out of its silo, transferred to the Canship, and shipped to the CRF. The above view indicates how this is done. The silo hall bridge crane moves the used Can to the Out Can Pit in the Transfer Module, lifts the spare Can out of the In Pit, and places it in the vacated silo. There is a large hatch above each Can pit. A crawler crane transfers a replacement Can from the ship to the now empty In Pit, pulls the old Can from the Out Pit, and loads it on the Canship. This leapfrog process continues until all the Cans are replaced.
When we need to change out the fuelsalt due to the build up of fission products — which will happen on an eight year cycle – the old salt will remain in its Can for close to four years. During this period, the old fuelsalt is as well protected as the salt in the operating Can. There is no need for a separate, vulnerable spent-fuel cooling and storage system. By the time we pump the old fuelsalt to shipping casks at the control room end of the silo hall, its decay heat will be down to 80 kW, 0.25% of the original.
The fuelsalt going both ways will be unattractive weapons material. The uranium will be both fully denatured and, after the initial load, contain enough U-232 to further complicate a bombmaker’s life, while at the same time allow tracking of any diversion. The plutonium will contain sufficient Pu-238 to make even a fizzle weapon infeasible for all but the most advanced weapons states. This material will be significantly more anti-proliferation resistant than the MOX fuel which is currently being transported.
This system of regular replacement of the most critical components means that major upgrades can be accomplished without significantly disrupting power generation. And since the returned Cans are disassembled and fully inspected, incipient problems will be caught before they can turn into casualties.