ThorCon is a thorium converter. The initial fuel charge is largely thorium. During the eight year fuel cycle, a portion of the fertile thorium is converted to fissile U-233 which then becomes part of the fuel. Each ThorCon will require 5.3 kg of 19.7% enriched uranium and 9.0 kg of thorium per day, on average.

ThorCon clobbers coal on fuel cost. An extreme lower bound on coal fuel cost is 2 cents per kWh. Even at $90/kg U3O8, about double the current yellowcake spot price, ThorCon’s fuel cost is less than 0.6 cents per kWh.

Even on a once-through basis, ThorCon is uranium efficient. Averaged over 8 years, we annually feed 1,930 kg of 19.7% enriched uranium derived from 72,500 kg of natural mined uranium. This equates to 145 tonnes of natural uranium per full power GW-year compared to about 250 tonnes for a standard light water reactor (LWR).

After 8 years ThorCon will have been fed 3 tonnes of fissile U-235 fuel, but its “spent” fuel will still contain 1 tonne of fissile fuels U-233 (408 kg) and U-235 (624 kg). ThorCon’s net consumption of fissile uranium is less than half that of a LWR, due to higher thermal efficiency, removal of Xe-135, and U-233 production from thorium.

In the future, re-enriching this back to 19.7% would take about 48 SWU per kg U-235. At competitive enrichment costs of $50/SWU, $2400 for 1 kg of U-235 is cheap. Such future re-enrichment would cut ThorCon’s uranium requirements by a third.