The safety case for X-energy starts with the fuel: the TRISO-X pebble is the containment vessel designed not to melt. The uranium oxycarbide kernels are encased in carbon and ceramic layers and set within a graphite matrix, which the company claims will not melt under any foreseeable adverse conditions within the reactor. For this reason, the Department of Energy describes TRISO fuel as “the most robust nuclear fuel on earth.” Global energy demand is projected to grow by close to 50% from 2018 to 2050.