There’s a layer of material between the fission fuel and the superconductors, same as the inside of a nuclear reactor. It has to withstand not just fission frag

There’s a layer of material between the fission fuel and the superconductors, same as the inside of a nuclear reactor. It has to withstand not just fission fragments, but also the infrared from the rather hot fuel pellets in the core. An earlier paper (<https://www.frontiersin.org/articles/10.3389/frspt.2023.1197347/full https://www.frontiersin.org/articles/10.3389/frspt.2023.1197...>) estimates that for a ship designed to go to Mars and back it would have to withstand 20MW/m² just from that alone.