All nuclear reactors run on fuel containing uranium and other isotopes, but filling a nuclear reactor is much more complicated than driving up to them with a dump truck filled with uranium ore and filling up. Although nuclear fission is simple enough that it can happen without human intervention, as happened for example at Oklo’s natural fission reactors, within a commercial reactor the goal is to create a nuclear chain reaction that targets a high burnout rate (fission rate), with a as constant as possible release of energy.
Each different fission reactor design makes a number of assumptions about the fuel rods inserted into it. These assumptions may concern the enrichment ratio of the fissionable isotopes such as U-235, the density of individual fuel pellets, the distance between the fuel rods containing these pellets, the configuration of said fuel rods together with any control, moderator and other elements. and so on.
Today’s light water reactors, heavy water reactors, fast neutron reactors, high-temperature reactors and relatives all have their own fuel preferences as a result, with high-analysis lava-enriched (HALEU) fuel being the new hot thing for new reactor designs. Let’s take a look at what goes into these fuel recipes.
Continue reading “The Intricacies of Making Nuclear Reactor Fuel”