> that can be used without refining It has to first be separated from the rest of the actinide waste, which is very challenging, as they're chemically similar

> that can be used without refining It has to first be separated from the rest of the actinide waste, which is very challenging, as they're chemically similar elements. Previously this had to be done with a centrifuge (separating by mass), but a lot of research effort has gone into developing more practical chemical refining methods.