A fissile isotope can readily undergo fission reaction, and a fertile isotope can be converted into a fertile isotope via neutron capture (this is how plutonium is made for nuclear bombs). Neutron capture is not part of the main waste reprocessing method [1], the neutron capture already happened in the reactor. Reprocessing separates the plutonium and other byproducts from the remaining uranium 235 fuel before the latter is re-used, no fertile material is being converted to fissile material.
So now I ask you: what relevance, at all, does the distinction between fissile and fertile material have with respect to magic_hamster's claims about the feasibility of waste reprocessing? That commenter claimed reprocessing was not feasible, I responded with dozens of examples of reprocessing being carried out. What does fertile vs. fissile have to do with this?