What becomes of spent fuel?
This diagram shows the route taken by irradiated fuel assemblies depending on whether or not they are reprocessed. At the top (the non-reprocessing option), no better solution has yet been found than the first stage, storage in a pool, pending a decision being made about final disposal or reprocessing at a later date using more advanced methods. In the case of reprocessing, the uranium and plutonium (destined for recycling) are separated from a highly radioactive residue. This residue, the final waste, is vitrified for disposal but decisions about the disposal method are also yet to be made.