Reprocessing of spent fuel recovers re-usable uranium and the activation product plutonium for further energy production. Fission products and other activation products are separated out and melted together with additives to form a glass. The solidified glass blocks have to be disposed of as high-level waste.
Spent fuel not destined for reprocessing is also treated as high-level waste. It is held in interim storage for several decades and then emplaced in a deep geological repository.
A disposal container will hold two glass moulds from reprocessing. (Image: Nagra)