Radioactive waste is divided into high-level radioactive waste and low-level radioactive waste. The difference is not level of radioactivity but also the way of disposal. Also, low-level radioactive waste is divided into many types by radioactivities and sources. A part of Near-surface disposal has been already carried out at Rokkasho-mura in Aomori prefecture.
○ Low-level radioactive waste
Some of the low-level radioactive waste will be geological disposal of high-level radioactive waste
○ High-level radioactive material
High-level radioactive waste arise from reprocessing of spent fuel. High-level radioactive waste is encapsulated in a thick steel container called overpack and emplaced in the disposal facility underground. This operation needs 100 years at least. Since overpacks have much generate heat, they are emplaced with enough space each other. On the other hand, TRU waste is stored in the large cavern. Because it has low heat generation.
Source : https://www.ene100.jp/map_8_en