KBS-3 (an abbreviation of kärnbränslesäkerhet, nuclear fuel safety) is a technology for disposal of high-level radioactive waste developed in Sweden by Svensk Kärnbränslehantering AB by appointment from Statens Strålskyddsinstitut (the radiation protection agency).
- The waste is first stored in intermediate storage for 30 years.
- The waste is encapsulated in iron.
- The iron capsule is encapsulated in copper.
- The capsule is deposited in a layer of bentonite clay, in a circular hole, 8 meters deep and with a diameter of 2 meters, drilled in a cave 500 metres down into primary rock.
- After the storage facility is full, the drill hole is sealed and the site marked.
- After 100.000 years of storage, the radioactivity level of the waste is at the same level as that of uranium ore.
If the holes into the rock from the cave are drilled vertically, the method is called KBS-3V and if they are drilled horizontally it is called KBS-3H. The only method used so far is KBS-3V.