The six classes of IAEA GSG-1, ordered by what disposal they require.
IAEA GSG-1 defines exempt waste, very short lived waste, very low level waste, low level waste, intermediate level waste, and high level waste. The classes are defined by the disposal they require, not by a single activity number.
Spent nuclear fuel is not itself a class. Where it is declared waste rather than a resource, it is managed as high level waste.
| Class | Korean | Disposal |
|---|---|---|
| Exempt waste (EW) | 규제면제폐기물 | Outside regulatory control |
| Very short lived waste (VSLW) | 극단수명폐기물 | Decay storage, then clearance |
| Very low level waste (VLLW) | 극저준위폐기물 | Landfill-type disposal |
| Low level waste (LLW) | 저준위폐기물 | Near-surface disposal |
| Intermediate level waste (ILW) | 중준위폐기물 | Greater depth than near-surface |
| High level waste (HLW) | 고준위폐기물 | Geological disposal |