2.8. The following waste types are considered in this Safety Guide4 :@@4) Very short lived waste and exempt waste are not considered further in this Safety Guide because they do not require specialized radioactive waste disposal facilities. @@- Very low level waste (VLLW): VLLW arises from the operation and decommissioning of nuclear facilities, from the mining or processing of ores and minerals, and from research, medical and educational applications of radioactive substances. VLLW has activity concentrations above the levels for the clearance of material from regulatory control. Some radiation protection provisions are required for safe management of VLLW, but these provisions are very limited in comparison to those required for radioactive waste with higher activity concentrations described in the classes below.@@- Low level waste (LLW): LLW is suitable for near surface disposal, and includes a very wide range of radioactive waste, from radioactive waste just above levels for VLLW, to radioactive waste with levels of activity that require shielding and containment and isolation for periods of up to several hundred years. Low concentrations of long lived radionuclides may be present in LLW, but the acceptable concentrations are limited by the time period over which near surface disposal can ensure the isolation of the waste and, in particular, can sufficiently reduce the likelihood of inadvertent human intrusion into the facility through institutional control.@@- Intermediate level waste (ILW): ILW contains long lived radionuclides in quantities that need greater (i.e. longer) containment and isolation from the biosphere than can be provided by near surface disposal. The boundary between LLW and ILW cannot be specified in terms of a particular level of activity concentration because allowable levels will depend on the actual waste disposal facility.@@- High level waste (HLW): HLW contains higher concentrations of radionuclides than ILW and generates significant quantities of heat from radioactive decay. Owing to the high concentrations of long lived radionuclides, significant heat generation may last for several centuries. HLW may include spent nuclear fuel where this has been declared as waste, vitrified waste from the processing of spent nuclear fuel, and any other waste requiring a comparable degree of containment and isolation.