The main nuclear material routes are (Fig. 4.1):

• clearance from regulatory control, which assumes unrestricted disposal of waste and unrestricted reuse of useful materials;

• authorized release, which assumes authorized discharge of waste to the environment and authorized reuse of useful materials;

• regulated disposal of waste and regulated transfer of useful materials to other practices.

There is great diversity in the types and amounts of radioactive waste in different countries. Technologies for management of the waste are also diverse, although the main technological approaches are likely to be similar everywhere. Adequate processes and technologies can be identified based on detailed information about the current or forecast waste, e. g. waste clas­sification, categorization, properties and inventory.

The IAEA provided an internationally accepted waste classification system [7] which define the following classes according to the activity and half-lives of radionuclides in waste:

• exempt waste (EW);

• very short lived waste (VSLW);

• very low level waste (VLLW);

• low level waste (LLW);

• intermediate level waste (ILW);

• high level waste (HLW).

The IAEA classification is based primarily on long-term safety and there­fore is oriented on the selection of the most appropriate disposal routes (end-points) for solid or solidified waste.

Management of waste in different steps prior to disposal (e. g., pre­treatment, processing, storage) requires complementary information on the waste properties relevant to particular activities. Categorization of waste is used to provide a consistent approach to waste processing and storage. Categorization of waste has to include information such as origin, physical state, types, properties and process options [8, 9] .

118 Radioactive waste management and contaminated site clean-up