10 D.F. McGinnes

Table 2.2

Example of radionuclide limits for the Centre de la Manche repository in northern France (RWMAC, 1997)

Exempt waste (EW) is defined as Very Low Level Waste (VLLW): activity in 0.1 m3 <400 kBq ( 4 Bq/g) and less than 40 kBq per single item

Low Level (LLW): Wastes exceeding VLLW levels but <4000 Bq/g and <12,000 Bq/g

Intermediate (ILW): Wastes exceeding LLW levels but not heat-generating

High Level Waste (HLW): Heat-generating

Finally, it should be pointed out that, while wastes can be classified using a simple system as outlined above, repositories often have individual limits for specific radionuclides, which must also be respected. These limits are normally defined as part of the licensing of such facilities and form part of what can be termed as waste ‘‘acceptance criteria’’. Examples of nuclide limits for the French Centre de la Manche L/ILW-SL repository are given in Table 2.2.

To complete the picture, it is necessary to mention a further category of wastes that are more problematic to regulate due to the fact that they arise from non-nuclear industrial activities that involve the handling of raw materials such as rocks, soils and minerals containing naturally occurring radioactive materials. These raw materials are known by the acronym ‘‘NORM’’ (naturally occurring radioactive materials). Industrial activity can sometimes concentrate these materials and therefore enhance their natural radioactivity. This may result in:

A risk of radiation exposure to workers or the public.

Unacceptable radioactive contamination of the environment.

The need to comply with regulatory waste disposal requirements.

The regulation of these materials differs from country to country and has only relatively recently been identified as requiring some measure of control to ensure the correct level of environmental protection. However, despite this, these types of waste are currently not controlled in a manner consistent with wastes containing similar levels of radioactivity arising in the nuclear industry.

2.4. Origins of radioactive waste

Before they are treated, radioactive wastes look no different to other industrial wastes. As in other industries, the waste typically produced in nuclear reactors consists of