The principal aims are to:

minimise the volumes of waste requiring management via optimised treatment processes

reduce the potential hazard of the waste by conditioning it into a stable solid form that immobilises it and provides containment, to ensure that the waste can be safely handled during transportation, storage and final disposal.

It should also be noted that the choice of process(es) used is dependent on the level of activity and the type (classification) of waste. Each country’s radwaste management policy and its national regulations also influence the approach taken.

2.5.1. Treatment

A principal objective of radioactive waste management is to ensure that the production of waste from nuclear fuel cycle activities is minimised. However, it is important to note that, while the volume of waste may be reduced, the amount of radioactivity remains the same, i.e., the radioactivity of the waste will become more concentrated as the volume is reduced. Examples of treatment processes that are currently used on a commercial basis include:

2.5.1.1. Compaction

Compaction is a well developed and reliable volume reduction technology that is used for processing mainly solid L/ILW-SL. Various types of compactors are used within the nuclear industry, ranging from small, low-force compactors ( 5 Mg) to supercompactors ( 1000 Mg). Volume reduction factors of between 3 and 10 are achievable depending on the waste material being treated.

With regard to compaction of ILW, this was, until recently, generally used for laboratory scale operations. The introduction in 2001 of commercial scale super-compaction of SF structural materials at the French reprocessing facility at La Hague is the first of its kind and is operating successfully.

2.5.1.2. Incineration

Incineration technology is generally employed to reduce the volume of low-level combustible wastes. This can be used to treat both liquid and solid wastes such as wood, paper, clothing, rubber and some organic wastes. Most incineration processes are adaptations of traditional, non-radioactive, industrial techniques, which produce a radioactive ash that is then conditioned by cementation. Typically, volume reduction factors of up to around 100 are achieved, depending on the density of the waste.

Alternative techniques such as plasma incineration (Fig. 2.13) have recently been introduced on a commercial scale in Switzerland (e.g., at the ZWILAG interim storage facility (www.zwilag.ch)) and, to date, in a pilot facility at INER in the ROC (www.iner.gov.tw). This process permits the treatment of mixtures of combustible and non-combustible wastes and, with the addition of glass-forming materials, results in a homogeneous waste form consisting of either metal or glass.