*3.3.2. Compaction*

simple, known, and cost effective if the valuable solvent is recycled or reused. The active

Solid wastes are produced by all applications and uses of radioactive materials, in normal operations and maintenance activities. Solid, low and intermediate level wastes are generally

Treatments for solid waste are used to reduce the waste volume and/or convert the waste into a form suitable for handling, storage and disposal (IAEA, 2001 and 2002; Chang, 2001; Adenot

Decontamination is defined as the removal of contamination from areas or surfaces of facilities or equipment by washing, heating, chemical or electrochemical action, mechanical cleaning or by other means. The decontamination objectives are mainly: to reduce the volume of equip‐ ment and materials requiring storage and disposal in licensed disposal facilities, to remove contamination from components or systems, to reduce dose levels in the installations and to restore sites and facilities to an unconditional-use condition. Decontamination processes may

**• Chemical decontamination.** In the chemical decontamination are used concentrated or dilute chemical reagents in contact with the contaminated item, to dissolve the contamina‐

**• Decontamination by melting** presents the particular advantage of homogenising a number of radionuclides in the ingots and concentrating other radionuclides in the slag and filter dust resulting from the melting process, thus decontaminating the primary material. The problem with inaccessible surfaces or complex geometries is eliminated and the remaining

**• Mechanical and manual decontamination** included wet or dry abrasive blasting, grinding of surfaces and removal of concrete by spalling or scarifying, washing, swabbing, foaming agents, and latex-peelable coatings. These techniques are most applicable to the decontami‐ nation of structural surfaces which may be cleaned by sweeping, wiping, scrubbing or

A wet abrasive-blasting system uses a combination of water, abrasive media and compressed air, and is normally applied in 24 a self-contained, leaktight, stainless steel enclosure. The dry abrasive-blasting technique, commonly called sandblasting or abrasive jetting, uses abrasive materials suspended in a medium that is projected onto the surface being treated, resulting in a uniform removal of surface contamination. The scarification process removes the top layers

of a contaminated surface down to the depth of the sound, uncontaminated surface.

tion layer, covering the base metal and eventually a part of the base metal.

radioactivity content is homogenised over the total mass of the ingot.

removed by grit blasting, scarifying, drilling and spalling.

residue could be either immobilized or destroyed by incineration (IAEA, 2001).

segregated into combustible, compactible and non-compactible forms.

divide into chemical, electrochemical and mechanical processes:

**3.3. Treatment of solid waste**

406 Environmental Risk Assessment of Soil Contamination

et al, 2005; NEA, 1999).

*3.3.1. Decontamination*

Compaction is performed in order to reduce the waste volume and concentrates the radionu‐ clides. Plastics, paper, absorbent material, and cloth are compatible in conventional compac‐ tors. Metal pipe, valves, conduit, wood, and other like items are compatible in super compactors. Compactors can range from low-force compaction systems (~5 tons or more) through to presses with a compaction force over 1000 tons (super compactors). Volume reduction factors are typically between 3 and 10, depending on the waste material being treated (IAEA, 2001 and 2002).

#### *3.3.3. Cutting*

Cutting and sawing operations are carried out mainly on large items which consist usually of metals or plastics. This waste has to be reduced in size to make it fit into packaging containers or to submit it to treatment such as incineration. The cutting is carried out either in the dry state in cells, using remote control when necessary and with conventional tools, or underwater. The cutting may also be done with plasma-jets, laser torches, or explosive fuses.

#### *3.3.4. Crushing*

Crushing techniques may be used for size reduction of friable solids (glass, concrete, ceramics). In principle, all types of mill, grinder, and crushing machines of conventional technology can be used.
