Lesson 6 6.10 Decontamination Techniques

Chemical decontamination is generally most effective on metallic and non-porous surfaces. The choice of chemical agents depends on the chemical nature of the contamination, the extent of contamination, the type of surface and the volume of likely secondary waste arisings.

Chemical AgentApplicationNotes
Nitric acidStainless steel, InconelStrong mineral acid; effective on oxide layers
Sulphuric acidCarbon steel, stainless steelDissolves surface contamination
Acid saltsGeneral metal surfacesMilder than pure acids
Organic acids (e.g. citric, oxalic)Metal and plastic surfacesLower secondary waste production
Bases and alkaline saltsCarbon steelEffective on specific contaminant types
Organic solventsMetal, plastic, concreteDissolves organic contaminants
Complexing agents (e.g. EDTA)MetalsChelates metal ions for removal
Multiphase treatment (LOMI, MODIX)Carbon steel, stainless steel, Inconel, ZircaloyLOMI = Low Oxidation-state Metal Ion process; uses V(II) to reduce Cr(III) oxides; highly effective on reactor circuits
Foam decontaminationPorous and non-porous surfacesChemical foam applied to surfaces; reduced liquid waste volumes
Chemical gelsPorous and non-porous surfacesGel applied, contaminants absorbed, gel removed