Strategic Guidance on the Management of LLW and ILW / LLW ...

LLW Repository LtdNational Waste ProgrammeNWP/REP/011Issue 2.1 – Jan 2013Page 30 of 585.2.6. Mechanical Surface Decontamination (Spongejet) [Ref. 5, 14, 15]UsageLLWILW/LLWSurface contaminatedVolumetricallycontaminatedActivatedAluminiumCopperMild steelMild steel (coated)Stainless steelStainless steel (coated)Description of techniqueSpongejet is a mechanical surface decontamination technique which uses a shot abrasive enclosed withinsponge media. The material is jetted at high speed against the surface of the contaminated item, uponwhich impact the sponge structure flattens to expose the abrasive. Upon leaving the surface of the item, thesponge media expands and creates a vacuum that entraps the contamination (which would have otherwisebecome airborne). The media can be recycled typically up to ten times. The process is typically operatedremotely, within a containment shield, to provide protection to operators. The secondary waste produced bythe process is a dry solid waste - the spent spongejet media.Outcomes Advantages Disadvantages• For LLW:o Waste metal decontaminated to EPRout-of-scope status; oro Waste metal decontaminated to enablefor further processing.o Secondary wastes – radiologicallycontaminated spent blast media.• For ILW / LLW:o Waste metal decontaminated to LLWstatus to enable further processing ordisposal.o Secondary wastes – radiologicallycontaminated spent blast media.Technique used at:• Applicable to widerange of metal types.• Applicable to wideactivity range.• Reduces volume ofcontaminated wasterequiring disposal.• Produces secondarywaste which is easy toretrieve, handle andmanage.• Not useful forvolumetricallycontaminated oractivated metals(unless as precursorstep for onwardtransfer).• Manual process.A company owned by UK Nuclear Waste Management LtdNOT PROTECTIVELY MARKED