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

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LLW Repository LtdNational Waste ProgrammeNWP/REP/011Issue 2.1 – Jan 2013Page 42 of 585.3. Technology summaries - pond furniture management R&DThis section provides a brief summary of the technologies that have been or are currentlybeing investigated by NDA estate SLCs in R&D programmes.A significant effort has been expended on research and development into wastemanagement approaches for pond furniture and other contaminated metals, particularlywith respect to decontamination techniques. Table 12 provides an overview of the keyresearch and development (both historical and current) pertinent to pond furniture. Thisoverview includes:• A brief description of the technique.• Identification of the key limitations and constraints in the use of the technique.• Identification of any trials undertaken by SLCs into the use of the technique.Any pertinent case study examples of this R&D – either on pond furniture or analogouswastes – are also provided to illustrate the purpose of the R&D and the outcome of thestudy.5.4. Other pond furniture waste management approachesA wide range of additional waste management practices have been developed within andoutwith the NDA estate for the management of waste metals, which may have synergiesor applicability to the challenges posed by pond furniture. As these waste managementapproaches are not in routine usage by SLCs, nor are the subject of specific R&D formanagement of pond furniture, detailed information on these techniques is not provided inthis document.Such techniques include:• Chemical decontamination – bases and alkaline salts• Chemical decontamination – bleaching• Chemical decontamination – organic solvents• Electrochemical decontamination – electropolishing / electrodeplating• Physical decontamination – dry ice crystal blasting• Physical decontamination – ice crystal blasting• Physical decontamination – laser ablation• Physical decontamination – scarifying, scabbling and planing• Physical decontamination – steam cleaning• Physical decontamination – thermal degradation• Physical decontamination – ultrasonic cleaningFurther detailed information about these waste management approaches is available onthe Environment Agencies Requirements Working Group (EARWG) website [Ref. 14].A company owned by UK Nuclear Waste Management LtdNOT PROTECTIVELY MARKED
LLW Repository LtdNational Waste ProgrammeNWP/REP/011Issue 2.1 – Jan 2013Page 43 of 58Table 12 – Summary of historic and current R&D into pond furniture managementTechnique Description Limitations and constraints Trials of process Outcome of trialsChemicaldecontamination (foam)[Ref. 14, 15]Foam decontamination is a chemical technique used toremove loose surface contamination and grease fromitems. The foam is a micro-dispersion of air and gas,which typically contains acids (either inorganic ororganic) and surfactants. Foams can be pumped orsprayed onto surfaces, and is suitable for either manualor remote deployment.The technique has the advantages of being relativelycheap, simple, with low residual levels of contaminationand is suitable for use on items with complexgeometries.• Only applicable to surfacecontaminated wastes.• Best suited to non-poroussurfaces (i.e. less useful forrusted surfaces).• Generates radiologicallycontaminated liquid secondarywastes.• Problems may be encounteredkeeping foam in-situ on verticalsurfaces; this can be overcomeby the use of organic additivesbut these may make secondarywaste disposal more complex.• Decontamination ofpond skips andpipelinesassociated withcooling pondsystems withchemical foam atSellafield (SellafieldLtd.).Foamdecontaminationdemonstrated to betechnically feasibleand to deliverappropriate level ofdecontamination ofpond skips andpipework.Foamdecontamination hasseen some routineuse for non-pondfurniture wastes(e.g. transportflasks).A company owned by UK Nuclear Waste Management Ltd• Technique potentially poseschemical hazards – e.g.corrosivity, toxicity and adversechemical reactivity.NOT PROTECTIVELY MARKED
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