Strategic Guidance on the Management of LLW and ILW / LLW ...
Strategic Guidance on the Management of LLW and ILW / LLW ...
Strategic Guidance on the Management of LLW and ILW / LLW ...
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<strong>LLW</strong> Repository LtdNati<strong>on</strong>al Waste ProgrammeNWP/REP/011Issue 2.1 – Jan 2013Page 47 <strong>of</strong> 58Technique Descripti<strong>on</strong> Limitati<strong>on</strong>s <strong>and</strong> c<strong>on</strong>straints Trials <strong>of</strong> process Outcome <strong>of</strong> trialsMetal milling[Ref. 14, 15]Rotary grinders <strong>and</strong> milling machines are used toremove thin layers <strong>of</strong> <strong>the</strong> item surface in order toremove surface c<strong>on</strong>taminati<strong>on</strong>. The sec<strong>on</strong>dary wastearisings are <strong>the</strong> solid metal shavings, which are easilyretrieved. There is some potential for liquid sec<strong>on</strong>darywastes from lubricati<strong>on</strong> <strong>of</strong> <strong>the</strong> milling machine.Milling can be deployed remotely, reducing operatordose, using computer numeric c<strong>on</strong>trol (CNC) millingmachines. They operate in a dry envir<strong>on</strong>ment, avoiding<strong>the</strong> creati<strong>on</strong> <strong>of</strong> wet sec<strong>on</strong>dary waste, <strong>and</strong> <strong>of</strong>ten have anenclosure to minimise <strong>the</strong> spread <strong>of</strong> c<strong>on</strong>taminati<strong>on</strong>.• May be time-c<strong>on</strong>suming,especially when changingbetween c<strong>on</strong>figurati<strong>on</strong>s fordifferent geometries <strong>of</strong> items.• May leave some residualsurface c<strong>on</strong>taminati<strong>on</strong>(depending <strong>on</strong> technique).• Potential for generati<strong>on</strong> <strong>of</strong>pyrophoric dust producti<strong>on</strong> ifused <strong>on</strong> aluminium.• Trial undertaken atBradwell during2012 to test <strong>the</strong>viability <strong>of</strong> millingas adec<strong>on</strong>taminati<strong>on</strong>technique forc<strong>on</strong>taminated metal(particularly skips).Milling proved to besuccessful in <strong>the</strong>removal <strong>of</strong> surfacec<strong>on</strong>taminati<strong>on</strong> <strong>and</strong> asmall surface layer<strong>of</strong> metal.Larger scale activetrials <strong>of</strong> <strong>the</strong>technology are to beundertaken atHinkley Point A <strong>and</strong>Chapelcross in <strong>the</strong>near future.A company owned by UK Nuclear Waste <strong>Management</strong> LtdNOT PROTECTIVELY MARKED
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