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 48 <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> trialsNitrocisi<strong>on</strong>[Ref. 14, 15]This is a cryogenic dec<strong>on</strong>taminati<strong>on</strong> technique involving<strong>the</strong> applicati<strong>on</strong> <strong>of</strong> liquid nitrogen at high pressure <strong>and</strong>low temperature to dec<strong>on</strong>taminate <strong>the</strong> surface <strong>of</strong> items.The surface residues can be removed ei<strong>the</strong>r throughvibrati<strong>on</strong>, ultras<strong>on</strong>ic cleaning or <strong>the</strong> inclusi<strong>on</strong> <strong>of</strong>abrasive media in <strong>the</strong> liquid nitrogen.This technique produces minimal sec<strong>on</strong>dary wastes(i.e. <strong>on</strong>ly <strong>the</strong> actual surface material removed by <strong>the</strong>process, with evaporati<strong>on</strong> <strong>of</strong> <strong>the</strong> nitrogen <strong>and</strong> release toatmosphere).• Process is undergoingdevelopment for transfer into<strong>the</strong> nuclear industry – this maypresent challenges in terms <strong>of</strong>scale <strong>of</strong> use.• Health <strong>and</strong> safety risksassociated with <strong>the</strong> use <strong>of</strong>cryogenic materials.• Limited to use <strong>on</strong> surfacec<strong>on</strong>taminated items.• Inactive trials havebeen undertakenby Magnox Ltd.Techniquedem<strong>on</strong>strated toremove <strong>the</strong>protective coatingfrom skip surfaces<strong>and</strong> potential fordec<strong>on</strong>taminatingbase metal with <strong>the</strong>use <strong>of</strong> abrasive in<strong>the</strong> nitrogen streamdem<strong>on</strong>strated.A company owned by UK Nuclear Waste <strong>Management</strong> LtdNOT PROTECTIVELY MARKED
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