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Low Level Waste (LLW) is radioactive waste or material that is contaminated by radioactivity through its use. Simple examples would include paper, plastic and protective clothing and when facilities cease operating may also include building rubble, soil and steel items such as pipework and storage vessels. Estimates of the volumes of LLW that will need to be managed between 2014 and 2029 have been generated using national inventory data for the nuclear industry. These estimate around 1.1 million m3 of LLW will need to be managed over this period, a proportion of which will be waste steel.

Given that LLW steel may typically only be contaminated to a surface layer of less than 100 microns, processes that can facilitate economic re-use rather than disposal of this waste steel, will therefore become increasingly attractive to waste owners or operators of disposal facilities.

The EASD process

The application of an electric current to steel, whilst in contact with a variety of cleansing acids to remove surface oxides or other contaminants is well established in the elds of electropickling and electropolishing.

However research work carried out by C-Tech Innovation has shown very significant improvements in process times, compared with acid descaling or DC electrolytic processes. In addition considerable reduction in required acid strengths was possible using EASD. These improvements could signal a major opportunity for the more rapid re-purposing of LLW steel waste resources.

EASD descaling chart

Descaling of oxidised stainless steel strip

EASD key features

  • Rapid scale/surface decontamination removal
  • High rate dissolution of the underlying clean metal if required, to prevent ‘sweating’ back of the contamination

Comparison of descaling times

CastingEASDMixed Acid
Austenitic 3045 to 10 min2 to 12 hours
Austenitic 31610 to 20 min10 to 30 hours
Duplex20 to 30 min24 to 48 hours
Stainless steel after EASD process

Stainless steel after EASD treatment

Electrochemistry group leader John Collins

John Collins

Principal Engineer, Electrochemistry

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