1 TW4-TSW-001/D1c: Watching brief activities in the field of radioactive waste management: Detritiation K. Dylst, J. Braet, A. Bruggeman SCKCEN Final meeting of contracts TW3 and TW4 17 Jan 2006 EFDA CSU, Garching

2  The Objective: Is to give a general overview of the research on this waste. This research can be an introductory step in a long term research program.  The Approach: A science based literature study focussed on:  on-going decommissioning activities in fission industry;  activities that can be applicable for future fusion reactors. The focus is on tritium waste generated during decommissioning and dismantling of a future fusion facility.

3 Operation and dismantling of fusion reactors is not possible without the production of tritiated waste. Current international adopted strategy for tritiated waste:  Inventory of different types of tritiated waste to be expected: during operation; during commissioning.  In most cases more or less easy transformation to tritiated water.  Conversion to tritiated water followed by water detritiation to obtain concentrated tritiated water.  Possibly tritium could be recuperated by, for example, cryogenic distillation.

4  Waste from consumables, solids  Soft Housekeeping Materials  Tritium storage beds  Molecular sieves  Waste from consumables, liquids  Tritiated water possibly chemically polluted  Organic solvents  Oils and liquid scintillation cocktails  Plasma facing components  In Situ detritiation  Ex Situ detritiation A lot of research has been done in European and international labs.

5  Metals  Modelling steel detritiation by melting and gas bubbling  Bulk detritiation of steel by heat treatment  Surface detritiation of metals using liquids  Surface detritiation of metals using gases  Concrete  Detritiation of concrete using superheated steam A lot of research has been done in European and international labs. (cont.)

6 Some detritiation techniques are ready for industrialisation. Water detritiation. A water detritiation system concept for JET has been developed and is ready to be build.  Oxidative detritiation of Personal Protective Equipment.  This system is currently in use at Princeton.  Mineralization of tritiated organic liquids.  This system was demonstrated at a pilot plant scale. These techniques have been proven to work at a pilot plant scale.

7 For other techniques the working principle is proven; but require further improvement.  Detritiation of plasma facing components.  Different hi-tech techniques like flash lights, laser ablation, plasma torch, HF heating have been proven to work. But the treatment speed needs to be increased and the techniques should be made in vessel compatible.  Concrete detritiation with superheated steam.  Detritiation of small concrete samples with superheated steam gives good results. Practical implementation needs to be worked out.  Detritiation of molecular sieves.  Regeneration molecular sieves can be a basis for detritiation. A new research program to improve the technology has been initiated (EFDA JW5-FT-2.25).

8 There are still challenges.  Detritiation of metals (other than stainless steel)  Detritiation of stainless steel seems well advanced, but there seems a lack of research for other metals.  Sufficient detritiation of getter materials for final disposal.  A strategy has been developed to ensure large detritiation ‘in- situ’ but not enough for final disposal. Extra research on additional and more aggressive methods in combination with pilot plant demonstration is recommended.