Production of Tritiated Organic Acids at Tritium-Bearing Stainless Steel Surfaces Exposed to Air

This presentation describes some experiments to investigate the reemission of tritium from stainless steel planchets that had been submitted to a reference cleaning procedure, exposed to elemental tritium under well defined conditions and stored under air in closed vessels for a long period of time (months). The nature of the evolved species was studied in short desorption experiments consisting of flowing an air stream at ambient temperature past one of the tritium-bearing planchets. It was shown that a substantial part of the reemitted activity was in the form of volatile tritiated organic acids. It seems that these products, accumulated on the planchet during the storage phase, are subsequently available for desorption and emission to the atmosphere when the planchet is swept by air. The possible origin of these tritiated organic acids is further discussed.