Decontamination and modification of liquid scintillators

A new technique for decontaminating and recyling used liquid scintillator (LS) is discussed. A modification of hydrophobic scintillator for use with aqueous samples is also described. Both aliphatic and aromatic based LS (Dioxane and Tritol) are effectively decontaminated by extraction with NaOH. A single extraction gives a decontamination factor (DF) of about 90%. Thus 3-4 such extractions decontaminate the LS to background level. Toluene scintillator is unsuitable for aqueous samples because it does not hold water. However, it can be solubilised by alcohol. This LS is decontaminated by separating two phases with excess of water. Recovered LS after proper dilutions gives about 96% efficiency with respect to fresh LS. In all the systems studied generation of active waste ranges from 12-47% depending upon the activity present in the sample. (H.K.)