Characterization of Tritiated Hydrocarbon Species and Measurement of Their Concentrations in Air During Vacuum Pump Maintenance

When organic materials are exposed to elemental tritium, the hydrocarbons incorporate the tritium as a result of radiation induced reactions. The use of oil based vacuum pumps in tritium service gives rise to waste oil which contains, in addition to significant amounts of dissolved HT and HTO, a complex mixture of dissolved hydrocarbon species with a wide range of volatilities. The behaviour of these species in the human body is not as well understood, and consequently, reliable dosimetry models only exist for the two most common tritiated species, HT and HTO. A quantitative radio-gas chromatography technique was developed to analyse the head space above waste vacuum pump oils. The technique was then applied at the Darlington Tritium Removal Facility (TRF) to assess the tritium exposure to personnel changing the oil from one of the high tritium cold boxes.