Purpose: To evaluate the ratio of tritium oxide and tritium organic compounds in the environment and in the body in order to justify the graded approach when calculating the dose for the personnel working in the presence of tritium and its compounds in the air of the working area.
Material and methods: The study covered the forms of tritium (HTO and OBT) in water, air and bodies of the personnel working under conditions of the presence of tritium and its compounds in the air of the working area. Samples of water, air and biological assays (urine) of the personnel were collected for the study. Sample preparation of the collected material was carried out according to the approved methods certified by the Federal State Unitary Enterprise “VNIIFTRI”. The liquid scintillation alpha-beta spectrometer Tri-Carb 3180TR/SL was used when estimating tritium concentrations in the preformed samples.
Results: It has been established that in the environment (water and air) and under the industrial conditions (air of the working area), tritium is to a greater extent in the form of OBT, which determines its predominant intake into the body of the personnel in the form of OBT. The ratio of tritium forms in biological fluids (urine) of the personnel was estimated using three methods. It was shown that OBT in the body of the personnel accounted for 70 to 90 %. These data indicate that OBT in the body of the personnel accounts for a larger share in comparison with HTO, therefore, the dose assessments of the personnel when working with tritium and its compounds should be revised.
Conclusion: Taking into account the developed methods for the separation of tritium oxide and its organic forms, the assessment of the dose induced by tritium exposure should be performed gradually, taking into account the ratio of these forms in the body of the particular worker.
