In this work, the concentration of tritium in D2O of various degrees of purity was measured. Samples were taken from the Arak heavy water plant and tritium concentrations were determined using a liquid scintillation detector (LSC) based on tritium decay. In this work, instead of simple distillation, is used the azeotropic distillation method. Absorption and fluorescence spectra were recorded using a Shimadzu UV-2100 spectrometer and an LS50B fluorescence spectrometer. The tritium concentration in the samples varied from 1.75 ± 0.80 to 6.16 ± 1.01 Bq/l in D2O enrichment from 0.35% to 77.50%. The correlation coefficient between tritium concentration and D2O purity in heavy water was obtained as R2 = 0.853. Deviation for 99.8% D2O enriched in heavy water. This was observed from a straight line, leading to a drop in R2. The results of this measurement showed that the tritium concentration did not exceed the value set by the Nuclear Regulatory Commission (NRC).
