Gamma activity analysis of RB reactor heavy water

The RB experimental nuclear reactor still works with heavy water obtained in 1959 in from USSR. Since then gamma activity of heavy water was periodically controlled. In this experiment, measurements were carried out with two samples: D2O taken from RB reactor and the D2O which was never used in reactor. Two germanium spectrometers were used as detectors. Data evaluation were done manually and with several computer codes. Results of the experiment show that gamma activity D2O of RB reactor is on the level of background in Vinca Institute, without contamination with fission products. (author)