The measurement test of uranium in a uranium-contaminated waste by passive gamma-rays measurement method

Sukegawa, Yasuhiro*; Suzuki, Satoshi*; Yoshida, Michihiro ; Oki, Koichi; not registered

This report is completed about the measurement test and the proofreading of passive -rays measurement method for Non-destructive assay of uranium in a uranium-contaminated waste. The following are the results of the test. (1)The estimation of the amount of uranium by ionization survey meter is difficult for low intensity of -rays emitted from uranium under about 50g. (2)The estimation of the amount of uranium in the waste by NaI detector is possible in case of only uranium, but the estimation from mixed spectrums with transmission source (60-cobalt) is difficult to confirm target peaks. (3)If daughter nuclides of uranium and thorium chain of uranium ore exist, measurement by NaI detector is affected by -rays from the daughter nuclides seriously. As a result, the estimation of the amount of uranium is difficult. (4)The measurement of uranium in a uranium-contaminated waste by germanium detector is possible to estimate of uranium and other nuclides. (5)As to estimation of the amount of uranium, energy at 1,001keV emitted from 234m-protoactinium radiative equilibrium to 238-uranium had nothing to overlap with other nuclides peaks is effective. The following are the results of measurement precision and sensitivity by the proofreading of germanium detector system. (1)Measurement sensitivity about a 200L drum of Gamma System1(GS1) is 4 g/600sec about 238-uranium, and measurement precision is about 50%. (2)Measurement sensitivity about a 200L drum of Gamma System2(GS2)is 2 g/600sec about 238-uranium, and measurement precision is about 100%.