Development of technique for measuring uranium quantity within containers using the passive gamma method (Technical document; Verification)

Suzuki, Satoshi*; Komatsuzaki, Takashi*; Sukegawa, Yasuhiro*; Oki, Koichi

It is important in the waste management to evaluate the quantity of radioactivity in the wastes. This report summarizes the improvement, examinations in the nondestructive measurement system using the passive method applied to the evaluation of the quantity of uranium in container waste. Results are followings. (1) Evaluation of the quantity of uranium in container waste was about 50% against true value. (2) Repeatedly accuracy of the evaluation value is about 50%. (3) The validity of the evaluation to container wastes was confirmed by cross-checking with the system for the drum. (4) When the radioactivity is higher than 1 Bq/g, the facing couple method is effective. (5) If the weight of container is 1t, the detection limit by NaI detector is about 20g (U-238) at the center of container, 3g (U-238) at the surface. Detection limit by Ge detector is about 70g (U-238) at the center, 10g (U-238) at the surface. (6) There is a possibility that about 80% of the container wastes become clearance wastes.