Determination of environmental uranium concentration by utilizing -ray emission from the progeny radionuclides

Tanaka, Tadao ; Shimada, Taro ; Ito, Takeshi*; Sukegawa, Takenori

-ray from the progeny radionuclides of U-238, such as Th-234, Pa-234m and Ra-226, has been utilized for the evaluation of uranium concentration. In the present study, we proposed an evaluation method for U-238 concentration of background level in environment and for probate of vast land areas, in which the -ray radiations from Th-234, Pa-234m, Ra-226 is measured with the portable Ge detector. The U-238 concentration estimated by the in-situ metrology with portable Ge detector was in the order of 0.01 Bq/g in radioactive concentration, and was in comparable level with the concentrations decided by the ICP-MS established as high sensitive uranium analytical method. The method may be available for the U-238 concentration determination in vast land areas for the site release after decommissioning nuclear fuel handling facilities.