Radiochemical analysis of rubble and trees collected from Fukushima Daiichi Nuclear Power Station

To characterize the rubble and trees contaminated by radionuclides released by the recent accident at the Fukushima Daiichi Nuclear Power Station, the radiochemical analysis protocols were modified using those developed by the Japan Atomic Energy Agency for the waste generated by research, industrial, and medical facilities. The radioactivity concentrations of gamma-ray-emitting nuclides 60 Co, 94 Nb, 152 Eu, and 154 Eu, and beta-particle-emitting nuclides 14 C, 129 I, 36 Cl, 79 Se, and 99 Tc were successfully applied by the modified analytical method. In contrast, the radioactivity concentrations of 3 H, 90 Sr, 137 Cs, and alpha-particle-emitting nuclides were applied by the conventional method. Unfortunately, 36 Cl, 94 Nb, 129 I, 152 Eu, 154 Eu, and alpha-particle-emitting nuclides were below the detection limit of the conventional method. The measured radioactivity concentrations, except for that of 3 H, were not uniform in the area but depended on the reactor unit. Although the radioactivity concentrations were varied widely, this analysis successfully clarified the characteristics of the radioactivity concentrations of the rubble and trees.