Development and Adaptability of a Topsoil Removal Machine for Decontaminating Peripheral Areas of Agricultural Land

5 YANMAR Co., Ltd. (Osaka, Osaka 530-8311, Japan) Abstractand reconstruction are the largest and most pressing tasks following the nuclear accident at Fukushima. In this paper we address the task of reducing external exposure to radiation from radioactive material that has accumulated in agricultural land or its peripheral areas, and report on the features of a machine developed to decontaminate the peripheral areas of agricultural embank- ments and roads, as well as the on-site testing results. Based on the results of analyzing the vertical distribution of radioactive Cs concentration in the soil, we set the removal depth of the machine to 5 cm and proceeded with operation. In terms of usability and the decontamination effects provided by the embankment topsoil removal machine, we achieved a field capacity of 4.4 a/h and reduced the concentration of radioactive Cs and the air dose rate after treatment by about 80%. And based on the test results of the agricultural road surface stripping machine, a field capacity of approximately 0.83 a/h and an extremely high reduction rate of about 90% were achieved after stripping and removal treatment of the soil. Furthermore, the results of surveying the dust exposure status as an operating environment factor related to worker safety (as pertaining to developed machinery) suggested that the fully enclosed construction of the operating section of both machines apparently contributed to reducing the scattering of dirt, sand and dust that degrade the surrounding environment during decontamination operation.