A study on environmental pollution caused by radioactive substances and its countermeasure techniques. Part 4. Radioactive pollution and decontamination in the wooden house and the park

As a consequence of the accident at the Fukushima Nuclear Power Plant 1, radioactive materials dispersed, soil pollution and building contamination occurred. In accordance with a common conviction that the human body is affected by nuclear pollution, the decontamination work of the contaminated living quarters is indispensable at early stages. To verify the process of artificial decontamination, the high-pressure washers were used on the roof and walls of a wooden house. The confirmation and accessing the effectiveness of this method were subject of this research. Since the schoolyard and park were presumed to be polluted by radioactivity, it is necessary to determine the actual status of contamination immediately. In present study, the air dose and the surface contamination density in the park at Fukushima were also measured in order to investigate the actual level of radioactive contamination. The positive effect of high-pressure washer decontamination was confirmed as the radiation decreased from 0.36 μSv/h to 0.29 μSv/h, measured at the toilet on the first floor. And from 1.60 [μSv/h] to 1.30 μSv/h measured at the site 'V'. And the results of the measurement in the park showed that the air dose rates at the park were 0.99-3.2 μSv/h and radioactive hot spots were found. Further, measuring the surface contamination of the bench and the playground equipment showed comparatively high dose. (author)