AIST REPORT 2012

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Geological Museum of AISTAIST Tsukuba HeadquartersGraph of the results of radiation measurements at the 3rd floor balconyContinuous radiation measurement pointsAIST Tsukuba Central 1Parking lot3rd floor balconyRadiation Measurement at AIST TsukubaEnvironmental radiation doses rose following the accident at the Fukushima Daiichi Nuclear Power Plant caused by the Great East Japan Earthquake. The radiation doses in the air at AIST Tsukuba have been published on AIST’s website since March 15, 2011. Since the data at the parking lot of AIST Tsukuba Central 1 decreased and became stable, the measurement was stopped on March 16, 2012. The continuous hourly measurements with an NaI scintillation survey meter at the balcony on the third floor of the main building of AIST Tsukuba Central 1 are continued. The survey meter was calibrated in January 2012.AIST’s published data only show the increase due to the nuclear power plant accident obtained by subtracting the previously measured value of 0.06 μSv/h※ of background radiation from the measured value. The graph shown below is also available on the website so that the change in radiation dose in the air can be easily recognized. The radiation dose shown in the graph gradually decreases and remains constant at a low level, indicating that no additional radioactive materials are transported from the Fukushima Daiichi Nuclear Power Plant in quantities that affect the radiation dose. The current radiation dose (of July 2012) attributable to the accident is 0.05 to 0.07 μSv/h, which is as low as the natural background level.※ This figure is reasonable compared to the average external exposure to natural background radiation in Japan [the average exposure to cosmic rays and telluric radiation = 0.076 μSv/h].Environmental Report|47

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