Radiation dose reduction efficiency of buildings after the accident at the Fukushima Daiichi Nuclear Power Station

• Published in: PloS one Vol. 9; no. 7; p. e101650
• Main Authors: Monzen, Satoru, Hosoda, Masahiro, Osanai, Minoru, Tokonami, Shinji
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 07.07.2014; Public Library of Science (PLoS)
• Subjects: Aluminum; Atomic structure; Background radiation; Buildings; Civilian evacuation; Concrete; Concrete construction; Contamination; Dosimetry; Earth Sciences; Earthquakes; Ecology and Environmental Sciences; Efficiency; Emergency medical care; Emergency preparedness; Evacuation; Exposure; Fukushima Nuclear Accident; Gamma rays; Health sciences; Hostages; Indoor air; Indoor environments; Life sciences; Mathematical analysis; Measuring instruments; Medicine and Health Sciences; Nuclear accidents; Nuclear accidents & safety; Nuclear electric power generation; Nuclear energy; Nuclear power; Nuclear Power Plants; Outdoor; Power plants; Public buildings; Radiation; Radiation Dosage; Radiation effects; Radiation Protection - instrumentation; Radioisotopes; Reduction; Reinforced concrete; Seismic activity; Thyroid gland; Towns; Tsunamis; Wood; United States > US; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0101650

Numerous radionuclides were released from the Fukushima Daiichi Nuclear Power Station (F1-NPS) in Japan following the magnitude 9.0 earthquake and tsunami on March 11, 2011. Local residents have been eager to calculate their individual radiation exposure. Thus, absorbed dose rates in the indoor and outdoor air at evacuation sites in the Fukushima Prefecture were measured using a gamma-ray measuring devices, and individual radiation exposure was calculated by assessing the radiation dose reduction efficiency (defined as the ratio of absorbed dose rate in the indoor air to the absorbed dose rate in the outdoor air) of wood, aluminum, and reinforced concrete buildings. Between March 2011 and July 2011, dose reduction efficiencies of wood, aluminum, and reinforced concrete buildings were 0.55 ± 0.04, 0.15 ± 0.02, and 0.19 ± 0.04, respectively. The reduction efficiency of wood structures was 1.4 times higher than that reported by the International Atomic Energy Agency. The efficiency of reinforced concrete was similar to previously reported values, whereas that of aluminum structures has not been previously reported. Dose reduction efficiency increased in proportion to the distance from F1-NPS at 8 of the 18 evacuation sites. Time variations did not reflect dose reduction efficiencies at evacuation sites although absorbed dose rates in the outdoor air decreased. These data suggest that dose reduction efficiency depends on structure types, levels of contamination, and evacuee behaviors at evacuation sites.