An assessment of radiation doses at an educational institution 57.8 km away from the Fukushima Daiichi nuclear power plant 1 month after the nuclear accident

Masayoshi Tsuji, Hideyuki Kanda, Takeyasu Kakamu, Daisuke Kobayashi, Masao Miyake, Takehito Hayakawa, Yayoi Mori, Toshiyasu Okochi, Akihiro Hazama, Tetsuhito Fukushima

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Objectives On 11 March 2011, the Great East Japan Earthquake occurred. Due to this earthquake and subsequent tsunami, malfunctions occurred at the Fukushima Daiichi nuclear power plant. Radioactive material even reached the investigated educational institution despite being 57.8 km away from the power station. With the goal of ensuring the safety of our students, we decided to carry out a risk assessment of the premises of this educational institution by measuring radiation doses at certain locations, making it possible to calculate estimated radiation accumulation. Methods Systematic sampling was carried out at measurement points spaced at regular intervals for a total of 24 indoor and outdoor areas, with 137 measurements at heights of 1 cm and 100 cm above the ground surface. Radiation survey meters were used to measure environmental radiation doses. Results Radiation dose rates and count rates were higher outdoors than indoors, and higher 1 cm above the ground surface than at 100 cm. Radiation doses 1 cm above the ground surface were higher on grass and moss than on asphalt and soil. The estimated radiation exposure for a student spending an average of 11 h on site at this educational institution was 9.80 μSv. Conclusions Environmental radiation doses at our educational institution 57.8 km away from the Fukushima Daiichi nuclear power plant 1 month after the accident were lower than the national regulation dose for schools (3.8 μSv/h) at most points. Differences in radiation doses depending on outdoor surface properties are important to note for risk reduction.

Original languageEnglish
Pages (from-to)124-130
Number of pages7
JournalEnvironmental Health and Preventive Medicine
Volume17
Issue number2
DOIs
Publication statusPublished - Mar 2012

Keywords

  • Environmental radiation measurements
  • Fukushima Daiichi nuclear power plant accident
  • Radiation
  • Risk assessment
  • Systematic sampling

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health

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