Changes of Absorbed Dose Rate in Air by Car-Borne Survey in Namie Town, Fukushima Prefecture After the Fukushima Daiichi Nuclear Power Plant Accident

Shiroma, Yoshitaka; Hosoda, Masahiro; Iwaoka, Kazuki; Hegedűs, Miklós; Kudo, Hiromi; Tsujiguchi, Takakiyo; Yamaguchi, Masaru; Kashiwakura, Ikuo; Tokonami, Shinji

doi:10.1093/rpd/ncz096

Cited by 8 publications

(5 citation statements)

References 10 publications

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“…The absorbed dose rates in air of the natural radionuclides, artificial ra-dionuclides, and their totals are 15-68, 14-11,861, and 47-11,900 nGy h −1 , respectively. The total absorbed dose rate in air obtained in this study is almost in agreement with the 0.041-11 µGy h −1 measured by Shiroma et al [21]. The absorbed dose rates in air of natural radionuclides, artificial radionuclides, and their totals in the evacuation order cancellation zone are 19-51, 14-2010, and 47-2040 nGy h −1 , respectively.…”

Section: Absorbed Dose Rate In Air and Dose Rate Mapsupporting

confidence: 91%

“…In addition, internal and external exposures from artificial radionuclides are being evaluated [14][15][16][17][18][19], and monitoring posts are installed in various locations to continuously measure the ambient dose equivalent rate [20]. In 2017, Shiroma et al conducted a car-borne su rvey in Namie Town, Fukushima Prefecture, and reported that the absorbed dose rate in air was 0.041-11 µGy h −1 [21]. More than nine years have passed since the FDNPP accident, and the relative contribution of natural radiation to ambient dose equivalent rates is increasing because the dose of artificial radiation is decreasing.…”

Section: Introductionmentioning

confidence: 99%

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Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture

Ogura

Hosoda

Tamakuma

et al. 2021

IJERPH

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Ten years have elapsed since the accident at the Fukushima Daiichi Nuclear Power Plant in 2011, and the relative contribution of natural radiation is increasing in Fukushima Prefecture due to the reduced dose of artificial radiation. In order to accurately determine the effective dose of exposure to artificial radiation, it is necessary to evaluate the effective dose of natural as well as artificial components. In this study, we measured the gamma-ray pulse-height distribution over the accessible area of Namie Town, Fukushima Prefecture, and evaluated the annual effective dose of external exposure by distinguishing between natural and artificial radionuclides. The estimated median (range) of absorbed dose rates in air from artificial radionuclides as of 1 April 2020, is 133 (67–511) nGy h−1 in the evacuation order cancellation zone, and 1306 (892–2081) nGy h−1 in the difficult-to-return zone. The median annual effective doses of external exposures from natural and artificial radionuclides were found to be 0.19 and 0.40 mSv in the evacuation order cancellation zone, and 0.25 and 3.9 mSv in the difficult-to-return zone. The latest annual effective dose of external exposure discriminated into natural and artificial radionuclides is expected to be utilized for radiation risk communication.

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Section: Absorbed Dose Rate In Air and Dose Rate Mapsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture

Ogura

Hosoda

Tamakuma

et al. 2021

IJERPH

View full text Add to dashboard Cite

show abstract

“…The ambient dose rate and detection rate of radiocesium were significantly higher in the ISF than in the evacuation order lifted area and SRRB in Futaba town and Okuma town (p < 0.001). In general, the efficient and thorough decontamination processes can reduce ambient dose by removing radioactive materials from affected areas (environmental remediation) 19 – 24 . In our previous study in Tomioka town, Fukushima Prefecture, a significant difference in ambient dose rate since 2017 was observed between the decontaminated and non-decontaminated areas 19 – 21 .…”

Section: Discussionmentioning

confidence: 99%

Temporal variation in environmental radioactivity and radiation exposure doses in the restricted areas around the Fukushima Daiichi Nuclear Power Plant

Liu,

Taira,

Matsuo

et al. 2023

Sci Rep

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Temporal variation and fluctuation in environmental contamination in Futaba town and Okuma town, the location of the Fukushima Daiichi Nuclear Power Plant (FDNPP), were evaluated based on a car-borne survey conducted from October 2021 to November 2022. Although the environmental radioactivity in the interim storage facility area (ISF) was higher than that in open areas (i.e., the evacuation order lifted areas in Futaba town and the Specific Reconstruction and Regeneration Base area [SRRB] in Okuma town), only minor temporal changes were seen in the ambient dose and detection rate of radiocesium (the proportion of radiocesium detected points per all measuring points) in those areas, respectively. These findings suggest that the observed variations may result from physical decay and environmental remediation. Resuspension caused by human activities and weather could also affect the detection rate of radiocesium. The annual external effective doses in Futaba town and Okuma town were estimated to be at a limited level (< 1 mSv/year). Nevertheless, to help ensure the safety and future prosperity of residents and communities in the affected areas around the FDNPP, long-term follow-up monitoring of temporal exposure dose levels during the recovery and reconstruction phases is extremely important.

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“…Moreover, in our previous study, decontamination was carried out effectively in Tomioka, reducing the ambient dose rates in the decontaminated area by 71.9% (from 1.0 µSv/h to 0.32 µSv/h within 1 year) 12 . Other studies have also reported the effectiveness of decontamination for reducing ambient dose rates to a low level 13,14,17 . Therefore, our ndings suggest that the environmental radioactivity in the SRRB and evacuation-order-lifted areas was continuously stable at extremely low levels as a result of decontamination.…”

Section: Discussionmentioning

confidence: 99%

Temporal variation in environmental radioactivity and radiation exposure doses in the restricted areas around the Fukushima Daiichi Nuclear Power Plant

Liu

Taira

Matsuo

et al. 2023

Preprint

View full text Add to dashboard Cite

Temporal variation and fluctuation in environmental contamination in Futaba town and Okuma town, the location of the Fukushima Daiichi Nuclear Power Plant (FDNPP), were evaluated based on a car-borne survey conducted from October 2021 to November 2022. Although the environmental radioactivity levels in the interim storage facility area (ISF) were higher than those in open areas (i.e., the evacuation-order-lifted areas in Futaba town and the specific reconstruction and regeneration base area [SRRB] in Okuma town), only minor changes were seen in the ambient dose and radiocesium detection rates in the ISF and SRRB, respectively. These findings suggest that such differences may be the result of multiple factors such as physical decay (decreasing factor) and radiocesium resuspension (non-decreasing factor) accompanied by human activity such as traffic and decontamination construction in these areas, in addition to weather conditions such as wind direction. However, the higher radiation exposure doses in the ISF and SRRB were estimated to be at a limited level (lower than the public dose). Therefore, to help ensure the safety and future prosperity of residents and communities in the affected areas around the FDNPP, long-term follow-up monitoring of temporal dose levels during the recovery and reconstruction phases is extremely important.

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Changes of Absorbed Dose Rate in Air by Car-Borne Survey in Namie Town, Fukushima Prefecture After the Fukushima Daiichi Nuclear Power Plant Accident

Cited by 8 publications

References 10 publications

Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture

Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture

Temporal variation in environmental radioactivity and radiation exposure doses in the restricted areas around the Fukushima Daiichi Nuclear Power Plant

Temporal variation in environmental radioactivity and radiation exposure doses in the restricted areas around the Fukushima Daiichi Nuclear Power Plant

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