scholarly journals A Remote-operated System to Map Radiation Dose in the Fukushima Daiichi Primary Containment Vessel

2018 ◽  
Vol 170 ◽  
pp. 06004
Author(s):  
M. Nancekievill ◽  
A. R. Jones ◽  
M. J. Joyce ◽  
B. Lennox ◽  
S. Watson ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Gamma Ray ◽  
Low Cost ◽  
Radiation Detectors ◽  
Radioactive Isotopes ◽  
Combined System ◽  
Dose Rates ◽  
Fukushima Daiichi ◽  
Small Form Factor ◽  
Cerium Bromide

This paper describes the development of a submersible system based on a remote-operated vehicle coupled with radiation detectors to map the interior of the reactors at the Fukushima Daiichi nuclear power station. It has the aim oflocating fuel debris. The AVEXIS submersible vehicle used in this study has been designed as a low-cost, potentially disposable, inspection platform that is the smallest of its class and is capable of being deployed through a 150 mm diameter access pipe. To map the gamma-ray environment, a cerium bromide scintillator detector with a small form factor has been incorporated into the AVEXIS to identify radioactive isotopes via gamma-ray spectroscopy. This provides the combined system with the potential to map gamma-ray spectra and particle locations throughout submerged, contaminated facilities, such as Units 1, 2 and 3 of the Fukushima Daiichi nuclear power plant. The hypothesis of this research is to determine the sensitivity of the combined system in a submerged environment that replicates the combination of gamma radiation and water submersion but at lower dose rates.

scholarly journals Radiation dose rates now and in the future for residents neighboring restricted areas of the Fukushima Daiichi Nuclear Power Plant

2014 ◽  
Vol 111 (10) ◽  
pp. E914-E923 ◽  
Author(s):  
Kouji H. Harada ◽  
Tamon Niisoe ◽  
Mie Imanaka ◽  
Tomoyuki Takahashi ◽  
Katsumi Amako ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Radiation Dose ◽  
Radiation Exposure ◽  
Dose Rate ◽  
Nuclear Power ◽  
Solid Cancer ◽  
External Dose ◽  
Dose Rates ◽  
Fukushima Daiichi

Radiation dose rates were evaluated in three areas neighboring a restricted area within a 20- to 50-km radius of the Fukushima Daiichi Nuclear Power Plant in August–September 2012 and projected to 2022 and 2062. Study participants wore personal dosimeters measuring external dose equivalents, almost entirely from deposited radionuclides (groundshine). External dose rate equivalents owing to the accident averaged 1.03, 2.75, and 1.66 mSv/y in the village of Kawauchi, the Tamano area of Soma, and the Haramachi area of Minamisoma, respectively. Internal dose rates estimated from dietary intake of radiocesium averaged 0.0058, 0.019, and 0.0088 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. Dose rates from inhalation of resuspended radiocesium were lower than 0.001 mSv/y. In 2012, the average annual doses from radiocesium were close to the average background radiation exposure (2 mSv/y) in Japan. Accounting only for the physical decay of radiocesium, mean annual dose rates in 2022 were estimated as 0.31, 0.87, and 0.53 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. The simple and conservative estimates are comparable with variations in the background dose, and unlikely to exceed the ordinary permissible dose rate (1 mSv/y) for the majority of the Fukushima population. Health risk assessment indicates that post-2012 doses will increase lifetime solid cancer, leukemia, and breast cancer incidences by 1.06%, 0.03% and 0.28% respectively, in Tamano. This assessment was derived from short-term observation with uncertainties and did not evaluate the first-year dose and radioiodine exposure. Nevertheless, this estimate provides perspective on the long-term radiation exposure levels in the three regions.

scholarly journals Visualization of Radiocesium Distribution in Surface Layer of Seafloor Around Fukushima Daiichi Nuclear Power Plant

2021 ◽  
Author(s):  
Yukihisa Sanada ◽  
Yoshimi Urabe ◽  
Toshiharu Misonou ◽  
Takehiko Shiribiki ◽  
Takahiro Nakanishi ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Sediment Core ◽  
Nuclear Power ◽  
Gamma Ray ◽  
Detection System ◽  
Aquatic Organisms ◽  
Core Sample ◽  
Seafloor Topography ◽  
Fukushima Daiichi

Abstract Large quantities of volatile radionuclides were released into the atmosphere and the hydrosphere following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident on March 11, 2011. Monitoring of radiocesium in sediment is important for evaluating the behavior of radiocesium in the environment and its effect on aquatic organisms. In this study, the radiocesium distribution in the surface sediment around the FDNPP was visualized as a radiocesium map using periodical survey data from a towed gamma-ray detection system. The uncertainty of the radiocesium map was evaluated via comparison with a large amount of sediment core sample data. The characteristics of the radiocesium distribution were examined considering the seafloor topography and a geological map, which were obtained via acoustic wave survey. The characteristics of the formation of 137Cs anomaly at the estuaries were analyzed using a contour map of 137Cs concentration combined with water depth. Validation of the created map showed that it was comparable with actual sediment core samples. The map generated using the towed radiation survey depicted the 137Cs concentration distribution as the position resolution of a 1 km mesh. Finally, the 137Cs concentration decreased with time in consideration of such uncertainty.

CHANGES OF ABSORBED DOSE RATE IN AIR BY CAR-BORNE SURVEY IN NAMIE TOWN, FUKUSHIMA PREFECTURE AFTER THE FUKUSHIMA DAIICHI NUCLEAR POWER PLANT ACCIDENT

2019 ◽  
Vol 184 (3-4) ◽  
pp. 527-530 ◽  
Author(s):  
Y Shiroma ◽  
M Hosoda ◽  
K Iwaoka ◽  
M Hegedűs ◽  
H Kudo ◽  
...  
Keyword(s):  
Power Plant ◽  
Dose Rate ◽  
Nuclear Power ◽  
Absorbed Dose ◽  
Local Distribution ◽  
Absorbed Dose Rate ◽  
Distribution Maps ◽  
Dose Rates ◽  
Fdnpp Accident ◽  
Fukushima Daiichi

Abstract The latest car-borne survey was carried out by Hirosaki University in order to grasp the local distribution of the absorbed dose rate in air after the evacuation order was lifted on Namie Town in 2017. The car-borne survey of absorbed dose rate in air was carried out on most of the roads which were accessible by car in Namie Town using a 3-in × 3-in NaI(Tl) scintillation spectrometer. The range of the absorbed dose rate in air was calculated to be 0.041–11 μGy h−1. The distribution maps of the absorbed dose rate in air were drawn based on the data obtained during the surveys in 2011, 2015 and 2017. The comparison of these absorbed dose rates in air suggests that the elevated absorbed dose rate in air in Namie Town caused by the FDNPP accident may be decreasing faster than natural decline which includes weathering effect and physical decay due to the artificial decontamination.

scholarly journals Gamma-Ray Dose-Rates from Radioactive Isotopes

1954 ◽  
Vol 41 (sup117) ◽  
pp. 105-110 ◽  
Author(s):  
W. E. Perry
Keyword(s):  
Gamma Ray ◽  
Radioactive Isotopes ◽  
Dose Rates

scholarly journals Optimizing long-term monitoring of radiation air-dose rates after the Fukushima Daiichi Nuclear Power Plant

2020 ◽  
Vol 220-221 ◽  
pp. 106281 ◽  
Author(s):  
Dajie Sun ◽  
Haruko M. Wainwright ◽  
Carlos A. Oroza ◽  
Akiyuki Seki ◽  
Satoshi Mikami ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Dose Rates ◽  
Long Term Monitoring ◽  
Fukushima Daiichi ◽  
Term Monitoring
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