IMPACT ON ABSORBED DOSE RATE IN AIR IN KANTO REGION BY FUKUSHIMA DAIICHI NUCLEAR POWER PLANT ACCIDENT

2019 ◽  
Vol 184 (3-4) ◽  
pp. 500-503
Author(s):  
K Inoue ◽  
M Arai ◽  
H Tsuruoka ◽  
K Saito ◽  
M Fujisawa ◽  
...  

Abstract Absorbed dose rates in air were measured for the whole area of the Kanto region in 2015, 2016 and 2017 (n = 31 147). The mean absorbed dose rates in air for each prefecture measured by car-borne surveys were from 44 to 67 nGy h−1 (13–289 nGy h−1). The absorbed dose rate in air from artificial radionuclides (134Cs + 137Cs) measured by fixed-point observation (n = 507) was from 1 to 14 nGy h−1 (0–105 nGy h−1), and meaning that the contribution ratios of 134Cs and 137Cs were 3–22%. The deposited location of artificial radionuclides was less than 1000 m from ground level and depended on the topography, wind direction and precipitation field.


2020 ◽  
Vol 24 (3) ◽  
pp. 435-442 ◽  
Author(s):  
M. Atipo ◽  
O. Olarinoye ◽  
B. Awojoyogbe ◽  
M. Kolo

Mineral mining and milling can be a source of national economic and technological development. However, mining of minerals has been confirmed to disturb the natural distribution of radioisotopes in the soil, air and water bodies in the biota. In an attempt to evaluate the radiological burden resulting from tin mining activities at Rayfield-Du area of Jos, the background gamma-radiation level in the mine was measured via a well calibratedhand-held dosimeter placed at 1 m above ground level. The mean absorbed dose rate, annual effective dose rate and excess lifetime cancer risk for the mine was 0.83 μSvh-1; 1.44 mSv-1 and 0.005 respectively. Generally, dose rates were higher in the mine pits and processing areas as compared to administrative areas of the mine. The mean measured dose rate and calculated dose parameters for the mine were all high when compared to the regulatory limit for public exposure. The potential of developing radiation-induced health defects as a result of high radiation absorbed dose rate by the miners and dwellers around the mine is highly probable.  Keywords: Gamma-radiation; mine; absorbed dose rate; radiation exposure.



Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3012
Author(s):  
Se Kye Park ◽  
Dong Yun Choi ◽  
Duyoung Choi ◽  
Dong Yun Lee ◽  
Seung Hwa Yoo

In this study, a high-density polyethylene (HDPE)-based carbon fiber-reinforced thermoplastic (CFRTP) was irradiated by an electron-beam. To assess the absorbed dose rate influence on its mechanical properties, the beam energy and absorbed dose were fixed, while the absorbed dose rates were varied. The tensile strength (TS) and Young’s modulus (YM) were evaluated. The irradiated CFRTP TS increased at absorbed dose rates of up to 6.8 kGy/s and decreased at higher rates. YM showed no meaningful differences. For CFRTPs constituents, the carbon fiber (CF) TS gradually increased, while the HDPE TS decreased slightly as the absorbed dose rates increased. The OH intermolecular bond was strongly developed in irradiated CFRTP at low absorbed dose rates and gradually declined when increasing those rates. X-ray photoelectron spectroscopy analysis revealed that the oxygen content of irradiated CFRTPs decreased with increasing absorbed dose rate due to the shorter irradiation time at higher dose rates. In conclusion, from the TS viewpoint, opposite effects occurred when increasing the absorbed dose rate: a favorable increase in CF TS and adverse decline of attractive hydrogen bonding interactions between HDPE and CF for CFRTPs TS. Therefore, the irradiated CFRTP TS was maximized at an optimum absorbed dose rate of 6.8 kGy/s.



2019 ◽  
Vol 184 (3-4) ◽  
pp. 527-530 ◽  
Author(s):  
Y Shiroma ◽  
M Hosoda ◽  
K Iwaoka ◽  
M Hegedűs ◽  
H Kudo ◽  
...  

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.



2020 ◽  
Vol 190 (4) ◽  
pp. 355-363
Author(s):  
Jahan Zeb ◽  
Mohammad Wasim ◽  
Muhammad Awais ◽  
Asad Ullah ◽  
Talat Iqbal ◽  
...  

Abstract This study presents a detailed measurement of indoor and outdoor terrestrial gamma radiation levels in different cities of Pakistan. The measurements covered dwellings in 27 cities, covering all provinces and region of Azad Kashmir. Most of the houses were of attached type, made of brick walls and concrete roofs. The measurements were made by a handheld radiation survey meter containing Geiger–Muller tube. The average absorbed dose rate in air was 100 ± 32 nGy h−1 for indoor and 74 ± 30 nGy h−1 for outdoor. The population-weighted mean terrestrial dose rates were 90 nGy h−1 for indoor and 78 nGyh−1 for outdoor. The ratio of indoor to outdoor absorbed dose rate was 1.5 as compared to 1.3 for the world average. The estimated average annual effective dose rate was 0.58 ± 0.18 mSv a−1 and the mean excess life time cancer risk was 2.0 × 10−3.



PLoS ONE ◽  
2019 ◽  
Vol 14 (10) ◽  
pp. e0224449
Author(s):  
Kazumasa Inoue ◽  
Hiroshi Tsuruoka ◽  
Hideo Shimizu ◽  
Moeko Arai ◽  
Nimelan Veerasamy ◽  
...  


2010 ◽  
Vol 58 (spe4) ◽  
pp. 25-32 ◽  
Author(s):  
Wagner de S. Pereira ◽  
Alphonse Kelecom ◽  
Delcy de A. Py Júnior

A methodology was developed for converting the activity concentration of radionuclides (Bq kg-1) into absorbed dose rate (Gy y-1), aiming an approach to environmental radioprotection based on the concept of standard dose limit. The model considers only the internal absorbed dose rate. This methodology was applied to the cubera snapper fish (Lutjanus cyanopterus, Cuvier, 1828) caught off the coast of Ceará. The natural radionuclides considered were uranium-238, radium-226, lead-210, thorium-232 and radium-228. The absorbed dose rates were calculated for individual radionuclides and the type of emitted radiation. The average dose rate due to these radionuclides was 5.36 µGy y-1, a value six orders of magnitude smaller than the threshold value of absorbed dose rate used in this study (3.65 10³ mGy y-1), and similar to that found in the literature for benthic fish. Ra-226 and U-238 contributed 67% and 22% of the absorbed dose rate, followed by Th-232 with 10%. Ra-228 and Pb-210, in turn, accounted for less than 1% of the absorbed dose rate. This distribution is somewhat different from that reported in the literature, where the Ra-226 accounts for 86% of the absorbed dose rate.



Author(s):  
Masahiko Matsuo ◽  
Yasuyuki Taira ◽  
Makiko Orita ◽  
Yumiko Yamada ◽  
Juichi Ide ◽  
...  

On 1 April 2017, six years have passed since the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, and the Japanese government declared that some residents who lived in Tomioka Town, Fukushima Prefecture could return to their homes. We evaluated environmental contamination and radiation exposure dose rates due to artificial radionuclides in the livelihood zone of residents (living space such as housing sites), including a restricted area located within a 10-km radius from the FDNPS, immediately after residents had returned home in Tomioka town. In areas where the evacuation orders had been lifted, the median air dose rates were 0.20 μSv/h indoors and 0.26 μSv/h outdoors, and the radiation exposure dose rate was 1.6 mSv/y. By contrast, in the “difficult-to-return zone,” the median air dose rate was 2.3 μSv/h (20 mSv/y) outdoors. Moreover, the dose-forming artificial radionuclides (radiocesium) in the surface soil were 0.018 μSv/h (0.17 mSv/y) in the evacuation order-lifted areas and 0.73 μSv/h (6.4 mSv/y) in the difficult-to-return zone. These findings indicate that current concentrations of artificial radionuclides in soil samples have been decreasing in the evacuation order-lifted areas of Tomioka town; however, a significant external exposure risk still exists in the difficult-to-return zone. The case of Tomioka town is expected to be the first reconstruction model including the difficult-to-return zone.



Author(s):  
Alaaddin VURAL ◽  
Ali KAYA

Within the scope of this study, the first evaluations of natural (226Ra, 232Th and 40K) and artificial (137Cs) radio isotope activities of the Arzular-Yitirmez-Dölek (Gümüşhane) mine/alteration site were carried out. Measurements were carried out with Poptop Ortec gamma rays detector on 22 soil samples collected from the field. When the natural 232Th, 226Ra and 40K activities of the area are compared with the weighted world averages, it has been determined that the 40K and 226Ra activities exceed the world averages in most of the sampling points, and the 232Th activities are below the weighted world average except for a few sampling points. It was observed that the artificial 137Cs activities in the field were above the detection limit and exceeded 2 Bq/kg except for a few sampling points. It has been evaluated that the high 137Cs activities in the field may be associated with a human-induced effect, especially the accident at the Chernobyl nuclear power plant. Parameters such as radiological hazard indices, Ra equivalent activity value, absorbed dose rate and annual effective dose rate were also calculated for the field. Considering the results obtained from these parameters, it was concluded that it would be beneficial to study the Arzular-Yitirmez-Dölek mineralization/alteration field in more detail in terms of natural and artificial radioisotope activities.



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