The Experts below are selected from a list of 2643 Experts worldwide ranked by ideXlab platform
Noboru Takamura - One of the best experts on this subject based on the ideXlab platform.
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measurement of individual doses of radiation by personal dosimeter is important for the return of residents from evacuation order areas after nuclear disaster
PLOS ONE, 2015Co-Authors: Makiko Orita, Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Takashi Kudo, Yoshiko Fukushima, Juichi Ide, Yuuko Endo, Noboru TakamuraAbstract:To confirm the availability of individual dose evaluation for the return of residents after the accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP), we evaluated individual doses of radiation as measured by personal dosimeters in residents who temporarily stayed in Evacuation Order Areas in Kawauchi village, which is partially located within a 20 km radius of the FNPP. We also compared individual doses with the external radiation doses estimated from the ambient dose rates and with doses estimated from the concentrations of Radionuclides in the soil around each individual’s house. Individual doses were significantly correlated with the ambient doses in front of the entrances to the houses (r = 0.90, p<0.01), in the backyards (r = 0.41, p<0.01) and in the nearby fields (r = 0.80, p<0.01). The maximum cumulative ambient doses in the backyards and fields around the houses were 6.38 and 9.27 mSv/y, respectively. The maximum cumulative individual dose was 3.28 mSv/y, and the median and minimum doses were 1.35 and 0.71 mSv/y. The estimated external effective doses from concentrations of Artificial Radionuclides in soil samples ranged from 0.03 to 23.42 mSv/y. The individual doses were moderately correlated with external effective doses in the backyards (r = 0.38, p<0.01) and in the fields (r = 0.36, p<0.01); however, the individual doses were not significantly correlated with the external effective doses in front of the entrances (r = 0.01, p = 0.92). Our study confirmed that individual doses are low levels even in the evacuation order area in Kawauchi village, and external effective dose levels are certainly decreasing due to the decay of Artificial Radionuclides and the decontamination of contaminated soil. Long-term follow-up of individual doses as well as internal-exposure doses, environmental monitoring and reconstruction of infrastructure are needed so that residents may return to their hometowns after a nuclear disaster.
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vertical distribution and estimated doses from Artificial Radionuclides in soil samples around the chernobyl nuclear power plant and the semipalatinsk nuclear testing site
PLOS ONE, 2013Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Jumpei Takahashi, Alexander Kazlovsky, Rimi Tsuchiya, Hitoshi Yamaguchi, Marat Urazalin, Tolebay Rakhypbekov, Noboru TakamuraAbstract:For the current on-site evaluation of the environmental contamination and contributory external exposure after the accident at the Chernobyl Nuclear Power Plant (CNPP) and the nuclear tests at the Semipalatinsk Nuclear Testing Site (SNTS), the concentrations of Artificial Radionuclides in soil samples from each area were analyzed by gamma spectrometry. Four Artificial Radionuclides (241Am, 134Cs, 137Cs, and 60Co) were detected in surface soil around CNPP, whereas seven Artificial Radionuclides (241Am, 57Co, 137Cs, 95Zr, 95Nb, 58Co, and 60Co) were detected in surface soil around SNTS. Effective doses around CNPP were over the public dose limit of 1 mSv/y (International Commission on Radiological Protection, 1991). These levels in a contaminated area 12 km from Unit 4 were high, whereas levels in a decontaminated area 12 km from Unit 4 and another contaminated area 15 km from Unit 4 were comparatively low. On the other hand, the effective doses around SNTS were below the public dose limit. These findings suggest that the environmental contamination and effective doses on the ground definitely decrease with decontamination such as removing surface soil, although the effective doses of the sampling points around CNPP in the present study were all over the public dose limit. Thus, the remediation of soil as a countermeasure could be an extremely effective method not only for areas around CNPP and SNTS but also for areas around the Fukushima Dai-ichi Nuclear Power Plant (FNPP), and external exposure levels will be certainly reduced. Long-term follow-up of environmental monitoring around CNPP, SNTS, and FNPP, as well as evaluation of the health effects in the population residing around these areas, could contribute to radiation safety and reduce unnecessary exposure to the public.
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evaluation of environmental contamination and estimated radiation doses for the return to residents homes in kawauchi village fukushima prefecture
PLOS ONE, 2012Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Hitoshi Yamaguchi, Yuukou Endo, Noboru TakamuraAbstract:To evaluate the environmental contamination and radiation exposure dose rates due to Artificial Radionuclides in Kawauchi Village, Fukushima Prefecture, the restricted area within a 30-km radius from the Fukushima Dai-ichi Nuclear Power Plant (FNPP), the concentrations of Artificial Radionuclides in soil samples, tree needles, and mushrooms were analyzed by gamma spectrometry. Nine months have passed since samples were collected on December 19 and 20, 2011, 9 months after the FNPP accident, and the prevalent dose-forming Artificial Radionuclides from all samples were 134Cs and 137Cs. The estimated external effective doses from soil samples were 0.42–7.2 µSv/h (3.7–63.0 mSv/y) within the 20-km radius from FNPP and 0.0011–0.38 µSv/h (0.010–3.3 mSv/y) within the 20–30 km radius from FNPP. The present study revealed that current levels are sufficiently decreasing in Kawauchi Village, especially in areas within the 20- to 30-km radius from FNPP. Thus, residents may return their homes with long-term follow-up of the environmental monitoring and countermeasures such as decontamination and restrictions of the intake of foods for reducing unnecessary exposure. The case of Kawauchi Village will be the first model for the return to residents’ homes after the FNPP accident.
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environmental contamination and external radiation dose rates from Radionuclides released from the fukushima nuclear power plant
Radiation Protection Dosimetry, 2012Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Takashi Kudo, Naoki Matsuda, Jumpei Takahashi, Alexander Gutevitc, Alexander Kazlovsky, Noboru TakamuraAbstract:To evaluate the environmental contamination and contributory external exposure after the accident at the Fukushima Nuclear Power Plant (FNPP), the concentrations of Artificial Radionuclides in soil samples from each area were analysed by gamma spectrometry. Six Artificial Radionuclides ((131)I, (134)Cs, (137)Cs, (129m)Te, (95)Nb and (136)Cs) were detected in soil samples around FNPP. Calculated external effective doses from Artificial radionuclide contamination in soil samples around FNPP were 1.9-2.9 μSv h(-1) (8.7-17.8 mSv y(-1)) in Fukushima city on 22 March 2011. After several months, these calculated external effective doses were 0.25-0.88 μSv h(-1) (2.2-7.6 mSv y(-1)) in Fukushima city on 29 June 2011. The present study revealed that the detected Artificial Radionuclides around FNPP mainly shifted to long-lived Radionuclides such as radioactive caesium ((134)Cs and (137)Cs) even though current levels are decreasing gradually due to the decay of short-lived Radionuclides such as (131)I, (129m)Te, (95)Nb and (136)Cs. Thus, radiation exposure potency still exists even though the national efforts are ongoing for reducing the annual exposure dose closer to 1 mSv, the public dose limit. Long-term environmental monitoring around FNPP contributes to radiation safety, with a reduction in unnecessary exposure to the residents.
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current concentration of Artificial Radionuclides and estimated radiation doses from 137cs around the chernobyl nuclear power plant the semipalatinsk nuclear testing site and in nagasaki
Journal of Radiation Research, 2011Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Jumpei Takahashi, Alexander Gutevitc, Alexander Kazlovsky, Marat Urazalin, Gopalganapathi M Brahmanandhan, Yuji Nagayama, Noboru TakamuraAbstract:To evaluate current environmental contamination and contributions from internal and external exposure due to the accident at the Chernobyl Nuclear Power Plant (CNPP) and nuclear tests at the Semipalatinsk Nuclear Testing Site (SNTS), concentrations of Artificial Radionuclides in edible mushrooms, soils and stones from each area were analyzed by gamma spectrometry. Annual effective doses were calculated for each area from the cesium contamination. Calculated internal effective doses of (137)Cs due to ingestion of mushrooms were 1.8 × 10(-1) mSv/year (y) in Gomel city (around CNPP), 1.7 × 10(-1) mSv/y in Korosten city (around CNPP), 2.8 × 10(-4) mSv/y in Semipalatinsk city, and 1.3 × 10(-4) mSv/y in Nagasaki. Calculated external effective doses of (137)Cs were 3.4 × 10(-2) mSv/y in Gomel city, 6.2 × 10(-2) mSv/y in Korosten city, 2.0 × 10(-4) mSv/y in Semipalatinsk city, and 1.3 × 10(-4) mSv/y in Nagasaki. Distribution of Radionuclides in stones collected beside Lake Balapan (in SNTS) were (241)Am (49.4 ± 1.4 Bq/kg), (137)Cs (406.3 ± 1.7 Bq/kg), (58)Co (3.2 ± 0.5 Bq/kg), and (60)Co (125.9 ± 1.1 and 126.1 ± 1.1 Bq/kg). The present study revealed that dose rates from internal and external exposure around CNPP were not sufficiently low and radiation exposure potency still exists even though current levels are below the public dose limit of 1 mSv/y (ICRP1991). Moreover, parts of the SNTS area may be still contaminated by Artificial Radionuclides derived from nuclear tests. Long-term follow-up of environmental monitoring around CNPP and SNTS, as well as evaluation of health effects in the population residing around these areas, may contribute to radiation safety with a reduction of unnecessary exposure of residents.
Yasuyuki Taira - One of the best experts on this subject based on the ideXlab platform.
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measurement of individual doses of radiation by personal dosimeter is important for the return of residents from evacuation order areas after nuclear disaster
PLOS ONE, 2015Co-Authors: Makiko Orita, Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Takashi Kudo, Yoshiko Fukushima, Juichi Ide, Yuuko Endo, Noboru TakamuraAbstract:To confirm the availability of individual dose evaluation for the return of residents after the accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP), we evaluated individual doses of radiation as measured by personal dosimeters in residents who temporarily stayed in Evacuation Order Areas in Kawauchi village, which is partially located within a 20 km radius of the FNPP. We also compared individual doses with the external radiation doses estimated from the ambient dose rates and with doses estimated from the concentrations of Radionuclides in the soil around each individual’s house. Individual doses were significantly correlated with the ambient doses in front of the entrances to the houses (r = 0.90, p<0.01), in the backyards (r = 0.41, p<0.01) and in the nearby fields (r = 0.80, p<0.01). The maximum cumulative ambient doses in the backyards and fields around the houses were 6.38 and 9.27 mSv/y, respectively. The maximum cumulative individual dose was 3.28 mSv/y, and the median and minimum doses were 1.35 and 0.71 mSv/y. The estimated external effective doses from concentrations of Artificial Radionuclides in soil samples ranged from 0.03 to 23.42 mSv/y. The individual doses were moderately correlated with external effective doses in the backyards (r = 0.38, p<0.01) and in the fields (r = 0.36, p<0.01); however, the individual doses were not significantly correlated with the external effective doses in front of the entrances (r = 0.01, p = 0.92). Our study confirmed that individual doses are low levels even in the evacuation order area in Kawauchi village, and external effective dose levels are certainly decreasing due to the decay of Artificial Radionuclides and the decontamination of contaminated soil. Long-term follow-up of individual doses as well as internal-exposure doses, environmental monitoring and reconstruction of infrastructure are needed so that residents may return to their hometowns after a nuclear disaster.
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vertical distribution and estimated doses from Artificial Radionuclides in soil samples around the chernobyl nuclear power plant and the semipalatinsk nuclear testing site
PLOS ONE, 2013Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Jumpei Takahashi, Alexander Kazlovsky, Rimi Tsuchiya, Hitoshi Yamaguchi, Marat Urazalin, Tolebay Rakhypbekov, Noboru TakamuraAbstract:For the current on-site evaluation of the environmental contamination and contributory external exposure after the accident at the Chernobyl Nuclear Power Plant (CNPP) and the nuclear tests at the Semipalatinsk Nuclear Testing Site (SNTS), the concentrations of Artificial Radionuclides in soil samples from each area were analyzed by gamma spectrometry. Four Artificial Radionuclides (241Am, 134Cs, 137Cs, and 60Co) were detected in surface soil around CNPP, whereas seven Artificial Radionuclides (241Am, 57Co, 137Cs, 95Zr, 95Nb, 58Co, and 60Co) were detected in surface soil around SNTS. Effective doses around CNPP were over the public dose limit of 1 mSv/y (International Commission on Radiological Protection, 1991). These levels in a contaminated area 12 km from Unit 4 were high, whereas levels in a decontaminated area 12 km from Unit 4 and another contaminated area 15 km from Unit 4 were comparatively low. On the other hand, the effective doses around SNTS were below the public dose limit. These findings suggest that the environmental contamination and effective doses on the ground definitely decrease with decontamination such as removing surface soil, although the effective doses of the sampling points around CNPP in the present study were all over the public dose limit. Thus, the remediation of soil as a countermeasure could be an extremely effective method not only for areas around CNPP and SNTS but also for areas around the Fukushima Dai-ichi Nuclear Power Plant (FNPP), and external exposure levels will be certainly reduced. Long-term follow-up of environmental monitoring around CNPP, SNTS, and FNPP, as well as evaluation of the health effects in the population residing around these areas, could contribute to radiation safety and reduce unnecessary exposure to the public.
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evaluation of environmental contamination and estimated radiation doses for the return to residents homes in kawauchi village fukushima prefecture
PLOS ONE, 2012Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Hitoshi Yamaguchi, Yuukou Endo, Noboru TakamuraAbstract:To evaluate the environmental contamination and radiation exposure dose rates due to Artificial Radionuclides in Kawauchi Village, Fukushima Prefecture, the restricted area within a 30-km radius from the Fukushima Dai-ichi Nuclear Power Plant (FNPP), the concentrations of Artificial Radionuclides in soil samples, tree needles, and mushrooms were analyzed by gamma spectrometry. Nine months have passed since samples were collected on December 19 and 20, 2011, 9 months after the FNPP accident, and the prevalent dose-forming Artificial Radionuclides from all samples were 134Cs and 137Cs. The estimated external effective doses from soil samples were 0.42–7.2 µSv/h (3.7–63.0 mSv/y) within the 20-km radius from FNPP and 0.0011–0.38 µSv/h (0.010–3.3 mSv/y) within the 20–30 km radius from FNPP. The present study revealed that current levels are sufficiently decreasing in Kawauchi Village, especially in areas within the 20- to 30-km radius from FNPP. Thus, residents may return their homes with long-term follow-up of the environmental monitoring and countermeasures such as decontamination and restrictions of the intake of foods for reducing unnecessary exposure. The case of Kawauchi Village will be the first model for the return to residents’ homes after the FNPP accident.
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environmental contamination and external radiation dose rates from Radionuclides released from the fukushima nuclear power plant
Radiation Protection Dosimetry, 2012Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Takashi Kudo, Naoki Matsuda, Jumpei Takahashi, Alexander Gutevitc, Alexander Kazlovsky, Noboru TakamuraAbstract:To evaluate the environmental contamination and contributory external exposure after the accident at the Fukushima Nuclear Power Plant (FNPP), the concentrations of Artificial Radionuclides in soil samples from each area were analysed by gamma spectrometry. Six Artificial Radionuclides ((131)I, (134)Cs, (137)Cs, (129m)Te, (95)Nb and (136)Cs) were detected in soil samples around FNPP. Calculated external effective doses from Artificial radionuclide contamination in soil samples around FNPP were 1.9-2.9 μSv h(-1) (8.7-17.8 mSv y(-1)) in Fukushima city on 22 March 2011. After several months, these calculated external effective doses were 0.25-0.88 μSv h(-1) (2.2-7.6 mSv y(-1)) in Fukushima city on 29 June 2011. The present study revealed that the detected Artificial Radionuclides around FNPP mainly shifted to long-lived Radionuclides such as radioactive caesium ((134)Cs and (137)Cs) even though current levels are decreasing gradually due to the decay of short-lived Radionuclides such as (131)I, (129m)Te, (95)Nb and (136)Cs. Thus, radiation exposure potency still exists even though the national efforts are ongoing for reducing the annual exposure dose closer to 1 mSv, the public dose limit. Long-term environmental monitoring around FNPP contributes to radiation safety, with a reduction in unnecessary exposure to the residents.
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current concentration of Artificial Radionuclides and estimated radiation doses from 137cs around the chernobyl nuclear power plant the semipalatinsk nuclear testing site and in nagasaki
Journal of Radiation Research, 2011Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Jumpei Takahashi, Alexander Gutevitc, Alexander Kazlovsky, Marat Urazalin, Gopalganapathi M Brahmanandhan, Yuji Nagayama, Noboru TakamuraAbstract:To evaluate current environmental contamination and contributions from internal and external exposure due to the accident at the Chernobyl Nuclear Power Plant (CNPP) and nuclear tests at the Semipalatinsk Nuclear Testing Site (SNTS), concentrations of Artificial Radionuclides in edible mushrooms, soils and stones from each area were analyzed by gamma spectrometry. Annual effective doses were calculated for each area from the cesium contamination. Calculated internal effective doses of (137)Cs due to ingestion of mushrooms were 1.8 × 10(-1) mSv/year (y) in Gomel city (around CNPP), 1.7 × 10(-1) mSv/y in Korosten city (around CNPP), 2.8 × 10(-4) mSv/y in Semipalatinsk city, and 1.3 × 10(-4) mSv/y in Nagasaki. Calculated external effective doses of (137)Cs were 3.4 × 10(-2) mSv/y in Gomel city, 6.2 × 10(-2) mSv/y in Korosten city, 2.0 × 10(-4) mSv/y in Semipalatinsk city, and 1.3 × 10(-4) mSv/y in Nagasaki. Distribution of Radionuclides in stones collected beside Lake Balapan (in SNTS) were (241)Am (49.4 ± 1.4 Bq/kg), (137)Cs (406.3 ± 1.7 Bq/kg), (58)Co (3.2 ± 0.5 Bq/kg), and (60)Co (125.9 ± 1.1 and 126.1 ± 1.1 Bq/kg). The present study revealed that dose rates from internal and external exposure around CNPP were not sufficiently low and radiation exposure potency still exists even though current levels are below the public dose limit of 1 mSv/y (ICRP1991). Moreover, parts of the SNTS area may be still contaminated by Artificial Radionuclides derived from nuclear tests. Long-term follow-up of environmental monitoring around CNPP and SNTS, as well as evaluation of health effects in the population residing around these areas, may contribute to radiation safety with a reduction of unnecessary exposure of residents.
Jordi Garciaorellana - One of the best experts on this subject based on the ideXlab platform.
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arctic ocean sea ice drift origin derived from Artificial Radionuclides
Science of The Total Environment, 2010Co-Authors: P Camaramor, Pere Masque, Jordi Garciaorellana, J K Cochran, Elena Chamizo, Claudia HanflandAbstract:Since the 1950s, nuclear weapon testing and releases from the nuclear industry have introduced anthropogenic Radionuclides into the sea, and in many instances their ultimate fate are the bottom sediments. The Arctic Ocean is one of the most polluted in this respect, because, in addition to global fallout, it is impacted by regional fallout from nuclear weapon testing, and indirectly by releases from nuclear reprocessing facilities and nuclear accidents. Sea-ice formed in the shallow continental shelves incorporate sediments with variable concentrations of anthropogenic Radionuclides that are transported through the Arctic Ocean and are finally released in the melting areas. In this work, we present the results of anthropogenic radionuclide analyses of sea-ice sediments (SIS) collected on five cruises from different Arctic regions and combine them with a database including prior measurements of these Radionuclides in SIS. The distribution of (137)Cs and (239,240)Pu activities and the (240)Pu/(239)Pu atom ratio in SIS showed geographical differences, in agreement with the two main sea ice drift patterns derived from the mean field of sea-ice motion, the Transpolar Drift and Beaufort Gyre, with the Fram Strait as the main ablation area. A direct comparison of data measured in SIS samples against those reported for the potential source regions permits identification of the regions from which sea ice incorporates sediments. The (240)Pu/(239)Pu atom ratio in SIS may be used to discern the origin of sea ice from the Kara-Laptev Sea and the Alaskan shelf. However, if the (240)Pu/(239)Pu atom ratio is similar to global fallout, it does not provide a unique diagnostic indicator of the source area, and in such cases, the source of SIS can be constrained with a combination of the (137)Cs and (239,240)Pu activities. Therefore, these anthropogenic Radionuclides can be used in many instances to determine the geographical source area of sea-ice.
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distribution of Artificial Radionuclides in deep sediments of the mediterranean sea
Science of The Total Environment, 2009Co-Authors: Jordi Garciaorellana, Pere Masque, Jackie M Pates, J M Bruach, Joanalbert SanchezcabezaAbstract:Artificial Radionuclides enter the Mediterranean Sea mainly through atmospheric deposition following nuclear weapons tests and the Chernobyl accident, but also through the river discharge of nuclear facility effluents. Previous studies of Artificial Radionuclides impact of the Mediterranean Sea have focussed on shallow, coastal sediments. However, deep sea sediments have the potential to store and accumulate pollutants, including Artificial Radionuclides. Deep sea marine sediment cores were collected from Mediterranean Sea abyssal plains (depth > 2000 m) and analysed for 239,240Pu and 137Cs to elucidate the concentrations, inventories and sources of these Radionuclides in the deepest areas of the Mediterranean. The activity — depth profiles of 210Pb, together with 14C dating, indicate that sediment mixing redistributes the Artificial Radionuclides within the first 2.5 cm of the sedimentary column. The excess 210Pb inventory was used to normalize 239,240Pu and 137Cs inventories for variable sediment fluxes. The 239,240Pu/210Pbxs ratio was uniform across the entire sea, with a mean value of 1.24 × 10− 3, indicating homogeneous fallout of 239,240Pu. The 137Cs/210Pbxs ratio showed differences between the eastern (0.049) and western basins (0.030), clearly significant impact of deep sea sediments from the Chernobyl accident. The inventory ratios of 239,240Pu/137Cs were 0.041 and 0.025 in the western and eastern basins respectively, greater than the fallout ratio, 0.021, showing more efficient scavenging of 239,240Pu in the water column and major sedimentation of 137Cs in the eastern basin. Although areas with water depths of > 2000 m constitute around 40% of the entire Mediterranean basin, the sediments in these regions only contained 2.7% of the 239,240Pu and 0.95% of the 137Cs deposited across the Sea in 2000. These data show that the accumulation of Artificial Radionuclides in deep Mediterranean environments is much lower than predicted by other studies from the analysis of continental shelf sediments.
Naomi Hayashida - One of the best experts on this subject based on the ideXlab platform.
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measurement of individual doses of radiation by personal dosimeter is important for the return of residents from evacuation order areas after nuclear disaster
PLOS ONE, 2015Co-Authors: Makiko Orita, Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Takashi Kudo, Yoshiko Fukushima, Juichi Ide, Yuuko Endo, Noboru TakamuraAbstract:To confirm the availability of individual dose evaluation for the return of residents after the accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP), we evaluated individual doses of radiation as measured by personal dosimeters in residents who temporarily stayed in Evacuation Order Areas in Kawauchi village, which is partially located within a 20 km radius of the FNPP. We also compared individual doses with the external radiation doses estimated from the ambient dose rates and with doses estimated from the concentrations of Radionuclides in the soil around each individual’s house. Individual doses were significantly correlated with the ambient doses in front of the entrances to the houses (r = 0.90, p<0.01), in the backyards (r = 0.41, p<0.01) and in the nearby fields (r = 0.80, p<0.01). The maximum cumulative ambient doses in the backyards and fields around the houses were 6.38 and 9.27 mSv/y, respectively. The maximum cumulative individual dose was 3.28 mSv/y, and the median and minimum doses were 1.35 and 0.71 mSv/y. The estimated external effective doses from concentrations of Artificial Radionuclides in soil samples ranged from 0.03 to 23.42 mSv/y. The individual doses were moderately correlated with external effective doses in the backyards (r = 0.38, p<0.01) and in the fields (r = 0.36, p<0.01); however, the individual doses were not significantly correlated with the external effective doses in front of the entrances (r = 0.01, p = 0.92). Our study confirmed that individual doses are low levels even in the evacuation order area in Kawauchi village, and external effective dose levels are certainly decreasing due to the decay of Artificial Radionuclides and the decontamination of contaminated soil. Long-term follow-up of individual doses as well as internal-exposure doses, environmental monitoring and reconstruction of infrastructure are needed so that residents may return to their hometowns after a nuclear disaster.
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vertical distribution and estimated doses from Artificial Radionuclides in soil samples around the chernobyl nuclear power plant and the semipalatinsk nuclear testing site
PLOS ONE, 2013Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Jumpei Takahashi, Alexander Kazlovsky, Rimi Tsuchiya, Hitoshi Yamaguchi, Marat Urazalin, Tolebay Rakhypbekov, Noboru TakamuraAbstract:For the current on-site evaluation of the environmental contamination and contributory external exposure after the accident at the Chernobyl Nuclear Power Plant (CNPP) and the nuclear tests at the Semipalatinsk Nuclear Testing Site (SNTS), the concentrations of Artificial Radionuclides in soil samples from each area were analyzed by gamma spectrometry. Four Artificial Radionuclides (241Am, 134Cs, 137Cs, and 60Co) were detected in surface soil around CNPP, whereas seven Artificial Radionuclides (241Am, 57Co, 137Cs, 95Zr, 95Nb, 58Co, and 60Co) were detected in surface soil around SNTS. Effective doses around CNPP were over the public dose limit of 1 mSv/y (International Commission on Radiological Protection, 1991). These levels in a contaminated area 12 km from Unit 4 were high, whereas levels in a decontaminated area 12 km from Unit 4 and another contaminated area 15 km from Unit 4 were comparatively low. On the other hand, the effective doses around SNTS were below the public dose limit. These findings suggest that the environmental contamination and effective doses on the ground definitely decrease with decontamination such as removing surface soil, although the effective doses of the sampling points around CNPP in the present study were all over the public dose limit. Thus, the remediation of soil as a countermeasure could be an extremely effective method not only for areas around CNPP and SNTS but also for areas around the Fukushima Dai-ichi Nuclear Power Plant (FNPP), and external exposure levels will be certainly reduced. Long-term follow-up of environmental monitoring around CNPP, SNTS, and FNPP, as well as evaluation of the health effects in the population residing around these areas, could contribute to radiation safety and reduce unnecessary exposure to the public.
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evaluation of environmental contamination and estimated radiation doses for the return to residents homes in kawauchi village fukushima prefecture
PLOS ONE, 2012Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Hitoshi Yamaguchi, Yuukou Endo, Noboru TakamuraAbstract:To evaluate the environmental contamination and radiation exposure dose rates due to Artificial Radionuclides in Kawauchi Village, Fukushima Prefecture, the restricted area within a 30-km radius from the Fukushima Dai-ichi Nuclear Power Plant (FNPP), the concentrations of Artificial Radionuclides in soil samples, tree needles, and mushrooms were analyzed by gamma spectrometry. Nine months have passed since samples were collected on December 19 and 20, 2011, 9 months after the FNPP accident, and the prevalent dose-forming Artificial Radionuclides from all samples were 134Cs and 137Cs. The estimated external effective doses from soil samples were 0.42–7.2 µSv/h (3.7–63.0 mSv/y) within the 20-km radius from FNPP and 0.0011–0.38 µSv/h (0.010–3.3 mSv/y) within the 20–30 km radius from FNPP. The present study revealed that current levels are sufficiently decreasing in Kawauchi Village, especially in areas within the 20- to 30-km radius from FNPP. Thus, residents may return their homes with long-term follow-up of the environmental monitoring and countermeasures such as decontamination and restrictions of the intake of foods for reducing unnecessary exposure. The case of Kawauchi Village will be the first model for the return to residents’ homes after the FNPP accident.
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environmental contamination and external radiation dose rates from Radionuclides released from the fukushima nuclear power plant
Radiation Protection Dosimetry, 2012Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Takashi Kudo, Naoki Matsuda, Jumpei Takahashi, Alexander Gutevitc, Alexander Kazlovsky, Noboru TakamuraAbstract:To evaluate the environmental contamination and contributory external exposure after the accident at the Fukushima Nuclear Power Plant (FNPP), the concentrations of Artificial Radionuclides in soil samples from each area were analysed by gamma spectrometry. Six Artificial Radionuclides ((131)I, (134)Cs, (137)Cs, (129m)Te, (95)Nb and (136)Cs) were detected in soil samples around FNPP. Calculated external effective doses from Artificial radionuclide contamination in soil samples around FNPP were 1.9-2.9 μSv h(-1) (8.7-17.8 mSv y(-1)) in Fukushima city on 22 March 2011. After several months, these calculated external effective doses were 0.25-0.88 μSv h(-1) (2.2-7.6 mSv y(-1)) in Fukushima city on 29 June 2011. The present study revealed that the detected Artificial Radionuclides around FNPP mainly shifted to long-lived Radionuclides such as radioactive caesium ((134)Cs and (137)Cs) even though current levels are decreasing gradually due to the decay of short-lived Radionuclides such as (131)I, (129m)Te, (95)Nb and (136)Cs. Thus, radiation exposure potency still exists even though the national efforts are ongoing for reducing the annual exposure dose closer to 1 mSv, the public dose limit. Long-term environmental monitoring around FNPP contributes to radiation safety, with a reduction in unnecessary exposure to the residents.
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current concentration of Artificial Radionuclides and estimated radiation doses from 137cs around the chernobyl nuclear power plant the semipalatinsk nuclear testing site and in nagasaki
Journal of Radiation Research, 2011Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Jumpei Takahashi, Alexander Gutevitc, Alexander Kazlovsky, Marat Urazalin, Gopalganapathi M Brahmanandhan, Yuji Nagayama, Noboru TakamuraAbstract:To evaluate current environmental contamination and contributions from internal and external exposure due to the accident at the Chernobyl Nuclear Power Plant (CNPP) and nuclear tests at the Semipalatinsk Nuclear Testing Site (SNTS), concentrations of Artificial Radionuclides in edible mushrooms, soils and stones from each area were analyzed by gamma spectrometry. Annual effective doses were calculated for each area from the cesium contamination. Calculated internal effective doses of (137)Cs due to ingestion of mushrooms were 1.8 × 10(-1) mSv/year (y) in Gomel city (around CNPP), 1.7 × 10(-1) mSv/y in Korosten city (around CNPP), 2.8 × 10(-4) mSv/y in Semipalatinsk city, and 1.3 × 10(-4) mSv/y in Nagasaki. Calculated external effective doses of (137)Cs were 3.4 × 10(-2) mSv/y in Gomel city, 6.2 × 10(-2) mSv/y in Korosten city, 2.0 × 10(-4) mSv/y in Semipalatinsk city, and 1.3 × 10(-4) mSv/y in Nagasaki. Distribution of Radionuclides in stones collected beside Lake Balapan (in SNTS) were (241)Am (49.4 ± 1.4 Bq/kg), (137)Cs (406.3 ± 1.7 Bq/kg), (58)Co (3.2 ± 0.5 Bq/kg), and (60)Co (125.9 ± 1.1 and 126.1 ± 1.1 Bq/kg). The present study revealed that dose rates from internal and external exposure around CNPP were not sufficiently low and radiation exposure potency still exists even though current levels are below the public dose limit of 1 mSv/y (ICRP1991). Moreover, parts of the SNTS area may be still contaminated by Artificial Radionuclides derived from nuclear tests. Long-term follow-up of environmental monitoring around CNPP and SNTS, as well as evaluation of health effects in the population residing around these areas, may contribute to radiation safety with a reduction of unnecessary exposure of residents.
Shunichi Yamashita - One of the best experts on this subject based on the ideXlab platform.
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measurement of individual doses of radiation by personal dosimeter is important for the return of residents from evacuation order areas after nuclear disaster
PLOS ONE, 2015Co-Authors: Makiko Orita, Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Takashi Kudo, Yoshiko Fukushima, Juichi Ide, Yuuko Endo, Noboru TakamuraAbstract:To confirm the availability of individual dose evaluation for the return of residents after the accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP), we evaluated individual doses of radiation as measured by personal dosimeters in residents who temporarily stayed in Evacuation Order Areas in Kawauchi village, which is partially located within a 20 km radius of the FNPP. We also compared individual doses with the external radiation doses estimated from the ambient dose rates and with doses estimated from the concentrations of Radionuclides in the soil around each individual’s house. Individual doses were significantly correlated with the ambient doses in front of the entrances to the houses (r = 0.90, p<0.01), in the backyards (r = 0.41, p<0.01) and in the nearby fields (r = 0.80, p<0.01). The maximum cumulative ambient doses in the backyards and fields around the houses were 6.38 and 9.27 mSv/y, respectively. The maximum cumulative individual dose was 3.28 mSv/y, and the median and minimum doses were 1.35 and 0.71 mSv/y. The estimated external effective doses from concentrations of Artificial Radionuclides in soil samples ranged from 0.03 to 23.42 mSv/y. The individual doses were moderately correlated with external effective doses in the backyards (r = 0.38, p<0.01) and in the fields (r = 0.36, p<0.01); however, the individual doses were not significantly correlated with the external effective doses in front of the entrances (r = 0.01, p = 0.92). Our study confirmed that individual doses are low levels even in the evacuation order area in Kawauchi village, and external effective dose levels are certainly decreasing due to the decay of Artificial Radionuclides and the decontamination of contaminated soil. Long-term follow-up of individual doses as well as internal-exposure doses, environmental monitoring and reconstruction of infrastructure are needed so that residents may return to their hometowns after a nuclear disaster.
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vertical distribution and estimated doses from Artificial Radionuclides in soil samples around the chernobyl nuclear power plant and the semipalatinsk nuclear testing site
PLOS ONE, 2013Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Jumpei Takahashi, Alexander Kazlovsky, Rimi Tsuchiya, Hitoshi Yamaguchi, Marat Urazalin, Tolebay Rakhypbekov, Noboru TakamuraAbstract:For the current on-site evaluation of the environmental contamination and contributory external exposure after the accident at the Chernobyl Nuclear Power Plant (CNPP) and the nuclear tests at the Semipalatinsk Nuclear Testing Site (SNTS), the concentrations of Artificial Radionuclides in soil samples from each area were analyzed by gamma spectrometry. Four Artificial Radionuclides (241Am, 134Cs, 137Cs, and 60Co) were detected in surface soil around CNPP, whereas seven Artificial Radionuclides (241Am, 57Co, 137Cs, 95Zr, 95Nb, 58Co, and 60Co) were detected in surface soil around SNTS. Effective doses around CNPP were over the public dose limit of 1 mSv/y (International Commission on Radiological Protection, 1991). These levels in a contaminated area 12 km from Unit 4 were high, whereas levels in a decontaminated area 12 km from Unit 4 and another contaminated area 15 km from Unit 4 were comparatively low. On the other hand, the effective doses around SNTS were below the public dose limit. These findings suggest that the environmental contamination and effective doses on the ground definitely decrease with decontamination such as removing surface soil, although the effective doses of the sampling points around CNPP in the present study were all over the public dose limit. Thus, the remediation of soil as a countermeasure could be an extremely effective method not only for areas around CNPP and SNTS but also for areas around the Fukushima Dai-ichi Nuclear Power Plant (FNPP), and external exposure levels will be certainly reduced. Long-term follow-up of environmental monitoring around CNPP, SNTS, and FNPP, as well as evaluation of the health effects in the population residing around these areas, could contribute to radiation safety and reduce unnecessary exposure to the public.
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evaluation of environmental contamination and estimated radiation doses for the return to residents homes in kawauchi village fukushima prefecture
PLOS ONE, 2012Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Hitoshi Yamaguchi, Yuukou Endo, Noboru TakamuraAbstract:To evaluate the environmental contamination and radiation exposure dose rates due to Artificial Radionuclides in Kawauchi Village, Fukushima Prefecture, the restricted area within a 30-km radius from the Fukushima Dai-ichi Nuclear Power Plant (FNPP), the concentrations of Artificial Radionuclides in soil samples, tree needles, and mushrooms were analyzed by gamma spectrometry. Nine months have passed since samples were collected on December 19 and 20, 2011, 9 months after the FNPP accident, and the prevalent dose-forming Artificial Radionuclides from all samples were 134Cs and 137Cs. The estimated external effective doses from soil samples were 0.42–7.2 µSv/h (3.7–63.0 mSv/y) within the 20-km radius from FNPP and 0.0011–0.38 µSv/h (0.010–3.3 mSv/y) within the 20–30 km radius from FNPP. The present study revealed that current levels are sufficiently decreasing in Kawauchi Village, especially in areas within the 20- to 30-km radius from FNPP. Thus, residents may return their homes with long-term follow-up of the environmental monitoring and countermeasures such as decontamination and restrictions of the intake of foods for reducing unnecessary exposure. The case of Kawauchi Village will be the first model for the return to residents’ homes after the FNPP accident.
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environmental contamination and external radiation dose rates from Radionuclides released from the fukushima nuclear power plant
Radiation Protection Dosimetry, 2012Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Takashi Kudo, Naoki Matsuda, Jumpei Takahashi, Alexander Gutevitc, Alexander Kazlovsky, Noboru TakamuraAbstract:To evaluate the environmental contamination and contributory external exposure after the accident at the Fukushima Nuclear Power Plant (FNPP), the concentrations of Artificial Radionuclides in soil samples from each area were analysed by gamma spectrometry. Six Artificial Radionuclides ((131)I, (134)Cs, (137)Cs, (129m)Te, (95)Nb and (136)Cs) were detected in soil samples around FNPP. Calculated external effective doses from Artificial radionuclide contamination in soil samples around FNPP were 1.9-2.9 μSv h(-1) (8.7-17.8 mSv y(-1)) in Fukushima city on 22 March 2011. After several months, these calculated external effective doses were 0.25-0.88 μSv h(-1) (2.2-7.6 mSv y(-1)) in Fukushima city on 29 June 2011. The present study revealed that the detected Artificial Radionuclides around FNPP mainly shifted to long-lived Radionuclides such as radioactive caesium ((134)Cs and (137)Cs) even though current levels are decreasing gradually due to the decay of short-lived Radionuclides such as (131)I, (129m)Te, (95)Nb and (136)Cs. Thus, radiation exposure potency still exists even though the national efforts are ongoing for reducing the annual exposure dose closer to 1 mSv, the public dose limit. Long-term environmental monitoring around FNPP contributes to radiation safety, with a reduction in unnecessary exposure to the residents.
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current concentration of Artificial Radionuclides and estimated radiation doses from 137cs around the chernobyl nuclear power plant the semipalatinsk nuclear testing site and in nagasaki
Journal of Radiation Research, 2011Co-Authors: Yasuyuki Taira, Naomi Hayashida, Shunichi Yamashita, Jumpei Takahashi, Alexander Gutevitc, Alexander Kazlovsky, Marat Urazalin, Gopalganapathi M Brahmanandhan, Yuji Nagayama, Noboru TakamuraAbstract:To evaluate current environmental contamination and contributions from internal and external exposure due to the accident at the Chernobyl Nuclear Power Plant (CNPP) and nuclear tests at the Semipalatinsk Nuclear Testing Site (SNTS), concentrations of Artificial Radionuclides in edible mushrooms, soils and stones from each area were analyzed by gamma spectrometry. Annual effective doses were calculated for each area from the cesium contamination. Calculated internal effective doses of (137)Cs due to ingestion of mushrooms were 1.8 × 10(-1) mSv/year (y) in Gomel city (around CNPP), 1.7 × 10(-1) mSv/y in Korosten city (around CNPP), 2.8 × 10(-4) mSv/y in Semipalatinsk city, and 1.3 × 10(-4) mSv/y in Nagasaki. Calculated external effective doses of (137)Cs were 3.4 × 10(-2) mSv/y in Gomel city, 6.2 × 10(-2) mSv/y in Korosten city, 2.0 × 10(-4) mSv/y in Semipalatinsk city, and 1.3 × 10(-4) mSv/y in Nagasaki. Distribution of Radionuclides in stones collected beside Lake Balapan (in SNTS) were (241)Am (49.4 ± 1.4 Bq/kg), (137)Cs (406.3 ± 1.7 Bq/kg), (58)Co (3.2 ± 0.5 Bq/kg), and (60)Co (125.9 ± 1.1 and 126.1 ± 1.1 Bq/kg). The present study revealed that dose rates from internal and external exposure around CNPP were not sufficiently low and radiation exposure potency still exists even though current levels are below the public dose limit of 1 mSv/y (ICRP1991). Moreover, parts of the SNTS area may be still contaminated by Artificial Radionuclides derived from nuclear tests. Long-term follow-up of environmental monitoring around CNPP and SNTS, as well as evaluation of health effects in the population residing around these areas, may contribute to radiation safety with a reduction of unnecessary exposure of residents.
