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Journal Articles

Thirty-year prediction of $$^{137}$$Cs supply from rivers to coastal waters off Fukushima considering human activities

Ikenoue, Tsubasa; Shimadera, Hikari*; Nakanishi, Takahiro; Kondo, Akira*

Water (Internet), 15(15), p.2734_1 - 2734_18, 2023/08

https://doi.org/10.3390/w15152734
 Times Cited Count：0 Percentile：0(Environmental Sciences)

The Fukushima Daiichi Nuclear Power Plant accident caused an accumulation of $$^{137}$$Cs in coastal sediment. The $$^{137}$$Cs supply from rivers to the ocean can affect the long-term fate of $$^{137}$$Cs in coastal sediment. Since the Fukushima coastal river basins include large decontaminated and evacuation order areas, considering the decontamination work and resumption of agriculture is important for predicting the $$^{137}$$Cs supply. We conducted a 30-year prediction of the $$^{137}$$Cs supply from the Fukushima coastal rivers to the ocean using a distributed radiocesium prediction model, considering the effects of human activities. In river basins with decontaminated and evacuation order areas, human activities reduced the total $$^{137}$$Cs outflow from agricultural lands, urban lands, and forest areas to the rivers and the $$^{137}$$Cs supply to the ocean by 5.0% and 6.0%, respectively. These results indicated that human activities slightly impacted the $$^{137}$$Cs outflow and supply. The $$^{137}$$Cs supply from rivers impacted by the accident to the coastal sediment was estimated to correspond to 11-36% of the total $$^{137}$$Cs in the coastal sediment in the early phase of the accident. Therefore, the $$^{137}$$Cs supply from rivers to the ocean is important for the long-term behavior of $$^{137}$$Cs in coastal sediment.

Journal Articles

Thirty-year simulation of environmental fate of $$^{137}$$Cs in the Abukuma River basin considering the characteristics of $$^{137}$$Cs behavior in land uses

Ikenoue, Tsubasa; Shimadera, Hikari*; Nakanishi, Takahiro; Kondo, Akira*

Science of the Total Environment, 876, p.162846_1 - 162846_12, 2023/06

https://doi.org/10.1016/j.scitotenv.2023.162846
 Times Cited Count：2 Percentile：52.26(Environmental Sciences)

We conducted 30 years simulation of environmental fate of $$^{137}$$Cs in the Abukuma River basin considering the characteristics of the $$^{137}$$Cs behavior in land uses. Overall, in the Abukuma River basin, the $$^{137}$$Cs transported into the ocean for 30 years was estimated to correspond to 4.6% of the initial deposition in the basin, and the effective half-life of $$^{137}$$Cs deposited in the basin was estimated to be 3.7 years shorter (by 11.6%) than its physical half-life. These results suggested that $$^{137}$$Cs deposited from the accident could still remain for decades. Based on the analysis of the $$^{137}$$Cs behavior in land use, in 2011, the contribution of $$^{137}$$Cs export to the ocean from urban lands was estimated to correspond to 70% of the total $$^{137}$$Cs export. Meanwhile, from 2012 to 2040, the contribution of $$^{137}$$Cs export from agricultural lands was estimated to correspond to 75% of the total $$^{137}$$Cs export. The reduction ratios excluding radioactive decay of $$^{137}$$Cs remained in areas with and without human activities for 30 years after the accident, defined as the ratios of the total outflow to the initial deposition, were estimated to be 11.5%-17.7% and 0.4%-1.4%, respectively. These results suggested that human activities enhance the reduction of $$^{137}$$Cs remaining in land in the past and future.

Journal Articles

Statistical analysis of simulated oceanic dispersion of dissolved radionuclide hypothetically released from the Fukushima Dai-ichi Nuclear Power Plant using long-term oceanographic reanalysis data

Ikenoue, Tsubasa; Kawamura, Hideyuki; Kamidaira, Yuki

Journal of Nuclear Science and Technology, 60(1), p.61 - 71, 2023/01

https://doi.org/10.1080/00223131.2022.2079569
 Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)

We conducted numerical simulations on the oceanic dispersion of dissolved radionuclide hypothetically released from the Fukushima Dai-ichi Nuclear Power Plant using long-term oceanographic reanalysis data. We evaluated the characteristics and trends of dissolved radionuclide behavior in the ocean using statistical analysis based on the simulation results. The surface meridional current at the release point in the Fukushima coastal ocean and the Kuroshio Extension significantly affected the north-south transport of the surface radionuclide in the Fukushima coastal ocean and the eastward transport of the offshore surface radionuclide, respectively. Because the surface kinetic energy in the coastal to the offshore area was larger, the range of the dispersed surface radionuclide tended to be larger. In summer (July-September), the increased frequency radionuclide entrainment by the Kuroshio Extension because of the surface southward radionuclide transport in the Fukushima coastal ocean and the large surface kinetic energy caused a large dispersed surface radionuclide. In winter (January-March), the decreased frequency radionuclide entrainment by the Kuroshio Extension because of the surface northward radionuclide transport in the Fukushima coastal ocean and the small surface kinetic energy caused a small dispersed surface radionuclide.

Journal Articles

Radiocesium concentration in flying insects collected from a radioactive contaminated area after the Fukushima Dai-ichi Nuclear Power Plant accident

Tanaka, Sota; Kakinuma, Hotaru*; Adachi, Taro*; Takahashi, Tomoyuki*; Takahashi, Sentaro*

KEK Proceedings 2019-2, p.179 - 182, 2019/11

The concentration of $$^{137}$$Cs in flying insects was investigated after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. The insects were collected at about 11 km north west of the FDNPP at two different sites in the forest and riverside. The median concentration of $$^{137}$$Cs in flying insects in the forest was significantly higher than riverside. However, high concentration of $$^{137}$$Cs in detritus fly (Diptera: Calliphoridae) was observed at both sites. The concentration of fly at the forest and riverside were 16$$times$$10$$^{2}$$ Bq/kg fw and 18$$times$$10$$^{2}$$ Bq/kg fw, respectively. The result shows that the concentration of radiocesium in detritus fly were still high 8 years after the accident. This suggests that detritus food chain is a dominant transfer pathway of radiocesium to higher trophic level species such as spiders.

Journal Articles

Fukushima $$^{137}$$Cs releases dispersion modelling over the Pacific Ocean; Comparisons of models with water, sediment and biota data

Peri$'a$$~n$ez, R.*; Bezhenar, R.*; Brovchenko, I.*; Jung, K. T.*; Kamidaira, Yuki; Kim, K. O.*; Kobayashi, Takuya; Liptak, L.*; Maderich, V.*; Min, B. I.*; et al.

Journal of Environmental Radioactivity, 198, p.50 - 63, 2019/03

https://doi.org/10.1016/j.jenvrad.2018.12.014
 Times Cited Count：21 Percentile：67.06(Environmental Sciences)

A number of marine radionuclide dispersion models were applied to simulate $$^{137}$$Cs releases from Fukushima Daiichi Nuclear Power Plant accident in 2011 over the northwest Pacific. Simulations extended over two years and both direct releases into the ocean and deposition of atmospheric releases on the ocean surface were considered. Dispersion models included an embedded biological uptake model (BUM). Three types of BUMs were used: equilibrium, dynamic and allometric. Model results were compared with $$^{137}$$Cs measurements in water, sediment and biota. A reasonable agreement in model/model and model/data comparisons was obtained.

JAEA Reports

Detailed investigation on the environmental effects from the liquid effluent of JNC reprocessing plant (IV); (April, 1996$$sim$$March, 2000)

; Shinohara, Kunihiko; ; ; ; Isozaki, Tokuju; ; *

JNC TN8440 2000-003, 93 Pages, 2000/08

JNC-TN8440-2000-003.pdf:2.2MB

The investigation on the radioactivity concentration for gross beta, $$^{3}$$H and $$^{137}$$Cs in seawater collected around the discharge point had been performed in order to grasp the change of the activity level of the coastal seawater offshore the JNC Tokai Works from the low level liquid effluent of the reprocessing plant. After the investigation on the radioactivity in seawater during the hot examination, the detailed investigation on the environmental effects from the liquid effluent of JNC reprocessing plant has been performed since July 1978 on the basis of the request from Ibaraki prefecture as the full-scale operation of the reprocessing plant. Consequently, no increase of the radioactive concentration due to the discharged effluent has been observed. And also, as the result of the consideration to the investigation on the environmental effect from the liquid effluent throughout 22 years since 1978, no change of the radioactive concentration level in seawater was recognized.

JAEA Reports

Decontamination factor of the commerciaI detergents for the skin (Part 3)

Miyabe, Kenjiro; Takasaki, Koji; Yasunaga, Hideo*; Izumi, Yuichi*

JNC TN8420 2000-007, 100 Pages, 2000/08

JNC-TN8420-2000-007.pdf:7.66MB

The commercial detergents, which are cleansing cream, shampoo, neutral detergent, etc., were examined in order to select the body cleaners that are substitutes for the titanium dioxide paste. JNC entrusted Japan Environment Research Corporation Limited with these examinations since 1997. In 1997 and 1998, the commercial detergents were examined for Ce-144, Cs-137 and Ru-106. In 1999, 22 detergents were examined for Co-60 from the result of the past examinations. In this examination, the radioactive solution of Co-60 was dropped on the pig-skin samples. These samples were washed with each detergent after 5 minutes and 40 minutes. The decontamination factors of detergents were estimated by the radioactive ratio of the samples before and after washing. As a result of this examination, the decontamination factors for Co-60 was the same as the decontamination factors for Ce-144 and Cs-137, and 11 detergents were nominated as the cleaner that have the decontamination factor more than that of titanium dioxide paste.

JAEA Reports

Exact solution of electric transitions and production probability of isomer state of FP

Wada, Hiroaki

JNC TN8400 2000-015, 37 Pages, 2000/03

JNC-TN8400-2000-015.pdf:0.8MB

This report describes the study done within the period of time when I was postdoctoral research worker at Japan Nuclear Cycle Development Institute. The report includes two parts as follows. (1) Exact Solution of Electric Transitions for High Energy photons. Technologies for creating high-energy $$gamma$$ beams have been rapidly developed. These advancements make the research using high-energy $$gamma$$-rays more important. The electric transition rates for high-energy $$gamma$$-rays were formulated. The electric multipole fields were treated strictly in the process of calculating the electric transition rates and the nuclear states were taken as the harmonic oscillator wave functions. (2) Production of the isomeric state of $$^{138}$$Cs in the thermal neutron capture reaction $$^{137}$$Cs(n, $$gamma$$)$$^{138}$$Cs. In order to obtain precise data of the neutron capture cross section of the reaction $$^{137}$$Cs(n, $$gamma$$)$$^{138}$$Cs, the production probability of isomer state $$^{rm 138m}$$Cs was measured in this work. The 1436 keV $$gamma$$-ray emitted from both of $$^{rm 138g}$$Cs and $$^{rm 138m}$$Cs was measured. A production ratio of $$^{rm 138m}$$Cs to ($$^{rm 138g}$$Cs and $$^{rm 138m}$$Cs) was deduced from time dependence of peak counts of 1436keV $$gamma$$-ray. The probability of the production of $$^{rm 138m}$$CS was obtained as 0.75$$pm$$0.18 and this value revised the effective cross section upwards 9$$pm$$2%. The effective cross section $$sigma$$ and the thermal neutron capture cross section $$sigma$$$$_{o}$$ were obtained as $$sigma$$=0.29$$pm$$0.02 b and $$sigma$$$$_{o}$$=0.27$$pm$$0.03 b with taking into account the production of $$^{138m}$$Cs.

JAEA Reports

Distribution of actinide elements among various environmental factors (II)

Kudo, Akira*; Fujikawa, Yoko*

JNC TJ8400 2000-010, 67 Pages, 2000/02

JNC-TJ8400-2000-010.pdf:2.17MB

The first and second environmental releases of man-made $$^{239+240}$$Pu came from nuclear explosions at Alamagordo and Nagasaki in 1945. The release at Nagasaki was more serious than at Alamagordo, because it happened in an area with a high population density. Unfissioned $$^{239+240}$$Pu and various fission products have been interacting here with various environmental materials (soils, sediments, and plants) under wet and temperature conditions for more than 45 years. To assess the environmental mobility of $$^{239+240}$$Pu, the distributions of radionuclides from this release were investigated at Nishiyama where heavy black rain containing unfissioned plutonium and fission products fell 30 minutes after the nuclear explosion. The vertical distributions of $$^{137}$$Cs and $$^{239+240}$$Pu were determined in unsaturated soil cores up to 450cm deep. Most radionuclides were found in the soil column 30cm from the ground surface. However, $$^{239+240}$$Pu were detected in the groundwater as well below a depth of 200cm. No $$^{137}$$Cs was found below 40cm from the ground surface or in groundwater. These observations reveal that about 3% of the total $$^{239+240}$$Pu have been migrating in the soil at a faster rate than the remaining $$^{239+240}$$Pu. Sharp peak of $$^{137}$$Cs and $$^{239+240}$$Pu, indicating heavy deposition from the Nagasaki local fallout of 1945, were found in sediment cores collected from the Nishiyama reservoir. $$^{239+240}$$Pu peaks were unexpectedly discovered in pre-1945 sediment core sections. NO $$^{137}$$Cs was found. By contrast to the distribution in sediment cores, $$^{137}$$Cs in tree rings had spread by diffusion from the bark to the center of the tree without holding a fallout deposition record. Most of the $$^{239+240}$$Pu was distributed in the tree rings following a similar deposition record to that found in sediment cores. Furthermore, a very small amount of $$^{239+240}$$Pu (about 1%) was found unexpectedly in pre-1945 tree rings. The only reasonable ...

JAEA Reports

None

PNC TJ1533 97-001, 461 Pages, 1997/03

PNC-TJ1533-97-001.pdf:14.27MB

None

JAEA Reports

None

*

PNC TJ1309 96-001, 113 Pages, 1996/03

PNC-TJ1309-96-001.pdf:3.42MB

no abstracts in English

Journal Articles

Colloidal migration behavior of radionuclides sorbed on mobile fine soil particles through a sand layer

Tanaka, Tadao; Onuki, Toshihiko

Journal of Nuclear Science and Technology, 33(1), p.62 - 68, 1996/01

https://doi.org/10.3327/jnst.33.62
 Times Cited Count：8 Percentile：58.77(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Effects of drying on desorption behavior of radionuclides adsorbed on a sand

Tanaka, Tadao

JAERI-Research 95-044, 21 Pages, 1995/06

JAERI-Research-95-044.pdf:0.79MB

no abstracts in English

JAEA Reports

None

; Sumiya, Shuichi;

PNC TN8450 94-006, 28 Pages, 1994/12

no abstracts in English

JAEA Reports

Environmental simulation test for radionuclide migration under wet-dry cycle condition in aerated zone

Tanaka, Tadao; Yamamoto, Tadatoshi

JAERI-Research 94-010, 30 Pages, 1994/08

JAERI-Research-94-010.pdf:1.34MB

no abstracts in English

Journal Articles

Influence of soil/solution ratio on adsorption behavior of cesium on soils

Tanaka, Tadao; Onuki, Toshihiko

Geochemical Journal, 28(5), p.369 - 376, 1994/00

https://doi.org/10.2343/geochemj.28.369
 Times Cited Count：5 Percentile：15.98(Geochemistry & Geophysics)

no abstracts in English

JAEA Reports

Influence of humic acid on migration of $$^{60}$$Co, $$^{85}$$Sr and $$^{137}$$Cs in coastal sandy soil

Tanaka, Tadao; N.Shiwei*

JAERI-M 93-185, 17 Pages, 1993/10

JAERI-M-93-185.pdf:0.64MB

no abstracts in English

JAEA Reports

Research and tests of position sensitive radiation detector

Emoto, Takehiko; ; Ando, Hideki

PNC TN9410 93-186, 65 Pages, 1993/09

PNC-TN9410-93-186.pdf:2.24MB

From the viewpoint of radiation protection and radiation shielding evaluation, the needs to know the positions that are irradiated by radiation are increasing, because measuring irradiated positions is useful for detecting local streaming at working areas in nuclear facilities and evaluating beam-loss from accelerators. We have investigated and experimented the characteristics of plastic scintillating fiber(PSF), that has been recently developed one of most popular position sensitive particle detectors in high energy physics, for purpose of that we can apply them to the radiation measurements as a position sensitive radiation detector. First, we referred to the results of the committed research performed in last year and to relative works. And, to aim for improvement of efficiency of gamma-ray and for stretch of the detector, we investigated efficiency and resolution of the detectors giving priorities to (a) variation of length and bundle of PSFs hamess, and (b) variation of the irradiated positions. As the results of referring to the works and the experiments on the detectors, we got the followings, (1)The method using the difference of reaching time between the scintillation photons from both ends of PSF is hopeful as position sensitive radiation detecting, because PSF has good time resolution and the time measurements have been recently developed to be rather easy and accurate methods. (2)Position resolution is 20cm to 30cm for collimated gamma-ray of $$^{137}$$Cs. And, the detectors bundled of ten PSFs have better characteristics of both efficiency and resolution. (3)When the detector is irradiated at near one of the ends, the efficiency and resolution will be 10% to 30% worse than irradiated at middle of it.

Journal Articles

Sorption and desorption behavior of $$^{60}$$Co,$$^{85}$$Sr and $$^{137}$$Cs in a porous tuff; Mechanisms and kinetics

C.K.Park*; S.I.Woo*; Tanaka, Tadao; Kamiyama, Hideo

Journal of Nuclear Science and Technology, 29(12), p.1184 - 1193, 1992/12

https://doi.org/10.3327/jnst.29.1184

no abstracts in English

JAEA Reports

None

Kase, Takeshi; Konashi, Kenji

PNC TN8420 92-022, 33 Pages, 1992/11

PNC-TN8420-92-022.pdf:0.97MB

None

41 (Records 1-20 displayed on this page)