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With combined use of the ocean-atmosphere simulation models and field observation data, we evaluate the parameters associated with the total caesium-137 amounts of the direct release into the ocean and atmospheric deposition over the Western North Pacific caused by the accident of Fukushima Daiichi nuclear power plant (FNPP) that occurred in March 2011. The Green's function approach is adopted for the estimation of two parameters determining the total emission amounts for the period from 12 March to 6 May 2011. It is confirmed that the validity of the estimation depends on the simulation skill near FNPP. The total amount of the direct release is estimated as 5.5-5.9x1015 Bq, while that of the atmospheric deposition is estimated as 5.5-9.7x1015 Bq, which indicates broader range of the estimate than that of the direct release owing to uncertainty of the dispersion widely spread over the Western North Pacific. [ABSTRACT FROM AUTHOR]

Spatiotemporal distributions of anthropogenic radionuclides in surface sediments off Miyagi, Fukushima, and Ibaraki Prefectures were analyzed on the basis of data collected during the monitoring program launched by the Japanese Ministry of Education, Sports, Science and Technology in 2011 right after the Fukushima Nuclear Power Plant accident. Concentrations of 137Cs in the surface sediments varied spatially by two orders of magnitude from 1.7 to 580 Bq kg-dry-1, and there was no obvious correlation between 137Cs concentration and the proximity of the sampling location to the site of the accident. The total inventory of 137Cs accumulated in the upper 3 cm of surface sediment in the monitoring area was estimated to be 3.78x1013 Bq, that is 0.1-2% of the total 137Cs flux from the plant to the ocean as a result of the accident (the percentage depends on the model used to estimate the total flux). The spatial variations of 137Cs concentration and inventory depended on two main factors: the 137Cs concentration in the overlying water during the first several months after the accident and the physical characteristics of the sediment (water content and bulk density). The tem-poral variations of the concentrations of other anthropogenic radionuclides (90Sr, 95Nb, 110mAg, 125Sb, 129Te, and 129mTe) in the sediments were also investigated. The temporal variations of the activity ratios of these nuclides to 137Cs suggest that before the Fukushima-derived nuclides became homogeneous in seawater, they were removed from the water to the sediment. [ABSTRACT FROM AUTHOR]

The March of 2011 earthquake and tsunami that caused a loss of power at the Fukushima nuclear power plants (FNPP) resulted in emission of radioactive isotopes into the atmosphere and the ocean. In June of 2011, an international survey of various radionuclide isotopes, including 137Cs, was conducted in surface and subsurface waters off Japan. This paper presents the results of numerical simulations aimed at interpreting these observations, investigating the spread of Fukushima-derived radionuclides off the coast of Japan and into the greater Pacific Ocean, studying the dominant mechanisms governing this process, as well as estimating the total amount of radionuclides in discharged coolant waters and atmospheric airborne radionuclide fallout. The numerical simulations are based on two different ocean circulation models, one inferred from AVISO altimetry and NCEP/NCAR reanalysis wind stress, and the second generated numerically by the NCOM model. Our simulations determine that > 95% of 137Cs remaining in the water within ~600 km of Fukushima, Japan in mid-June 2011 was due to the direct oceanic discharge. The estimated strength of the oceanic source is 16.2±1.6 PBq, based on minimizing the model-data mismatch. We cannot make an accurate estimate for the atmospheric source strength since most of the fallout cesium would have moved out of the survey area by mid-June. The model explained several features of the observed 137Cs distribution. First, the absence of 137Cs at the southern- most stations is attributed to the Kuroshio Current acting as a transport barrier against the southward progression of 137Cs. Second, the largest 137Cs concentrations were associated with a semi-permanent eddy that entrained 137Cs-rich waters collecting and stirring them around the eddy perimeter. Finally, the intermediate 137Cs concentrations at the westernmost stations were attributed to younger, and therefore less Cs-rich, coolant waters that continued to leak from the reactor in June of that year. [ABSTRACT FROM AUTHOR]

Quantifying the amount of cesium incorporated into marine sediments as a result of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident has proven challenging due to the limited multi-core sampling from within the 30 km zone around the facility, the inherent spatial heterogeneities in ocean sediments, and the potential for inventory fluctuations due to physical, biological, and chemical processes. Using 210Pb, 234Th, 137Cs, and 134Cs profiles from 20 sediment cores, coastal sediment inventories were reevaluated. A minimum 137Cs sediment inventory of 100 ± 50 TBq was found for an area of 55 000 km² using cores from this study and a total of 130 ± 60 TBq using an additional 181 samples. These inventories represent less than 1% of the estimated 15-30 PBq of cesium released during the FDNPP disaster and constitute ~90% of the total coastal inventory of 137Cs remaining in 2012. The time needed for surface sediment activities (0 to 3 cm) at the 20 locations to reduce by 50% via bioturbation was estimated to range from 0.4 to 26 years, indicating a much greater persistence of cesium in the sediments relative to coastal water activities. However, due to the observed variability in mixing rates, grain size, and inventories, additional cores are needed to further improve estimates and capture the full extent of cesium penetration into the shallow coastal sediments, which was deeper than 14 cm for all cores retrieved from water depths less than 150 m. [ABSTRACT FROM AUTHOR]

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident led to the release of large amounts of radionuclides into the atmosphere as well as direct discharges into the sea. In contrast to the intensive studies on the distribution of the released high volatility fission products, such as 131I, 134Cs and 137Cs, similar studies of the actinides, especially the Pu isotopes, are limited. To obtain the vertical distribution of Pu isotopes in marine sediments and to better assess the possible contamination of Pu from the FDNPP accident in the marine environment, we determined the activities of 239+240Pu and 241Pu as well as the atom ratios of 240Pu/239Pu and 241Pu/239Pu in sediment core samples collected in the western North Pacific off Fukushima from July 2011 to July 2012. We also measured surface sediment samples collected from seven Japanese estuaries before the FNDPP accident to establish the comprehensive background baseline data. The observed results of both the Pu activities and the Pu atom ratios for the sediments in the western North Pacific were comparable to the baseline data, suggesting that the FDNPP accident did not cause detectable Pu contamination to the studied regions prior to the sampling time. The Pu isotopes in the western North Pacific 30 km off Fukushima coast originated from global fallout and Pacific Proving Ground close-in fallout. [ABSTRACT FROM AUTHOR]

Using a hedonic regression approach, this research aims to identify what factors affected land price fluctuations in Fukushima Prefecture following the Great East Japan Earthquake and the Fukushima Daiichi Nuclear Power Station accident in 2011. In this paper, taking a long-term perspective, the analysis focuses on Iwaki City in Fukushima, where the real estate market behaved unexpectedly following the two catastrophic events, and land price fluctuation rates were rising abnormally. Results based on analysis of data for eight-year indicate the following: The impact of radiation air dose rate and distance from the nuclear power plant on land price fluctuation rate changed significantly from the fourth year after the disaster. Being located in a reconstruction base area had a negative impact on land price fluctuation rate, while access to sewers and city gas had a positive impact. It appears that the stigma associated with the accident had a little disappeared after approximately four years. [ABSTRACT FROM AUTHOR]

The activities of artificial radionuclides in seawater samples collected off the coast of Miyagi, Fukushima, and Ibaraki Prefectures were measured as part of a monitoring program initiated by the Japanese government Ministry of Education, Sports, Science and Technology immediately after the Fukushima Dai-ichi nuclear power plant accident. The spatial and temporal distributions of those activities are summarized herein. The activities of strontium-90, iodine-131, cesium-134 and -137 (i.e. 90Sr, 131I, 134Cs, and 137Cs) derived from the accident were detected in seawater samples taken from areas of the coastal ocean adjacent to the power plant. No 131I was detected in surface waters (≤5m depth) or in intermediate and bottom waters after 30 April 2011. Strontium-90 was found in surface waters collected from a few sampling stations in mid-August 2011 to mid-December 2011. Temporal changes of 90Sr activity in surface waters were evident, although the 90Sr activity at a given time varied widely between sampling stations. The activity of 90Sr in surface waters decreased slowly over time, and by the end of December 2011 had reached background levels recorded before the accident. Radiocesium, 134Cs and 137Cs, was found in seawater samples immediately after the accident. There was a remarkable change in 137Cs activities in surface waters during the first 7 months (March through September 2011) after the accident; the activity reached a maximum in the middle of April and thereafter decreased exponentially with time. Qualitatively, the distribution patterns in surface waters suggested that in early May 137Cs-polluted water was advected northward; some of the water then detached and was transported to the south. Two cores of the water with high 137Cs activity persisted at least until July 2011. In subsurface waters 137Cs activity was first detected in the beginning of April 2011, and the water masses were characterized by ςt (an indicator of density) values of 25.5-26.5. From 9-14 May to 5-16 December 2011, the depths of the water masses increased with time, an indication that deepening of the isopycnals with time can be an important mechanism for the transport of 137Cs downward in coastal waters. During 4-21 February 2012, the water column became vertically homogeneous, probably because of convective mixing during the winter, the result being nearly constant values of 137Cs activity throughout the water column from the surface to the bottom (~200m depth) at each station. [ABSTRACT FROM AUTHOR]

Recent events have highlighted the need for unmanned remote sensing in dangerous areas, particularly where structures have collapsed or explosions have occurred, to limit hazards to first responders and increase their efficiency in planning response operations. In the case of the Fukushima nuclear reactor explosion, an unmanned helicopter capable of obtaining overhead images, gathering radiation measurements, and mapping both the structural and radiation content of the environment would have given the response team invaluable data early in the disaster, thereby allowing them to understand the extent of the damage and areas where dangers to personnel existed. With this motivation, the Unmanned Systems Lab at Virginia Tech has developed a remote sensing system for radiation detection and aerial imaging using a 90 kg autonomous helicopter and sensing payloads for the radiation detection and imaging operations. The radiation payload, which is the sensor of focus in this paper, consists of a scintillating type detector with associated software and novel search algorithms to rapidly and effectively map and locate sources of high radiation intensity. By incorporating this sensing technology into an unmanned aerial vehicle system, crucial situational awareness can be gathered about a post-disaster environment and response efforts can be expedited. This paper details the radiation mapping and localization capabilities of this system as well as the testing of the various search algorithms using simulated radiation data. The various components of the system have been flight tested over a several-year period and a new production flight platform has been built to enhance reliability and maintainability. The new system is based on the Aeroscout B1-100 helicopter platform, which has a one-hour flight endurance and uses a COFDM radio system that gives the helicopter an effective range of 7 km. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a report on the situation at Fukushima and present two lessons that were learned involving: (1) multi-robot operation and (2) robot operation by workers. Workers with no prior experience with robots operated multi-robots in dynamically changing environments. We focus on the following two themes in multi-robot operations: (1) communication between operators and (2) pairing of operators. An experiment using a rescue robot operation training platform based on Unified System for Automation and Robot Simulation is shown, and the results of the experiment are discussed. We believe that these verify that the training platform is useful for recue robot operation. [ABSTRACT FROM PUBLISHER]

Summary Using cross-country data, this paper investigates how freedom of media influenced views regarding the security of nuclear energy after the Fukushima accident in Japan. Key findings are: (1) citizens are less likely to agree that nuclear power plants are properly secured against accidents with the presence of a free media and higher levels of freedom of expression; and (2) freedom of expression and free media are positively associated with the presence of nuclear plants. These findings indicate that sufficient information leads citizens to both understand the risk of nuclear energy and to accept the existence of nuclear plants. [ABSTRACT FROM AUTHOR]

The Japanese government's attempt to discharge the water contaminated by the Fukushima nuclear reactor into the sea raises some international legal issues. International law prescribes settlement mechanisms for disputes relating to transboundary environmental damage; however, legal challenges have appeared in the disposal of the Fukushima contaminated water discharge. This paper argues that despite the uncertainty of the potential pollution damage of the discharge plan, Japan's decision has already violated multiple obligations arising from international conventions, customary international laws, and the general principles of law. This paper, after a wide examination of the possible international dispute settlement mechanisms, proposes that certain actions will be beneficial for potentially affected states: applying for an advisory procedure or requesting provisional measures under a contentious procedure. Furthermore, the Fukushima incident presents the international community with an opportunity to consider legal questions related to the consequences of nuclear accidents in the future, including the disposal standards and procedures of nuclear-contaminated materials particularly. Furthermore, to concretize the procedural and substantive requirements according to the international laws, a new international cooperative mechanism is needed. [Display omitted] • Japan's decision to discharge the radioactive water violates international law. • Opposing States may benefit from the advisory procedure and provisional measures. • Existing dispute settlement mechanisms are applicable, but not sufficient. • A new cooperative mechanism dedicated to the disposal of nuclear contaminants. [ABSTRACT FROM AUTHOR]

The earthquake and tsunami which occurred in the Tohoku region of Japan (northern Japan) on 11 March 2011 have taken the lives of more than 15,000 people. The disaster and the accident in the nuclear reactors in Fukushima have left about 330,000 people homeless. The catastrophe has affected not only Japanese politics, economics, society and people’s mentalities, but also its cultural industries. This article attempts to investigate two contemporary issues tracing the effects of the Great East Japan Earthquake (the Tohoku Disaster) on Japan’s media landscape: its impact on Japanese media production and distribution, particularly of its most transnationally famous forms, manga and anime; and how perceptions of ‘soft power’ have fluctuated in this difficult media moment. The research uses a cultural and industrial studies approach based on discourse analysis, focusing on the period immediately following the Tohoku Disaster in order to map significant shifts and unexpected results and responses from within Japan’s cultural industries to the earthquake, tsunami and Fukushima power plant disasters. [ABSTRACT FROM AUTHOR]

S-net is a large-scale seafloor observation network for earthquakes and tsunamis around the Japan Trench, consisting of 150 observatories equipped with seismometers and pressure gauges. The sensors have been set up inside cylindrical pressure vessels, which have been buried in the shallow-water regions (water depth <1,500 m), while the vessels have been laid freely on the seafloor in the deeper-water regions. Previous studies showed that the cylindrical pressure vessels rotate during strong shakings due to poor coupling with the seabed sediments, thus making it difficult to retrieve the actual ground motions. We investigated the static changes in the orientations of S-net accelerometers due to shakings from 1,878 earthquakes of Mj greater than 4 that occurred around the network, and found that rotations as large values as 16° were observed during the 2022,Mj 7.4, off-Fukushima Prefecture earthquake. We estimated the threshold acceleration levels after which the sensors are likely to rotate at all S-net stations separately and found that the threshold values lie mostly between 5 and 50 cm/s². Finally, we discussed the observed peak accelerations and velocities at the S-net stations with those recorded on land, where high-quality records were obtained, during the 2022, Mj 7.4 earthquake, which was also the largest magnitude earthquake to occur in the region after the network commenced operation. The results presented herein complement several previous studies and form the basis for more comprehensive future investigations. [ABSTRACT FROM AUTHOR]

The Great East Japan Earthquake and the successive accidents at the Fukushima Daiichi Nuclear Power Station are stark reminders of the importance of energy, which is the basis of economic activity and national governance. Urgent responses have been conducted since March 11, 2011, including controlling the consequences of the nuclear accident, dealing with the short-term power shortages, and a comprehensive review of Japan's long-term national energy policy. Nationwide discussions and reviews of these issues are still continuing. Even today, more than 2 years after March 11, many problems remain unsolved and Japanese society has to face uncertainty and challenges about its energy future. In the current difficult situation, Japan needs to achieve '3 Es ( energy security, environmental protection, and economic efficiency)' plus ' S' ( safety) and ' M' ( macro economy protection) simultaneously, taking account of the new realities following the Fukushima accident. This paper tries to identify the energy-related challenges that Japan has to face and tries to recommend the concept of the 'energy best mix policy' for Japan, by describing the present status of energy issues in Japan and the national debate on energy policy. [ABSTRACT FROM AUTHOR]

Described is the process of trial, adjustment, and development of the joint complex of models consisting of the WRF-ARW (Weather Research and Forecasting) regional hydrodynamic model (the United States) and radionuclide transport model from the NOSTRADAMUS package. Using these models, the computation is carried out of the fallout and radiation dose rate on the territory of Japan after the Fukushima nuclear power plant accident. To adjust the hydrodynamic model, its results were preliminarily compared with the data of observations at the mast and the assessment of the model complex was based on the data of atmospheric tracer concentration measurements during the in situ experiments carried out in 1983-1985 near Karlsruhe (Germany). Described is the version of hydrodynamic prognostic model and radionuclide transport model prepared for the present paper. Given are the results of the statistical analysis of different numerical experiments of the model complex and the results of the simulation of radiation conditions on the territory of Japan after the Fukushima Dai-ichi nuclear power plant accident. It is demonstrated that the errors in the vertical distribution of the model wind are extremely sensitive to the type of parameterization of surface and boundary layers in the model. The comparison of computed and measured values demonstrated their satisfactory coincidence. [ABSTRACT FROM AUTHOR]

The accident at the Fukushima I Nuclear Power Plant in Japan on 11 March 2011 has led to widespread public exposure to high levels of radiation. At present, the government allows people to live in an area where the level of radiation is lower than 20 mSv/year. But, unless the level of radiation is reduced markedly to lower than 1 mSv/year, people should not be allowed to return to the area. Nevertheless, Nuclear Emergency Response Headquarters removed the designation of ‘zones in preparation for emergency evacuation’ on 30 September with this fundamental problem yet to be solved. The paper examines the legal context for this problem. [ABSTRACT FROM PUBLISHER]

Twelve years after the nuclear accident that occurred at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in March 2011, radiocesium contamination (with a large dominance of 137 Cs, with a 30-year half-life) remains a major concern in various municipalities of north-eastern Japan. The Japanese authorities completed an unprecedented soil decontamination programme in residential and cultivated areas affected by the main radioactive plume (8953 km 2). They implemented a complex remediation programme scheme to remediate soils that are fundamental to life on Earth, relying on different decision rules depending on the waste type, its contamination level and its region of origin, after delineating different zones exposed to contrasted radiation rates. The central objective was not to expose local inhabitants to radioactive doses exceeding 1 mSv yr -1 in addition to the natural levels. At the onset of the full reopening of the Difficult-to-Return Zone (DTRZ) in spring 2023, the current review provides an update of a previous synthesis published in 2019 (Evrard et al., 2019). Although this ambitious soil remediation and reconstruction programme has almost been completed in the 12 municipalities of Fukushima Prefecture in which an evacuation order was imposed in at least one neighbourhood in 2011, from the 147 443 inhabitants who lived there before the accident, only 29.9 % of them had returned by 2020. Waste generated by decontamination and tsunami cleaning/demolition work is planned to have been fully transported to (interim) storage facilities by the end of 2023. The cost of the operations conducted between 2011 and 2020 for the so-called "nuclear recovery" operations (including decontamination) was estimated by the Board of Audit of Japan in 2023 as JPY 6122.3 billion (∼ EUR 44 billion). Decontamination of cropland was shown to have impacted soil fertility, and potassium fertilisation is recommended to limit the transfer of residual radiocesium to new crops. In forests that cover 71 % of the surface area of Fukushima Prefecture and that were not targeted by remediation, radiocesium is now found in the upper mineral layer of the soil in a quasi-equilibrium state. Nevertheless, 137 Cs concentrations in forest products (including wood for heating and construction, wild plants, wildlife game, mushrooms) often keep exceeding the threshold values authorised in Japan, which prohibits their exploitation in the area affected by the main plume. Radionuclides from forests were shown to be exported in dissolved and particle-bound forms to downstream river systems and floodplains, although multiple monitoring records showed the continuous decrease in radiocesium concentrations in both river water and sediment across the main plume between 2011 and 2021. Fish contamination is now generally found to be below the threshold limits although reputational damage remains a major concern for local fishing communities. The remobilisation of radiocesium from sediment accumulated in reservoirs of the region is also of potential concern as it may lead to secondary contamination of fish or irrigation waters supplied to decontaminated fields. Overall, this synthesis demonstrates the need to continue monitoring post-accidental radiocesium transfer in these environments and to keep sharing data in order to refine our predictive understanding of radiocesium mobility and consolidate the tools available to model contaminant transfer in ecosystems. In forests in particular, novel countermeasures and wood uses remain to be developed and tested. Furthermore, the hydrologic connectivity between soils under different ecosystems greatly influences long-term radiocesium transport. The consequences of extreme phenomena (e.g. typhoons, forest fires) that may become more frequent in the future as a result of global change in these contaminated environments should be further anticipated. [ABSTRACT FROM AUTHOR]

Booster vaccination reduces the incidence of severe cases and mortality related to COVID-19, with cellular immunity playing an important role. However, little is known about the proportion of the population that has achieved cellular immunity after booster vaccination. Thus, we conducted a Fukushima cohort database and assessed humoral and cellular immunity in 2526 residents and healthcare workers in Fukushima Prefecture in Japan through continuous blood collection every 3 months from September 2021. We identified the proportion of people with induced cellular immunity after booster vaccination using the T-SPOT.COVID test, and analyzed their background characteristics. Among 1089 participants, 64.3% (700/1089) had reactive cellular immunity after booster vaccination. Multivariable analysis revealed the following independent predictors of reactive cellular immunity: age < 40 years (adjusted odds ratio: 1.81; 95% confidence interval: 1.19–2.75; p-value: 0.005) and adverse reactions after vaccination (1.92, 1.19–3.09, 0.007). Notably, despite IgG(S) and neutralizing antibody titers of ≥500 AU/mL, 33.9% (349/1031) and 33.5% (341/1017) of participants, respectively, did not have reactive cellular immunity. In summary, this is the first study to evaluate cellular immunity at the population level after booster vaccination using the T-SPOT.COVID test, albeit with several limitations. Future studies will need to evaluate previously infected subjects and their T-cell subsets. [ABSTRACT FROM AUTHOR]

Between September 2011 and August 2015, the International Commission on Radiological Protection (ICRP) organised a series of 12 stakeholder dialogue workshops with residents of Fukushima Prefecture. Discussions focused on recovery, addressing topics such as protection of children, management of contaminated food, monitoring, and self-help measures. The OECD Nuclear Energy Agency (NEA) supported, and the Committee on Radiation Protection and Public Health (CRPPH) Secretariat attended, all 12 meetings to listen directly to the concerns of affected individuals and draw lessons for CRPPH. To summarise the dialogue results, ICRP organised a final meeting in Date, Japan with the support of NEA and other organisations. The lessons from and utility of the dialogue meetings were praised by dialogue participants and sponsors, and ICRP agreed that some form of dialogue would continue, although with ICRP participation and support rather than leadership. This paper summarises the internationally relevant lessons learned by CRPPH from this important process. [ABSTRACT FROM AUTHOR]

We present the atmospheric anomalies instigated through seismogenic sources by a multichannel observation using ground- and satellite-based systems. This study emphasizes the seismic event which happened on the east coast of Japan, near the Fukushima Prefecture on November 21, 2016 (in UTC), with a magnitude of 6.9 and a depth of 11.4 km. We mainly focus on the atmospheric and ionospheric irregularities via acoustic and electromagnetic channels originating from earthquakes in the process of the lithosphere, atmosphere, and ionospheric coupling (LAIC) mechanism. In the acoustic channel, we study the seismogenic atmospheric gravity wave (AGW) which perturbs the local lower atmosphere. The observation of nighttime fluctuations in the very low frequency (VLF) signals and total electron content (TEC) is used to investigate the atmospheric perturbation through the electromagnetic channel. For the ground-based observations, a VLF signal network consisting of 5 receivers in Japan is used to study by recording the VLF amplitude transmitted from the Japanese transmitter JJI (22.2 kHz). VLF nighttime fluctuation is used to check the unusualities due to the earthquake. Preseismic wavelike structures having periods of AGW are observed in the nighttime signal. Direct investigation of such AGWs is done by computing the potential energy related to AGW from the sounding of the atmosphere using broadband emission radiometry (SABER) temperature profiles mounted on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. Ionospheric TEC inspection is done by using a ground-based global navigation satellite system (GNSS) receiver from the International GNSS Survey (IGS) station MIZU in Japan and observing anomalies in diurnal TEC around 6 and 10 days prior to the earthquake. We also obtain the wavelike structure of AGW from the small-scale fluctuation of TEC using wavelet analysis. All the parameters are found to be preseismic for this earthquake; the acoustics channel gives more consistent outcomes than the electromagnetic channel. [ABSTRACT FROM AUTHOR]

Rupture directions and directivity effects of moderate‐sized intraslab and interplate earthquakes off the coast of Fukushima Prefecture were estimated using seafloor S‐net records and onshore K‐NET and KiK‐net records. The azimuthal dependance of the source spectral ratio of each earthquake relative to a reference earthquake observed at the same station was modeled based on a ω−2 model assuming unilateral rupture. The azimuthal dependance of the source spectral ratio observed for most earthquakes reached a maximum at 2–3 Hz and weakened at higher and lower frequencies. The rupture directivity effect contributes to stations located up to the maximum hypocentral distance of 150 km used in this study. All four down‐dip compressional intraslab earthquakes were estimated to rupture toward the up‐dip, i.e., the land. In addition, the six interplate earthquakes were estimated to rupture either up‐dip or in the opposite direction of the strikes, i.e., between south and southeast directions. Only one interplate earthquake was estimated to rupture down‐dip, i.e., toward the land. In the case of intraslab earthquakes, the regions of large radiation patterns and large rupture directivity overlap in the onshore coastal area. Therefore, when only onshore records were used, the estimates of short‐period spectral levels were biased. [ABSTRACT FROM AUTHOR]

Purpose: Evaluating sediment fingerprinting source apportionments with artificial mixtures is crucial for supporting decision-making and advancing modeling approaches. However, artificial mixtures are rarely incorporated into fingerprinting research and guidelines for model testing are currently lacking. Here, we demonstrate how to test source apportionments using laboratory and virtual mixtures by comparing the results from Bayesian and bootstrapped modeling approaches. Materials and methods: Laboratory and virtual mixtures (n = 79) with known source proportions were created with soil samples from two catchments in Fukushima Prefecture, Japan. Soil samples were sieved at 63 µm and analyzed for colorimetric and geochemical parameters. The MixSIAR Bayesian framework and a bootstrapped mixing model (BMM) were used to estimate source contributions to the artificial mixtures. In addition, we proposed and demonstrated the use of multiple evaluation metrics to report on model uncertainty, residual errors, performance, and contingency criteria. Results and discussion: Overall, there were negligible differences between source apportionments for the laboratory and virtual mixtures, for both models. The comparison between MixSIAR and BMM illustrated a trade-off between accuracy and precision in the model results. The more certain MixSIAR solutions encompassed a lesser proportion of known source values, whereas the BMM apportionments were markedly less precise. Although model performance declined for mixtures with a single source contributing greater than 0.75 of the material, both models represented the general trends in the mixtures and identified their major sources. Conclusions: Virtual mixtures are as robust as laboratory mixtures for assessing fingerprinting mixing models if analytical errors are negligible. We therefore recommend to always include virtual mixtures as part of the model testing process. Additionally, we highlight the value of using evaluation metrics that consider the accuracy and precision of model results, and the importance of reporting uncertainty when modeling source apportionments. [ABSTRACT FROM AUTHOR]

Fukushima nuclear power plant accident has become a hot topic in debates among professional communities. It also caused knowledge searching and knowledge sharing among social groups. However, there is a lack of empirical studies investigating nuclear power-related knowledge flow in social communities. This paper examines nuclear power-related knowledge flow by focusing on the case of college students in South Korea. The research investigates the following objectives: the types of knowledge shared, the mechanism of knowledge flow, effectiveness of knowledge flow, and the factors influencing the knowledge flow. The results show that different types of nuclear energy-related knowledge were shared; mass media play an important role in knowledge flow; trust relationship, personal interests and cultural factors influence the effectiveness of knowledge flow. [ABSTRACT FROM AUTHOR]

Resuspension of 137 Cs from the contaminated ground surface to the atmosphere is essential for understanding the environmental behaviors of 137 Cs and estimating external and inhalation exposure of residents. Kajino et al. (2016) assessed the 137 Cs resuspension flux from bare soil and forest ecosystems in eastern Japan in 2013 using a numerical simulation constrained by surface air concentration measurements. However, the simulation was found to underestimate the observed deposition amounts by 2 orders of magnitude. The reason for this underestimation is that the simulation assumed that resuspended 137 Cs is carried by submicron aerosols, which have low deposition rates. Based on the observational indications that soil dust and bioaerosols are the major carriers of resuspended 137 Cs, a new simulation is performed with higher deposition rates constrained by both surface concentrations and deposition amounts. In the new estimation, the total areal annual resuspension of 137 Cs in 2013 is 25.7 TBq, which is equivalent to 0.96 % of the initial deposition (2.68 PBq). Due to the rapid deposition rates, the annual redeposition amount is also large at 10.6 TBq, approximately 40 % of the resuspended 137 Cs. The resuspension rate through the atmosphere (0.96 % yr -1) seems slow, but it (2.6 × 10 -5 d -1) may not be negligibly small compared to the actual decreasing trend of the ambient gamma dose rate obtained in Fukushima Prefecture after the radioactive decay of 137 Cs plus 134 Cs in 2013 is subtracted (1.0–7.9 × 10 -4 d -1): resuspension can account for 1 %–10 % of the decreasing rate due to decontamination and natural decay through land surface processes. The current simulation underestimated the 137 Cs deposition in Fukushima city in winter by more than an order of magnitude, indicating the presence of additional resuspension sources. The site of Fukushima city is surrounded by major roads. Heavy traffic on wet and muddy roads after snow removal operations could generate superlarge (approximately 100 µ m in diameter) road dust or road salt particles, which are not included in the model but might contribute to the observed 137 Cs at the site. [ABSTRACT FROM AUTHOR]

Nuclear energy is indispensable and important energy to human society. Fukushima nuclear accident produced great harm and will seriously affect the development of nuclear energy. In this paper, the importance and necessity of the development of nuclear energy are introduced based on the development of world nuclear energy and the energy demand in China. The basic situation of Fukushima nuclear accident is introduced and the reasons of the accident are also analyzed. The influence of Fukushima nuclear accident on the development of world nuclear power, the nuclear power development plan of China, the nuclear power plant siting, the design and operation of nuclear power plant, and the research of nuclear power technology, nuclear safety culture and personnel training of nuclear major are analyzed and discussed. Nuclear safety is the most important thing in the development of nuclear power. [ABSTRACT FROM AUTHOR]

Abstract: There was a missed opportunity for implementing important disaster preparedness measures following an earthquake prediction that was announced as an alarm in mid-2001. This intermediate-term middle-range prediction was the initiation of a chain of alarms that successfully detected the time, region, and magnitude range for the magnitude 9.0 March 11, 2011 Great East Japan Earthquake. The prediction chains were made using an algorithm called M8 and is the latest of many predictions tested worldwide for more than 25 years, the results of which show at least a 70% success rate. The earthquake detection could have been utilized to implement measures and improve earthquake preparedness in advance; unfortunately this was not done, in part due to the predictions'' limited distribution and the lack of applying existing methods for using intermediate-term predictions to make decisions for taking action. The resulting earthquake and induced tsunami caused tremendous devastation to north-east Japan. Methods that were known in advance of the predication and further advanced during the prediction timeframe are presented in a scenario describing some possibilities on how the 2001 prediction may have been utilized to reduce significant damage, including damage to the Fukushima nuclear power plant, and to show prudent cost-effective actions can be taken if the prediction certainty is known, but not necessarily high. The purpose of this paper is to show how the prediction information can be strategically used to enhance disaster preparedness and reduce future impacts from the world''s largest earthquakes. [Copyright &y& Elsevier]

The extreme events that led to the prolonged electrical power outage and finally to sever damage of four units of the Fukushima nuclear plant have highlighted the importance of ensuring a technical means for stable, long-term cooling of the nuclear fuel and the containment following a complete station blackout. This paper presents an overview of the advanced passive safety systems designed for the NuScale nuclear power plant and their role in addressing extreme events. The NuScale plant may include up to 12 power modules, and each module incorporates a reactor pressure vessel (core, steam generator, and pressurizer) and a containment vessel that surrounds the reactor vessel. During normal operation, each containment vessel is fully immersed in a water-filled, stainless steel-lined concrete pool that resides underground. The pool, housed in a Seismic Category I building, is large enough to provide 30 days of core and containment cooling without adding water. After 30 days, the core decay heat generation is so small that the natural convection heat transfer to air at the outside surface of the containment, coupled with thermal radiation heat transfer, are completely sufficient to remove the core decay heat for an unlimited period. These passive safety systems can perform their function without requiring an external supply of water or electric power. Computational and experimental assessments of the NuScale passive safety systems are being performed at several institutions, including the one-third scale NuScale integral system test facility at Oregon State University. [ABSTRACT FROM AUTHOR]

Ouchi district of Simogou Town in Fukushima Prefecture prospered during the early Edo Era as a rest stop on the main Aizu West Road, but it was left behind in the transport revolution of the Meiji Era because of its remote mountainous location. As a result, a "lived-space" containing an abundant "rotating time" was created in it. After the post-war reconstruction and into the latter half of the 1960s. however, the people of Ouchi were rather disrupted by frequent waves of modernization such as dam development, legislative selection to the "Preservation Districts for Groups of Traditional Buildings." tourism, and resort development. This paper studies the case of Ouchi by focusing on preserving the rest stop and developing tourism and by studying their spatial practices to determine in what different dimension they have introduced the modernization and how the contradictory order and system was formed within it. In order to approach this subject, the author has traced the spatial practices in modern Ouchi. The "representation of space" -the touristic space in Ouchi-was built through the practices that prioritize to maintaining the local life system. In consequence, the "lived-space" was variously created in the "representation of space" -Ouchi-where "rotating time" flows. In this "spatial practice" at Ouchi. we would find a perception that connects the "lived-space" and "rotating time" to the alternative production process of social organization and structure. [ABSTRACT FROM AUTHOR]

After the nuclear accident in Fukushima Prefecture, Japan, in 2011, 137Caesium (Cs) contaminated nearby agricultural regions. Studies in these rice fields found that low K and high N fertilizer application enhanced Cs uptake in rice shoots. However, the influence of root and soil physics on these findings, as well as precise nutrient levels, remain to be clarified.We sought to analyse these relationships utilizing hydroponically grown rice plants. The rice plants were subjected to various concentrations of K and N nutrient solutions. We measured Cs allocation within the plants and performed transcript analyses using root tissues.Under low‐K conditions, low‐N plants accumulated less Cs in shoots and more in roots when compared to control‐N conditions, even though overall Cs uptake remained unchanged. Expression analyses of root mRNAs showed that low‐N plants accumulated reduced levels of OsAKT1 mRNA, encoding a K transporter. We also found a negative relationship between shoot Cs and K status in control‐N but not in low‐N conditions.Our results suggest that the application of N shifts Cs from roots into the shoots and that OsAKT1 in root vascular tissues influences Cs allocation. In practice, fine tuning N/K application and targeted breeding of K transporters might mitigate Cs contamination in rice plants. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Japanese Society of Snow & Ice / Seppyo is the property of Japanese Society of Snow & Ice and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Radioactively contaminated soils sampled at Fukushima (Japan) underwent microwave treatment to remove cesium ions. An aqueous suspension (20 mL) containing 5.0 g of the soil (7.2×105 Bq/kg) and one of three chemical reagents was sealed in a Teflon vessel (4.0 cm i.d.×5.0 cm). The effects of the following three reagents were examined: 3.0 M Mg(NO3)2, 6.5 M NH4F/HF, and 1.5 M H2SO4. The vessel was irradiated with microwaves at 800 W for 3 min. After the vessel was cooled to room temperature, the contents were removed and centrifuged, and the radioactivity of the solid precipitate was measured. The elemental composition of the filtrate was determined using ICP-MS. The XRD patterns of the solid precipitates were recorded before and after the treatment. Results indicated that: (i) in the radioactive Cs+ ions leaching experiment with 3.0 M Mg(NO3)2 from a reference saponite, 85% 137Cs+ ions were desorbed after 3 min of microwave irradiation, indicating the effectiveness of the microwave treatment for radioactively contaminated soils, (ii) less than 5% of the radioactive Cs+ (or 137Cs+) ions were eliminated through ion-exchange with 3.0 M Mg(NO3)2; (iii) more than 90% of the 137Cs+ ions were effectively eliminated with 6.5 M NH4F/HF via dissolution of silica; (iv) approximately 70% of the 137Cs+ ions were eliminated with 1.5 M H2SO4 via dissolution of alumina. These results demonstrated that 137Cs+ ions in the soil were fixed firmly in clay minerals (possibly weathered biotite) and could be removed only when their adsorbing structures were disrupted. [ABSTRACT FROM AUTHOR]

The article presents a case study examining the responses of librarians to the 2011 Great East Japan Earthquake and Fukushima Daiichi nuclear power plant disaster. Topics address include a poster created by a librarian from Fukushima, Japan that documented librarians efforts to provide reading and information services despite damages to library buildings, as well as the use of libraries as shelters.

This study illustrates how citizen-driven radiation monitoring has emerged in post-Fukushima Japan, where citizens generate their own radiation data and measurement devices to provide public with actionable data about their environments. Drawing on ethnographic fieldwork in and around Fukushima Prefecture, it highlights the multifaceted character of these bottom-up, citizen-led efforts, contrasting these initiatives with the emergence of "citizen participatory" science policy discourses in Japan. Recognizing the contested nature of citizenship in Japan and in the nuclear arena, the article considers how terms and definitions shape the participation of citizens and other stakeholders (local communities, public authorities, regulators, and professional scientists) in science and technology in culturally and historically specific ways. It builds on these observations to open up new spaces of expertise, which engage all stakeholders through social-scientific intervention. [ABSTRACT FROM AUTHOR]

Prime Minister Abe's return to power in Japan dealt a blow to the anti-nuclear movement and returned the country to broadly pro-nuclear policies. Meanwhile, eight years on, although the effects of the Fukushima disaster are still being felt, Japan's anti-nuclear movement has struggled to move forward or effect changes in policy. This article argues that prospects for change will not emerge until Japan's anti-nuclear movement is able to look beyond its national borders and articulate a perspective on nuclear power that takes into account other countries within East Asia. The 3.11 Great East Japan Earthquake revealed heretofore hidden aspects of the Japanese state and society. The truth is that Japan's postwar state (Sengo-kokka) is actually a nuclear power state (Genpatsu-kokka), a byproduct of the US-Japan alliance under the East Asian Cold War system, which insulated nuclear policy from the standard operation of democratic politics. As a product of the Cold War, the issue of nuclear power and development extends beyond Japan's national borders and relates to the questions of US superpower sponsorship and the armistice system in East Asia that pertain broadly to the politics of East Asia. It is important to understand that Japan's nuclear energy is a product of the Cold War in East Asia, and the armistice system that constitutes the international system in East Asia must be discarded if Japan is to become a post-nuclear energy state. [ABSTRACT FROM AUTHOR]

We investigated radiocesium concentrations in the suspended solids (SS) of two large rivers discharging into the Sea of Japan. Higher 134Cs concentrations in SS sampled from upstream area in 2013 (711 Bq/kg-SS) reflected the larger effect of radioactive depositions in western Fukushima Prefecture. However, smaller but less variable concentrations in downstream areas (< 100 Bq/kg-SS) indicated a continual supply of 134Cs-contaminated SS from 2013 to 2017. The particulate 134Cs concentrations in normal flow conditions were at approximately similar levels with those in coastal waters (< ~1 mBq/L), suggesting that the impact of SS on the Sea of Japan was negligible after 2013. [ABSTRACT FROM AUTHOR]

Copyright of Island Arc is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to know whether principal stress orientations in the source area rotated after the 2011 April 11 Mw 6.6 Fukushima-Hamadori earthquake in NE Japan, we investigated detailed spatial distributions of stress orientations for both the pre- and post-main shock periods using a large amount of focal mechanism data. We applied stress tensor inversions to focal mechanism data from Japan's National Research Institute for Earth Science and Disaster Prevention's F-net broadband seismic network and the Japan Meteorological Agency (JMA). The σ3-axes estimated for the pre-main shock period are predominantly oriented WSW-ENE, and are relatively homogeneously in space. In contrast, the orientations of the σ3-axes show a significantly heterogeneous distribution in space for the post-main shock period. In the northern subarea of the focal region, the σ3-axes are oriented NW-SE. In the east and west portions of the central subarea, they are oriented NNW-SSE and WNW-ESE, respectively, almost perpendicular to each other. In the southern subarea, the σ3-axes are oriented WSW-ENE. On the whole, the σ3-axis orientations show concentric circle-like distribution surrounding the large slip area of the Mw Mw 6.6 main shock rupture. The change of principal stress axis orientations after the earthquake is not significant because of the sparse data set for the pre-main shock period.We calculated static stress changes from the Mw 6.6 main shock and three Mw > 5.5 earthquakes to compare with the observed stress axis orientations in the post-main shock period. The σ3-axis orientations of the calculated total static stress change show a concentric circle-like distribution surrounding the large slip area of the main shock, similar to that noted above. This observation strongly suggests that the spatially heterogeneous stress orientations in the post-main shock period were caused by the static stress change from the M Mw 6.6 main shock and other large earthquakes. In order to estimate the differential stress magnitude in the focal area, we calculated deviatoric stress tensors in the post-main shock period by assuming that they are the sum of the deviatoric stress tensors in the pre-main shock period and the static stress changes. Comparison of the calculated and observed stress tensors revealed differential stress magnitudes of 2-30 MPa that explain the observed stress orientations, considering the probable range of estimated stress ratios in the pre-main shock period. [ABSTRACT FROM AUTHOR]

The Great East Japan Earthquake that struck in March 2011 directly damaged Fukushima Prefecture. Due to the ensuing nuclear accident of Fukushima Daiichi plant, the Prefecture's power output decreased by 9GW. However, Fukushima Prefecture has more than just nuclear power. Prior to the earthquake, the prefecture was Japan's biggest power-supplying prefecture because of its abundant hydro and thermal power. After the nuclear power plant accident, aversion to nuclear power naturally intensified in Fukushima Prefecture. Despite this, in the future, the prefecture will continue to be a power-supplying prefecture primarily via thermal and hydro power. The author, living in Fukushima, argues that the revival and bolstering of thermal and hydro power will help to dispel concerns about Japan's power supply and may also facilitate local economic recovery. [ABSTRACT FROM AUTHOR]

Abstract: Instrumentation and data processing methods to continuously map the distribution of radionuclides on the seafloor have been developed and applied to survey radioactive discharge from the Fukushima Dai-ichi Nuclear Power Plant following the M9.0 earthquake and tsunami that struck the east coast of Japan on March 11 2011. The instrument consists of a flexible rubber hose with an integrated gamma ray spectrometer that measures the full gamma spectrum between 0.1 and 1.8MeV while being towed along the seafloor by a ship. The data processing methods described allow for quantification of 137Cs and 134Cs concentration in marine sediments, and a technique has been developed to optimize the spatial resolution of the measurements for each radioactive species for a given level of statistical uncertainty. The system was deployed during August and November 2012 to measure the distribution of radionuclides along three transects within an 80km radius of the plant. Increased levels of 137Cs and 134Cs were recorded and their distributions mapped continuously over distances of 1.6, 12.5 and 22km respectively. The levels of 137Cs and 134Cs were found to vary significantly with location. The in situ measurements show good agreement with laboratory analyzed samples obtained during the surveys. The results demonstrate that the instrument and data processing techniques described enable high resolution, quantitative measurements of 137Cs and 134Cs in marine sediments, and provide an effective solution for rapid, low cost monitoring of radioactive material on the seafloor. [Copyright &y& Elsevier]

Previous research assessed media reporting on nuclear accidents and risks, whilst studies about the Fukushima accident focused on the impact of the Internet on coverage of the inci-dent. However, little research has addressed news framing or comparisons of the perceptions of journalists in relation to reporting nuclear accidents. The aim of this study is to apply fram-ing analysis to news content in The New York Times, the Los Angeles Times, and USA Today about the Fukushima accident. It explores the question of how journalists view reporting on complex events. Content analysis of these three newspapers shows that conflict, responsibil-ity, and economic consequences were the most frequently used frames. According to the journalists interviewed, the biggest problem was the inability to assess information due to contrary positions held by experts. It is argued that the Fukushima accident was framed as a conflict of experts and officials' opinions, utility and government officials' responsibility, and economic consequences for the United States. Adherence to professional norms of objec-tivity and impartiality was signified as the best approaches to risk reporting. [ABSTRACT FROM AUTHOR]

Aerosol collections were initiated at several locations by Pacific Northwest National Laboratory (PNNL) shortly after the Great East Japan earthquake of May 2011. Aerosol samples were transferred to laboratory high-resolution gamma spectrometers for analysis. Similar to treaty monitoring stations operating across the Northern hemisphere, iodine and other isotopes which could be volatilized at high temperature were detected. Though these locations are not far apart, they have significant variations with respect to water, mountain-range placement, and local topography. Variation in computed source terms will be shown to bound the variability of this approach to source estimation. [ABSTRACT FROM AUTHOR]

We present how radioactive Cs was deposited on wheat, rice, peach tree and soil after nuclear accident in Fukushima. The deposition of radioactive Cs was found as spots at the surface of the leaves, branch or trunk of the trees, as well as in soil using one of the imaging method, autoradiography. The deposited radioactive Cs was not easily washed out, even with the treatment of acid solution. When the wheat was harvested 2 months after the accident, high radioactivity of Cs was found only on the leaves developed and expanded at the time of the accident. In the case of the rice grain, most of the radioactivity was found in bran and the radioactivity was drastically reduced in milled rice. Most of the radioactive Cs accumulation in rice plants was estimated from the absorption of the Cs ion dissolved in water, rather than Cs adsorbed in soil. [ABSTRACT FROM AUTHOR]

Two independent radionuclide aerosol air samplers were operated at Pacific Northwest National Laboratory in close proximity during the Fukushima reactor releases. One system was an automated aerosol collection and analysis unit, whereas the other was a manual sampler of simpler design. The samples collected from each sampler showed correlation in radionuclide activity, although some variations were observed. During this unique event, the small variations observed between the co-located air samplers illustrate the effectiveness of a way to acquire useful parallel samples for scientific purposes. The results in radionuclide activity concentration show that, in some circumstances, use of a manual high volume air sampler in parallel to a complex automated sampler can produce results that are of comparable quality to International Monitoring System samples. [ABSTRACT FROM AUTHOR]

Results of forward and backward modeling of air mass transport from Fukushima Daiichi nuclear power plant to Slovakia were compared with aerosol radioactivity measurements. Several radionuclide maxima (I, Cs and Cs) were observed in the Bratislava ground-level air in March-April 2011. The I/Cs activity ratio records showed the presence of two different fresh air masses in the Bratislava air, supported by simulations of forward and backward trajectories between Fukushima and Bratislava. [ABSTRACT FROM AUTHOR]

“Urushi” syrup from Rhus vernicifera DC. was collected monthly from June to October 2011, to represent sieve tube exudates from trees, and the radioactivity of samples was measured. In the syrup, the cesium (Cs) concentration (134Cs and 137Cs) originating from the meltdown at the Tokyo Electric Power Company, Inc. (TEPCO) Nuclear Power Station in Fukushima peaked in July and decreased to a minimum in October, while the natural radioactive potassium-40 (40K) remained constant during the same period. On the basis of these results, we assumed that the radioactive Cs in the urushi syrup was directly translocated from the fallout adsorbed to tree bark rather than from contaminated soil. [ABSTRACT FROM AUTHOR]

A 1-kW small horizontal-axis wind turbine "Airdolphin," capable of high wind operation up to 50 m/s without pitch control system, is now under global round robin tests. The present paper reports a series of technical approach including design/analysis, track tests, and field tests conducted in support to the design process. One windy site "Erimo" and one offshore site "Fukushima" were chosen. For example, at "Erimo," a record of one-day generation was 8.831 kWh on November 13, 2006 (day-averaged wind speed; 11.8 m/s) with 36.8% of capacity factor. An operation data under an attack of typhoon with 50 m/s maximum wind speed demonstrated the technical concepts of high wind operation and safety. A new term "capatureability" as an indicator of WT performance was proposed. [ABSTRACT FROM AUTHOR]

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 mSv/h (3.7-63.0 mSv/y) within the 20-km radius from FNPP and 0.0011-0.38 mSv/h (0.010-3.3 µSv/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. [ABSTRACT FROM AUTHOR]

Large quantities of radionuclides have leaked from the Fukushima Daiichi Nuclear Power Plant into the surrounding environment. Effective prevention of health hazards resulting from radiation exposure will require the development of efficient and economical methods for decontaminating radioactive wastewater and aquatic ecosystems. Here we describe the accumulation of water-soluble radionuclides released by nuclear reactors by a novel strain of alga. The newly discovered green microalgae, Parachlorella sp. binos (Binos) has a thick alginate-containing extracellular matrix and abundant chloroplasts. When this strain was cultured with radioiodine, a light-dependent uptake of radioiodine was observed. In dark conditions, radioiodine uptake was induced by addition of hydrogen superoxide. High-resolution secondary ion mass spectrometry (SIMS) showed a localization of accumulated iodine in the cytosol. This alga also exhibited highly efficient incorporation of the radioactive isotopes strontium and cesium in a light-independent manner. SIMS analysis showed that strontium was distributed in the extracellular matrix of Binos. Finally we also showed the ability of this strain to accumulate radioactive nuclides from water and soil samples collected from a heavily contaminated area in Fukushima. Our results demonstrate that Binos could be applied to the decontamination of iodine, strontium and cesium radioisotopes, which are most commonly encountered after nuclear reactor accidents. [ABSTRACT FROM AUTHOR]

The article offers information on a study related to removal of radioactivity from soil in Fukushima-ken, Japan. It informs about the removal of radioactivity from polluted soil in Fukushima-ken was done using a photosynthetic bacterium, rhodobacter spliaeroides SSI, immobilized in alginate beads by aerobic treatments.

Infrequently, it seems that a significant accident precursor or, worse, an actual accident, involving a commercial nuclear power reactor occurs to remind us of the need to reexamine the safety of this important electrical power technology from a risk perspective. Twenty-five years since the major core damage accident at Chernobyl in the Ukraine, the Fukushima reactor complex in Japan experienced multiple core damages as a result of an earthquake-induced tsunami beyond either the earthquake or tsunami design basis for the site. Although the tsunami itself killed tens of thousands of people and left the area devastated and virtually uninhabitable, much concern still arose from the potential radioactive releases from the damaged reactors, even though there was little population left in the area to be affected. As a lifelong probabilistic safety analyst in nuclear engineering, even I must admit to a recurrence of the doubt regarding nuclear power safety after Fukushima that I had experienced after Three Mile Island and Chernobyl. This article is my attempt to 'recover' my personal perspective on acceptable risk by examining both the domestic and worldwide history of commercial nuclear power plant accidents and attempting to quantify the risk in terms of the frequency of core damage that one might glean from a review of operational history. [ABSTRACT FROM AUTHOR]