Power Plant Accident In Japan Research Articles

지리 교과에서 안전교육 내용 구성을 위한 방사능에 대한 위험 인식 분석

Objectives This study aims to provide basic data for the construction of safety education contents in geography subject by examining university students' risk perception of radioactivity with an optimism bias through a real case of the Fukushima nuclear power plant accident in Japan.
 Methods To this end, a questionnaire composed of questions asking about risk perception of radioactivity and optimism bias in risk perception of radioactivity was distributed and collected to 134 university students in Seoul, South Korea. A one-way ANOVA was conducted to see the difference in risk perception of radioactivity according to the type of visit to Japan (visit to Tokyo, non-visit to Japan, visit to Japan). In addition, factor analysis and multiple regression analysis were performed to identify the optimism bias in the risk perception of radioactivity, and then the difference in optimism bias according to the type of visit to Japan was analyzed through MANOVA (Multivariate Analysis of Variance).
 Results The terms of risk perception of radioactivity, the degree of perception that Tokyo is safe from radiation was significantly higher in the Tokyo visiting group than in the other two groups. As a result of factor analysis to identify optimism bias, three factors (optimistic perception, avoidance perception, and wait-and-see perception) were derived, and as a result of multiple regression analysis, it was found that optimistic perception and avoidance perception had a positive effect on optimism bias in order. As a result of MANOVA, the Tokyo visiting group showed significantly higher perceptions of both optimistic and avoidance compared to the other two groups.
 Conclusions Optimism bias and its sub-factors, optimistic perception and avoidance perception, were identified in the risk perception of radioactivity. Because optimism bias makes it difficult to make logical judgments and rational decision-making in risk situations, meta-cognition for optimism bias in relation to risk perception should be considered when constructing safety education contents in geography subject.

Intra-mediary expertise: Trans-science and expert understanding of the public.

What is the role of experts and their expertise in the context of trans-science, in which issues that are raised in scientific terms cannot be answered by science alone? This article examines the discourses and practices around safety of low-dose exposure to radiation in the ongoing aftermath of the Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011. Following the nuclear fallout, scientific experts and STS scholars in Japan debated what forms of science communication were adequate to address the situation. Ethnographic research and textual analysis of their debates show a shift in emphasis on the role of experts from cultivating 'public understanding of science' for the sake of science and policy to an 'expert understanding of the public' for the sake of the public and its diverse everyday concerns. Two forms of expertise are emerging: 'co-expertise' and 'intra-mediary expertise'. Both are parts of a transition from a paternalistic form of expertise to one that acknowledges the need to engage the public to address issues of scientific uncertainty. However, co-expertise ultimately upholds the existing political structures that shape risk governance, while intra-mediary expertise engages those often excluded from current structures of accountability. Discussion of the potentials and limitations of emerging forms of expertise in Japan show that epistemic justice is not enough. Civic justice that acknowledges diverse publics and their needs must be upheld in the uncertain sphere between science, politics, and everyday life.

The rule of law: A fragile tool for the development of emerging nuclear technologies

Before the Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011, the nuclear industry had strongly promoted the idea that the time of nuclear renaissance had come after a long, fallow period in the wake of the nuclear accidents at Three Mile Island (1979) and Chernobyl (1986). During the post-Fukushima period, there were few new projects, but growing demand for energy and anxieties raised by climate change have brought us to a turning point. Despite the Fukushima accident, which led to some nuclear projects being delayed or cancelled, there is still a great deal of interest in the use of nuclear power for civil purposes. This is primarily because, as the International Energy Agency’s (IEA) Executive Director Fatih Birol has rightly pointed out: “Without an important contribution from nuclear power, the global energy transition will be that much harder.”1 In this regard, in 2010, 67 reactors were under construction, 120 planned and 441 in operation.2 In 2022, 11 years after the Fukushima Daiichi accident, there were 60 under construction, 104 planned and 338 proposed.3 The International Atomic Energy Agency (IAEA) estimates that nuclear electric power capacity will have increased by as much as 23% by 2030 and more than doubled by 2050.4 In addition to this renewed interest, many projects are now in development, opening up new prospects for the use of the atom for civil purposes. Nuclear fusion, small modular reactors (SMRs), the use of artificial intelligence, floating, underwater and space reactors, and nuclear batteries, to name but a few of the projects on the table, lead us to think that the “nuclear renaissance” is slowly shifting to a “nuclear spring”. In this view, where the concept of a renaissance involves new impetus for nuclear energy, with the construction of new facilities, the concept of “spring” refers to a determination to break with nuclear traditions, in terms of concepts, means and players. Consequently, this phenomenon calls for new legal rules which, in some cases, have already started to be debated.

Mode of Atmospheric Deposition in Forests Demonstrates Notable Differences in Initial Radiocesium Behavior.

The March 2011 Fukushima Dai-ichi Nuclear Power Plant accident in Japan released 520 PBq of radionuclides compared to a total release of 5300 PBq from the Chornobyl Nuclear Power Plant accident. Both nuclear accidents resulted in deposition of radiocesium throughout the northern hemisphere, and a plethora of studies have been performed regarding radiocesium (137Cs) behavior. However, few studies have assessed the impact of precipitation on 137Cs deposition in forests. Wide-scale environmental measurements from 2011 and 2016 were used to determine the differences in 137Cs deposition because of precipitation following the Fukushima accident. In areas where wet deposition processes were dominant, dense forests generally had lower ambient dose rates and levels of contamination on forest floors than other stands with fewer stems per hectare in 2011. Similar tendencies were not observed in areas that were primarily subject to dry deposition nor were any trends observed in 2016. 137Cs was retained in dense forest canopies for an extended period regardless of the deposition mode. Additionally, it was found that the initial retention of radionuclides by forest canopies is in general higher for areas with predominantly dry deposition. Incorporation of radiocesium into wood tissues was the same for both wet and dry deposition.

Structure, stability, and actinide leaching of simulated nuclear fuel debris synthesized from UO2, Zr, and stainless-steel

To evaluate the chemical structure and stability of nuclear fuel debris comprising UO2, Zr, and stainless-steel (SUS) generated during the Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011, the simulated debris of a UO2–SUS–Zr system and those of other fundamental-component-containing systems were synthesized and characterized. The simulated debris was synthesized by heat treatment at 1600 °C under inert (Ar) or oxidative (Ar + 2% O2) atmospheres for 1–12 h. 237Np and 241Am tracers were doped for leaching tests from the simulated debris. The simulated debris was characterized using X-ray diffraction, scanning electron microscopy–energy-dispersive X-ray spectroscopy, Raman spectroscopy, and Mössbauer spectroscopy, and the results revealed that the major uranium phase of the UO2–SUS–Zr debris comprised a Zr(IV)-and-Fe(II)-containing UIVO2 solid-solution, regardless of the treatment conditions. The results of a long-term immersion test of the simulated debris in pure water and seawater revealed that the macroscale crystal structure of the simulated debris was chemically durable under wet conditions for at least a year. Furthermore, the leaching test results indicated that the leaching ratios of U, Np, and Am from the UO2–SUS–Zr debris were small and lower than 0.08% for all the experiments in this study.

Radiocesium-bearing microparticles cause a large variation in 137Cs activity concentration in the aquatic insect Stenopsyche marmorata (Tricoptera: Stenopsychidae) in the Ota River, Fukushima, Japan.

After the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Plant accident in Japan, freshwater ecosystems near the site remained contaminated by radiocesium (RCs). Clarifying RCs concentrations in aquatic insects is crucial because fishes consume these insects that transfer RCs into freshwater ecosystems. As aquatic insects are usually measured for radioactivity in bulk samples of several tens of insects, variation in RCs concentration among individuals is not captured. In this study, we investigated the variability in 137Cs activity concentration in individual aquatic insects in detritivorous caddisfly (Stenopsyche marmorata) and carnivorous dobsonfly (Protohermes grandis) larvae from the Ota River, Fukushima. Caddisfly larvae showed sporadically higher radioactivity in 4 of the 46 caddisfly larvae, whereas no such outliers were observed in 45 dobsonfly larvae. Autoradiography and scanning electron microscopy analyses confirmed that these caddisfly larvae samples contained radiocesium-bearing microparticles (CsMPs), which are insoluble Cs-bearing silicate glass particles. CsMPs were also found in potential food sources of caddisfly larvae, such as periphyton and drifting particulate organic matter, indicating that larvae may ingest CsMPs along with food particles of similar size. Although CsMP distribution and uptake by organisms in freshwater ecosystems is relatively unknown, our study demonstrates that CsMPs can be taken up by aquatic insects.

Factors Affecting the Sense of Coherence (SOC) for Long-term Evacuees after a Large-Scale Disaster in Japan

Disasters has been occurring frequently all over the world, and an increasing number of people have been forced to continue their evacuation life for a long time. In the aftermath of the 2011 Great East Japan Earthquake and the Fukushima nuclear power plant accident in Japan, some people are still unable to return to their homes due to radioactive contamination and are forced to live as evacuees for long periods of time. It is considered a serious public health issue to keep mentality healthy under the stress of living after the disaster. Therefore, the purpose of this study was to examine the factors that affect the sense of coherence (SOC), which is considered as the ability to cope with stress and maintain health, in residents who continue to live as evacuees after a large-scale disaster. The method was a self-administered questionnaire survey of 1,602 long-term evacuees in Japan. Multiple logistic regression analysis was conducted with the high and low SOC score groups as dependent variables in order to identify factors that predicted high and low SOC. The results showed that the SOC tended to decrease in the elderly and those with deteriorating mental health. On the other hand, those who were active in education and hobbies, and those who socialized with their neighbors and friends tended to have the higher SOC. In order to support residents who have been forced to continue living as evacuees for a long period of time, it is important to provide them with psychological and emotional support to prevent them from being emotionally overwhelmed, as well as living environment improvement and economic support. It was suggested that the promotion of resident-led activities that lead to mental relaxation and the introduction of stress reduction methods that can be easily adopted by residents are effective in maintaining mental health.

Long-lasting effects of distrust in government and science on mental health eight years after the Fukushima nuclear power plant disaster.

We aimed to explore the effects of erosion of trust in authorities on the long-term mental health of community residents after the 2011 Fukushima nuclear power plant accident in Japan. We investigated the effects of distrust in authorities on mental health in a cohort study following non-evacuee community residents after the 2011 Fukushima nuclear power plant accident. A baseline questionnaire survey was administered five years after the accident for a random sample of 4900 residents outside the evacuation zone in Fukushima. Distrust in the national government and in science were assessed using a four-point single-item scale. Psychological distress was measured using the K6. Posttraumatic stress symptoms were measured using an abbreviated version of the Posttraumatic Stress Disorder Checklist-Specific version. Longitudinal associations of distrust in the government and science at baseline and psychological distress and posttraumatic stress symptoms eight years after the accident were examined, controlling for the baseline level of distress or symptoms using multivariate logistic regression analyses. Valid responses were obtained from 927 (18.9%) residents. Distrust in the government at baseline was significantly associated with posttraumatic stress symptoms at follow-up, albeit controlling for baseline symptoms. While distrust in the government was also associated with psychological distress at follow-up, the association became non-significant after controlling for baseline distress. Distrust in science at baseline was not associated with posttraumatic stress symptoms or psychological distress at follow-up. Distrust in government after a nuclear power plant accident may have adverse effects on mental health in the long-term.

Spectroscopic analysis of radioactive strontium with low isotopic abundance using laser resonance ionization

Strontium-90 (90Sr, half-life of 28.8 years) is one of the major fission products released in the Fukushima Daiichi Nuclear Power Plant accident in Japan. Due to the high concentrations of Sr stable isotopes in marine products, an upper limit for 90Sr isotopic abundance in them is of the order of 1 ppb or less. Resonance ionization technique using narrow linewidth lasers is suitable for analysis requiring high elemental and isotopic selectivity. In this study, we have investigated on 689.4 nm - 487.4 nm - 393.8 nm three-step resonance ionization of Sr atoms, where the 90Sr isotope shifts in the second and third transitions were predicted using a King plot approach to evaluate the optical isotopic selectivity. As the first step in measuring real samples, the influence of coexisting elements in seawater was also derived.

The trajectories of local food avoidance after the Fukushima Daiichi nuclear plant disaster: A five-year prospective cohort study

After the Fukushima Daiichi nuclear power plant accident in Japan, residents continue to be concerned about radiations despite strict regulations on radionuclides in foods and decontamination. We examined the trajectory of the avoidance tendency of local food among residents in the affected area. Growth mixture modelling was adapted to ten waves cohort of parents of all elementary school children (N = 1606) in the affected area (Minami soma city). The trajectory was examined for six types of food: mushrooms, milk, vegetables/fruits, meat, fish, and rice. A three-class trajectory model (Low concern adaptors, High concern adaptors, High concern maintainers) was identified regardless of the types of food. While about half of the sample was classified as high concern maintainers regarding rice, fish, and mushrooms, the proportions of the three groups were roughly equal regarding other types of food. Local food avoidance has prominently decreased five years after the accident. Multinomial logistic regression revealed that the higher the air dose rate at the place of residence at the time of the accident, the higher the probability of belonging to the high concern adaptors rather than to the low concern adaptors. Local food avoidance, which increased after the nuclear accident, decreased substantially with the lifting of evacuation orders. As local food avoidance trajectories are associated with air doses rate in the immediate post-accident residence, risk communication concerning the residence's air dose is needed.

Study on the chemical structure and actinide leaching of MCCI debris

To understand the chemical structure and stability of molten core-concrete interaction (MCCI) debris generated by the Fukushima Daiichi nuclear power plant accident in Japan in 2011, simulated MCCI debris consisting of the U–Zr–Ca–Si–O system and other simpler systems were synthesized and characterized. 237Np and 241Am tracers were doped for the leaching tests of these elements and U from the simulated debris. The MCCI debris were synthesized by heat treatment at 1200 °C or 1600 °C, in reductive (Ar + 10% H2) or oxidative (Ar + 2% O2) atmospheres. Subsequently, the debris were used for actinide leaching tests with water. Zr and Ca formed a solid-solution with the UO2 matrix, such as (ZryU1-y)O2+x, (CayU1-y)O2+x, and (CazZryU1-y-z)O2, which stabilized the matrix and suppressed actinide leaching from the simulated debris. On the other hand, the cement components (CaO and SiO2) in the debris formed a glass-like coating on the debris, which also remarkably suppressed the leaching of actinides.

Temporal dynamics of 137Cs distribution in soil and soil-to-crop transfer factor under different tillage systems after the Fukushima Daiichi Nuclear Power Plant accident in Japan

The accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in Japan in 2011 released a large amount of radionuclides, primarily radiocesium-137 (137Cs; half-life: 30 years), resulting in long-term contamination of soil and consequently crops. Tillage is a common agricultural management practice that alters the vertical distribution of nutrients in the soil. However, the effect of tillage on 137Cs contamination in soil and crops over time remains unclear. In this study, we investigated the temporal changes in the vertical distribution of 137Cs in the soil, concentration of 137Cs in soybean and cover crops, and the transfer factor (TF) of 137Cs from the soil to crops under three tillage systems (rotary cultivation [RC], moldboard plow [MP], and no tillage [NT]; main factors) using three cover crops (hairy vetch, winter rye, and fallow weeds; side factors). The amount of 137Cs in the soil decreased exponentially with soil depth under the NT and RC treatments. By contrast, 137Cs showed uniform distribution at each soil depth tested under the MP treatment since 2012. The exchangeable 137Cs demonstrated a similar tendency as 137Cs. The 137Cs concentration in soybean (including grain and residue) and cover crops decreased exponentially with time. Consistently higher 137Cs concentration was observed in soybean grains under the NT treatment, suggesting that tillage continuously reduced the concentration of 137Cs in soybean over 7 years since the FDNPP accident. The TF of 137Cs from soil to soybean and cover crops decreased continuously over time; however, 137Cs concentration of soybean grain showed a positive linear correlation with its annual variation rate. Additionally, TF showed a positive logarithmic correlation with 137Cs relaxation depth in the soil. These results enhance our understanding of the long-term behavior and radioecology of 137Cs in agroecosystems in Japan since the radionuclide accident.

Bioethanol Production from Molasses by Yeasts with Stress-Tolerance Isolated from Aquatic Environments in Japan

Bioethanol is a safe and renewable source of energy that continues to be a research focus, since fossil fuels have been linked to global warming and nuclear energy sources are affected by the increased safety concerns following the 2011 nuclear power plant accident in Japan. In general, bioethanol is converted from a biomass by yeast fermentation. The production efficiency of this bioethanol is not sufficiently high, and its practical use as a substitute for fossil fuels and nuclear energy is thus limited. For the industrial production of bioethanol, the yeast fermentation of biomass cultures containing high concentration sugar, NaCl, and ethanol is necessary, but this might induce phenomena in which the stresses arising in the yeasts weaken their cells during fermentation. As described herein, we isolated 1028 strains of yeasts from natural aquatic environments: Japan’s Tama River and Lake Kasumigaura. Among them, 412 strains were fermentative yeasts and 31 strains showed high fermentation ability under a 30% sorbitol + 10% ethanol condition. These strains were identified as Torulaspola delbrueckii, Wickerhamomyces anomalus, Candida glabrata, Pichia kudriavzevii, Saccharomyces cf. cerevisiae/paradoxus, and Lachancea kluyveri. The strains T. delbrueckii, W. anomalus, and C. glabrata also showed tolerance against 15% NaCl. Most importantly, S. cf. cerevisiae/paradoxus H28 and L. kluyveri F2-67 produced 57.4 g/L and 53.9 g/L ethanol from molasses (sucrose 104.0 g/L, fructose 33.4 g/L, and glucose 24.8 g/L) within 48 hrs at 25°C, respectively.

Model Intercomparison of Atmospheric 137Cs From the Fukushima Daiichi Nuclear Power Plant Accident: Simulations Based on Identical Input Data

AbstractA model intercomparison of the atmospheric dispersion of cesium‐137 (137Cs) emitted after the Fukushima Daiichi Nuclear Power Plant accident in Japan was conducted to understand the behavior of atmospheric 137Cs in greater detail. The same meteorological data with a fine spatiotemporal resolution and an emission inventory were applied to all models to exclude the differences among the models originating from differences in meteorological and emission data. The meteorological data were used for initial, boundary, and nudging data or offline meteorological field. Furthermore, a horizontal grid with the same resolution as that of the meteorological data was adopted for all models. This setup enabled us to focus on model variability originating from the processes included in each model, for example, physical processes. The multimodel ensemble captured 40% of the atmospheric 137Cs events observed by measurements, and the figure of merit in space for the total deposition of 137Cs exceeded 80. The lower score of the atmospheric 137Cs than that of the deposition originated from the difference in timing between observed and simulated atmospheric 137Cs. Our analyses indicated that meteorological data were most critical for reproducing the atmospheric 137Cs events. The results further revealed that differences in 137Cs concentrations among the models originated from deposition and diffusion processes when the meteorological field was simulated reasonably well. The models with small deposition fluxes produced higher scores for atmospheric 137Cs, and those with strong diffusion succeeded in capturing the high 137Cs concentrations observed; however, they also tended to overestimate the concentrations.

Nuclear Disaster and Culture : Cultural Framing of the Fukushima Nuclear Power Plant Accident in Japan by South Korean Anti-nukes Activism

본 논문은 2011년 3월 11일 일본 동북지역을 강타한 대지진과 쓰나미로 인한 후쿠시마 원전사고 이후 전개되었던 한국탈핵운동의 임시적 부활을 재해 인류학적 관점에서 살펴본다. 구체적으로 본 논문은 재해와 문화 간 어떤 관계가 있는지를 알아보고자 한다. 다시 말해 사 람들이 재난/재해를 어떻게 받아들이는지 그리고 사건 이후 서로의 관계를 어떻게 재구성하 는지 살펴보고자 한다. 재해는 사람들이 자신들이 처한 위험을 어떻게 구성하거나 프레이밍 (외면도 포함하여)하는지, 어떻게 자신들의 환경과 생존 수준을 인식하고 있는지, 그리고 어 떻게 설명을 만들어내고 인간의 지속성과 약속을 미래에 투영하는지를 보여준다. 2010년􋹲2013년 동안 진행된 탈핵운동과 기후변화반대 캠페인에 대한 현지조사를 통해 본 논문은 한국탈핵운동의 반응을 2가지 재해에 대한 일반적인 인류학적 관점인 사회변화적 접 근법과 정치적 접근법으로 살펴보고자 한다. 한국 탈핵운동의 임시부활을 맥락화하기 위하여 본 논문은 미디어가 보여준 3중 대재해에 대한 한국사회의 다양한 반응에 대한 담론 분석을 시도하고 있다. 다양한 반응에서 4가지 주요 주제를 발견할 수 있다: 1) 국민의 자연화와 재 해의 문화화, 2) 수입식료품의 안전, 3) 경제적 이해관계, 그리고 4) 방사능 위험. 사회변화적 접근법과 정치적 접근법으로 보면 한국탈핵운동은 후쿠시마 사고를 운동의 부 활, 새로운 아젠다 제시, 새로운 권력관계 형성의 맥락으로 삼은 것이 분명하다. 더 나아가, 세계화 접근법으로 한국 탈핵운동의 다양한 반응을 보면 먼저 초국적 네트워크가 형성되는 반면 복잡하고 모순적인 과정을 전개해 나가고 있다는 것을 보여준다. 본 논문은 한국 탈핵 운동이 후쿠시마 사고와 관련해서 ‘동아시아 내션스케이프’이라고 할 수 있는 새롭고 유동적 인 동아시아를 공간화 한다는 것을 설명하려고 한다. ‘동아시아 내션스케이프’는 다양한 행위 자들에 의해 다양하게 해석되고 있다. 끝으로 본 논문은 공공 이슈에 대해 인류학이 무엇을 할 수 있는지에 대한 논의를 활성화 하고 있는 공공인류학의 일환이라고 할 수 있다.

Study on the leaching behavior of actinides from nuclear fuel debris

For the prediction of the leaching behavior of actinides contained in the nuclear fuel debris generated by the Fukushima Daiichi nuclear power plant accident in Japan, simulated fuel debris consisting of a UO2–ZrO2 solid solution doped with 137Cs, 237Np, 236Pu, and 241Am tracers was synthesized and investigated. The synthesis of the debris was carried out by heat treatment at 1200 °C at different oxygen partial pressures, and the samples were subsequently used for leaching tests with Milli-Q water and seawater. The results of the leaching tests indicate that the leaching of actinides depends on the redox conditions under which the debris was generated; for example, debris generated under oxidative conditions releases more actinide nuclides to water than that generated under reductive conditions. Furthermore, we found that, as Zr(IV) increasingly substituted U(IV) in the fluorite crystal structure of the debris, the actinide leaching from the debris decreased. In addition, we found that seawater leached more actinides from the debris than pure water, which seems to be caused by the complexation of actinides by carbonate ions in seawater.

Stabilization of cesium in alkali-activated municipal solid waste incineration fly ash and a pyrophyllite-based system

Environmentally sound treatments are required to dispose of municipal solid waste incineration fly ash (MSWIFA) contaminated with radioactive cesium (Cs) from the Fukushima Daiichi nuclear power plant accident in Japan. This study focuses on the stabilization of Cs using an alkali-activated MSWIFA and pyophyllite-based system. Three composite solid products were synthesized after mixtures of raw materials (dehydrated pyrophyllite, MSWIFA, 14 mol/L aqueous sodium hydroxide, and sodium silicate solution) were cured at 105 °C for 24 h. Three types of MSWIFAs were prepared as raw fly ash, raw fly ash with 0.1% CsCl, and raw fly ash with 40% CsCl to understand the stabilization mechanism of Cs. Cs stabilization in two solid products was successful, with less than 6.9% leaching observed from two types tests, and was partly successful for the solid product with the highest concentration of Cs. X-ray diffraction showed that all of the solid products produced several crystalline phases, and that pollucite was formed in the highest Cs concentration product. The X-ray absorption fine structure and scanning electron microscopy with X-ray analysis suggested that most Cs species formed pollucite in the two solid products from MSWIFA with added CsCl. This system provides a technique for the direct stabilization of Cs in MSWIFA.

Specific activities and radiological hazard assessment in beach sand samples in Songkhla province, Thailand after Fukushima Dai-Ichi nuclear power plant accident in Japan

According to the Fukushima Dai-Ichi Nuclear Power Plant Accident in Japan on March 11, 2011, specific activities of natural (40K, 226Ra and 232Th) and anthropogenic (137Cs) radionuclides in 210 beach sand samples which were collected from Maharat, Sai Kaew, Samila, Chalatat, Na Thab, Sakom and Soi Sawan beaches in Songkhla Province along the eastern coast of Thailand, have been studied and evaluated. The specific activity levels of 40K, 226Ra, 232Th and 137Cs in the area were found in the range 110.13 – 4574.12, 6.99 – 451.87, 3.75 – 665.76 and 0.58– 9.91 Bq/Kg, respectively. Furthermore, the median values of specific activities of 40K, 226Ra, 232Th and 137Cs were calculated and compared with other research data in Thailand as well as global measurements and evaluations. Moreover, four radiological hazard indices for the studied area were also assessed by using the median values of specific activities of 40K, 226Ra and 232Th.

Experimental Verification of Steel Pipe Collapse under Vacuum Pressure Conditions

Steel pipes are used widely in hydroelectric systems and in pumping systems. Both systems are subject to hydraulic transient effects caused by changes in boundary conditions, such as sudden valve closures, pump failures, or accidents. Water column separation, and its associated vaporization pressure inside the pipe, can cause the collapse of thin walled steel pipes subject to atmospheric pressure, as happened during the well known Oigawa Power Plant accident in Japan, in 1950.The conditions under which thin walled pipes subject to external pressure can collapse have been studied mathematically since the second half of the XIX century, with classical authors Southwell and Von Mises obtaining definitive equations for long and short pipes in the second decade of the XX century, in which the fundamental variables are the diameter to thickness ratio D/t and the length to diameter ratio L/D.In this paper, the predicted critical D/t ratio for steel pipe collapse is verified experimentally, in a physical model able to reproduce hydraulic transients, generating vacuum pressures through rapid upstream valve closures.

Increases in perinatal mortality in prefectures contaminated by the Fukushima nuclear power plant accident in Japan: A spatially stratified longitudinal study.

Descriptive observational studies showed upward jumps in secular European perinatal mortality trends after Chernobyl. The question arises whether the Fukushima nuclear power plant accident entailed similar phenomena in Japan. For 47 prefectures representing 15.2 million births from 2001 to 2014, the Japanese government provides monthly statistics on 69,171 cases of perinatal death of the fetus or the newborn after 22 weeks of pregnancy to 7 days after birth. Employing change-point methodology for detecting alterations in longitudinal data, we analyzed time trends in perinatal mortality in the Japanese prefectures stratified by exposure to estimate and test potential increases in perinatal death proportions after Fukushima possibly associated with the earthquake, the tsunami, or the estimated radiation exposure. Areas with moderate to high levels of radiation were compared with less exposed and unaffected areas, as were highly contaminated areas hit versus untroubled by the earthquake and the tsunami. Ten months after the earthquake and tsunami and the subsequent nuclear accident, perinatal mortality in 6 severely contaminated prefectures jumped up from January 2012 onward: jump odds ratio 1.156; 95% confidence interval (1.061, 1.259), P-value 0.0009. There were slight increases in areas with moderate levels of contamination and no increases in the rest of Japan. In severely contaminated areas, the increases of perinatal mortality 10 months after Fukushima were essentially independent of the numbers of dead and missing due to the earthquake and the tsunami. Perinatal mortality in areas contaminated with radioactive substances started to increase 10 months after the nuclear accident relative to the prevailing and stable secular downward trend. These results are consistent with findings in Europe after Chernobyl. Since observational studies as the one presented here may suggest but cannot prove causality because of unknown and uncontrolled factors or confounders, intensified research in various scientific disciplines is urgently needed to better qualify and quantify the association of natural and artificial environmental radiation with detrimental genetic health effects at the population level.