Nuclear Plant Accident Research Articles

The Faultline of Kokoro no Kea: Mental Distress and Post-Disaster Psychosocial Care After the Great East Japan Earthquake

The Japanese concept of “ kokoro no kea” (care for the heart/mind) plays a crucial role in shaping disaster mental health response systems. Following the 2011 Great East Japan Earthquake and tsunami, and the subsequent nuclear plant accident, the government quickly implemented kokoro no kea initiatives. However, many locals reported reluctance to seek support from kokoro no kea teams. This article explores therapeutic governance in response to these disasters, a multifaceted, disavowed, and diffusive mode of governing. It highlights how recovery politics emphasized solidarity—referred as “kizuna” (social bonds)—while also gendering and pathologizing women’s fears and anxieties regarding radiation exposure. Through a narrative review of ethnographic studies, this analysis demonstrates that kokoro no kea is not simply a static post-disaster mental health and psychosocial support system; rather, it is an open, fluid, and evolving process where diverse actors—such as politicians, men, women, health professionals, and religious practitioners—interact with socio-political forces and cultural values, creating unique pathways for individuals and communities to foster connections, build trust, and nurture resilience in coping with psychological pain and loss.

Structure shielding of school and gymnasium buildings against fallout gamma radiation from the Fukushima Daiichi Nuclear Power Plant accident

The radiation dose reduction factor represents a building’s shielding capability against radiation in scenarios of potential nuclear accidents. Notably, the radiation dose reduction for school buildings and gymnasiums have not yet been determined, even though the building types are planned to be used as evaluation shelters in Japan. This study evaluated dose reduction factors in relation to the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP). In this study, we separately measured the indoor and outdoor ambient dose equivalent rates and the dose rates from natural radionuclides at two school sites in an evacuation-order-lifted area in Fukushima Prefecture, Japan, to evaluate the dose reduction factors of the school buildings and gymnasiums. The factors depended not only on the structure and materials of the buildings, but also on the geographical characteristics of the building locations, which could govern the geometries of irradiation. We noted a non-negligible overestimation of the dose reduction factors by the conventional method, due to the presence of natural radiation in areas with low dose rates (<1 μSv/h). Note that the dose reduction factor is used as an uncertainty source for external dose evaluation related to the FDNPP accident. This study can serve as a foundation for future investigations on improving the resilience of buildings confronted by artificial radiation due to scenarios of nuclear plant accidents.

Picture Sound Book with Ninja-Essence Targeting Older People Affected by the Fukushima Daiichi Nuclear Plant Accident: Development and Evaluation Before-after Pilot Clinical Trial

Health and well being are critical concerns for the older people affected by the 2011 Fukushima Daiichi Nuclear Power accident, particularly those who experienced evacuation. This study investigates the feasibility of utilizing a picture sound book infused with Ninja elements to sustain or enhance physical well being among this demographic. A pre–post intervention study was conducted to assess the efficacy of the picture sound book among returnees and evacuees after the lifting of evacuation restrictions. A total of 29 participants took part in the study, divided into returnees and evacuees groups, both of whom were provided with the tool. Analysis of pre–post changes involved descriptive statistics, including Fisher’s exact test and t-test. Significant improvements were observed in both groups, particularly in left and right hand-grip strength, maximum phonation time among participants regularly engaging in exercise, and in activities related to swallowing exercises and vocal practices (p &lt; 0.013 and 0.033). Furthermore, 16 out of 29 participants reported enjoyment of the program. These results suggest promising avenues for further investigation with larger sample sizes, indicating potential for enhanced outcomes.

137Cesium (137Cs) assessment in wild boars from northwestern Italy.

Radionuclide contamination is a serious health issue caused by nuclear experiments and plant accidents, as seen for the Chernobyl and Fukushima nuclear plants. Italy has been especially interested in northwestern alpine regions, as have several other nations. The aim of this work was to indagate 134Cs and 137Cs contamination in wild boars, which were considered bioindicators sampled in the Chisone/Germanasca Valley and the Pellice Valley districts (Piedmont, Italy) in two hunting seasons (2014 and 2016). In the 2014 season, only the livers of the animals (n = 48) were sampled, whereas in 2016, five different anatomical sampling sites were sampled for each animal (n = 16). The analyses were conducted in an accredited laboratory (Agenzia Regionale per la Protezione dell'Ambiente-ARPA) by the aid of an HPGe detector (Ortec) with a relative efficiency of 50%. In general, the contamination levels registered in 2014 were under the detection limit for 134Cs and low for 137Cs (Chisone/Germanasca valley: min: 0.0, max: 23.9 median 11.0 Bq/kg vs Pellice valley: min 0, max: 31.7, median: 9.6 Bq/kg) and no health concern can be supposed. In the first-year samples, the liver showed a negative correlation between age and contamination level. In the second year of sampling, low levels were confirmed (min: 3.1 Bq/kg, max: 113.3; median 17.7 Bq/kg). Multiple sampling from the same animal showed that the diaphragm (median = 27.7 Bq/kg) kidney (27.4) and tongue (27.6) were more contaminated than the liver (17.7) and spleen (15.3). Moreover, a linear mixed model revealed a negative organ-by-age interaction, meaning that interorgan differences in contamination level were greater in younger (5-11 months) than in older (18-36 months) animals. Different feeding habits can be the explanation. Our paper shows that muscle sites (diaphragm and tongue) can be useful for radionuclide pollution surveillance in wild boar populations and that younger animals show more interorgan variability in contamination levels than older animals. More investigations are needed to confirm this correlation and to fulfill the request for more data to achieve better risk assessment.

The ghosts of “internal colonisation”: Anthropogenic impacts of Russian imperial ambitions in Ukraine

The Anthropocene denotes an era of accelerated human impact on the environment. Although discourses of the Anthropocene are often criticized for representing colonial and specifically capitalist interests of economic growth, this paper examines, in the case of Ukraine, how these discourses can be applied to uncover and address social (post)colonial impacts of non-capitalist regimes (those also not classified as “Global North”). In particular, the analysis focuses on the aftermath of the 1986 Chernobyl nuclear plant accident on local communities in Ukraine. As academics of Ukrainian background, authors share their first-hand experiences of such impact on their lives and wellbeing of their families, communities, and land. The narrative research framework is used to engage with the modern Ukrainian community and discuss the implications of geopolitical and cultural proximity of the coloniser, with a particular focus on displacement and forced migration. This is especially relevant as it is reflected in the current refugee crisis and tactics of nuclear terrorism used by the Russian government in the war against Ukraine. This paper is a valuable resource for promoting and giving a voice to the Ukrainian people and potentially other peoples in post-Soviet space to unveil their colonial legacy and utilise the discourses of the Anthropocene to aid more effective decolonisation processes in the future of the region.

Development of a dose estimation system for external exposure assessment at the late phase for individuals living in areas affected by the Fukushima nuclear accident.

Although the elevated ambient dose equivalent (ADE) rates in areas radiologically affected by the 2011 Fukushima nuclear plant accident decreased as time passed, the assessment of Fukushima residents' external dose is still important. A dose estimation system for external exposure assessment at the late phase for individuals living in Fukushima Prefecture was developed for this purpose. The developed system enables the estimations of external doses over the future based on an individual behavioral pattern and ADE-rate distributions from aerial monitoring data and its predicted ADE rate. To validate the system, the estimated results were compared with the measured readings of personal dosemeters. The results indicate that the developed system properly reproduced the individual external doses of subjects living in areas where the outdoor ADE rates exceeded 0.2μSvh-1.

Concept of accident tolerant fuel in nuclear reactors

The excellent behavior of zirconium alloy under normal operating state as well as significant advantage of neutron economy have resulted in the use of zirconium alloy as the cladding material. However, extensive metal-water reaction in the event of severe accidents and subsequent hydrogen generation can be considered to be a big disadvantage for zirconium alloy. The Fukushima Daiichi Nuclear Plant accident has brought challenges to the nuclear industry and renewed attention about the idea of accident tolerant fuels (ATFs). Concept of ATFs is to mitigate the devastating interaction of steam at high temperature with fuel clad in off-normal condition of the reactor. These materials have higher resistance to core degradation, lower oxidation kinetics and can withstand against high temperature for a longer duration of time. Being in the direct contact with the coolant the accident tolerant fuel cladding plays an important role at high temperature in off-normal conditions. Many studies have been initiated worldwide to find an advanced oxidation-resistant alternative cladding material to enhance fuel performance and safety, specifically under accident conditions. One of the candidate materials for fuel cladding in LWRs is oxidation-resistant iron alloys. The stainless steel technology and the material science have been studied extensively and several new generations of increasingly higher performance steels are now commercially available that may offer significant performance improvements over the relatively simple austenitic steels that were utilized as cladding in some early commercial fission reactors. One study has been performed to find the reactivity impact of SiC and stainless steel as clad material on various parameters. This paper presents the results of a study that has been made to understand the reactor physics implications of using SiC and stainless steel as the cladding material.

X-ray radiation-induced intestinal barrier dysfunction in human epithelial Caco-2 cell monolayers

Radiation therapy and unwanted radiological or nuclear exposure, such as nuclear plant accidents, terrorist attacks, and military conflicts, pose serious health issues to humans. Dysfunction of the intestinal epithelial barrier and the leakage of luminal antigens and bacteria across the barrier have been linked to various human diseases. Intestinal permeability is regulated by intercellular structures, termed tight junctions (TJs), which are disrupted after radiation exposure. In this study, we investigated radiation-induced alterations in TJ-related proteins in an intestinal epithelial cell model. Caco-2 cells were irradiated with 2, 5, and 10 Gy and harvested 1 and 24 h after X-ray exposure. The trypan blue assay revealed that cell viability was reduced in a dose-dependent manner 24 h after X-ray exposure compared to that of non-irradiated cells. However, the WST-8 assay revealed that cell proliferation was significantly reduced only 24 h after radiation exposure to 10 Gy compared to that of non-irradiated cells. In addition, a decreased growth rate and increased doubling time were observed in cells irradiated with X-rays. Intestinal permeability was significantly increased, and transepithelial electrical resistance values were remarkably reduced in Caco-2 cell monolayers irradiated with X-rays compared to non-irradiated cells. X-ray irradiation significantly decreased the mRNA and protein levels of ZO-1, occludin, claudin-3, and claudin-4, with ZO-1 and claudin-3 protein levels decreasing in a dose-dependent manner. Overall, the present study reveals that exposure to X-ray induces dysfunction of the human epithelial intestinal barrier and integrity via the downregulation of TJ-related genes, which may be a key factor contributing to intestinal barrier damage and increased intestinal permeability.

Diamond Princess Cruise Ship. COVID-19 Medical Operation by the National EMT, Japan DMAT.

Introduction:The Diamond Princess cruise ship (DP) arrived in Yokohama, Japan, on February 3, 2019, with a confirmation of the Polymerase Chain Reaction test (PCR) positive for the Coronavirus disease 2019 (COVID-19) in a passenger who disembarked at Hong Kong. Japan National Emergency Medical Team (N-EMT), and Japan Disaster Medical Assistance Team (DMAT), were dispatched and measures to prevent the spread of viruses were taken for 3,711 (2,666 passengers and 1,045 crew members) on board.Method:Japan DMAT was dispatched and managed the medical operation for DP passengers and crew members. The records of communication logs for the DMAT were evaluated. In this study, evaluation of DMAT medical operations in the DP was conducted to find any positive effectsResults:472 (157 doctors, 123 nurses, 161 medical logisticians, 31 pharmacists) members responded. Among them, 283 (97 doctors, 66 nurses, 91 medical logisticians, 29 pharmacists) worked inside the DP, and 189 (60 doctors, 57 nurses, 70 medical logisticians, two pharmacists) operated outside mainly for patient transport. DMAT conducted a strategic operation and developed categorization for medical care and patient transport. Eventually, DMAT constructed flow to provide rapid medical care and prescription distributions for passengers and crew members.Conclusion:DMAT has been required to respond to unforeseen disasters in the framework since the Fukushima Nuclear Plant accident in 2011. All the past several types of disaster response were contributed to managing medical operations at the DP. These operations are thought to reduce preventable deaths from COVID-19.

Chemical species of cesium and iodine in condensed vaporized microparticles formed by melting nuclear fuel components with concrete materials.

In this study, we report chemical species of Cs and I in condensed vaporized particles (CVPs) produced by melting experiments using nuclear fuel components containing CsI with concrete. Analyses of CVPs by SEM with EDX showed the formation of many round particles containing Cs and I of diameters less than ∼20 μm. X-ray absorption near-edge-structure and SEM-EDX analyses showed two kinds of particles: one containing large amounts of Cs and I, suggesting the presence of CsI, and the other containing small amounts of Cs and I with large Si content. When CVSs were placed in contact with deionized water, most of the CsI from both particles was dissolved. In contrast, some fractions of Cs remained from the latter particles and possessed different chemical species from CsI. In addition, the remaining Cs was concomitantly present with Si, resembling chemical components in the highly radioactive cesium-rich microparticles (CsMPs) released by nuclear plant accidents into the surrounding environments. These results strongly suggest that Cs was incorporated in CVSs along with Si by melting nuclear fuel components to form sparingly-soluble CVMPs.

The ratio of plant 137Cs to exchangeable 137Cs in soil is a crucial factor in explaining the variation in 137Cs transferability from soil to plant.

To mitigate radioactive cesium from soil to plant, increasing and maintaining the exchangeable potassium (ExK) level during growth is widely accepted after Tokyo Electric Company's Fukushima Dai-ichi Nuclear Plant accident in Japan. This is because the antagonistic relationship between soil solution K and 134Cs + 137Cs (RCs) concentrations changes the transfer factor (TF: designated as the ratio of radioactivity of plant organ to soil) of RCs. As the relationship between ExK and TF depends on the soil types, crop species, and other environmental factors, the required amount of ExK should be set to a safe side. Eleven years after the accident, as the activity of 134Cs was almost negligible, 137Cs became the main RCs in most of the agricultural fields in Fukushima Prefecture. We propose a new indicator, the concentration ratio of plant 137Cs to soil exchangeable 137Cs (Ex137Cs), instead of TF, which showed a better correlation with ExK even among soils with different properties (or mineralogy).

The effect of exposure on cattle thyroid after the Fukushima Daiichi nuclear power plant accident

Nuclear plant accidents can be a risk for thyroid cancer due to iodine radioisotopes. Near the Fukushima Daiichi nuclear power plant, cattle were exposed to radiation after the accident occurred in May 2011. Here we estimated the total radiation exposure to cattle thyroid and its effects on thyroid function. Until October 2016, the estimated external exposure dose in Farm A was 1416 mGy, while internal exposure dose of 131I, 134Cs, and 137Cs were 85, 8.8, and 9.7 mGy in Farm A and 34, 0.2, and 0.3 mGy in Farm B, respectively. The exposed cattle had thyroid with relatively lower weight and lower level of stable iodine, which did not exhibit any pathological findings. Compared with the control, the plasma level of thyroid-stimulating hormone (TSH) was higher in Farm A cattle born before the accident, while the plasma thyroxine (T4) was higher in Farm A cattle born after the accident, suggesting that exposed cattle showed slight hyperactivation of the thyroid gland. In addition, Farm A cattle have higher level of cortisol, one of the anterior pituitary gland-derived hormones. However, we did not observe a causal relationship between the radiation exposure and cattle thyroid.

Prenatal diagnosis and management of fetal arhinia during pregnancy in order to optimize neonatal outcome

Objectives: To discuss the prenatal diagnosis and management of fetal arhinia in order to optimize neonatal outcome Methods: This is a case report and discussion of the clinical management of fetal arhinia and review of appropriate literature Results: A fetus with arhinia diagnosed prenatally by ultrasound was managed optimally for neonatal outcome Conclusion: Prenatal diagnosis of arhinia is a rare congenital malformation that requires consultation and delivery at a specialized children’s hospital with the capability of immediate respiratory support at delivery..

Relationship Between Annual Airborne Pollen Levels And Occurrence Of Thyroid, Skin, Esophagus, Kidney And Ovary Cancers, And Leukemia, Multiple Myeloma And All Cancers: A Retrospective Study Based On The National Registry Database Of Cancer Incidence In Japan, 1975–2015

Background: In Japan, pollen counts increased between 1977 and 1987, including three peaks (1978- 1980, 1982, 1984-1986) coinciding with Kawasaki disease (KD) outbreaks. Epidemiological findings have been gradually accumulated that KD and related specific intractable diseases and further cancers may be correlated to pollen exposure (PE). Methods and results: To elucidate the effects of PE on occurrence of thyroid, skin, esophagus, kidney and ovary cancers, and leukemia, multiple myeloma and all cancers, we evaluated the annual onsets of malignant tumors in relation to pollen counts using data from a national database. Increased rates of these cancers were observed during pollen counts increasing period between 1977 and 1987. Significant correlations were observed between the annual number of newly registered patients (nRPs) and the annual pollen levels (PL) measured with a lag of 2 years for skin and kidney cancers, 4 years for thyroid cancer, 6 years for skin, esophagus cancers, leukemia and multiple myeloma, 8 years for thyroid cancer, and 2,3 and 6 years for all cancers. Peaks of number of thyroid cancer in 2013, 1990 and 1980 are discussed about as compared with other cancers regarding effect of radioactive pollutants occurred from three nuclear plant accidents. Conclusion: Data suggest newly that the cumulative effects of PE within 2,3,4,6,8 years prior to diagnosis might possibly trigger incidence of eight cancers and malignant tumors.

Radiation dose and gene expression analysis of wild boar 10 years after the Fukushima Daiichi Nuclear Plant accident

The Fukushima Daiichi Nuclear Power Plant accident led to contamination with radioactive cesium in an extensive environment in Japan in 2011. We evaluated the concentration of radioactive cesium in the skeletal muscles of 22 wild boars and the expression of IFN-γ, TLR3, and CyclinG1 in the small intestine and compared them with those of wild boar samples collected from Hyogo prefecture. The average 137Cs radioactivity concentration in wild boars in the ex-evacuation zone was 470 Bq/kg. Most of samples still showed radioactivity concentration that exceeded the regulatory limit for foods, but the dose remarkably decreased compared with samples just after the accident. IFN-γ expression was significantly higher in wild boars in the ex-evacuation zone than in samples from Hyogo prefecture. TLR3 expression was also upregulated. CyclinG1 expression also tended to be high. Hence, wild boars might have received some effects of low-dose radiation, and immune cells were activated to some extent. However, pathological examination revealed no inflammatory cell infiltration or pathological damage in the small intestine of wild boars in the ex-evacuation area. Long-term monitoring would be necessary, but we consider that the living body responds appropriately to a stimulus from a contaminated environment.

MicroGrid Designer: user-friendly design, operation and control assist tools for resilient microgrid and autonomous community

During this decade, many countries have experienced natural and accidental disasters, such as typhoons, floods, earthquakes, and nuclear plant accidents, causing catastrophic damage to infrastructures. Since the end of 2019, all countries of the world are struggling with the COVID-19 and pursuing countermeasures, including inoculation of vaccine, and changes in our lifestyle and social structures. All these experiences have made the residents in the affected regions keenly aware of the need for new infrastructures that are resilient and autonomous, so that vital lifelines are secured during calamities. A paradigm shift has been taking place toward reorganizing the energy social service management in many countries, including Japan, by effective use of sustainable energy and new supply schemes. However, such new power sources and supply schemes would affect the power grid through intermittency of power output and the deterioration of power quality and service. Therefore, new social infrastructures and novel management systems to supply energy and social service will be required. In this paper, user-friendly design, operation and control assist tools for resilient microgrids and autonomous communities are proposed and applied to the standard microgrid to verify its effectiveness and performance.

Cooling time and CHF enhancement of reactor vessel cooling process by flame sprayed porous coating in different orientations

External reactor vessel cooling (ERVC) is an effective strategy to achieve in-vessel retention (IVR) under severe nuclear plant accidents. Earlier transition from film boiling to nucleate boiling can lead to faster cooling and the critical heat flux (CHF) of the reactor pressure vessel (RPV) determines the success of IVR-ERVC. In this study, a porous coating of 316L was prepared on the surface of SA508 steel by flame spraying. Quenching experiments of plain surface and coating surface were performed to investigate the enhancement of reactor vessel cooling process at atmospheric pressure in saturated deionized water by using a variable orientation quenching device. The orientations of all experimental surfaces were varied between 0°(downward) and 90°(vertical). The experimental results show that the cooling time of coating surface was reduced by more than 56% compared with plain surface, which is mainly due to the reduction of duration in film boiling phase and the early appearance of Leidenfrost point (LFP). The CHF of coating surface achieved about 30% enhancement compared with plain surface in all orientations. In addition, the cooling time decreased and CHF increased with the increase of orientation because the bubbles separation was easier in the larger orientation angle. The visualization of cooling process was conducted in the vertical orientation and demonstrated that there were more nucleation sites of bubbles and the bubbles grew and separated faster in coating surface.

Performance evaluation of Accident Tolerant Fuel under station blackout accident in PWR nuclear power plant by improved ISAA code

The Accident Tolerant Fuel (ATF) is a new concept of fuel, which can not only withstand the consequences of the accident for a longer time, but also maintain or improve the performance under operating conditions. ISAA is a self-developed severe accident analysis code, which uses modular structures to simulate the development processes of severe accidents in nuclear plants. The basic version of ISAA is developed based on UO2–Zr fuel. To study the potential safety gain of ATF cladding, an improved version of ISAA, referred to as ISAA-ATF, is introduced to analyze the station blackout accident of PWR using ATF cladding. The results show that ATF cladding enable the core to maintain a longer time compared to zirconium alloy cladding, thereby enhancing the accident mitigation capability. Meanwhile, the generation of hydrogen is significantly reduced and delayed, which proves that ATF can improve the safety characteristics of the nuclear reactor.

Taurine Deficiency in Tissues Aggravates Radiation-Induced Gastrointestinal Syndrome.

Ionizing radiation administered for cancer treatment or from nuclear plant accidents are two common causes of radiation exposure. Ionizing radiation exposure generates reactive oxygen species and free radicals, which cause oxidative stress. We previously reported that taurine contributes to the recovery from radiation-induced injuries, suggesting its potential as a radioprotector and radiation mitigator. However, the effect of taurine on radiation-induced gastrointestinal syndrome remains poorly understood. The aim of this study was to examine the effect of taurine tissue depletion on radiation-induced gastrointestinal syndrome. Mouse models of radiation-induced gastrointestinal syndrome were established in TauT+/+ and TauT-/- mice by whole-body X-irradiation. We examined the 30-day survival rate, as well as the crypt-villus structure and proliferation of proliferating cell nuclear antigen (PCNA)+cells in the small intestine. The survival rate of TauT-/- mice was significantly lower than that of TauT+/+ mice. The villi in the small intestine of TauT-/- mice were significantly shorter than those in TauT+/+ mice. Additionally, there were significantly fewer PCNA+ cells in TauT-/- mice than in TauT+/+ mice. These data demonstrate that taurine is a key regulator of crypt stem cells and plays an important regulatory role in intestinal cell survival, proliferation, and fate. Therefore, taurine may reduce radiation-induced gastrointestinal syndrome.

Influence of corium temperature, concrete composition and water injection time on concrete ablation during MCCI: New insights

Molten corium, a mixture of molten nuclear fuel, cladding, thermo-hydraulic and structural elements, can originate in a nuclear plant accident after a reactor core meltdown. This un-cooled corium could penetrate through the reactor pressure vessel and cause concrete ablation via basement melt-through, a process known as Molten Corium Concrete Interaction (MCCI). The MCCI analysis because of its complex nature is still uncertain and needs thorough investigation of various parameters. In this study the use of CORQUENCH simulator is presented to model the molten corium, composition of concrete and heat transfer along with related chemical reactions. Using this modeling technique, the chemical reaction capabilities of CORQUENCH is successfully utilized enabling the modeling of interaction between molten corium and concrete. The developed model is validated against experimental data at PWR and BWR conditions. The results showed that the temperature of corium, composition of concrete and water injection time have a pronounced effect on mitigating ablation and reactor integrity in case of a nuclear accident. In addition, the composition of concrete was found to be the main controlling factor to mitigate ablation. An alternative to concrete is to utilize igneous rock (pyrolite) and this approach could lead to comparatively very low rates of ablation due to its high thermal resistant properties. Furthermore, the injection of water (as a cooling agent) into the reactor cavity should also be optimized to enhance corium quenching to avoid ablation via basement melt-through. The concrete ablation mechanisms during MCCI are very case-dependent on the concrete solidus, liquidus and ablation temperatures, respectively.