Nuclear Accident Research Articles

Evaluation of proton and alpha particles interaction parameters of selected cholinergic medications: a computational approach

In neuroimmune communication, the cholinergic system plays a key role in transmitting information vis-à-vis the peripheral immune status to the central nervous system and vice versa. Exposure to ionizing radiations (photons and charged particles) either for medical purposes (radiotherapy and radiodiagnostic) or during radiation accidents can affect the cholinergic system. As such, the administration of cholinergic medications, before or after exposure, can minimize the side effects of ionizing radiation on the cholinergic system. In literature, photon interaction parameters of cholinergic medications have been calculated. However, proton and alpha particle interactions parameters of cholinergic medications have not been investigated. This study, therefore, investigated the mass-stopping power (S(E)/ρ), effective atomic number (Zeff), and electron density (Neff) of 12 cholinergic medications, namely arecoline, carbachol, diisopropyl fluorophosphate, donepezil, malathion, parathion, physostigmine, pilocarpine, rivastigmine, sarin, soman, and tabun for proton and alpha particles interaction. To investigate the parameters of each of the cholinergic medications, a compact and comprehensible cross-platform computer software known as PAGEX was used to compute the S(E)/ρ, Zeff, and Neff for the proton and alpha particle interactions at an energy of 1 keV-10 GeV and 1 keV-1 GeV, respectively. The maximum value of the S(E)/ρ of the cholinergic medications occurred at lower energy regions of about 0.045 ≤ E ≤ 0.1 MeV and 0.5 ≤ E ≤ 0.75 MeV for proton and alpha particle interactions, respectively. Based on the S(E)/ρ, rivastigmine and parathion show the best and least radioprotective ability against proton and alpha particle radiations, respectively. Generally, it was observed that the medications with a lower Zeff have a higher S(E)/ρ than those with a higher Zeff. For both proton and alpha particle interactions, the variation of the Neff with the Zeff has been observed to be linear throughout the entire energy region. It is thought that the S(E)/ρ, Zeff, and Neff of the cholinergic medications for proton and alpha particle interactions investigated in this study will be useful in radiation dosimetry and will also be a buildup on future work that will focus on experimental findings on the radioprotective ability of the investigated medications against charged particle radiations.

Central Nervous System Response Against Ionizing Radiation Exposure: Cellular, Biochemical, and Molecular Perspectives.

Gamma radiation is known to induce several detrimental effects on the nervous system. The hippocampus region, specifically the dentate gyrus (DG) and subventricular zone (SVZ), have been identified as a radiation-sensitive neurogenic niche. Radiation alters the endogenous redox status of neural stem cells (NSCs) and other proliferative cells, especially in the hippocampus region, leading to oxidative stress, neuroinflammation, and cell death. Planned (i.e., radiotherapy of brain tumor patients) or unplanned radiation exposure (i.e., accidental radiation exposure) can induce nonspecific damage to neuronal tissues, resulting in chronic or acute radiation syndrome. Although anatomical alterations in the neuronal tissues have been reported at higher doses of gamma radiation, biochemical and molecular perturbations may be evident even at much lower radiation doses. They may manifest in the form of neuronal deficits and cognitive impairment. In the present review, several molecular events and signaling pathways, such as oxidative stress, neuroinflammation, apoptosis, cognition, neuroplasticity, and neurotoxicity induced in neuronal cells upon ionizing radiation exposure, are reviewed. Furthermore, brain-specific radioprotectors and mitigators that protect normal neuronal cells and tissues against ionizing radiation during radiotherapy of cancer patients or nuclear emergencies are also discussed.

The effect of heavy metals on the radiation shielding capabilities of borated polyethylene: a Geant4 study

Abstract Research has increasingly focused on polymers for radiation shielding in medical and industrial applications due to their beneficial properties. Polyethylene, a common polymer, is extensively used as a neutron shield in radiation-related environments, particularly in hospitals. Recently, borated polyethylene-created by combining polyethylene with 5% boron by weight-has been employed in hospital doors due to its exceptional durability across a wide temperature range and its effective neutron shielding capabilities. Hospital doors must protect against radiation leakage that could endanger patients and staff while also being lightweight, resistant to moisture and chemicals, sound-absorbent, and flexible during manufacturing. Borated polyethylene meets all these criteria, leading many manufacturers to produce hospital doors from borated high-density polyethylene (BHDPE). In this study, the shielding effectiveness of borated polyethylene, enhanced with 5% of heavy metals such as iron, bismuth, and tungsten, was theoretically analyzed using Geant4 against photons and neutrons with energies ranging from 10 keV to 20 MeV. The results indicated that iron-borated high-density polyethylene (Fe-BHDPE) offers the best neutron shielding, followed by tungsten-borated high-density polyethylene (W-BHDPE) and bismuth-borated high-density polyethylene (Bi-HDPE). For photon shielding, Bi-HDPE performed the best. The choice of metal and its proportion in radiation protection doors should be tailored to the specific type of radiation present in the facility, considering potential interactions, surrounding conditions, scattering effects, and any secondary particles that may be produced.

Long-term mental health crisis among municipal public employees caused by the Fukushima nuclear accident and subsequent disasters: Questionnaire survey 10 years postdisaster.

After the Fukushima nuclear accident in 2011, several municipal offices were forced to evacuate, and municipal public employees (MPEs) had to perform many administrative tasks related to the disaster. Typhoons and the COVID-19 pandemic also affected the area afterwards. We conducted a survey for MPEs to investigate the mental health impacts and related factors. This survey was conducted in the 10th year after the accident. Participants were MPEs working in the severely affected areas. We used a self-administered questionnaire that included participants' psychological distress (K6), experience during/after the disaster, job-related stress, current problems, and the impacts of subsequent disasters. Based on K6 total scores, we analyzed factors related to mental health and the current problems among high-risk MPEs. Of all the 775 participants, the number of high-risk MPEs was 101 (13.0%) and many of those had comorbid suicide risk. Factors related to high-score K6 were some individual-related stress factors, including male and younger people, and some job-related stress factors, including unaccustomed work and uncertainty about the future. The mental health status of MPEs in areas severely affected by the disaster has remained very serious more than 10 years later. The problems and processes caused by the nuclear disaster, such as long-term evacuation, were very specific compared to those of natural disasters. Compared to affected residents, MPEs could be more severely affected by the disasters over the long term. We consider it important to develop a mental health care system to prepare for future disasters.

Stories of Disaster as Sites of Mitigation: Knowledge Production and Affective Engagement in the Narrativization of Nuclear Incidents in Different Media

Stories of Disaster as Sites of Mitigation: Knowledge Production and Affective Engagement in the Narrativization of Nuclear Incidents in Different Media

Factors associated with radiation risk perception among Japanese university students.

After the Fukushima Daiichi Nuclear Power Station accident, various information about radiation circulated throughout Japan, leading to diverse perceptions regarding the situation in Fukushima. These perceptions contributed to the social challenges faced by the residents of Fukushima at the time, including prejudice and discrimination. This heightened concern about radiation exposure, particularly among younger generations who were considering marriage or starting families. In the present study, we aimed to investigate the present status of radiation risk perception among university students in Japan and the factors associated with radiation risk perception among these students. A questionnaire survey was administered to university students throughout Japan. We collected demographic information as well as queried their perception of radiation risk (delayed health effects and genetic effects). The results showed that approximately 60% and 40% of respondents believed that delayed effects and genetic effects would occur among residents of Fukushima, respectively. Additionally, having a university major other than studying radiation techniques and living in western Japan were associated with these perceptions of risk. In the future, enhancing risk communication, especially among young populations in western Japan, is necessary to dispel anxiety about the risks from radiation exposure.&#xD.

A Cause Analysis Model of Nuclear Accidents in Marine Nuclear Power Plants Based on the Perspective of a Socio-Technical System

A Cause Analysis Model of Nuclear Accidents in Marine Nuclear Power Plants Based on the Perspective of a Socio-Technical System

Peening Techniques for Mitigating Chlorine-Induced Stress Corrosion Cracking of Dry Storage Canisters for Nuclear Applications.

Fusion-welded austenitic stainless steel (ASS) was predominantly employed to manufacture dry storage canisters (DSCs) for the storage applications of spent nuclear fuel (SNF). However, the ASS weld joints are prone to chloride-induced stress corrosion cracking (CISCC), a critical safety issue in the nuclear industry. DSCs were exposed to a chloride-rich environment during storage, creating CISCC precursors. The CISCC failure leads to nuclear radiation leakage. Therefore, there is a critical need to enhance the CISCC resistance of DSC weld joints using promising repair techniques. This review article encapsulates the current state-of-the-art of peening techniques for mitigating the CISCC in DSCs. More specifically, conventional shot peening (CSP), ultrasonic impact peening (UIP), and laser shock peening (LSP) were elucidated with a focus on CISCC mitigation. The underlying mechanism of CISCC mitigation in each process was summarized. Finally, this review provides recent advances in surface modification techniques, repair techniques, and developments in welding techniques for CISCC mitigation in DSCs.

Integrating collision avoidance strategies into multi-robot task allocation for inspection

Recent research topics have been placed on reinforcing security and safety measures within high-risk industries to protect both equipment and the environment. Numerous industries carry substantial implications for their surroundings. During significant incidents like chemical spills, or nuclear accidents, swiftly gathering precise and dynamic data poses a considerable challenge. Subsequently, this paper focuses on optimizing a mission involving multiple mobile robots charged with inspecting an industrial zone. The aim of this research is to efficiently collect measurements from diverse positions using a fleet of sensing robots operating from a central depot, that is, developing an algorithm for robot decision-making that optimizes mission planning by minimizing an objective function. Initially, we explore our previous proposed solutions and we improve the system by integrating a navigational layer to manage collision avoidance between robots. Then, we delve into scenarios involving multiple homogeneous tasks distributed in a limited geographical environment. To demonstrate feasibility, extensive simulations, numerical experiments, and comparative analysis are conducted, showing the efficiency of the proposed approaches in terms of solution quality and computational complexity.

Modeling tritium release to the atmosphere during the Fukushima Daiichi Nuclear Power Plant accident and application to estimating post-accident water system transit times.

During the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident on March 11, 2011, radionuclides such as tritium were released into the environment across Japan, obscuring the natural background signal of tritium in precipitation. This anthropogenic component was rapidly washed out by precipitation according to measurements in Japan. However, the impact of the accident on the natural tritium-based estimation of water system transit times in Fukushima and other prefectures in Japan remains uncertain. For the first time, anthropogenic tritium from the FDNPP accident together with natural tritium were simulated in an atmospheric general circulation model with a good ability to represent tritium variations in daily and monthly precipitation. For the FDNPP accident, we estimate the maximum tritium atmospheric emission of 0.815 PBq with a tritium in precipitation peak of 68.7 Bq/L (582 tritium units) on March 2011 at Fukushima, which are consistent with previous estimations. Using our modeled outputs with tritium measurements, we improve tritium-tracer application for estimating mean transit times of Fukushima surface and groundwater systems impacted by the anthropogenic tritium from the FDNPP accident. While the anthropogenic impact of the FDNPP accident was limited compared to the tritium peak due to the thermonuclear testing, globally modeled tritium in precipitation is useful to apply for other areas of tritium-tracer studies.

Radiation accidents associated with violation of rules of gathering and recycling of ferrous and non-ferrous metal scrap in the Russian Federation in 2010-2023

Radiation accidents associated with violation of rules of gathering and recycling of ferrous and non-ferrous metal scrap in the Russian Federation in 2010-2023

Fukushima twelve years after the nuclear accident

PurposeThis paper analyzes the structure of recovery policies in Fukushima, discusses the current situation of the affected areas and the affected people of Fukushima 12 years after the Fukushima nuclear accident occurred and points out issues concerning revitalization of Fukushima based on the results of field surveys of the affected areas, as well as interviews and questionnaires of the affected people and literature reviews.Design/methodology/approachAfter the Fukushima nuclear accident occurred in March 2011, what policies have been implemented? To what extent have the affected areas of Fukushima been regenerated? To what extent have the affected people of Fukushima rebuilt their lives? What are the issues that need to be addressed for the revitalization of Fukushima? Since the Fukushima nuclear accident occurred, the author has continued to conduct field surveys of the affected areas, as well as interviews and questionnaires of the affected people, and literature review. This paper aims to answer three questions based on the results of these surveys and reviews.FindingsFirst, the nuclear disaster is characterized by its wide-area and long-term nature. Second, recovery of the affected areas by public projects do not have sufficient effect on rebuilding of the lives of the affected people since most of the affected people do not return to the affected areas. Third, it is necessary to establish a legal system for disaster prevention, recovery and revitalization suited to the characteristics of the nuclear disaster in order to promote rebuilding of the lives of the affected people and for the recovery of the affected areas.Originality/valueThere is little literature that has been systematically examined regarding the recovery from the Fukushima nuclear accident. This paper discusses the current status and issues of recovery from nuclear disaster 12 years after the nuclear accident, based on my experiences as the chairperson of the Fukushima Prefecture Recovery Planning Committee and the chairperson of the Recovery Planning Committee in several municipalities where evacuation orders were issued after the Fukushima nuclear accident occurred.

Radiation hygienic aspects of emergency response to major radiation accidents

Radiation hygienic aspects of emergency response to major radiation accidents

Beyond the Surface: Evaluating the Impacts of Fukushima Nuclear Wastewater Release

Following the 2011 Fukushima nuclear power plant accident in Japan, managing contaminated water became a long-term challenge. In August 2023, Japan began discharging treated atomic wastewater into the Pacific Ocean, sparking global concern. Since nuclear wastewater discharge involves environmental safety, public health, and international relations, understanding various perspectives and presenting scientific data is crucial for formulating reasonable policies. This study aims to analyse the attitudes of different countries towards the Fukushima nuclear wastewater discharge, assess its scientific basis, and explore its economic impact on Japan's fishing industry. The results show that Japan's wastewater discharge complies with international safety standards, based on an evaluation of publicly available data from the Tokyo Electric Power Company and the International Atomic Energy Agency. The analysis encompassed both safety measures and environmental impacts of this specific nuclear wastewater release. Despite scientific studies confirming that the treated nuclear wastewater meets safety standards, ongoing public concerns and geopolitical tensions have caused significant economic impacts on Japan's fishing industry. Therefore, enhanced scientific dialogue and research are needed to effectively address the potential long-term challenges that nuclear wastewater discharge may pose to marine ecosystems and global food safety

In-situ gamma-ray measurement to estimate depth distribution of 137Cs in farmland in Fukushima Prefecture.

Radioactive cesium released into the atmosphere caused by the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011 has contaminated the surrounding area. We confirmed the applicability of in-situ methods to evaluate the depth distribution of 137Cs by employing the ratio of Compton-scattering and photo-peak components (rC) obtained from measured gamma-ray spectra. In the present study, we applied the in-situ method to farmlands in Fukushima Prefecture whose sites were disturbed by decontamination and plowing operations. rC and the net count of the 662-keV photo-peak, npeak, were obtained from gamma-ray spectra measured using a portable CsI detector. Reasonable rC was obtained by removing the contribution of naturally occurring radioactive materials through a simple and versatile procedure. The depth distribution of 137Cs measured using the conventional sampling method was reproduced using the Fermi distribution function. The concentration of 137Cs on the ground surface, N(0), and the depth at which the concentration becomes half of N(0), d1/2, can be described by simple functions of npeak and rC, respectively. We also confirmed that the Monte Carlo simulation is useful to reproduce the present results, taking into account the contribution of 134Cs and the detection system properly.

Application of the DRASTIC Model to Assess the Vulnerability of Groundwater Contamination Near Zaporizhzhia Nuclear Power Plant, Ukraine.

Russia's invasion of Ukraine continues to have a devastating effect on the well-being of Ukrainians and their environment. We evaluated a major environmental hazard caused by the war: the potential for groundwater contamination in proximity to the Zaporizhzhia Nuclear Power Plant (NPP). We quantified groundwater vulnerability with the DRASTIC index, which was originally developed by the United States Environmental Protection Agency and has been used at various locations worldwide to assess relative pollution potential. We found that there are two major gradients of groundwater vulnerability in the region: (1) broadly higher risk to the northeast of the NPP and lower risk to the southeast driven by a regional gradient in water availability and water table depth; and (2) higher risk in proximity to the channels and floodplains of the Dnipro River and tributaries, which host coarser-textured soils and sedimentary deposits. We also found that the DRASTIC vulnerability index can be used to identify and prioritize groundwater well-network monitoring. These and more detailed assessments will be necessary to prioritize monitoring and remediation strategies across Ukraine in the event of a nuclear accident, and more broadly demonstrate the utility of the DRASTIC approach for prognostic contamination risk assessment.

90Sr and 137Cs distribution in Chornobyl forests: 30 years after the nuclear accident.

The primary aim of this study was to quantify patterns in the distribution of 90Sr and 137Cs activity in pine (Pinus sylvestris L.: 18 sites) and birch (Betula pendula Roth.: 2 sites) forests within the Chornobyl exclusion zone, 30 years after the Chornobyl nuclear power plant (NPP) accident (1986). To achieve this, radionuclide activity concentrations were measured in the mineral and organic soil horizons, the green forest floor (grasses, mosses, and lichens), and trunk wood in forest plots dominated by either pine or birch trees.Our results showed that the geometric mean of the 90Sr aggregated transfer factors from mineral soil to the trunk wood of pine trees (Tag) for Scots pines was 24 x 10-3m2kg-1, which is an order of magnitude higher than the IAEA Handbook (2010)reference value (1.7 x 10-3m2kg-1), which were based on studies conducted after the Kyshtym accident (Ural region, Russia) and in the first years following the Chornobyl accident (Ukraine and Belarus). The observations suggest that the above-ground biomass (soil organic layers, green forest floor, and trees) may contribute more to the 90Sr inventory than the mineral soil at the stand level. In contrast, the 137Cs Tag values for pine and birch stands were consistent with those reported in the literature (ranging from 0.1 to 10 and 0.5-1.1 x 10-3m2kg-1, respectively). Both results align with the known bioavailability of radionuclides from previous studies: low for 137Cs, leading to limited soil depth migration (less than 30cm in the mineral horizon), and higher for 90Sr, resulting in greater soil migration (up to 1m in the mineral horizon). This study highlighted significant correlations between the radionuclides' activity concentrations in the litter layers and their content in the trunk wood of pine trees.

Assessment of scattered and leakage radiation from ultra-portable X-ray systems in chest imaging: An independent study.

Ultraportable (UP) X-ray devices are ideal to use in community-based settings, particularly for chest X-ray (CXR) screening of tuberculosis (TB). Unfortunately, there is insufficient guidance on the radiation safety of these devices. This study aims to determine the radiation dose by UP X-ray devices to both the public and radiographers compared to international dose limits. Radiation dose measurements were performed with four UP X-ray devices that met international criteria, utilizing a clinically representative CXR set-up made with a thorax phantom. Scatter and leakage radiation dose were measured at various positions surrounding the phantom and X-ray tube, respectively. These measurements were used to calculate yearly radiation doses for different scenarios based on the median of all UP X-ray devices. From the yearly scatter doses, the minimum distances from the phantom needed to stay below the international public dose limit (1 mSv/year) were calculated. This distance was longest in the direction back towards the X-ray tube and shortest to the left/right sides of the phantom, e.g., 4.5 m and 2.5 m resp. when performing 50 exams/day, at 90 kV, 2.5 mAs and source skin distance (SSD) 1 m. Additional calculations including leakage radiation were conducted at a typical radiographer position (i.e., behind the X-ray tube), with a correction factor for wearing a lead apron. At 2 m behind the X-ray tube, a radiographer wearing a lead apron could perform 106 exams/day at 2.5 mAs and 29 exams/day at 10 mAs (90 kV, SSD 1 m), while keeping his/her radiation dose below the public dose limit (1 mSv/year) and well below the radiographer dose limit (20 mSv/year). In most CXR screening scenarios, the radiation dose of UP X-ray devices can be kept below 1 mSv/year by employing basic radiation safety rules on time, distance and shielding and using appropriate CXR exposure parameters.

Interaction of cesium compounds with abundant inorganic compounds of atmosphere: Effect on cloud formation potential and settling.

Experiments were conducted in controlled laboratory conditions to determine the size-resolved CCN (Cloud Condensation Nuclei) activity of sub micrometer-sized aerosols containing nuclear fission products (CsI and CsOH) and abundant ambient inorganic aerosols ammonium sulphates ((NH4)2SO4), ammonium chloride (NH4Cl), sodium nitrate (NaNO3), and sodium chloride (NaCl). The presence of these atmospheric-relevant compounds internally mixed with fission product compounds has the potential to affect the capacity of ambient particulates of aerosols to absorb water and function as CCN. Once in the atmosphere, the dynamics of airborne radionuclides and subsequently their fate gets affected by dry and wet deposition processes. The interplay of source and decay terms determines the transit of radioactivity and impacts its local and/or global spread. After being exposed to a sufficiently humid atmosphere, released cesium particles have a high potential to act as CCN. However, the CCN properties of the resulting mixed particles may be altered due to their interaction with atmospheric particles. DMT-CCN counter was used to acquire CCN activation curves with initial dry particle size variation (20-300 nm) for mixed particles (ratio 1:1) at 0.1-1 % supersaturation (SS). For a variety of particle sizes and mixtures of soluble materials, activation ratio curves were obtained under various SS conditions. From the study of CCN spectra, an estimate of the hygroscopicity parameter (κ) was made, which is sensitive to the chemical composition of aerosols. Under different SS conditions, the CCN activation diameters of mixed aerosols were found to be affected greatly in comparison to pure compounds. For the first time, the spectral efficiency of CCNs and the activation diameters of CsI and CsOH particles combined with important atmospheric aerosols were described at various SS levels. Terminal settling velocities for the mixed particles having a representative diameter as critical activation droplet diameter (wet diameter at particular SS), and varying effective density (based on droplet composition) were obtained and compared with the pure state of particles at different SS levels. The relative difference was significant for some combinations and SS conditions. Any modification in settling velocity ultimately impacts the particle's lifetime and deposition flux estimations. Hence neglecting the presence of atmospheric salts affects the accuracy of the source term estimates for a postulated nuclear reactor accident scenario. Data on these features is crucial for modelling the behavior of these particles in simulations. In the extremely improbable event of a containment breach occurring under severe nuclear accident conditions, the outcome has the potential to enhance environmental source-term estimations.

Factors ensuring healthy work environments for municipal office workers in the disaster area after the Fukushima Daiichi nuclear power plant accident: A qualitative analysis

Factors ensuring healthy work environments for municipal office workers in the disaster area after the Fukushima Daiichi nuclear power plant accident: A qualitative analysis