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Experience from earlier nuclear accidents has clearly shown the need for maintaining and developing appropriate modelling capabilities. Dealing with complex issues such as human exposure following a nuclear accident necessitates the implementation of a set of interconnected models such as FDMT. FDMT is an integrated module within the two main European decision support systems for radiological emergency preparedness, ARGOS and JRODOS, to simulate the transfer of radionuclides along terrestrial food chains and to predict their activity concentrations in foodstuffs. In order to make the module more fit-for-purpose, FDMT has been implemented in a new modelling platform (ECOLEGO) which provides a high degree of flexibility with regard to conducting developmental work. This paper presents improvements in FDMT further through either the incorporation of new models or further elaboration of existing ones, as well as updates in default parameters. Models have also been made more fit-for-purpose through consideration of regional-specific parameters. Specific improvements include modelling developments related to dry deposition, radioactive particle weathering, radiocaesium transfer influenced by soil characteristics and, for a region-specific case, animal uptake. In addition, the paper presents new pathways and parameters (and updated values) to be considered for making FDMT more adapted for Norwegian conditions. Overall, the improvements made in the present work should significantly reduce the uncertainties associated with the outputs of the FDMT models., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Human survival hinges on access to water, which provides vital necessities. It is crucial to secure reliable, affordable, and uncontaminated water to maintain health and sustain life. For the potential impact of radioactive water pollution on human well-being, a scintillation-based smart RnDuo detector was employed in the Pattan region of North Kashmir Baramulla to quantify radon levels in diverse underground water. The dose contribution to various organs through inhalation and ingestion pathways has been analyzed. The study assesses the levels of radon in water, which varied from 19.88 to 74.37 Bq/L with an average of 37.65 Bq/L. All of the values were higher than the United States Environmental Protection Agency(USEPA) suggested guideline of 11 Bq/L but lower than the 100 Bq/L prescribed by the World Health Organization (WHO). The age group-wise inhalation and ingestion doses are higher than the 100 μSv/y recommended by WHO but within the prescribed range of 3-10 mSv/y as suggested by the International Commission on Radiological Protection (ICRP). Doses to various organs (lungs and stomach) are also calculated in the present study. The results of the present investigation will help to enhance the quality of the water and guide future epidemiological studies., Competing Interests: Declarations. Conflict of interest: The authors declare no competing interests. Ethical approval: All procedures performed in studies were in accordance with the ethical standards of the institutional and/or national research committee., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The oil and natural gas industry is one of the largest producers of Naturally Occurring Radioactive Material (NORM) worldwide. The scale and sludge are NORM wastes with the highest activity concentration levels, reaching 3500 Bq per g of 226Ra (scale). As wastes (sludge, scale, and produced water) are constantly produced in routine activities, a specific regulation for these wastes is necessary. Therefore, this study presents the regulatory requirements that may serve as a basis for the responsible regulatory body to prepare a specific regulation for the NORM waste generated by the oil industry. As a study published showing that the disposal of bulk NORM waste (not packaged wastes) is viable in Brazil, requirements for the management of these wastes and the characteristics of the landfill for disposal were included., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Beach sediments are mineral deposits formed through weathering and erosion of either igneous or metamorphic rocks. Among the rock constituent minerals are some natural radionuclides that contribute to ionizing radiation exposure on Earth. Kolatoli and Kuakata are the two major beaches with heavy mineral deposits and important tourist sites in Bangladesh. Natural radioactivity in Kolatoli and Kuakata beach sand deposits along the southern coast of Bangladesh was assessed and compared to identify the sources, causes, and possible environmental impact. Result shows most of the radionuclides have higher activity concentrations than the background level, and the activity varies with the sample locations. The dominant radionuclides were found to be the radionuclides of thorium series i.e. Th-232 and Ra-228 followed by uranium series and K-40. The radioactivity in Kolatoli beach sands was observed to be much higher than Kuakata beach due to the presence of a higher content of heavy minerals i.e. illmenite, rutile, zircon, garnet and monazite. Furthermore, monazite and zircon are the two radioactive minerals that are considered to be the main contributors to the radioactivity in Kolatoli beach sand. These minerals are dominated by the activity of thorium series radionuclides i.e. Th-232 and Ra-228 surpass the activity of all other radionuclides such as U-238, U-234, Th-230, Ra-226, Po-210, and K-40. However, major contribution of radioactivity in Kuakata beach sand comes from uranium series radionuclides such as U-238, U-234, Ra-226, and Po-210. Beach morphology, sedimentological, and geochemical evolution of those minerals might be important areas of further study for the radioactivity monitoring activity in those areas., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Aim: The aim of this study was to evaluate the occupational radiation exposure of staff during endoscopic retrograde cholangiopancreatography (ERCP), with a focus on individuals closest to the radiation source, and to identify potential increases in exposure to hands and eye lenses. Patient radiation exposure during ERCP was also assessed., Materials and Methods: Staff organ doses were monitored using a Philips Allura Xper FD 20 fluoroscopy system, during 24 ERCP procedures for a period of 7 months. Staff doses were measured using thermoluminescence dosemeters and electronic personal dosemeters, and patient effective doses were simulated and calculated., Results: Physicians' annual organ doses ranged from 0.2 to 1.6 mSv for shoulders, 0.1 to 0.4 mSv for eye lenses, and 0.3 to 1.6 mSv for fingers. The annual organ dose of the nursing staff ranged from 0.08 to 2.4 mSv for shoulders, 0.02 to 2.3 mSv for eye lenses, and 1.2 to 5.3 mSv for fingers. The effective dose to patients ranged from 0.009 to 0.46 mSv., Conclusion: Staff doses were within safe limits, but patient doses were high, emphasizing the need for improved radiation protection., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The energy response of gross gamma dose rate monitors needs to be flat in order to prevent overestimation of dose at low gamma energies. In this paper, a discriminator threshold modulation based electronic energy compensation algorithm has been proposed for SiPM-scintillator based gamma detectors. Theoretical simulation studies were carried out in order to optimize the parameters of the periodic ramp voltage used for modulation of the discriminator threshold of a SiPM-GGAG:Ce,B based gamma dose rate monitor. A customized threshold modulation circuit and signal processing electronics were developed for this gamma detector. For experimentally optimizing the parameters, the energy response studies of the detector, with and without the discriminator threshold modulation, were carried out. With the optimized parameters for a periodic ramp threshold, the count rates for 241Am (60 keV) and 60Co (1173 and 1332 keV) were observed to be within ±30% of the count rate obtained for 137Cs (662 keV). Using the electronic energy compensation techniques presented in this paper, a flat energy response of the SiPM-scintillator gamma detector for the energy range of 60 keV to 1.5 MeV could be achieved., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

In the present study, liquid scintillation counting triple to double coincidence ratio technique is used to ascertain the gross α and β activity in groundwater samples collected from the Beldih mine region in the vicinity of the South Purulia Shear Zone (SPSZ) of Chota Nagpur Plateau in eastern India. A total of sixty samples were collected from deep tube wells located in the study area to assess the potential health threats caused by α and β emitting radionuclides present in these water samples. Average gross α activity in the region of study is 0.09 ± 0.05 Bq/L, with a maximum of 3.22 ± 0.07 Bq/L. On the other hand, the average gross β activity is found to be 0.13 ± 0.02 Bq/L, with a maximum of 0.29 ± 0.02 Bq/L. It was observed that gross α activity level in three samples exceeds the safety limit of 0.5 Bq/L recommended by the World Health Organization. No significant gross β activity was observed. However, the radiological parameters for assessment of potential health threats due to ionizing radiation have been observed to be significantly high for adults. The results of this study indicate that the radiological assessment of groundwater in the Beldih mine region may be extended in future., Competing Interests: Declarations Conflict of interest The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Electromagnetic compatibility testing plays an important role in the type testing of radiation protection dosemeters in view of technical developments and the associated increase in electromagnetic fields. Lately, the use of inductive charging devices has grown as a user-friendly type of charging mobile-phones. In this article, we investigate their impact on active personal dosemeters (APD). The measurements show a substantial additional dose reading of up to several tens of mSv when exposed to the field of an inductive charger for 20 s. According to the widely used Qi standard, the charging devices operate at frequencies of between 87 kHz and 205 kHz for power transfers between 5 W and 30 W. These parameters fall outside the scope of type-testing standards for APD. An update of the standards might therefore be necessary., (Creative Commons Attribution license.)

The study presented here elucidate the concentrations of radionuclides and potentially toxic elements in the soil samples around the Novaya Zemlya in the Russian Arctic zone, determined using HPGe gamma spectrometry, inductively coupled plasma optical emission spectrometry and direct mercury analyzer. The average detected concentrations for 226 Ra, 232 Th, 40 K, 235 U and 137 Cs were 36.40, 46.06, 768, 2.06 and 4.71 Bq/kg, respectively. At many sampling sites, the concentrations of potentially toxic elements (Zn, Cu, Pb, Cd, Ni, and Cr) were higher than the natural levels. Positive Matrix Factorization analysis revealed the contribution of oil dumps (32%), natural sources (16%), bird colonies (32%) and atmospheric deposition (20%) for elevated elements content. In the case of radionuclides, the natural occurring contamination (38%) was primary source followed by dumped material (32%) and bird colonies (30%). The radiological risk from radionuclides was relatively high, yet still under permissible levels. For potentially toxic elements, Fe was predominant non-carcinogenic pollutant and Ni emerged as major carcinogenic contaminant. Keeping in view the high content of some elements, future studies are required to keep the human and ecological risk low, and to establish scientific grounds for the contribution of settled bird species. The findings of the study advance the present knowledge about the contamination of the study area and lays the path for further effort., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

To overcome the time-resolution limitation inherent in the airflow-through scintillation cell method for radon measurement, this study introduces a compartmental model elucidating the behaviors of radon and its progeny within such cells. The computed results of the normalized equilibrium functions derived from the compartmental model, provide quantitative insights into the equilibrium progression of 222Rn and its progeny over time, substantiating the identified time-resolution limitation of 2-3 hours. Laboratory experiments confirm the efficacy of the proposed correction algorithm, showcasing its ability to surmount the time-resolution limitation and achieve a rapid response in radon measurement using airflow-through scintillation cells., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The combustion process of the organically bound tritium (OBT) analysis method is difficult and requires sophisticated techniques. For ease, safety, and reproducibility a semi-automatic combustion system was developed. An arbitrary combustion program that prevents sudden ignition was devised and combustion tests were conducted. Analytical test runs were conducted using fish standard samples to confirm the validity of the developed system. The test values were compared with values obtained with another analysis method, and the recovery rate of the combustion water was evaluated. The results confirmed that the analytical values obtained with this combustion system were equivalent to those obtained with another analytical method and were valid for OBT analysis., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Radiocesium released into the atmosphere from accidents at nuclear facilities, can be deposited on the surface of the surrounding crop fields as dry and wet deposits. Radiocesium deposition can occur at any time during the growth season. In this study, we used stable cesium (Cs) to investigate the changes in dry Cs deposits on surfaces of aboveground parts of Chinese yam (Dioscorea polystachya) during different growth stages. Chinese yam seedlings were grown for eight different lengths of time and were then simultaneously exposed to aerosol particles containing stable Cs in an aerosol exposure chamber for 5 h. The deposition density of Cs on the aboveground parts of the seedlings decreased from 29 to 72 d after transplantation (DAT) and did not change significantly after 72 DAT. The Cs deposition density on the seedlings on different DAT correlated with the leaf area available for the deposition of aerosol Cs particles., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

This study aimed to measure tritium (3H) concentrations in Thailand. Nationwide tap water samples were collected in July 2021. Rainwater samples were collected monthly during May-October 2020, April-October 2021, and February-March 2022 in Chonburi province and in Chiang Mai province during July-November 2021, January 2022, and March-June 2022. The measurements of 3H activity concentrations were conducted by Osaka Sangyo University (OSU) and were compared with measurements by the Thailand Institute of Nuclear Technology (TINT). The results from OSU and TINT showed that 3H concentrations in tap water were matched in the ranged from 0.08 ± 0.03 to 0.28 ± 0.04 Bq L-1, while those in rainwater samples collected from Chonburi province and Chiang Mai province are also matched in the ranged from 0.11 ± 0.02 to 0.21 ± 0.03 Bq L-1 and 0.19 ± 0.02 to 0.57 ± 0.04 Bq L-1, respectively. Our measured result suggests that 3H concentration in tap water and rainwater shows a similar relation depending on latitude., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Long-term changes in particulate and dissolved 137Cs concentrations in rivers and dam reservoirs have been reconstructed using 137Cs depth distributions in bottom sediments near Chornobyl and Fukushima. However, few studies have applied this method to pond water. This study tested the applicability of this reconstruction method in ponds within the Fukushima evacuation zone. Bottom sediments in ponds were collected in November 2019. Our reconstruction of a shallow closed pond disagreed with our observations. Even in ponds where the reconstruction agreed well with observations, underestimations may have occurred because the time constant for the decrease in 137Cs concentration was lower than those previously reported. We conclude that the present reconstruction method may be applied to deeper Fukushima ponds with inflow and outflow, but underestimations of initial 137Cs concentrations in water may lead to uncertainties. For realistic reconstruction, attention should be paid to pond characteristics, catchment conditions, and sediment core selection., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The final disposal of the soils removed from the area affected by the Fukushima nuclear accident will be carried out by 2045. This study investigated how acceptance of final disposal differed between top-down, opinion-aggregative, and opinion-reflective approaches to the decision outcome, and what factors influenced these differences. In 2022, a survey of 3000 randomly selected participants living outside Fukushima Prefecture was conducted using the postal method, with responses obtained from 871 consenting participants. The proportions of respondents who agreed to accept the final disposal were 22.6, 37.6 and 56.9% for the top-down, opinion-aggregative, and opinion-reflective approaches, respectively. The preferences for both opinion-aggregative and opinion-reflective approaches showed significant positive associations with interest in final disposal and social benefits, and significant negative associations with intergenerational expectations and age. This study highlights the importance of procedural fairness in determining final disposal sites, and identifies factors that contribute to greater acceptance through this process., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

To understand the regional properties of atmospheric 7Be and 210Pb concentrations at Hirosaki, aerosol samples were collected weekly for the investigation. Total suspended particles (TSP) concentration ranged from 0.14 to 1.19 mg m-3 with a mean value of 0.29 ± 0.08 mg m-3. The activity concentrations during the observation period have shown a similar trend between 7Be and 210Pb, comparable to reported studies. The activity concentrations of 7Be and 210Pb ranged from 0.46 to 4.94 mBq m-3 with an average of 2.22 mBq m-3 and from 0.26 to 1.29 mBq m-3 with an average of 0.64 mBq m-3, respectively. The relation between precipitation and radionuclide concentrations indicated that precipitation is an essential factor in the radionuclide removal process. The rainfall/snowfall had a significant impact on the deposition, and the process was greatly affected by the changes in the features of raindrops and snowflakes, such as intensity, shape, surface area, and falling speed., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

This study aimed to determine the annual effective dose resulting from radon and thoron progeny inhalation. The levels of radon, thoron, and progeny were assessed in residences situated in the Doi Lo region of Chiang Mai, Thailand. Indoor radon and thoron concentrations were detected using passive discriminative detectors. Using a progeny deposition rate detector, this study evaluates radon and thoron progeny [equilibrium-equivalent radon concentration (EERC) for radon and equilibrium-equivalent thoron concentration (EETC) for thoron]. Data were collected from 44 dwellings between March and May 2020. The results found that indoor radon concentrations ranged from 17 to 118 Bq m-3, while thoron concentrations ranged from 12 to 72 Bq m-3. The radon progeny (EERC) ranged from 4 to 173 Bq m-3, whereas thoron progeny (EETC) ranged from 1 to 15 Bq m-3. The total annual effective dose received from radon and thoron progeny inhalation varied from 0.5 to 5 mSv y-1., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

To precisely evaluate the concentration of iodine-129 (129I) in soil samples, changes in this concentration after thermal drying under several temperature conditions were investigated. The soil sample used in this study was collected from a site located near a nuclear fuel reprocessing plant, which atmospherically released 129I in a test operation in 2006-2008, resulting in the soil sample containing higher 129I concentrations than their natural levels. Thermal drying was conducted from 60°C to 110°C and compared with lyophilization result, showing that the 129I concentration in the soil sample was statistically comparable among all the drying treatments., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Tokyo Electric Power Company, TEPCO, has started tritiated water release into the Pacific Ocean. In order to reduce unreasonable rumor caused by tritium release, flounder, abalone, and sarggasum were exposed to tritium enriched seawater, and time dependent Tissues Free Water Tritium (TFWT) concentration was measured. Estimating the concentration of Organically Bound Tritium (OBT) is important to assess tritium impact because it has a longer biological half-life than TFWT. Current models estimate OBT concentrations using TFWT concentration. Understanding equilibration time is critical for making accurate TFWT concentration predictions. TFWT intake rate was analysed by the compartment model., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Passive radon monitors with CR-39s are widely used in major epidemiological surveys. However, the conventional CR-39 track density determining strategy makes it difficult to accurately estimate the concentration because of the heterogeneity of tracks on CR-39s. This study introduced a stochastic method, Latin hypercube sampling, to improve the track density determining strategy and provide the probability distribution of 222Rn concentration and equilibrium equivalent thoron concentration. The first 222Rn and 220Rn discriminated survey was conducted in Wuhan, China, in 2018 using RADUET® and deposition-based passive 220Rn progeny monitors and applying the stochastic method to the measurement. The results indicate that the stochastic method could decrease the effects of the track heterogeneity on the CR-39s and provide reliable results. The 220Rn progeny contributed more than 40% of the total inhalation dose in the survey, which cannot be ignored in urban family dwellings., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

In the progress of nuclear fusion development, environmental radiation monitoring in the vicinity of the facility would be an important issue. At the National Institute of Fusion Science (NIFS), the deuterium plasma experiment, which produces tritium and neutrons using d-d fusion reactions, was conducted from 2017 to 2022. Environmental radiation and tritium in environmental water were monitored before and during the deuterium plasma experiment for public acceptance. As a result, there was no significant change in the observed dose rate and tritium concentration in the rainwater, and no statistically significant difference was identified in the statistical analysis of the data observed before and during the deuterium plasma experiment. Therefore, the environmental impact of the deuterium plasma experiments at NIFS is considered to be negligible., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The concentration of the radioactive cesium (134Cs and 137Cs) in soils and in atmospheric fallouts has been measured at the Koriyama campus, Nihon University, after the Fukushima Dai-ichi Nuclear Power Plant accident for 13 y, from October 2011 till September 2023 and now ongoing. The concentration of them decreased very rapidly due to decontamination activities and weathering effects, with an environmental half-life of 1.21 and 2.82 y in soils, with those of 1.58 and 2.08 y in atmospheric fallouts for 134Cs and 137Cs, respectively. The behavior of the decrease was not simple, due to particles raised from the surface soil in wooded areas that had not been thoroughly decontaminated or that had been accumulated due to the re-release of radioactive cesium by trees after decontaminated activity., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Applicability of biomimetic approach with simulation of plant uptake for assessment of radiocesium availability in soil was investigated. The soil spiked with 137Cs tracer was contacted with wicking material and copper-substituted prussian blue (Cu-PB), which simulate transpirationally induced mass flow and concentration gradient-induced diffusion of radiocesiumin the soil, respectively. Comparison of the removed 137Cs to the wick and the wick + Cu-PB from the soil during the contact period of 12 weeks suggested that the diffusion process has larger contribution than the mass flow process in radiocesium dynamics in root zone. The change of the removed rate of 137Cs from the soil was reflected that its availability decreased with the time elapsing and with subjecting repeated wet-dry treatment. The results suggest that the biomimetic approach can be applicable to the realistic evaluation of the availability of radiocesium in soil., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

This article mainly discusses tritium concentrations in monthly precipitation at Hiroshima City during 2021. The tritium concentrations, which were measured with a low background liquid scintillation counter, fluctuated from 0.16 to 0.78 Bq L-1. Additionally, hydrogen and oxygen stable isotopes and ionic species were measured in order to characterize precipitation, and their trends including tritium concentrations were compared with data collected in other regions of Japan in previous studies. Although the results showed the characteristics of precipitation were similar to those observed in the other regions, the tritium concentrations were found to be contrary to behavior expected from the latitude effect and some of the observed ionic components were suggested to be continental in origin. Since these results are not common at other sites in Japan, the tritium concentration in the westernmost region of Honshu, including Hiroshima City, may be influenced by Asian continental influences., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Using D2 gas as a substrate, this study investigated the hydrogen deposition velocities of farmland soils around a reprocessing plant located in Rokkasho Village, Aomori, Japan. To determine the hydrogen deposition velocities, closed chambers with fans were set on the soils of farmlands that grow Japanese radishes, and changes in D2 concentration in the chambers were measured by gas chromatography. Results showed hydrogen deposition velocities of six soils were within the range of 1.0 × 10-4 ~ 2.0 × 10-4 m s-1. The heavy water (HDO) formations were detected in the soil after the experiment, showing the oxidation of D2 and conversion to water. Relationships between the obtained hydrogen deposition velocities and environmental conditions such as soil temperature, moisture and porosity were examined. A correlation was found between the hydrogen deposition velocities and soil gas phase rate (r = 0.98, p < 0.05)., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Radioactive ruthenium may be accidentally released from spent nuclear fuel reprocessing plants to the surrounding environment. However, research on the chemical behavior of radioactive Ru in the environment is limited, and the complex chemical properties of this element complicate the application of extraction methods for the analyses of its chemical forms. To obtain basic information regarding the outcome of radioactive Ru in the environment, we investigated the changes in the form of stable Ru added to soil through X-ray absorption fine-structure (XAFS) analysis. This study uses ruthenium tetroxide (RuO4), ruthenium dioxide (RuO2), ruthenium nitrosyl nitrate (Ru(NO)(NO3)3) and ruthenium chloride (RuCl3) as test sources. These are added to ultrapure water, soil solution or fresh soil samples, which are analyzed using XAFS immediately or 5 days after Ru addition. The Ru K-edge X-ray absorption near edge structure spectra acquired immediately after Ru addition differed with respect to the source. The XAFS results suggest that RuO4 immediately changes to tetravalent form after deposition from air to soil. For RuCl3, the ionic structure in the vicinity of Ru is affected by the soil even if the valence does not change immediately. By contrast, RuO2 and Ru(NO)(NO3)3 are highly stable in soil. The results show that the chemical forms of RuO2 and Ru(NO)(NO3)3 added to the soil solution and soil are retained for 5 days, whereas those of RuCl3 and RuO4 are affected by the soil solution and soil within a short period. These results emphasize the need to focus on the chemical form of Ru deposits and the form change after Ru addition when investigating the environmental fate of radioactive Ru., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

A spectroscopy method of alpha particles with the track geometry parameters in CR-39 plastic nuclear track detectors is proposed. The relationship between the track registration sensitivity and incident angle of each etch pit is analyzed. The components of alpha particles emitted from radon, thoron and 241Am can be roughly separated when the etching level is not exceeded beyond the range in CR-39. This work aims at improving the dose assessment accuracy from exposure to indoor radon and thoron., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The World Health Organization (WHO) recommends that countries adopt the reference level of 100 Bq m-3 for indoor radon gas. Adopting the reference level requires a preliminary assessment of the indoor radon concentration. In the preliminary investigation, a cut-off value is useful, which is a value for selecting samples that can be reliably determined to be below the reference level (in this paper, the WHO reference level) using a straightforward method. If the true value was the WHO reference level, then the cut-off value of the PicoRad collector for selecting samples was determined as 80 Bq m-3 through the analysis of the 95% prediction interval., (© The Author(s) 2024. Published by Oxford University Press.)

This study aimed at understanding the background concentration level of tritium in precipitation in southern Japan, where precipitation samples were collected monthly in 2022 in Okinawa and Kagoshima. Tritium concentration in monthly precipitation collected in Okinawa since 2014 ranged from 0.05 to 0.39 Bq per L with the mean value (2015-2022) of 0.15 ± 0.06 Bq per L. That of Kagoshima since 2022 ranged from < 0.11 to 0.58 Bq per L with the mean value of 0.30 ± 0.13 Bq per L. Our observed values were summarized with reported values, from which a clear latitude effect for tritium concentration was found in precipitation of southern Japan., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

In this study, we selected the Japanese red fox (Vulpes vulpes japonica) as a representative mid-size mammal from the forests near the spent nuclear fuel reprocessing plant at Rokkasho. A fox voxel phantom was constructed based on magnetic resonance imaging of a female red fox caught in Rokkasho. This phantom consisted of 264 × 321 × 383 voxels (each voxel size: 0.78 × 0.78 × 2 mm) with internal organs. The external radiation dose rate to the voxel phantom by beta and gamma rays from environmental radionuclides was estimated using a Monte Carlo code (EGS4 and UCPIXEL). We estimated the dose rates to the phantom on the ground and in an average fox burrow in the Rokkasho forest, which were 11 and 27 nGy h-1, respectively. Assuming that the animal on the ground was irradiated by cosmic rays of 27 nGy h-1, the total external dose rate was evaluated to be 38 nGy h-1. Based on the assumption that the fox lives on the ground for 12 h and in the burrow for 12 h, the dose rate was estimated to be 33 nGy h-1., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

As the integrated measurements of radon progeny are essential to its risk assessment, a new method based on the morphological analysis of tracks on CR-39 was established for the discrimination of alpha particles emitted from different progenies. The preliminary experiment confirmed its feasibility and revealed its potential for application in long-term surveys of indoor radon progeny. This new attempt was expected be benefit to the improvement of integrated measurements of radon progeny., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The present radiation protection paradigm and its associated recommendations as developed by bodies such as the ICRP have performed very well over past decades both for those occupationally exposed to radiation and for the public in planned exposures. There is, however, growing evidence that the role played by this paradigm in the decision-making process to protect the public in nuclear emergencies in the past may have, unwittingly and unintentionally, caused more harm than good to some sections of the public. This seems to have been the case in the use of population evacuation as the principal protection response to the Chernobyl (1986) and Fukushima (2011) accidents. There is thus a need to develop improved guidelines or tools on how to apply radiation protection recommendations for the public compatible with the Principle of Justification in the event of any future major radiation emergencies. It can also be argued that the present radiation protection paradigm, with its emphasis primarily on the physical health detriments from radiation, should be more inclusive and needs to shift to a more holistic or total health approach than heretofore to include mental health effects associated with nuclear emergencies. For severe mental health effects, some of the consequences, such as suicide, can even be as or more severe than most physical detriments likely to be suffered by those affected., (© The Author(s) 2024. Published by Oxford University Press.)

TEPCO planned the release of Advanced Liquid Processing System (ALPS)-treated water, which is decontaminated stagnated water by ALPS, to the Pacific Ocean in 2023 after diluting it more than a hundred times in accordance with the policy of the Japan government. Since the low level of I-129 can remain in ALPS-treated water, the background I-129 concentration in seaweed samples around 1F NPS before the release of ALPS-treated water was recorded in this study. The iodine in seaweed samples was extracted via TMAH alkali-dissolution, and the I-129 concentration was measured by 8900 Triple Quadrupole ICP-MS. The resulting I-129 concentration was <5.4 × 10-2 Bq/kg-wet (sargassum) and <2.7 × 10-2 Bq/kg-wet (laminaria), respectively., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

In applying fluorescent nuclear track detectors for heavy ion measurement, the fluorescence intensity directly influences linear energy transfer (LET) estimation. However, the conventional analysis highly depends on the analyzed depth and the reference frames from the optical readout. To improve the accuracy of measurements of heavy ions, the gradient of intensity and moving average fluorescence intensity were acquired and calculated to optimize the measurement conditions. The results indicate that the intensity gradient is an alternative quantity to discriminate ions with different LET, and the moving average fluorescence intensity is readily differentiated among individual ions without overlapping values in fluorescence intensity. The scanned range of 25-45 μm is suggested to be the most suitable depth for measurement. To exclude the impact of the variation in fluorescence intensity on evaluation, it is recommended to use the quantities calculated in moving averages with depth in the future., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Surface collection efficiency (SCE) of a cellulose membrane filter (CMF) and a cellulose-glass fiber filter used in environmental monitoring for alpha-emitting radionuclides from nuclear facilities and natural radioactivity sources was evaluated for particles in the size range of 0.03-0.1 μm at different levels of face velocity. The SCE of the CMF was higher than that of the cellulose-glass fiber filter, and only the membrane filter showed the dependence of SCE on the particle size at higher face velocity. The use of the CMF at higher face velocity in environmental radioactivity monitoring leads to measurements of the background alpha spectrum with more degradation under the changing particle size condition in the atmosphere. Consequently, that fact needs to be taken into account, along with the expected particle size distribution and concentration of the airborne radioactivity being sampled, when selecting a face velocity to achieve the best possible detection limit., (© The Author(s) 2024. Published by Oxford University Press.)

For systematic monitoring of radioactive nuclides in marine products, this study aimed at streamlining and simplifying the analysis method for the prominent radioisotope, strontium-90 (90Sr). The DGA chelate solid-phase extraction technique was employed for enhanced efficiency. The study focused on optimizing the necessary pretreatment procedures while minimizing the steps involving HNO3 leaching. This protocol enabled the quantitative recovery of strontium, and it facilitated a rapid analysis without the need for a time-consuming evaporation step and without waiting for secular equilibrium between 90Sr and its progeny to be reached. The method incorporating the optimized pretreatment protocol was applied to three diverse marine fish species and the accurate quantification of 90Sr at background levels in surface seawater was achieved. The method obtained concentrations in bone samples from these species that ranged from 0.036 to 0.120 mBq per kg-dry, and chemical yield values were notably high, ranging from 87.7% to 92.5%., (© The Author(s) 2024. Published by Oxford University Press.)

The commercial spent-nuclear-fuel reprocessing plant in Rokkasho, Japan, is scheduled for completion in 2024. Its fuel rods were cut into segments and chemically processed between 2006 and 2008, as part of the plant's test operations. During the test, 14C (4.4 TBq) were discharged from the plant's main stack into the atmosphere. At reprocessing plants, 14C has the largest contribution to the effective dose to the public among the nuclides released into the atmosphere, and it important to understand the concentration distribution and impact of 14C in the surrounding environment. This study conducts a continuous monitoring of 14C in aquatic biota samples around the plant from 2006 to 2022. The 14C concentration in most samples was determined at the background level, and the effect of the plant was slightly recognized in some samples. Moreover, the specific radioactivity of 14C decreased faster than the theoretical decay from 0.242 to 0.225 Bq-g C-1., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The International Commission on Radiological Protection recommended a significant reduction of the equivalent dose limit for the eye lens. Reportedly, medical staff in charge of diagnostic imaging procedures may exceed the new dose limits for the eye lens. The use of dosimeters dedicated to the eye lens remains low, and dosimeters for the neck region were often used to assess eye lens doses. However, measurements by neck badges may overestimate or underestimate the recommended eye lens doses because the height of the neck differs from that of the eye. This study aimed to evaluate the air dose distribution in the vertical plane to understand the difference between neck and eye doses. H*(10) in the height of the eye position was 52.8% lower than that in the height of the neck position in the under-table position. Thus, the equivalent eye lens dose evaluated using a neck badge dosimeter may be overestimated., (© The Author(s) 2024. Published by Oxford University Press.)

222Rn is recognized as a matter of international concern for human health risk. Because 220Rn as well as 222Rn coexist in the natural environment, thoron sometimes influences the experiment for radon measurement. It is important to measure radon and thoron separately to evaluate the risk of the exposure to 222Rn. As a discriminative measurement method for 222Rn and 220Rn, a simple technique with a single scintillation cell is well known. However, in recent years, the influence of atmospheric environment on the geometrical efficiency of the scintillation cell has not yet been investigated. In this study, environmental dependence of geometrical efficiency for the scintillation cell in 222Rn and 220Rn measurement was investigated using the Lucas type scintillation cell and Monte Carlo particle simulation. It was found that the influence of temperature and pressure on the geometrical efficiencies were larger than that of relative humidity., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

A survey meter was developed to reliably detect and visualize surface contamination of suits and objects by α-nuclides in high γ/n-rays background radiation environment. The survey meter features a semi-opaque ZnS:Ag scintillator mounted directly onto a multi-anode photomultiplier tube (MA-PMT) and amplification circuits, ensuring output gain equalization for all channels. α-ray events induce localized light emission in thin-film scintillators. By directly mounting the scintillator, diffusion of light before reaching the MA-PMT is suppressed, concentrating it in just a few channels, thereby facilitating discrimination from background radiation. This design also enables clear visualization of the shape of surface contamination. The prototyped survey meter is capable of responding up to 2.1 × 107 cpm, with no γ-ray response even in high-radiation environments exceeding 1 Sv/h. In actual environments with high background radiation, contamination of ~1/100th of the surface contamination density limit of 4 Bq/cm2 could be reliably detected., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The new electrolytic enrichment system with compact glass cell was designed. Three (Ni-Fe-Ni) electrodes are used, and electrolysis is carried out at a rate of 2.45 g per h with constant current density of 120 mA per cm2. This enrichment system allows the enrichment for small, limited sample volumes (e.g. Tritiated Water (HTO) recovered from air). With an initial water volume of 100 ml, the tritium enrichment factor of 7 within 2 days and a detection limit of 0.12 Bq per L can be obtained by Liquid Scintillation Counter (LSC) measurement for 1000 minutes, which is better than the direct measurement with 50 ml sample water using large vial. It is also possible to perform the high enrichment process. The initial sample volume of 700 ml enriched for 12 days by manual refilling yields a tritium enrichment factor of around 43 and detection limit of 0.02 Bq per L for 1000 minutes of LSC measurement., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Radiation disasters can lead to a myriad of direct and indirect health effects. The term 'disaster-related deaths' is commonly used in Japan; however, comprehensive studies in regions severely impacted by nuclear accidents are scarce. Our research primarily focuses on Minamisoma City, situated north of the Fukushima Daiichi Nuclear Power Plant (FDNPP), and aimed to study the risks associated with evacuation and disaster-related death. We introduce the following studies: (1) risks from evacuation in elderly care facilities after the FDNPP accident; (2) detailed case reports on hospital evacuation and (3) detailed reports on disaster-related deaths. A critical lesson from the FDNPP accident is the significant risk to life posed by evacuation actions taken to avoid radiation exposure. Despite evacuation being an effective measure to reduce exposure, our preparation and knowledge are insufficient for safe execution. This paper ensures that the lessons from Fukushima are leveraged in future radiation protection measures., (© The Author(s) 2024. Published by Oxford University Press.)

This paper summarises key findings of United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2020/2021 Report on the evaluations of medical and occupational exposures to ionising radiation. Medical exposure remains by far the largest human-made source of radiation exposure of the population. In the period 2009-18, about 4.2 billion medical radiological examinations were performed annually, resulting in an effective dose per caput of 0.57 mSv. The worldwide annual number of workers exposed to natural and human-made sources of ionising radiation is estimated to be ~24 million in the period 2010-14. About 52% of those were employed in the sectors that involve exposure to natural sources of radiation. The annual effective dose was estimated to be around 2.0 mSv for workers exposed to natural sources (excluding radon exposure in workplaces other than mines) and 0.5 mSv for workers exposed to human-made sources. It is important to motivate United Nations Member States to fully participate in UNSCEAR's global surveys on radiation exposure. Future surveys will be relevant and useful and adapted to changing data sources and uses of radiation across the world., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Elementary processing techniques such as cutting or grinding of foodstuffs are deemed adequate, particularly in the context of post-nuclear accidental situations, ensuring expeditious and effective testing for the gamma-ray spectrometry. Nevertheless, it is worth acknowledging that this straightforward procedure may predispose itself to appreciable variances in the detection efficiency of gamma-ray spectrometry, primarily attributable to the heterogeneity of the radioactivity distribution within the sample container, thereby incurring unexpected discrepancies or uncertainties. To investigate this impact, the precision of the actual sample measurements was scrutinised through statistical analysis., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Nuclear fuel reprocessing plant releases several kinds of radioactive nuclides, mainly 3H and 129I, into the oceans. Radio iodine causes thyroid dose. Iodine accumulates in several marine species such as wakame and abalone, which are food materials. Therefore, an analysis of iodine behavior in the marine environment is important to assess the impact of 129I. Iodine in seawater exists mainly in two chemical forms: iodide (I-) and iodate (IO3-). Their environmental behaviors are different. Thus, understanding these behaviors is important to assess the environmental behavior of total iodine. In this study, iodate and iodide transfer between seawater and abalone (Haliotis discus hannai) with 125I tracer was observed., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

People generally wish to return home after being evacuated due to disaster situations. Evacuation orders have now been lifted in the Fukushima region following the nuclear accident in 2011, and the Japanese government is promoting a return policy. However, many residents who wish to return home remain unable to and continue living in evacuation sites or other areas. Sixteen residents of Katsurao village were interviewed after evacuation orders were lifted in 2016 who have not yet returned. Concerns were cited regarding radiation, prolonged evacuation, health problems, buying a house in the evacuation area and schooling. The problems identified were primarily due to the rapid ageing and decline of the regional population, reflecting similar issues throughout Japan. In particular, health problems and intention to return were thought to be closely related. Over 10 y have passed since the evacuation, and many residents have experienced familial separation and divided living situations., (© The Author(s) 2024. Published by Oxford University Press.)

The radon (Rn) and thoron (Tn) concentrations and other environmental parameters were measured in the vicinity of active faults in two regions with different geology structure of Japan. The range of measured values was from 1.2 to 74 kBq m$^{-3}$, 1.1 to 38.9 kBq m$^{-3}$, 0% to 4.35%, and 2$\times $10$^{-13}$ to 4$\times $10$^{-11}$ m$^{2}$, for Rn, Tn, CO$&#95;{2}$, and soil permeability, respectively. Significant differences in the measured parameters were observed, suggesting that Rn concentrations near faults are strongly influenced by geological structure and fault type. Based on statistical analysis, good correlations were found between Rn, Tn, and CO$&#95;{2}$ (carried gas ) concentrations. It is planned to continue the study with measurements at a number of additional sites., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

This study measured the atmospheric concentration and deposition flux of radiocesium in Koriyama City, Fukushima Prefecture, Japan, from November 2011 to October 2014. The results show synchronous seasonal change in atmospheric concentration and deposition flux of radiocesium, which is high during winter to early spring and low during summer to autumn. These seasonal variations are similar to those observed in Fukushima City but differ from those in Namie Town, Fukushima Prefecture, comprising a larger contaminated forest area. The evaluation of the relationship between atmospheric 137Cs concentration or 137Cs specific activity in atmospheric particulate matter (PM) and deposition density of 137Cs in PM source area suggest that stronger winds blowing from areas with relatively large 137Cs deposition (west of Koriyama City) toward the study site affect the site's atmospheric 137Cs concentrations., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The National Metrology Institute of Japan plan to use an inner-through-type ionization chamber (IC) as a working standard to calibrate radon monitors. Novel methods to calibrate the IC were described, and the calibration factor, CF [Bq m -3 A-1], of the IC with its expanded uncertainty (k = 2) was evaluated to be (2.0 ± 0.2) × 1016 Bq m-3 A-1 in the order of 10-13 A in the IC output current. In this study, the CFs, evaluated under sampling conditions between continuous gas flowing and stationary gas filled inside the IC, were in agreement within the uncertainty., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Modeling carbon accumulation in crop plants is key to evaluating the transfer of atmospheric 14C into the edible parts of the plants growing near nuclear facilities. Chinese yam 'Nagaimo' (Dioscorea polystachya Turcz.) is a major crop cultivated near a spent nuclear fuel reprocessing plant in Rokkasho, Aomori, Japan. We developed a dynamic compartment model for assessing carbon and 14C accumulation in Chinese yam grown from a seed bulbil in the field. Light and temperature dependence of leaf photosynthesis and temperature dependence of respiration in leaves, stems and belowground parts (tuber and root) were incorporated into the model. Estimated amounts of carbon in the leaves, stems and belowground parts were good agreement with the measured data from the field. Simulation results of 14C accumulation using this model indicated that the accumulation of 14C in belowground parts at the harvest depends on the rate of photosynthesis on the day of exposure., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)