Nuclear Accident Research Articles

Decline in the Conception Rate of Wild Japanese Monkeys after the Fukushima Daiichi Nuclear Power Plant Accident

We examined the conception rate of wild Japanese monkeys (Macaca fuscata) in Fukushima City that were exposed to radiation as a result of the Fukushima Daiichi Nuclear Power Plant accident in March 2011. The conception rate in the year of delivery from 2009 to 2022 was estimated by dissecting individuals that were euthanized by the government for population control as a countermeasure against crop damage. To evaluate the effects of exposure, the cumulative exposure dose for each individual was calculated using the concentration of radiocesium deposited in the soil at the capture site and the concentration of radiocesium in muscle estimated from the aggregated transfer factor. There were no significant differences in conception rates across all age classes over time. In terms of conception rates by age class, there was a significant decrease post-exposure compared with pre-exposure in the age class ≥ 8 years, but no significant differences in the age class 5–7 years. The non-ovulation rate did not significantly differ between the pre- and post-exposure periods for any age class. Body fat index, which can affect fertility, was compared between the pre- and post-exposure periods, and no significant differences were found in either age class. In contrast, the median total cumulative exposure (cumulative internal exposure + cumulative external exposure) was significantly higher in the age class ≥ 8 years compared with the age class 5–7 years. These results suggest that the total cumulative exposure dose may be one of the reasons for the lower conception rate in the post-exposure period among the age class ≥ 8 years.

Steam Condensation Heat Transfer in the Presence of Noncondensable Gases (NCGs) in Nuclear Power Plants (NPPs): A Comprehensive Review of Fundamentals, Current Status, and Prospects for Future Research

Efficient steam condensation is crucial for safe nuclear power plant (NPP) operations, preventing pressure buildup, overheating, and the release of radioactive materials. However, the presence of noncondensable gases (NCGs), such as air, nitrogen, hydrogen, or helium, can hinder the condensation process by creating a thermal resistance layer that impedes steam diffusion and condensation on the system’s surface. Maximizing the efficiency of steam condensation requires a thorough grasp of the fundamental processes, theories, advancements, and technical hurdles. Therefore, this work thoroughly addresses these needs, with a particular emphasis on addressing the challenges posed by NCGs by dividing the work into four thematic areas. The first theme relates to a comprehensive examination of pure steam condensation phenomena, which includes an exploration of familiar condensation scenarios and various film condensation types. The second theme examines condensation in the presence of NCGs, their mixture properties, and related theories and modelling of heat and mass transfer. The third theme investigates condensation in NPP by exploring passive cooling systems and condensation phenomena under both natural and forced convection conditions during nuclear accidents, the origin of NCGs in NPP and their transportation aspects. This is followed by experimental work related to condensation scenarios and scale. Finally, the last theme looks upon the recent advancements in computational fluid dynamics (CFD) modelling of wall condensation, system analysis codes coupling with CFD, and the implementation of machine learning (ML) for predicting the condensation HTC. By bridging the gap between fundamental knowledge and practical applications, the four thematic areas presented in this work are aimed at providing a comprehensive foundation for researchers and experts in the field of steam condensation when NCGs are involved. The ultimate objective is to bolster the safety and efficacy of NPP operations by understanding the heat and mass transfer mechanisms while mitigating the risk of catastrophic events.

Radiological or nuclear emergency OSL dosimetry using commonplace salt

During recovery phases following a nuclear or radiological incident, it is crucial to assess the radiation exposure of both the general public and responders. This assessment is vital for directing protective actions and for conducting subsequent analyses of the incident's impact. Several methods have been employed at different timescales after an incident, including assessments based on measurements of materials present at the time of the incident. Common salt has previously been shown to have potential for retrospective dosimetry in the μGy-mGy dose range using portable OSL instruments. This study aims to explore the effects of sample storage under light and dark conditions on OSL signals. The OSL signals indicate a brief decrease in luminescence during the initial days after irradiation, followed by a gradual rise with extended storage. The period from 8 days to 64 days is characterized by relatively stable results, which encompass a significant portion of the timeframe relevant for dose estimation during both the early and later phases of responding to radiological emergencies. Light exposure (simulated daylight) results in an extremely rapid loss of OSL signals. Results are discussed with reference to TL measurements of associated trapping systems which provide insight into potential zeroing mechanisms and the observed fading behaviour. The results are sufficiently favourable to conclude that these characteristics, together with the widespread availability and low cost of household salt, support its use for prompt emergency assessment and as a retrospective dosimeter, below 100 μGy.

Targeted lung therapy with rosmarinic acid encapsulated in PLGA microspheres for radiation-induced pulmonary fibrosis

Radiation-induced pulmonary fibrosis (RIPF) is a frequent complication among individuals affected by nuclear accidents and patients undergoing chest radiation therapy for tumors. However, the availability of effective drugs for prevention and treatment of RIPF remains limited. Rosmarinic acid (RA), which displays inhibitory properties against RIPF, suffers from poor targeting in previous drug studies. To overcome this issue and achieve optimal therapeutic effects, continuous administration over several days is usually employed. In this study, we developed PLGA microspheres with an average size of 17 μm and drug loading efficiency of 24.97 % (±0.97 %), loaded with RA (RA/PLGAMS) using the membrane emulsification method. By controlling the size of microspheres in the pulmonary capillaries, we achieved lung targeting of microspheres, and based on the release of drugs as PLGA degrades, the residence time of drugs in the body is prolonged. And it was confirmed by in vivo imaging and SEM imaging that PLGAMS could exist in the lungs for at least 7 days. Our results demonstrated successful targeting of the lungs in a mouse model and sustained release of RA encapsulated in the PLGA microspheres. Notably, under the same administration conditions, the therapeutic efficacy of PLGA-encapsulated RA surpassed that of ordinary RA. We observed decreased expression of inflammatory factors, reduced M2 macrophage polarization, and weakened epithelial mesenchymal transformation following our treatment, which might explain the radiation damage alleviating effect of RA. After treatment, it was shown that the deep inspiratory capacity of the mice improved by 57.8 %, and WB showed a decrease of 52.4 % and 28.3 % in the expression of epithelial mesenchymal transition related proteins (TGF-β1 and α-SMA). In summary, PLGA microspheres offer a promising drug delivery system and treatment strategy for radiation-induced pulmonary fibrosis.

Pearson Correlation and Chi-Squared Methods Applied to the Sensitivity and Uncertainty Analysis of Hydrogen Generation During a Boiling Water Reactor STSBO Using MAAP5 and AZTUSIA

Abstract After the nuclear accident at the Fukushima Daiichi nuclear power plant, hydrogen generation has resurfaced as a key issue, with respect to its quantification in the simulation of severe accidents (SAs), because of the potential risk of deflagration or detonation, which would compromise the integrity of the plant facilities. Severe accident simulation codes may have different models to predict cladding oxidation rates and the consequent hydrogen generation. Thus, sensitivity and uncertainty analysis can be applied to determine which input variables of the code have a significant impact in the implemented models, and consequently on the overall predicted values of key figures of merit. In this work, the generation of hydrogen in the reactor core during a short-term station blackout (STSBO) is studied as a figure of merit for a boiling water reactor (BWR). The scope of the analysis is until the failure of the reactor pressure vessel (RPV). This study shows a sensitivity and uncertainty analysis through the complementary calculations of two methods: Chi-squared parameter and Pearson simple correlation coefficient (PSCC). The severe accident simulation code was MAAP 5.0.3 (Modular Accident Analysis Program, EPRI, USA) and the AZTUSIA code (AZtlan Tool for Uncertainty and SensItivity Analysis, Mexico) was used as the statistical tool for the sensitivity and uncertainty analysis. Ten uncertain parameters were chosen, of which two are MAAP models options, and the values were generated via the simple random Monte Carlo technique. The results show that the Chi-squared parameter in conjunction with correlation coefficients provides a more comprehensive understanding of the impact of both quantitative and qualitative input variables on the figures of merit.

Radiation accidents in X-ray and radionuclide diagnostics and therapy: comparison of Russian and international approaches to the terminology and classification

Introduction of new methods of nuclear medicine, X-ray diagnostics and therapy using medical sources of ionizing radiation inevitably leads to an increase in the number and types of accidents (abnormal situations). In international practice in recent years, special attention has been paid to the prevention of radiation accidents and incidents from medical exposure. The main focus is put on accidental exposure (overexposure) of patients in X-ray and radionuclide diagnostics and therapy. These approaches are implemented in Russian regulatory and methodological documents in a limited and formal way. The main attention is paid to large-scale technogenic radiation accidents, and accidents (abnormal situations) from medical irradiation are undeservedly ignored. The aim of the work was to analyze the terminology and classification of radiation accidents and incidents from medical exposure in the Russian Federation and foreign countries to develop proposals to improve approaches to their classification within the framework of revision of existing regulatory and methodological documents. The results of the work indicate that it is necessary to actualize Russian approaches to the definition and classification of radiation accidents in medicine considering the specifics of medical exposure. For this purpose, it is advisable to introduce different levels of accidents (abnormal situations), differing from each other by the scale of impact and consequences for patients, workers and public. Considering the absence of elaborated scenarios of accidents (abnormal situations) in Russian regulatory and methodological documents, such gradation can be borrowed from international regulatory documents provided that it is adapted to the specifics and realities of the Russian health care system

Solid cancer mortality risk in the cohort of Urals population exposed to radiation for up the age of 20

The objective of the current study is the direct assessment of the excess relative risk of solid cancer mortality in people affected by low dose-rate chronic exposure mainly in low-to medium dose range (up to 1 Gy) at the age of <20. The study cohort consists of the population exposed at the age of <20 as a result of two large radiation accidents at the “Mayak” Production Association. The size of the cohort is 32,762 persons, follow-up period – 71 years (from 1950 through 2020), the number of person-years at risk is – 1 218 855. For this cohort the mortality catchment area includes Chelyabinsk and Kurgan Oblasts. Over a 71-year follow-up period 1,788 solid cancer deaths were registered in the cohort. Mean dose accumulated in the stomach walls over the whole follow-up period was 0.04 Gy, maximum dose was 1.1 Gy. Statistical processing of data was performed using Amfit and Datab software packages (Epicure statistics software package). Solid cancer mortality risk was analyzed with the Poisson regression using simple parametric excess relative risk model. Statistical significance of the results was estimated using the maximum likelihood method with 95% probability. For the first time the direct assessments of the excess relative risk of solid cancer mortality have been obtained in the Urals Cohort of population exposed at age <20 for a 71-year period (Excess Relative Risk was 0.84/Gy, 95% confidence interval: 0.24-1.55 for 10-years minimal latency period and 0.83 (0.24-1.55) for 5-year minimal latency period). Statistically significant estimates of the excess relative risk have been obtained for specific groups within the cohort selected according to the sex, age at the onset of exposure, and Oblast of residence at the time of exposure.

Mental health of residents of radioactively contaminated territories of the Chelyabinsk region in the late period after the resettlement

In case of radiation accidents, one of the radical protective measures is the evacuation of residents from contaminated areas. Its purpose is to reduce the possible radiation effect to the population. At the same time, evacuation itself becomes a serious stressful factor that has a negative impact on a person’s health and mental status. The objective of this work is to assess the state of mental health of residents of the Muslyumovo settlement in the Chelyabinsk region (the territory exposed to radioactive contamination as a result of radioactive waste releases into the Techa River) who participated in the resettlement program in the period from 2006 to 2010. Mental health was assessed twice: primarily in 2008-2010 against the background of resettlement, and again in 2019-2020, 10 or more years after the resettlement. The study includes 2 groups formed by random selection. The main group consisted of 100 persons from among the participants of the resettlement program. The comparison group included 80 persons living in the territories exposed to radioactive contamination, but not participating in the resettlement program. According to the main socio-hygienic characteristics, the groups are homogeneous and comparable. The following methods were used: clinical, clinical and psychological, and the method of statistical processing of materials. As a result, it was found that both in the primary and in the repeated study, residents of the Muslyumovo settlement, Chelyabinsk region, participating in the resettlement program, were statistically significantly more likely (p<0.001) to have mental disorders and behavioral disorders (neurotic, stress-related and somatoform disorders (F 40)), compared with the control group. Also, according to the results of the survey, statistically significantly more often the psychogenic effect of resettlement (p≤0.001) was detected in patients of the main group. The data obtained suggest a long-term effect of resettlement on the mental health of the population involved. Understanding the consequences of the protective measures carried out (resettlement) will clarify the criteria for their application, as well as predict the manifestations of mental maladaptation in the population with the potential development of radiation accidents.

Liquidity of Non-US and Energy Stocks Listed on the NYSE in the Aftermath of the Fukushima Daiichi Nuclear Incident

In this paper, we investigate the impact of the Fukushima Daiichi nuclear incident on the liquidity of non-US stocks in the Asia-Pacific region, specifically those listed on the New York Stock Exchange (NYSE). The Fukushima Daiichi nuclear incident occurred in March 2011, following a severe earthquake and tsunami in Japan, and its consequences have extended beyond the borders of Japan. Our study shows that non-US stocks from Japan are associated with significantly wider spreads and higher price impacts. Additionally, we find a similar negative liquidity effect for energy stocks listed on the NYSE and stocks from neighboring countries such as China and South Korea, primarily due to geographic proximity. However, we do not observe any significant changes in the liquidity of stocks from the remaining Asia-Pacific countries. Furthermore, we examine the duration of this negative shock and observe that the illiquidity of stocks from Japan persists for over three weeks. In contrast, the liquidity of energy stocks and stocks from China and South Korea recovers within one week following the incident.

Proteomic and phosphoproteomic characterization of cardiovascular tissues after long term exposure to simulated space radiation.

Introduction: It may take decades to develop cardiovascular dysfunction following exposure to high doses of ionizing radiation from medical therapy or from nuclear accidents. Since astronauts may be exposed continually to a complex space radiation environment unlike that experienced on Earth, it is unresolved whether there is a risk to cardiovascular health during long-term space exploration missions. Previously, we have described that mice exposed to a single dose of simplified Galactic Cosmic Ray (GCR5-ion) develop cardiovascular dysfunction by 12months post-radiation. Methods: To investigate the biological basis of this dysfunction, here we performed a quantitative mass spectrometry-based proteomics analysis of heart tissue (proteome and phosphoproteome) and plasma (proteome only) from these mice at 8months post-radiation. Results: Differentially expressed proteins (DEPs) for irradiated versus sham irradiated samples (fold-change ≥1.2 and an adjusted p-value of ≤0.05) were identified for each proteomics data set. For the heart proteome, there were 87 significant DEPs (11 upregulated and 76 downregulated); for the heart phosphoproteome, there were 60 significant differentially phosphorylated peptides (17 upregulated and 43 downregulated); and for the plasma proteome, there was only one upregulated protein. A Gene Set Enrichment Analysis (GSEA) technique that assesses canonical pathways from BIOCARTA, KEGG, PID, REACTOME, and WikiPathways revealed significant perturbation in pathways in each data set. For the heart proteome, 166 pathways were significantly altered (36 upregulated and 130 downregulated); for the plasma proteome, there were 73 pathways significantly altered (25 upregulated and 48 downregulated); and for the phosphoproteome, there were 223 pathways significantly affected at 0.1 adjusted p-value cutoff. Pathways related to inflammation were the most highly perturbed in the heart and plasma. In line with sustained inflammation, neutrophil extracellular traps (NETs) were demonstrated to be increased in GCR5-ion irradiated hearts at 12-month post irradiation. NETs play a fundamental role in combating bacterial pathogens, modulating inflammatory responses, inflicting damage on healthy tissues, and escalating vascular thrombosis. Discussion: These findings suggest that a single exposure to GCR5-ion results in long-lasting changes in the proteome and that these proteomic changes can potentiate acute and chronic health issues for astronauts, such as what we have previously described with late cardiac dysfunction in these mice.

Valley Pseudospin Polarized Evanescent Coupling between Microwave Ring Resonator and Waveguide in Phononic Topological Insulators.

A coupled ring-waveguide structure is at the core of bosonic wave-based information processing systems, enabling advanced wave manipulations such as filtering, routing, and multiplexing. However, its miniaturization is challenging due to momentum conservation issues in rings with larger curvature that induce significant backscattering and radiation leakage and hampering stable operation. Here, we address it by taking an alternative approach of using topological technology in wavelength-scale and microwave ring-waveguide coupled systems built in nanoengineered phononic crystals. Our approach, which leverages pseudospin conservation in valley topological systems, eliminates phonon backscattering and achieves directional evanescent coupling. The resultant hypersonic waves in the tiny ring exhibit robust transport and resonant circulation. Furthermore, the ring-waveguide hybridization enables critical coupling, where valley-dependent ring-waveguide interference blocks the transmission. Our findings reveal the capability of topological phenomena for managing ultrahigh-frequency phonons in nano/microscale structures and pave the way for advanced phononic circuits in classical and quantum signal processing applications.

C@MOF composite material for rapid and efficient capture of gaseous iodine

In addressing the urgent challenge of mitigating gaseous iodine, a highly volatile and hazardous element in nuclear incidents, this study synthesized composite adsorbents with diverse C/Zn molar ratios using MOF and carbon powder. The saturated iodine adsorption at 75 °C exhibited the sequence: CZ-3 (1.15 g g−1) > CZ-2 (1.08 g g−1) > CZ-1 (0.93 g g−1) > C (0.79 g g−1), displaying 2.3–10.1 times increase in adsorption rate compared to carbon powder and Zn-MOF-2. At an elevated temperature of 95 °C, it achieved saturated adsorption of 1.29 g g−1(CZ-3). The adsorbed iodine primarily manifested in the forms of I2, I3-, and I5-. The dynamic maximum iodine adsorption capacity under specific conditions (75 °C, 300 ppm, 100 mL min−1, 0.5 MPa, 4 cm column length, and 6 mm diameter) reached 1077 mg g−1. Leveraging the Levenberg-Marquardt backpropagation neural network (LM-BPNN) algorithm, a superior fit was achieved. This research provides a theoretical foundation for the rapid and efficient treatment of gaseous iodine in nuclear scenarios.

Health Effects of Ionizing Radiation on the Human Body.

Radioactivity is a process in which the nuclei of unstable atoms spontaneously decay, producing other nuclei and releasing energy in the form of ionizing radiation in the form of alpha (α) and beta (β) particles as well as the emission of gamma (γ) electromagnetic waves. People may be exposed to radiation in various forms, as casualties of nuclear accidents, workers in power plants, or while working and using different radiation sources in medicine and health care. Acute radiation syndrome (ARS) occurs in subjects exposed to a very high dose of radiation in a very short period of time. Each form of radiation has a unique pathophysiological effect. Unfortunately, higher organisms-human beings-in the course of evolution have not acquired receptors for the direct "capture" of radiation energy, which is transferred at the level of DNA, cells, tissues, and organs. Radiation in biological systems depends on the amount of absorbed energy and its spatial distribution, particularly depending on the linear energy transfer (LET). Photon radiation with low LET leads to homogeneous energy deposition in the entire tissue volume. On the other hand, radiation with a high LET produces a fast Bragg peak, which generates a low input dose, whereby the penetration depth into the tissue increases with the radiation energy. The consequences are mutations, apoptosis, the development of cancer, and cell death. The most sensitive cells are those that divide intensively-bone marrow cells, digestive tract cells, reproductive cells, and skin cells. The health care system and the public should raise awareness of the consequences of ionizing radiation. Therefore, our aim is to identify the consequences of ARS taking into account radiation damage to the respiratory system, nervous system, hematopoietic system, gastrointestinal tract, and skin.

Factors associated with anxiety about handling contaminated patients during a nuclear disaster among disaster medical assistant teams in Japan: a cross-sectional study

Factors associated with anxiety about handling contaminated patients during a nuclear disaster among disaster medical assistant teams in Japan: a cross-sectional study

Applicability of an Ionising Radiation Measuring System for Real-Time Effective-Dose-Optimised Route Finding Solution during Nuclear Accidents

The reduction in the effective dose of evacuated injured persons through contaminated areas of nuclear accidents is an essential emergency services requirement. In this context, there appeared a need to develop a dose-optimised route finding method for firefighting rescue vehicles, which includes the development of a real-time decision support measurement and evaluation system. This determines and visualises the radiation exposure of possible routes in a tested area. The system inside and outside of the vehicle measures the ambient dose equivalent rate, the gamma spectra, and also the airborne radioactive aerosol and iodine levels. The method uses gamma radiation measuring NaI(Tl) scintillation detectors mounted on the outside of the vehicle, to determine the dose rate inside the vehicle using the previously recorded attenuation conversation function, while continuously collecting the air through a filter and using an alpha, beta, and gamma radiation measuring NaI(Tl)+ PVT + ZnS(Ag) scintillator to determine the activity concentration in the air, using these measured values to determine the effective dose for all routes and all kinds of vehicles. The energy-dependent shielding effect of the vehicle, the filtering efficiency of the collective protection equipment, and the vehicle’s speed and travel time were taken into account. The results were validated by using gamma point sources with different activity and energy levels. The measurement results under real conditions and available real accident data used in our simulations for three different vehicles and pedestrians proved the applicability of the system. During a nuclear accident based on our model calculations, the inhalation of radioactive aerosols causes a dose almost an order of magnitude higher than the external gamma radiation caused by the fallout contamination. The selection of the appropriate vehicle and its route is determined by the spectrum that can be measured at the accident site but especially by the radioactive aerosol concentration in the air that can be measured in the area. In the case of radiation measuring detectors, the shielding effect of the carrier vehicle must be taken into account, especially in the case of heavy shielding vehicles. The method provides an excellent opportunity to reduce the damage to the health of accident victims and first responders during rescue operations.

Long-term neurocognitive, psychosocial, and physical outcomes after prenatal exposure to radiotherapy: a multicentre cohort study of the International Network on Cancer, Infertility, and Pregnancy

The main data available on the safety of radiation during pregnancy originate from animal studies and from studies of survivors of atomic or nuclear disasters. The effect of radiotherapy to treat maternal cancer on fetal development is uncertain. This report presents a unique cohort and aims to determine the long-term neurocognitive, psychosocial and physical outcomes of offspring of mothers treated with radiotherapy during pregnancy. In this international, multicentre, mixed retrospective-prospective cohort study, we recruited participants between Aug 5, 2006, and Aug 24, 2023, aged between 1·5 and 46 years, at three referral centres in Belgium, the Netherlands, and the USA. Participants were eligible if they were born from mothers treated with radiotherapy during pregnancy. Fetal radiation doses were obtained from medical records and participants were followed up at predefined ages (1·5, 3, 6, 9, 12, 15, and 18 years) and 5-yearly in adulthood, based on age at enrolment, using a neurocognitive test battery (measuring intelligence, attention, and memory), parent-reported executive function and psychosocial questionnaires, and a medical assessment. Results were compared with test-specific normative data. Linear regression models investigated associations between radiotherapy factors (fetal radiation dose, gestational age at the start and end of radiotherapy, and radiotherapy duration) and outcomes. 68 maternal cases of radiotherapy during pregnancy were registered by the three participating centres, of which 61 resulted in a livebirth and were therefore eligible to participate in the child follow-up study. After excluding those who did not give consent, 43 participants born from 42 mothers treated with radiotherapy during pregnancy were included in the study (median age at first assessment 3 years [IQR 2-11]; median age at last assessment 12 years [9-18]; median number of assessments two [1-4]). 18 (42%) of the included participants were female and 25 (58%) male, and 37 (86%) were of White ethnicity. Mean neurocognitive outcomes of the entire cohort were within normal ranges. No associations were found with fetal radiation dose or timing of radiotherapy during pregnancy. Six (16%) of 38 participants with neurocognitive outcomes scored lower than one SD on at least one neurocognitive outcome, three (7%) reported chronic medical conditions (spasmophilia, spastic diplegia, and IgG deficiency), and three (7%) were diagnosed with attention-deficit hyperactivity disorder (of whom two scored lower on attention). Of ten (23%) participants with lower neurocognitive score(s), a chronic medical condition, or attention-deficit hyperactivity disorder, eight were born preterm. The remaining 33 (77%) participants showed no neurocognitive, psychosocial, or chronic physical problems. We show on average normal neurocognitive, psychosocial, and physical outcomes after prenatal exposure to radiotherapy. Differences in outcomes could not be explained by exposure to radiotherapy during pregnancy. These results suggest that extra-abdomino-pelvic radiotherapy exposure during pregnancy in general does not adversely affect outcomes of liveborn children. Further research with a larger sample is necessary to confirm these findings. Kom Op Tegen Kanker, KWF Kankerbestrijding, Stichting Tegen Kanker, Research Foundation Flanders.

Surrogate Model of Solved Poisson Kriging Method for Radiation Field Reconstruction

Reverse reconstruction methods for the radiation field do not require information on the radioactive source and are capable of constructing the radiation field using a small amount of monitoring data, showing huge significance for radiation protection. However, in previous studies, inverse reconstruction methods have given less consideration to variations in the time dimension. Herein, the principle of the Poisson Kriging method solved by the surrogate model has been analyzed, and the Poisson Kriging method has been applied to the inverse reconstruction of two-dimensional radiation fields at different moments. On this basis, this work also investigated the effects of the principal function and correlation coefficient model on the objective function, the results of which demonstrate that the quadratic polynomial principal function and the Gaussian model correlation coefficient have good stability and convergence. Compared with the inverse distance weighting methods and the radial basis function methods, the Poisson Kriging method has smaller errors, showing that it is more suitable for reconstructing complex radiation fields. Finally, the Poisson Kriging method was applied to the Fukushima nuclear accident radiation field calculation. The Pearson correlation coefficient of its results was r = 0.49, reflecting the validity of this method. Our work provides a calculation method for the spatial distribution and trend of the radiation field in the early stages of a nuclear accident, which is helpful for furthering radiation protection and emergency responses to nuclear accidents.

Nuclear Challenges of Neglected Lessons of Chornobyl

The article is dedicated to the analysis of new nuclear challenges resulting from Russia’s nuclear blackmail and attacks at civic nuclear facilities in Ukraine. It is shown that Russia’s actions concerning civic nuclear facilities correspond to the criteria of nuclear terrorism and demonstrate the violation of the internationally accepted principles of non-proliferation and nuclear taboo. This attitude to potentially dangerous objects and behavior is rooted in the non-acceptance of the post-Chornobyl safety culture. For the Russian Federation, it is the exploitation of human fears of new nuclear disasters and radiation pollution. European and global communities in close cooperation with the Ukrainian authority, scientists, and civic society urgently need to work out efficient instruments to translate and convert nuclear fear and concern into efficient actions for the enforcement of international legislation in the sphere of nuclear safety and terrorism prevention and the empowerment of international institutions and organizations. Translated article was published for Czech readers in Ekolist (with small changes): https://ekolist.cz/cz/publicistika/eseje/jaderne-vyzvy-a-ignorovani-zkusenosti-z-cernobylu

A Study on Boiling Heat Transfer Performance of TiO2-CNTs Hybrid Nanofluid on a Downward-Facing Heating Surface

In-vessel retention through external reactor vessel cooling (IVR-ERVC) is a strategy used to respond to nuclear reactor accidents. One of the key performance indicators determining its feasibility is critical heat flux (CHF). Our focus is on simulating real-world scenarios through surface pool boiling to improve the implementation of the IVR-ERVC strategy with hybrid nanofluids. Two groups of TiO2/COOH-CNTs hybrid nanofluids were prepared: group 1 with different concentrations at the same proportion and group 2 with different proportions at the same total concentration. Researchers compared the improvement of the two groups’ CHF and heat transfer coefficient (HTC), and analyzed the potential mechanism of heat transfer enhancement through roughness of surface, hydrophilicity, and scanning electron microscopy observations. The results showed that a mass concentration of 8 mg:8 mg per liter exhibited the best heat transfer performance, with a CHF enhancement up to 28.21% and an improvement in HTC as well. Meanwhile, correlations between alterations in surface roughness, hydrophilicity, and enhancements in CHF were observed. Finally, by detecting the deposition surface, the possible mechanism of TiO2/COOH-CNTs hybrid nanofluids in enhancing heat transfer was inferred.

3D skin bioprinting as promising therapeutic strategy for radiation-associated skin injuries.

Both cutaneous radiation injury and radiation combined injury (RCI) could have serious skin traumas, which are collectively referred to as radiation-associated skin injuries in this paper. These two types of skin injuries require special managements of wounds, and the therapeutic effects still need to be further improved. Cutaneous radiation injuries are common in both radiotherapy patients and victims of radioactive source accidents, which could lead to skin necrosis and ulcers in serious conditions. At present, there are still many challenges in management of cutaneous radiation injuries including early diagnosis, lesion assessment, and treatment prognosis. Radiation combined injuries are special and important issues in severe nuclear accidents, which often accompanied by serious skin traumas. Mass victims of RCI would be the focus of public health concern. Three-dimensional (3D) bioprinting, as a versatile and favourable technique, offers effective approaches to fabricate biomimetic architectures with bioactivity, which provides potentials for resolve the challenges in treating radiation-associated skin injuries. Combining with the cutting-edge advances in 3D skin bioprinting, the authors analyse the damage characteristics of skin wounds in both cutaneous radiation injury and RCI and look forward to the potential value of 3D skin bioprinting for the treatments of radiation-associated skin injuries.