Nuclear Emergency Research Articles

Should the current radiation protection paradigm and its recommendations be modified to make them more fit to protect the public in future nuclear emergencies?

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.

Comparison of codes for calculation of projocted radiation-induced cancer risks.

The lifetime attributable risk (LAR) of cancer caused by radiation exposure is crucial when deciding on radiological protection measures or protective actions for nuclear emergency preparedness and response. Although a model for estimating LAR among the Japanese population has been developed based on epidemiological data from A-bomb survivors, a flexible projection code implementing this model must be developed. This study investigated existing codes to contribute to the development of a projection code. Based on these investigations, we compared their LAR calculation results and explored the causes of their differences.

Evaluation of emergency nurses’ knowledge of medical response in nuclear and radiological emergencies : a cross-sectional study

BackgroundEvaluating emergency room nurses’ knowledge of radiation protection, health effects, and decontamination procedures is crucial for preparedness in nuclear and radiological emergencies. This study aims to evaluate the level of knowledge among emergency nurses in Saudi Arabia regarding medical responses to nuclear and radiological emergencies.MethodsA multicenter cross-sectional study was conducted via a self-structured questionnaire with 15 true‒false questions divided into three domains, namely, radiation protection measures, radiation health effects, and decontamination procedures, each with five items and a possible score of 1 point per correct answer. The collected data were analyzed via descriptive and inferential statistics. The study followed the STROBE checklist for methodological rigor.ResultsA total of 594 emergency nurses participated in this study, with the majority being young (64.50% aged ≤ 30), female (68.69%), bachelor’s degree-holding (67.68%), single (63.64%), having ≤ 4 years of experience (56.06%), working in public health facilities (88.89%), and lacking training in medical response (85.35%). The mean knowledge scores for participants were highest for radiation exposure effects (3.27 ± 0.91), followed by radiation protective measures (2.32 ± 0.99), and lowest for decontamination procedures (1.46 ± 1.07). Overall knowledge was measured at a mean score of 7.06 ± 1.68, with 97.47% of the nurses categorized as having poor knowledge level. Nurses in private hospitals scored higher (7.77 ± 1.82) than those in public hospitals (6.97 ± 1.65) on overall mean knowledge (P = 0.034). Concerning findings include emergency nurses’ misconceptions about the protection provided by dense materials, the effectiveness of increasing distance from a radiation source, and prioritizing decontamination of victims over life-saving measures. Additionally, they were unaware of the immediate symptoms following radiation exposure and misunderstood that the primary threat in a radioactive bomb event is the explosion rather than the radiation itself.ConclusionThis study revealed poor knowledge among emergency nurses regarding medical responses to radiation emergencies and highlighted the critical need for enhanced and standardized training in radiation emergency preparedness among nurses. The gaps in knowledge identified in this study could significantly impact the effectiveness of healthcare responses in radiation emergency scenarios. Therefore, targeted educational interventions and policy changes are recommended to address these shortcomings.

Comparison of quench correction methods for 90Sr/90Y assessment in waters after nuclear incident

One important matter of environmental radioactivity monitoring is the accuracy and precision of the 90Sr/90Y measurement techniques. When Cherenkov counting is carried out in coloured waters, the reduction in detection efficiency can cause significant errors in the obtained results. Two colour quench correction methods were considered in this study: the conventional SCR (Sample Channels Ratio) technique and the Muonic peak method. The latter indicates the quench level via the position of the muonic peak in the cosmic background spectrum. So far, there have been no reports about the Muonic peak method’s implementation in Cherenkov counting of 90Sr/90Y in waters. The performance, limitations, advantages, and drawbacks of two methods have been compared based on the analysis of coloured spiked test samples. The Muonic peak method provided similar accuracy as the SCR method in test samples. The adequacy and effectiveness of both techniques have been confirmed during 90Sr routine monitoring in the event of a nuclear emergency or radioactive leakage from nuclear facilities.

Research on in-vivo electron paramagnetic resonance spectrum classification and radiation dose prediction based on machine learning

The in-vivo electron paramagnetic resonance (EPR) method can be used for on-site, rapid, and non-invasive detection of radiation dose to casualties after nuclear and radiation emergencies. For in-vivo EPR spectrum analysis, manual labeling of peaks and calculation of signal intensity are often used, which have problems such as large workload and interference by subjective factors. In this study, a method for automatic classification and identification of in-vivo EPR spectra was established using support vector machine (SVM) technology, which can in-batch and automatically identify and screen out invalid spectra due to vibration and dental surface water interference during in-vivo EPR measurements. In this study, a spectrum analysis method based on genetic algorithm optimization neural network (GA-BPNN) was established, which can automatically identify the radiation-induced signals in in-vivo EPR spectra and predict the radiation doses received by the injured. The experimental results showed that the SVM and GA-BPNN spectrum processing methods established in this study could effectively accomplish the automatic spectra classification and radiation dose prediction, and could meet the needs of dose assessment in nuclear emergency. This study explored the application of machine learning methods in EPR spectrum processing, improved the intelligence level of EPR spectrum processing, and would help to enhance the efficiency of mass EPR spectra processing.

Biological effectiveness of combined exposure to neutrons and gamma radiation applied in two orders of sequence: Relevance for biological dosimetry after nuclear emergencies

ObjectiveAfter a nuclear detonation, people will be exposed to varying mixtures of neutrons and gamma radiation and the biological effectiveness of mixed beams is not well known. Additionally, it is not known how far both radiation types interact, a question that is relevant for generating calibration curves for the purpose of biological dosimetry. The objective of this study was to investigate the potential impact of two different combinations of neutron and gamma radiation on gene expression and dicentric chromosomes in peripheral blood mononuclear cells (PBMC). MethodsWhole blood from 3 human donors was exposed to neutrons with an energy spectrum similar to that of the Hiroshima uranium bomb, to gamma radiation from a 60Co source and to a 50:50 combination of both radiations, given in two orders of sequence. In all cases the total doses were 0.5, 0.75 and 1.0 Gy. Dicentric chromosomes were analyzed by light microscopy and the expression of six known radiation-responsive genes BBC3, CDKN1A, FDXR, GADD45A, MDM2, and XPC were analyzed by RT-qPCR. ResultsPer unit dose, exposure to neutrons lead to a higher level of dicentrics and gene expression as compared to gamma radiation. Dose-response relationships for both endpoints were linear, allowing calculating the expected outcome of combined exposure by arithmetic. For dicentric chromosomes, the RBE values for 60Co→neutrons, neutrons→60Co and neutrons were 4.05, 3.62 and 7.30 respectively. For gene expression the RBE values were gene-specific, but showed values in the range of 1.14–3.01 for 60Co→neutrons, 1.33–2.68 for neutrons→60Co and 1.39–3.91 for neutrons. ConclusionsThe results demonstrate that combined exposure to neutrons and gamma radiation, regardless of the order of sequence, leads to an additive response at both endpoints. This indicates that calibration curves for mixed beams can be constructed from dose response relationships of the single beam components.

High-risk nuclide screening and parameter sensitivity analysis based on numerical simulation and machine learning

During nuclear accidents, large quantities of radionuclides will be released into the environment, posing serious health hazards to local residents. The screening of high-risk nuclides is critical for the development of subsequent nuclear emergency response measures. In order to overcome the shortcomings of traditional screening methods, a machine learning method was proposed to screen high-risk nuclides and predict their contamination to groundwater more effectively. The performances of Support Vector Machine (SVM), Random Forest (RF) and Back Propagation Neural Network (BPNN) algorithms were compared, and sensitivity analyses of the initial leakage concentration ratio (C0/Cp), distribution coefficient (Kd) and decay coefficient (λ) on the model outputs were performed. Results showed that RF classification model achieved the highest prediction accuracy for screening high-risk nuclides. The contribution of the input parameters ranked as Kd > λ > C0/Cp. BPNN regression model was found to be the best for predicting when high-risk nuclides would pollute groundwater. The output was negatively correlated with C0/Cp and positively correlated with Kd and λ, with the parameter influence ranking as Kd > C0/Cp > λ. The contribution of Kd mainly came from itself, and the contribution of C0/Cp and λ mainly due to their interaction with other parameters.

Sensitivity of horizontal resolution and land surface model in operational WRF forecast for Online Nuclear Emergency Response System (ONERS)

Accurate Meteorological forecasts are crucial for the assessment of plume dispersion and dose prediction in nuclear power plant (NPP) sites. In this work the forecast sensitivity of the Weather Research and Forecasting (WRF) model is tested by running a series of forecast simulations for horizontal resolution, and land surface models (LSM) in the context of Online Nuclear Emergency Response System (ONERS) for Indian NPP sites. 72 h forecast simulations are made for three seasons viz. summer, southeast and northeast monsoon using the Global Forecast data. Three simulation experiments, namely 2 km-NOAH, 3 km-NOAH and 3 km-NOAHMP are conducted using two different nested domain configurations (18–6–2 km and 9–3 km) and two LSM schemes (NOAH and NOAH-MP) and tested at four different NPP sites. Forecast comparison of surface winds, relative humidity, temperature, heat fluxes and planetary boundary layer heights with data from meteorological tower, radiosonde and the Modern-Era Retrospective analysis for Research and Applications 2 (MERRA-2) shows 3 km-NOAH is equally capable in predicting surface parameters as well as vertical profiles compared to 2 km-NOAH with marginal differences. 3 km-NOAHMP shows less mean bias and better correlation for boundary layer height and heat fluxes. Comparison of spatial flow-field with 5th generation European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA5) data shows synoptic scale seasonal winds, sea level pressure systems and temperature hot-spots are better captured by 3 km-NOAHMP compared to 6 km coarse domain in the 18–6–2 km configuration. The daily accumulated rainfall by all simulations is overestimated compared to ERA5 data. The predictions by 3 km-NOAHMP better agree with Integrated Multi-satellite Retrievals for Global Precipitation Measurement (GPM-IMERGE) data whereas 2 km-NOAH predicts delayed rainfall occurrence. Dispersion simulations of hypothetical plume release from a coastal NPP site with all three forecasts properly show the influence of local scale diurnal land-sea breeze and seasonal winds on the plume movement. Therefore the 9–3 km domain with NOAHMP LSM is found to be a suitable choice for operational weather forecast in ONERS for Indian NPP sites.

STRENGTHENING RESPONSE CAPABILITIES FOR CBRN INCIDENTS: A CALL TO ACTION

We have read with great interest the article titled "Evaluation of Emergency Department Personnel’s Preparedness for Chemical, Biological, Radiation, and Nuclear Emergencies" authored by Bıçakcı and Bıcakcı, published in the final issue of your journal for the year 2023. In their research, the authors examined the preparedness level of emergency department personnel for chemical, biological, radiation, and nuclear (CBRN) incidents and their ability to respond to such events. They highlighted the inadequacy of education, drills, and knowledge level regarding CBRN incidents, emphasizing the necessity for emergency department personnel to be prepared for such events. We extend our thanks to the authors and the editorial board for this insightful contribution and congratulate them. However, we would like to offer two additional suggestions to enhance the response to CBRN incidents.

Evaluating Saudi Arabian nurses' willingness to respond to nuclear and radiological disasters.

We evaluated Saudi Arabian nurses' willingness to engage in nuclear and radiological disaster response. In the face of rising nuclear and radiological threats, it is essential that nurses are fully prepared to handle the health consequences of such emergencies. As frontline responders, nurses play a critical role in managing high-stakes situations, making their readiness a key factor in ensuring public safety during these crises. A cross-sectional survey was conducted among 612 registered nurses in Saudi Arabia. The survey used a structured questionnaire based on the theory of planned behavior, identifying behavioral intentions as the primary outcome and attitudes toward these behaviors, subjective norms, and perceived behavioral control as influencing factors. The data were analyzed using descriptive and inferential statistics. Most respondents lacked specialized training and reported strong behavioral intentions. Attitude and perceived behavioral control were key drivers of these behavioral intentions, with less impact from subjective norms. Behavioral intentions were also shaped by education, the perceived likelihood of nuclear and radiological emergencies in their region, peer influence, perceived self-efficacy, and family concerns. Younger and married nurses showed significantly stronger behavioral intentions. Although most nurses lacked specialized training, their strong engagement intentions and positive responses to active learning and training indicate a desire to close this gap through further education. However, inadequate institutional support, trouble communicating with family, and concerns about personal radiation exposure emerged as potential barriers. Targeted educational initiatives and support systems are needed to enhance nurses' confidence, competence, and willingness to engage in radiological and nuclear emergency scenarios. Policymakers should prioritize the development of specialized training programs and support mechanisms for nurses, ensuring they are adequately prepared to respond effectively to increasing radiological and nuclear threats.

Recommendations for Protective Actions Based on Projected Public Health Risks Following a Postulated Nuclear Power Plant Accident

This study conducted a regional assessment of the environmental and health consequences due to the release of radionuclides, including the most harmful, such as Cs-137 and I-131, from a hypothetical reactor accident at the first Nuclear Power Plant (NPP), Akkuyu Nuclear Power Plant, in Turkiye under different meteorological conditions. Simulations of the atmospheric flow were done using a Gaussian-based probabilistic model. Based on the estimated air and land contamination, radiation doses and cancer risks to the population were calculated. The assessment results were then compared with the criteria for protective actions in the event of a radioactive release and were subsequently used to assess the sufficiency of the Precautionary Action Zone (PAZ) and Urgent Protective Zone (UPZ) provided by regulations. The assessment indicated that evacuation outside the UPZ would likely be required during the early phase of the emergency, while sheltering indoors might be necessary up to 80 km. Protective actions such as restrictions on being outdoors or iodine prophylaxis are needed far beyond the radius of the UPZ. These results provide important insights into safe protective measures to reduce the risk of radiation-related cancer when considering a hypothetical severe nuclear accident. In addition, the results of this study aim to improve the current nuclear emergency response program and support nuclear decision-making.

Comparative analysis of the dispersion modeling and dose projection results performed under BARCO international project

Radiological assessments on zones to take protective actions in case of a nuclear or radiological emergency involve a series of real-time forecasts of radiological impact on the public at various distances from the release point, using actual weather or forecast data, information on the source term or facility status, and primary radiation monitoring data. This practice is implemented during the operation of emergency centers around the world in order to promptly report the occurrence and possible consequences of radiological accidents in the country and abroad in the event of a possible transboundary impact. Since the Chornobyl disaster, a lot of emergency exercises, research programs and projects, in particular, benchmarking, have served as international platforms for improving modeling capacity in atmospheric dispersion. This activity is carried out both on the basis of past severe accidents with significant atmospheric releases and corresponding radiological consequences, and on the basis of specific conditional (hypothetical) events that are developed in accordance with the purpose of the study. The paper is focused on the comparison results performed under the international project “Benchmarking on Assessment of Radiological COnsequences” (BARCO) conducted in 2020–2021 between five technical support organisations – members of the European Technical Safety Organisations Network (ETSON). The work contains a short overview of relevant international activity conducted in the past, a description of the BARCO project and its objectives, a list of participants, project tasks, initial data (source term, meteorology, list of benchmarking quantities, approach to data exchange, codes used). The study presents some of comparative analysis results obtained via two techniques such as code-to-code analysis (CTCA) and matched-pair analysis (MPA). The results discussion concentrates on the overall recommendations for code users. Conclusions provide the main outputs of the project.

Evaluation of neutron dosimetry capabilities with the MC-15 portable multiplicity counter

This work proposes a preliminary neutron dose rate estimation method for a neutron multiplicity detector through measurement- and simulation-based analyses. Uncharacterized neutron-emitting sources may be encountered in situations such as nuclear emergency response, safeguards, and treaty verification. These circumstances may present irradiation risk to personnel conducting field assay, search, and characterization measurements. It is therefore of interest to provide a field neutron dosimetry capability with the existing neutron multiplicity counting (NMC) capabilities. To date, no commercially-available neutron detection systems are capable of both accurate NMC and real-time neutron dosimetry. This work will focus on estimating dose rate using input from a single fielded NMC called the MC-15. The energy-dependent neutron detection efficiency response of the MC-15 was quantified in monoenergetic neutron simulations and evaluated in response to two neutron-emitting sources and to a polyethylene-moderated source. The results were compared to existing neutron dosimeters and established the proof of concept for further investigation of the MC-15 for dose estimation. Measurement results were also replicated in simulations; additional simulations were then conducted to expand upon the limited empirical data. The initial empirical results provided a conversion factor appropriate for use when measuring 252Cf neutrons that is independent of polyethylene shielding presence and thickness. The simulated data sets were then used to evaluate a fit equation allowing estimation of the neutron dose rate for less restricted geometric configurations and dependent only on the distance between the source and the detector. Additionally, the energy dependence of the efficiency response indicates that further empirical evaluations could provide energy-dependent conversion factors for broader neutron dosimetry capabilities with a wider range of neutron-emitting sources.

OSL dosimetry with table salt for mass screening of individual doses during radiological or nuclear emergencies

The ongoing war in Ukraine is associated with unprecedented radiological threats to the public in Ukraine and the neighboring countries. This calls for fundamental revision of the preparedness plans and established approaches to radiological monitoring of the populations affected by potential radiological emergencies. Dosimetric information will be needed for triage of victims and support to decision makers for prioritizing mitigation actions. Retrospective dosimetry methods strive to find a solution that would achieve this and enable fast and accurate feedback with information on individual doses to the concerned public. All known approaches to emergency dosimetry, both in biological and physical (instrumental) dosimetry have limitations, in particular – preventive cost, limited availability of samples for analysis, insufficient sensitivity (high dose threshold) and/or stability of radiation-induced markers (i.e. high fading). At the moment each of considered dose assessment methods possesses some combination of the aforesaid limitations. A suggestion to overcome these deficiencies is to use ordinary table salt (NaCl), read by optically stimulated luminescence (OSL), with well-known good dosimetric properties, and which allows anybody to prepare improvised individual dosemeters at home to be carried like a regular personal dosemeter until readout of the OSL signal is possible. This paper considers pros and cons of the use of NaCl as an OSL dosemeter in an emergency situation, with emphasis on practical aspects of its application for mass dose assessments for individuals among populations affected by radiological emergency situations.

Calibration for in vivo monitoring of thyroid of exposed population at risk of intakes of radioiodine isotopes due to a nuclear or radiological emergency

This work presents an improvement of the calibration of a broad energy germanium detector (BEGe) using age dependent neck-thyroid phantoms for thyroid monitoring of exposed individuals (workers and members of the public), allowing the detection and quantification of incorporated radioiodine isotopes in a nuclear medicine frame or in case of accident of a nuclear reactor.A BEGe detector was calibrated using a family of age-dependent thyroid-neck phantoms that simulate thyroids of 1, 5, 10, 15 year-old children and (male and female) adults, based in ICRP Publication 8 (ICRP, 2002) and ANSI 13.44 Standard (ANSI, 2014).The calibration of the BEGe detector for all neck phantoms was performed with the same counting geometry, centered under the BE Ge detector and at the same distance of 15 cm. Using same counting parameters allows to compare efficiency curves of thyroid monitoring depending with age. The in vivo measurements with the BE Ge detector allow to identify X rays and gamma emissions between 10 and 1000 keV with a great resolution and to quantify activities of radioiodine isotopes in the thyroid of exposed population.Calibration curves have been obtained for different sizes of the thyroid, depending with age. This study of counting efficiency using the main energies of the most important radioiodine isotopes result in accurate activity calculations. Detection limits were obtained for each radioiodine isotope, using blank phantoms of each age.

Evaluating the Overall Quality of Online Information on Nuclear Power Plant Accidents in Japanese

Information on professionally produced materials is beyond the reading level of the average adult and is difficult to read and understand. Additionally, the readability of nuclear emergency preparedness manuals in Japan is not clear. The purpose of this study is to evaluate the understandability, actionability, readability, and quality of nuclear emergency preparedness manuals. A systematic quantitative content analysis of online resources was conducted from November 27 to December 8, 2023. The selection criteria were websites in Japanese related to nuclear disaster prevention and aimed at the general public. The PEMAT-P, jReadability, Journal of the American Medical Association benchmark criteria, and Global Quality Scale were used to evaluate each web page. The number of respondents who scored 70 or higher on the PEMAT-P was 71 (61.2%) for Understandability and 57 (49.1%) for Actionability. Regarding the difficulty level of the texts by jReadability, "Difficult" was the most frequent response with 82 responses (70.7%). The JAMA Benchmark Criteria was 35.3% in 41 patients for attribution, 80.2% in 93 patients for currency, and a mean GQS of 4.1 (SD=1.0). This study quantitatively evaluated the understandability, actionability, readability, and quality of nuclear disaster prevention materials for the Japanese public. The findings suggest that text pertaining to nuclear disaster prevention materials may not be easily understood because it is beyond the reading comprehension of the average adult.

Comparison of dose measurements using environmental and personal dosimeters in real scenarios to deal with radiological and nuclear emergencies

Assessment of dose rates with environmental dosimeters typically takes much longer than with personal dosimeters. This work compares the results of two dosimetry systems with the aim of showing how to use personal dosimeters as environmental dosimeters in the case of radiological and nuclear emergencies, when the processing of a large number of dosimeters is essential. For this purpose, a long-term study has been carried out on the variability of the response of personal (CaSO4:Tm) and environmental (LiF:Mg,Cu,P) dosimeters corrected for the influence of secondary cosmic radiation (SCR). Comparison with each other provided a correlation factor between measurements made using these two passive dosimetry systems. The SCR response of the personal dosimeter was found to be 0.41 (σ = 0.03) significantly lower than 1.24 (Uk=2 = 0.12) that of the environmental dosimeter, which notably affects the comparison of dose measurements made with these two systems in free field. The correlation factor found of 0.86 (σ = 0.08) between the personal and environmental dosimeters allows preparing the personal dosimeters to be used in environmental radiation monitoring.

Preparedness and emergency response strategies for chemical, biological, radiological and nuclear emergencies in disaster management: A qualitative systematic review

AbstractDisaster management, mainly related to chemical, biological, radiological and nuclear (CBRN) incidents, is a critical field that requires constant evaluation to improve preparedness and response strategies. This review synthesises evidence on global health sector strategies for CBRN preparedness, gathering lessons to enhance policymaking for future response and readiness. This review included original English and French research addressing healthcare preparedness for CBRN threats. Database searches, such as EBSCO, ScienceDirect, PubMed, Ovid, Lissa, and Santécom, were conducted until November 2022. The Joanna Briggs Institute's tools were utilised to assess the risk of bias. Al‐Raayan® and Nvivo® version 12 software were employed for the review and analysis. 57 articles in English and 6 in French met the inclusion criteria. The analysis identified numerous strategies, concentrating on chemical and biological incidents (Chemical and biological bioterrorism: n = 27; Epidemics and Outbreak: n = 15). “Hospitals”, “responsibility”, and “health” emerged as prominent keywords, emphasising institutional roles and health outcomes in CBRN incidents preparedness. Key findings highlighted the need for a unified global definition of bioterrorism to align international efforts. Hospital‐level initiatives were emphasised as the foundation for national preparedness, emphasising specialised training, community engagement, and robust coordination mechanisms. Geographical variability in response strategies was noted, necessitating a harmonised global approach. Continuous research, epidemic management, and addressing radiological/nuclear threats emerged as crucial elements. Among others, strategies defined under “Emergency Response Preparedness” and “Intersectoral Policy Development” outlined comprehensive preparedness contexts for CBRN incidents. The review suggests an imperative shift towards building collaborative networks and enhancing health sector operational readiness to mitigate the impacts of CBRN incidents.

Selective Adsorption of Sr(II) from Aqueous Solution by Na3FePO4CO3: Experimental and DFT Studies.

The efficient segregation of radioactive nuclides from low-level radioactive liquid waste (LLRW) is paramount for nuclear emergency protocols and waste minimization. Here, we synthesized Na3FePO4CO3 (NFPC) via a one-pot hydrothermal method and applied it for the first time to the selective separation of Sr2+ from simulated LLRW. Static adsorption experimental results indicated that the distribution coefficient Kd remained above 5000 mL·g-1, even when the concentration of interfering ions was more than 40 times that of Sr2+. Furthermore, the removal efficiency of Sr2+ showed no significant change within the pH range of 4 to 9. The adsorption of Sr2+ fitted the pseudo-second-order kinetic model and the Langmuir isotherm model, with an equilibrium time of 36 min and a maximum adsorption capacity of 99.6 mg·g-1. Notably, the adsorption capacity was observed to increment marginally with an elevation in temperature. Characterization analyses and density functional theory (DFT) calculations elucidated the adsorption mechanism, demonstrating that Sr2+ initially engaged in an ion exchange reaction with Na+. Subsequently, Sr2+ coordinated with four oxygen atoms on the NFPC (100) facet, establishing a robust Sr-O bond via orbital hybridization.

Rapid nuclide identification algorithm based on self-attention mechanism neural network

Nuclide identification technology plays a critical role in various fields such as nuclear energy, medicine, environmental monitoring, and defense. However, traditional nuclide identification algorithms face challenges, such as high computational complexity and long response time, when handling large-scale data. The adaptability and universality of these algorithms for different domains and tasks are also confronted with certain challenges. In recent years, numerous nuclide identification methods based on convolutional neural networks have been proposed, to some extent, addressing the issues present in traditional nuclide identification algorithms. Yet, in the context of unmanned nuclear emergencies, nuclear counterterrorism, and post-nuclear contamination processing, there is a widespread need for rapid nuclide identification methods suitable for deployment on edge computing devices. Therefore, this paper combines the advantages of self-attention mechanisms and convolutional neural networks to design a novel network architecture which can meet the aforementioned application requirements. We simulated and measured energy spectrum data for radioactive sources, including 241Am, 57Co, 60Co, 99mTc, 131I, 133Ba, 137Cs, 226Ra, 232Th, and 40K, as the training dataset. In experiments with a training set containing only individual radioactive source energy spectra, the model achieves 99.49% accuracy, with an average inference time of 0.14 ms per sample. It has 0.27 million parameters and 1.55 billion FLOPs. When the training set includes both individual and mixed radioactive source energy spectra, the model achieves 99.84% accuracy, with an average inference time of 0.25 ms per sample. It has 0.83 million parameters and 1.58 billion FLOPs.