Atomic Energy Research Articles

A Benchmark for Neutron Kinetics Methods in Hexagonal Geometry

A new benchmark solution has been developed to aid in the development of neutron kinetics solvers for hexagonal geometries, such as those in water-water energetic reactors. This benchmark problem is based on the two-dimensional, two-group, International Atomic Energy Agency–Hex steady-state benchmark problem. Two transient problems are presented: a ramp and a step transient. To create a benchmark-quality solution to this transient problem, a basic neutron kinetics model was added to the computer program LUPINE (Liquid metal–cooled fast reactor Utility for Physics Informed Nuclear Engineering). LUPINE solves neutron kinetics equations in general unstructured mesh. First, the LUPINE kinetics solvers are verified using the TWIGL benchmark problems. Then the methods in LUPINE are used to perform a spatiotemporal convergence analysis to ensure that the solutions are sufficiently converged. Finally, Richardson extrapolation is performed to obtain the reference solutions for these new kinetics benchmark problems.

Potential applications of microbial genomics in nuclear non-proliferation

As nuclear technology evolves in response to increased demand for diversification and decarbonization of the energy sector, new and innovative approaches are needed to effectively identify and deter the proliferation of nuclear arms, while ensuring safe development of global nuclear energy resources. Preventing the use of nuclear material and technology for unsanctioned development of nuclear weapons has been a long-standing challenge for the International Atomic Energy Agency and signatories of the Treaty on the Non-Proliferation of Nuclear Weapons. Environmental swipe sampling has proven to be an effective technique for characterizing clandestine proliferation activities within and around known locations of nuclear facilities and sites. However, limited tools and techniques exist for detecting nuclear proliferation in unknown locations beyond the boundaries of declared nuclear fuel cycle facilities, representing a critical gap in non-proliferation safeguards. Microbiomes, defined as “characteristic communities of microorganisms” found in specific habitats with distinct physical and chemical properties, can provide valuable information about the conditions and activities occurring in the surrounding environment. Microorganisms are known to inhabit radionuclide-contaminated sites, spent nuclear fuel storage pools, and cooling systems of water-cooled nuclear reactors, where they can cause radionuclide migration and corrosion of critical structures. Microbial transformation of radionuclides is a well-established process that has been documented in numerous field and laboratory studies. These studies helped to identify key bacterial taxa and microbially-mediated processes that directly and indirectly control the transformation, mobility, and fate of radionuclides in the environment. Expanding on this work, other studies have used microbial genomics integrated with machine learning models to successfully monitor and predict the occurrence of heavy metals, radionuclides, and other process wastes in the environment, indicating the potential role of nuclear activities in shaping microbial community structure and function. Results of this previous body of work suggest fundamental geochemical-microbial interactions occurring at nuclear fuel cycle facilities could give rise to microbiomes that are characteristic of nuclear activities. These microbiomes could provide valuable information for monitoring nuclear fuel cycle facilities, planning environmental sampling campaigns, and developing biosensor technology for the detection of undisclosed fuel cycle activities and proliferation concerns.

Triple Electron Attachments with a New Intermediate-Hamiltonian Fock-Space Coupled-Cluster Method.

The implementation of a new intermediate-Hamiltonian Fock-space coupled-cluster (IHFSCC) scheme for the (3,0) sector of the Fock space is reported. In this IHFSCC approach, the three-body contributions in the cluster operator S(3,0) corresponding to the (3,0) sector of the Fock space are considered, while S(1,0) and S(2,0) at the (1,0) and (2,0) level only include one- and two-body operators. By introducing a suitable partition of the wave operator, the intermediate Hamiltonian, which only depends on the two-body operator of S(1,0), is obtained. S(2,0) and S(3,0) are not required within this new IHFSCC scheme, and a large reference space can be possibly employed. The performance of this (3,0) IHFSCC method in calculating triple ionization potentials and excitation energies for atoms and cations with a ground p3 configuration as well as adiabatic excitation energies for some molecules is investigated. The effect of the number of active virtual orbitals and three different types of orbitals, i.e., reference orbitals, restricted open-shell Hartree-Fock orbitals (ROHF) of the target systems, and canonicalized ROHF orbitals, on IHFSCC results, is also studied. Our calculations indicate that reasonable results can be achieved with this (3,0) IHFSCC method when a minimal reference space is employed. Further increasing the number of active orbitals does not necessarily improve the results. In addition, the IHFSCC results using canonicalized ROHF orbitals generally agree well with reference values, and they are not very sensitive to the number of active orbitals compared with results using the reference orbitals. The new (3,0) IHFSCC method can be applied to open-shell systems with three unpaired electrons with reasonable accuracy at a relatively low computational cost.

Crystallographic Dependence of Field Evaporation Energy Barrier in Metals Using Field Evaporation Energy Loss Spectroscopy Mapping.

Atom probe tomography data are composed of a list of coordinates of the reconstructed atoms in the probed volume. The elemental identity of each atom is derived from time-of-flight mass spectrometry, with no local chemical information readily available. In this study, we use a data processing technique referred to as field evaporation energy loss spectroscopy (FEELS), which analyzes the tails of mass peaks. FEELS was used to extract critical energetic parameters that are related to the activation energy for atoms to escape from the surface under intense electrostatic field and dependent of the path followed by the departing atoms. We focused our study on pure face-centered cubic metals. We demonstrate that the energetic parameters can be mapped in two-dimensional with nanometric resolution. A dependence on the considered crystallographic planes is observed, with sets of planes of low Miller indices showing a lower sensitivity to the field. The temperature is also an important parameter in particular for aluminum, which we attribute to an energetic transition between two paths of field evaporation between 25 and 60 K close to (002) pole. This paper shows that the information that can be retrieved from the measured energy loss of surface atoms is important both experimentally and theoretically.

Validating the application of the revised ICRP's biokinetic models for organic 14C and organically bound tritium to members of the public.

In 2016, the International Commission on Radiological Protection (ICRP) has revised the biokinetic models for carbon and tritium in Publication 134 to calculate the dose coefficients of these radionuclides for workers. The following publication for members of the public is now in the process of revising by the ICRP. According to the draft manuscript published for consultation in 2023, the same models will be adopted for members of the public, although the parameters in these models are not corroborated by the metabolic data of radionuclides in foods. Dose coefficients were estimated using the modified models developed in this study to validate the application of the revised models to members of the public. In the modified models, several parameters were replaced based on the metabolic data of these nuclides in foods and compartments of radio-insensitive tissues were introduced. For these estimations, we utilised the an inhouse program for internal-dose calculation developed by the Japan Atomic Energy Agency. The estimated dose coefficient values for ingestion of organic 14C and organically bound tritium ranged from 3.2×10-11 to 7.6×10-11 Sv Bq-1 and from 3.5×10-11 to 5.4×10-11 Sv Bq-1, respectively. We concluded that the dose coefficient value of 1.6×10-10 Sv Bq-1 obtained by the revised ICRP's carbon model was conservative, while the value of 5.1×10-11 Sv Bq-1 for organically bound tritium was appropriate.&#xD.

Cavity ionization chamber responses in the JAEA and the NMIJ high-energy photon reference fields for radiation protection.

The dosimeter response should be calibrated in a reference field near the user's radiation environment. Environments around nuclear reactors and radition therapy facilities have high-energy photons with energies exceeding that of60Co gamma rays, and controlling exposure to these photons is important. The Japan Atomic Energy Agency (JAEA) and National Metrology Institute of Japan (NMIJ) have high-energy reference fields with energies above several MeV for different types of accelerators. Their reference fields have different fluence-energy distributions. In this study, the energy dependencies of the two-cavity ionization chambers, which are often used by secondary laboratories, were experimentally and computationally evaluated for each high-energy field. These results agreed well with relative expanded uncertainties (k= 2), and their capabilities for air kerma measurements in each high-energy reference field were confirmed. Therefore, the capabilities of the air-kerma measurements can be verified in the two high-energy reference fields.&#xD.

Synergistic Effects of Deterrence by Denial and Safeguards in the Biological Weapons Convention: Building on the History of International Nuclear Safeguards

ABSTRACT The notion of deterrence by denial has been introduced in relation to biosecurity. The goal of deterrence by denial in biosecurity extends beyond dissuading attacks. It also encompasses the protection of citizens in the event of an attack. In this vein, it may be considered as including the elements of deterrence and safeguards in terms of the protection of complying states from the hazards of violations and evasions. In presenting a historical overview of nuclear safeguards and shedding light on the limitations of the safeguard system of the International Atomic Energy Agency, this paper delineates the distinction between safeguards and verification for deterrence. Subsequently, it examines the case of the Biological Weapons Convention in which verification is considered a crucial factor for deterrence and investigates the potential for deterrence by denial to serve as an alternative to verification in effective safeguards. It argues that the adoption of deterrence by denial in biosecurity could exert synergistic effects by rectifying the shortcomings of the verification system within the Biological Weapons Convention and providing effective safeguards without the need for coercive measures.

Learning grain boundary segregation behavior through fingerprinting complex atomic environments

Although continuum-scale segregation is a well-documented behavior in multi-species materials, detailed site-specific behavior remains largely unexplored. This is partially due to the complexity of analyzing materials at the requisite time and length scales for describing segregation with full atomic accuracy. Here, we better evaluate the segregation behavior of disordered grain boundary (GB) atomic environments through leveraging a set of Strain Functional Descriptors (SFDs) to generate an atomic descriptor (i.e., fingerprint). Using this atomic fingerprint, we resolve key relationships between atomic structure and segregation energy. Machine learning (ML) techniques are utilized in concert with this SFD fingerprint to elucidate complex relationships relating segregation potential to changes in specific features of the local Gaussian density captured by the SFDs. Finally, we identify relationships that indicate both individual and joint structure-property correlations. Linking atomic segregation energy to key structural features demonstrates the value of higher-order descriptors for uncovering complex structure-property relationships at an atomic scale.

Phenomenological constitutive laws for the dissipative behaviour of highly compressible elastomers and their finite element implementation

This paper deals with the development of constitutive equations to model the mechanical behaviour of compressible elastomers. These materials are naturally incompressible but can be made compressible by the addition of hollow microspheres, for example. Such a material is referred to as syntactic foam. The CEA (French Commission for Atomic and Alternative Energies) employs such compressible materials as seals in complex structures to reduce the internal stresses in vulnerable components and prevent their failure. The behaviour of these structures is predicted by finite element simulations. It is important to know and model the mechanical behaviour of the seals. Like elastomers, they can undergo large deformations. The microspheres enable the material to undergo large volume change unlike pure elastomer that is nearly incompressible. This compressibility also intensifies dissipative phenomena encountered in elastomers such as viscosity or plasticity. Furthermore, the Mullins stress softening effect is also intensified even for loadings that only bring about volumetric changes. To model these behaviours, a phenomenological approach was developed based on the isochoric/volumetric decomposition of the deformation gradient. The method of intermediate dissipative configurations was employed to introduce multiple phenomena, including viscosity (with several characteristic times) and viscoplasticity, for these two parts of the deformation. The constitutive equations and their flow rules were implemented in Abaqus through a UMAT subroutine and using a numerical approach to define the tangent operator. The parameters of the behaviour law were identified using a model reduction technique known as shape manifold approach. The resulting model can be compared with experimental data.

Steering the Atoms for Peace and Development: Legal Aspects of the Board of Governors of the International Atomic Energy Agency

International Atomic Energy Agency (IAEA) is the leading international organization in the field of nuclear energy and nuclear non-proliferation. This paper examines the most important policy body of the Agency, the Board of Governors (BoG). The legal foundation of the BoG will be discussed in light of its constitutional documents, most notably the Statute of the IAEA and the Rules of Procedure of the BoG. The research question will be approached from the theoretical angle of functionalism. The paper suggests that in fact, the practical role of the BoG is even more important than could be concluded on the basis of the legal documents whence the powers of the BoG derive. Over the years, the normative framework of the IAEA has enabled the BoG to adapt to rapidly changing decision-making environments and political situations. Furthermore, this has made it possible for the BoG to contribute in a relatively effective manner to the development of substantive international nuclear policy and law.

Pacific Interannual and Multidecadal Variability Recorded in δ18O of South American Summer Monsoon Precipitation

AbstractThe South American summer monsoon (SASM) generates important hydroclimatic impacts in (sub‐)tropical South America and isotopic tracers recorded in paleoclimatic archives allow for assessing its long‐term response to Pacific variability prior to modern observations. Stable oxygen isotopes in precipitation integrate hydroclimatic changes during the SASM mature phase from December to February (DJF) in response to the Interdecadal Pacific Oscillation (IPO) and El Niño—Southern Oscillation (ENSO), respectively. Here, results from the isotope‐enabled Community Atmosphere Model v.5 are compared with highly resolved and precisely dated isotopic records from speleothems, tree rings, lake and ice cores during the industrial era (1880–2000 CE) and validated against observations from the International Atomic Energy Agency (IAEA) network. Pacific sea surface temperatures (SSTs) are coupled to the isotopic composition of SASM precipitation through perturbations in the Walker circulation associated with low‐ (IPO) and high‐frequency (ENSO) variability, impacting convective activity over tropical South America and the tropical Atlantic. Changes in convection over this monsoon entrance region ultimately control the downstream oxygen isotopic composition of precipitation recorded in paleoclimate archives. Overall, model results, paleoclimate records and IAEA data agree on the isotopic response to Pacific SST forcing. These results highlight the potential for long isotopic paleoclimate records to reconstruct Pacific climate variability on both high‐ and low‐frequency timescales. Furthermore, the isolation of the IPO signal in a diverse set of isotopic archives invites the reinterpretation of other paleoclimate proxies for identifying this historically overlooked forcing.

Burnout syndrome, anxiety, and depression symptoms among workers in radiation field

BackgroundJob burnout is defined as physical, emotional, and mental exhaustion due to persistent work stress, and it includes emotional exhaustion (EE), cynicism (CY), and reduced personal accomplishment (PA) and usually leads to symptoms of depression, lack of motivation, and decreased enthusiasm. Previous studies from different countries have suggested that job burnout, depression, and anxiety are a common work-related problems. This study aims to assess for job burnout, depression, and anxiety among radiation workers in order to investigate the effects of radiation exposure during work on the mental health. This comparative cross-sectional study was performed on 208 workers in the Egyptian Atomic Energy Authority (EAEA) and the Egyptian Nuclear and Radiological Regulatory Authority (ENRRA) at Cairo Governorate, Egypt. Study participants were divided into 2 groups: 1st group which included 104 workers among radiation field and 2nd group which included 104 workers and employees who do not often work among radiation field. Maslach Burnout Inventory Scale (MBI), Hamilton Rating Scale for Depression (HAM-D), and Hamilton Rating Scale for Anxiety (HAM-A) were used to assess for burnout, depression, and anxiety among study participants.ResultsThe prevalence and severity of depression, anxiety, burnout, and among workers inside radiation field group were statistically significantly higher than those working outside radiation field group. Work type (WIRF) and number of working hours per week (> 40 h) were the significant risk factors for all the burnout, depression, and anxiety, while age (> 40–60 years old) was a significant predictor for depression, female gender was a significant predictor for anxiety, and both age (20–40 years old) and years of experience (≤ 10 years) were significant predictors for burnout among workers inside radiation field.ConclusionsBurnout, depression, and anxiety are common among workers inside radiation field with higher prevalence and severity than those working outside radiation field. Younger age, fewer years of experience, and more working hours per week are significantly associated risk factors for burnout among workers inside radiation field.

Stroke and Disability: Incidence, Risk Factors, Management, and Impact

Stroke is a leading cause of disability worldwide, leaving a significant portion of the population grappling with its long-term effects. The incidence of stroke is 3.6 on average higher compared to high-income countries. This study explores the global and Saudi Arabian burden of stroke-induced disability, highlighting its prevalence, risk factors, and the need for comprehensive rehabilitation strategies. The primary source of information was the international trusted databases, including Web of Science, Scopus, PubMed, and the websites and reports from international organizations such as the International Atomic Energy Agency, World Stroke Organization, and World Health Organization. The study revealed that women, especially after menopause, should be aware of their increased stroke risk and take steps to manage their risk factors such as high blood pressure, diabetes, and high cholesterol. Managing established risk factors such as high blood pressure, diabetes, and cholesterol remains the cornerstone of stroke prevention for all individuals, regardless of profession. Workplace wellness programs that promote healthy lifestyles and stress management can be beneficial for employees in any occupation. Overall, stroke presents a growing public health challenge in Saudi Arabia. While the incidence may be lower than in some high-income countries, it is on the rise. More research is needed to gain a clearer picture of stroke-related disability, develop effective prevention and treatment strategies, and solidify the connection between specific occupations and stroke incidence.

Neighboring Catalytic Sites Are Essential for Electrochemical Dechlorination of 2-Chlorophenol.

The electrocatalytic reduction process is a promising technology for decomposing chlorinated organic pollutants in water but is limited by the lack of low-cost catalysts that can achieve high activity and selectivity. In studying electrochemical dechlorination of 2-chlorophenol (2-CP) in aqueous media, we find that cobalt phthalocyanine molecules supported on carbon nanotubes (CoPc/CNT), which is a highly effective electrocatalyst for breaking the aliphatic C-Cl bonds in 1,2-dichloroethane (DCA) and trichloroethylene (TCE), are completely inactive for reducing the aromatic C-Cl bond in 2-CP. Detailed mechanistic investigation, including volcano plot correlation between dechlorination rate and atomic hydrogen adsorption energy on various transition metal surfaces, kinetic measurements, in situ Raman spectroscopy, and density functional theory calculations, reveals that the reduction of the aromatic C-Cl bond in 2-CP goes through a hydrodechlorination mechanism featuring a bimolecular reaction between adsorbed atomic hydrogen and 2-CP on the catalyst surface, which requires neighboring catalytic sites, whereas the aliphatic C-Cl bonds in DCA and TCE are cleaved by direct electron transfer from the catalyst, which can occur on isolated single sites. This investigation leads to the discovery of metallic Co as a highly selective and active electrocatalyst for 2-CP dechlorination. This work provides new insights into the fundamental chemistry and catalyst design of electrochemical dechlorination reactions for wastewater treatment.

International intercomparison and quality assessment of passive and active 222Rn measuring devices in the Asia-Pacific region

Intercomparison exercise is an integral part of the quality assurance programmes in 222Rn measurements using active and passive devices. Ensuring the accuracy of data generated through measurements necessitates periodic performance checks. To achieve harmonization of methods, quantify biases and errors in measurements, and identify the reasons for discrepancies, there is a pressing need for periodic intercomparison exercises. To address this need of numerous laboratories, particularly in the Asia-Pacific region, a calibration facility for 222Rn measuring devices has been established at the Centre for Advanced Research in Environmental Radioactivity (CARER), Mangalore University, India. An international intercomparison exercise for the 222Rn measuring devices was conducted at this facility in the year 2022 with the participation of 10 laboratories from six countries. A total of 354 devices (comprising of both active and passive detectors) were subjected to intercomparison measurements by exposing them to three concentration levels: (5.97±0.29)×103 Bq m-3, (0.70±0.09)×103 Bq m-3 and (2.02±0.20)×103 Bq m-3 in separate experiments and the exposure durations were 7 days, 15 days, and 10 days respectively. The performance of each laboratory was evaluated following the criterion adopted by the International Atomic Energy Agency (IAEA) in its worldwide proficiency test programmes. This exercise brought out the fact that some of the laboratories need to improve their measurement practices to produce reliable data.

Soil-to-Rice Transfer Factors of Naturally Occurring Radionuclides in Rice Cultivated in Bangladesh and Associated Health Implications

This study investigates the uptake of naturally occurring radionuclides (226Ra, 232Th, and 40K) from soil by rice plants in extensively cultivated regions in Bangladesh. It also evaluates the potential radiation risks associated with rice consumption by the Bangladeshi populace. High purity germanium (HPGe) gamma-ray spectrometry was employed to measure the concentrations of radionuclides in both soil and rice samples. For 40K, our results agree with the International Atomic Energy Agency’s (IAEA) published value; however, the transfer factors (TF) for the other two radionuclides differ considerably. Despite the fact that the IAEA based its publication of TFs for 226Ra and 232Th on clay soil, the majority of the soil profile in the present study was silty clay with a little alkalinity. Moreover, the data obtained may have been impacted by the growing seasons, cultivation methods, and soil fertility. Additionally, the annual effective dose due to the ingestion of radioactivity resulting from rice consumption was evaluated and the results agree with UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation), 2000. With a few exceptions, the excess lifetime cancer risk (ELCR) values for 226Ra, 232Th, and 40K were below the globally average permissible level (1×10-3). In light of this, the current study indicates that consuming rice does not pose an immediate health risk to the general public. By studying TFs among various rice varieties and geographical areas, scientists can develop models to forecast the possible radiation exposure from rice consumption and pinpoint activities or areas that require additional attention.

Establishment of a 241Am gamma calibration field based on international standards and its conversion coefficients.

A 241Am gamma (γ)-ray calibration field that meets the requirements for a γ-ray reference field as specified in the ISO 4037 standard series was established in the Facility of Radiation Standards of the Japan Atomic Energy Agency. The reference air kerma rates were measured using a reference ionization chamber calibrated by the N-80 quality X-ray calibration field of the national metrology standard in Japan and with a correction to account for differences in photon energy due to the calibration field. Conversion coefficients for the 241Am γ-ray calibration field, including those not listed in the ISO 4037 standard series, were calculated based on the measured γ-ray fluence rate spectra.

Two-Dimensional Mammography Imaging Techniques for Screening Women with Silicone Breast Implants: A Pilot Phantom Study

This study aimed to evaluate the impact of three two-dimensional (2D) mammographic acquisition techniques on image quality and radiation dose in the presence of silicone breast implants (BIs). Then, we propose and validate a new International Atomic Energy Agency (IAEA) phantom to reproduce these techniques. Images were acquired on a single Hologic Selenia Dimensions® unit. The mammography of the left breast of a single clinical case was included. Three methods of image acquisition were identified. They were based on misused, recommended, and reference settings. In the clinical case, image criteria scoring and the signal-to-noise ratio on breast tissue (SNRBT) were determined for two 2D projections and compared between the three techniques. The phantom study first compared the reference and misused settings by varying the AEC sensor position and, second, the recommended settings with a reduced current-time product (mAs) setting that was 13% lower. The signal-difference-to-noise ratio (SDNR) and detectability indexes at 0.1 mm (d’ 0.1 mm) and 0.25 mm (d’ 0.25 mm) were automatically quantified using ATIA software. Average glandular dose (AGD) values were collected for each acquisition. A statistical analysis was performed using Kruskal–Wallis and corrected Dunn tests (p < 0.05). The SNRBT was 2.6 times lower and the AGD was −18% lower with the reference settings compared to the recommended settings. The SNRBT values increased by +98% with the misused compared to the recommended settings. The AGD increased by +79% with the misused settings versus the recommended settings. The median values of the reference settings were 5.8 (IQR 5.7–5.9), 1.2 (IQR 0.0), 7.0 (IQR 6.8–7.2) and 1.2 (IQR 0.0) mGy and were significantly lower than those of the misused settings (p < 0.03): 7.9 (IQR 6.1–9.7), 1.6 (IQR 1.3–1.9), 9.2 (IQR 7.5–10.9) and 2.2 (IQR 1.4–3.0) mGy for the SDNR, d’ 0.1 mm, d’ 0.25 mm and the AGD, respectively. A comparison of the recommended and reduced settings showed a reduction of −6.1 ± 0.6% (p = 0.83), −7.7 ± 0.0% (p = 0.18), −6.4 ± 0.6% (p = 0.19) and −13.3 ± 1.1% (p = 0.53) for the SDNR, d’ 0.1 mm, d’ 0.25 mm and the AGD, respectively. This study showed that the IAEA phantom could be used to reproduce the three techniques for acquiring 2D mammography images in the presence of breast implants for raising awareness and for educational purposes. It could also be used to evaluate and optimize the manufacturer’s recommended settings.

Factors influencing the stability of Pt-based ORR electrocatalysts in HT-PEMFCs: A theoretical investigation

Electrocatalyst stability is a key parameter for commercializing high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Here, we used density functional theory (DFT) to investigate the stability of Pt-based electrocatalysts by calculating the binding energy (ΔEb) of surface Pt atoms under working conditions. Our results show that Pt(111) is more stable than Pt(100) and Pt(110) under vacuum conditions. Stress hurts the stability of Pt(111), regardless of compressive or tensile stress. Most of the transition metals alloyed with Pt improve the stability of Pt(111), especially PtV, PtY, and PtTa, which increase the ΔEb by 0.60–0.70 eV (ΔΔEb). However, the stability of Pt is significantly destroyed under the working conditions of oxygen reduction reaction (ORR). The specific adsorption of ORR intermediates and electrolyte ions decreases the ΔEb of Pt(111) by 0.35–0.95 eV, and the effect of PO43-* is more significant. Furthermore, when the electric field of the electrochemical double layer is coupled with PO43-* specific adsorption, ΔΔEb further increases to 1.12 eV. Our results highlight the importance of the intrinsic ΔEb and the working conditions for the stability of Pt-based electrocatalysts. This work provides important guidelines for the design of stable ORR electrocatalysts for HT-PEMFCs.

Influence of He injection amount on the microstructure of ion irradiated Cr0.8FeMnNi medium entropy alloy compared with 316L stainless steel

In recent years, medium and/or high-entropy alloys (M/HEAs) have attracted attention due to their excellent mechanical properties, positioning them as potential candidates for structural materials in advanced nuclear reactors. This study investigated the effect of He injection amount on the microstructural evolution in Cr0.8FeMnNi MEA and 316L stainless steel. Helium atoms were injected, followed by Fe2+ irradiation. Transmission electron microscopy was used to characterize the irradiation-induced defects. The primary irradiation-induced defects observed across all He injection amounts were black dots; no voids were seen under any irradiation conditions. In He-injected Cr0.8FeMnNi, the number density of black dots was significantly lower than in non-He-injected Cr0.8FeMnNi, while the average size of black dots increased with higher He injection rates. As the He injection amount increased, the binding energy of the self-interstitial atom (SIA) to the He-V complex decreased. This reduction facilitated the nucleation and growth of numerous SIA clusters within the matrix, consequently increasing the number density of black dots. The change in the number density of black dots in Cr0.8FeMnNi was much smaller than that observed in 316L. This could be ascribed to the enhanced self-healing process caused by the diversity of point defects and higher lattice distortion in Cr0.8FeMnNi.