The selective transport of ions in nanopores attracts broad interest due to their potential applications in chemical separation, ion filtration, seawater desalination, and energy conversion. The ion selectivity based on the ion dehydration and steric hindrance is still limited by the very similar diameter between different hydrated ions. The selectivity can only separate specific ion species, lacking a general separation effect. Herein, we report the highly ionic selective transport in charged nanopore through the combination of hydraulic pressure and electric field. Based on the coupled Poisson–Nernst–Planck (PNP) and Navier–Stokes (NS) equations, the calculation results suggest that the coupling of hydraulic pressure and electric field can significantly enhance the ion selectivity compared to the results under the single driven force of hydraulic pressure or electric field. Different from the material-property-based ion selective transport, this method endows the general separation effect between different kinds of ions. Through the appropriate combination of hydraulic pressure and electric field, an extremely high selectivity ratio can be achieved. Further in-depth analysis reveals the influence of nanopore diameter, surface charge density and ionic strength on the selectivity ratio. These findings provide a potential route for high-performance ionic selective transport and separation in nanofluidic systems.

The FeCoNiCrTi_0.2 high-entropy alloys fabricated by vacuum arc melting method, and the annealed pristine material, are face centered cubic structures with coherent γ’ precipitation. Samples were irradiated with 50 keV He⁺ ions to a fluence of 2 × 10¹⁶ ions/cm² at 723 K, and an in situ annealing experiment was carried out to monitor the evolution of helium bubbles during heating to 823 and 923 K. The pristine structure of FeCoNiCrTi_0.2 samples and the evolution of helium bubbles during in situ annealing were both characterized by transmission electron microscopy. The annealing temperature and annealing time affect the process of helium bubbles evolution and formation. Meanwhile, the grain boundaries act as sinks to accumulate helium bubbles. However, the precipitation phase seems have few effects on the helium bubble evolution, which may be due to the coherent interface and same structure of γ’ precipitation and matrix.

The development of accident-tolerant materials is of great significance for preventing the zirconium–water reactions and improving the inherent safety of nuclear reactors. In this study, ZrC/Ni multilayers with average layer thicknesses of 5, 10, 20, 50, and 100 nm were designed and successfully fabricated by magnetron sputtering. The characterization results of GIXRD, SEM, AFM, TEM, etc., show that the series of films are mainly composed of alternately deposited Ni crystalline layers and ZrC amorphous layers, and the interface is clear. The films were irradiated with 50 keV He⁺ with a fluence of 1.0 × 10¹⁷ ions/cm² at room temperature, and the films with different layer thicknesses kept the original phase composition. It was found that an amorphous transition layer with a thickness of about 30 nm appeared between the amorphous and crystalline interface of the 100 nm film by TEM characterization. The analysis shows that this layer is formed by the mixing of Ni and Zr elements induced by irradiation, which is not conducive to He⁺ migration and produces large-sized helium bubbles. The appearance of the transition layer improves the irradiation stability of the amorphous/crystalline composite film, thus providing a theoretical basis for the application of this type of material in fuel cladding.

In a serious accident, after the core of a nuclear reactor melts and collapses, In-Vessel Retention in the External Reactor Vessel Cooling (IVR-ERVC) is an effective technology to maintain the integrity of lower head by reducing heat load on it. The various factors affecting the melting of the lower head have been widely studied. The mass of the molten metal layer may affect the consequences of the accident, since it is where the focusing effect occurs. However, the related research is still absent. In this paper, we systematically calculated the heat transfer behavior and melting process under different metal layer heights conditions. The temperature distribution, the velocity distribution, the heat flux of the outer wall of the Reactor Pressure Vessel (RPV), and the change of the thickness of the RPV were obtained through Large Eddy Simulation (LES). Interestingly, the heat flux increases with the metal layer height at first and achieve the maximum in the middle height. These results increase the understanding towards the serious accidents.

To investigate the radiation stability of the intermetallic in PH 13–8 Mo steel, precipitates with different sizes were generated and then the samples are irradiated with 400 keV Fe⁺ at room temperature with maximum damage up to 8 dpa. The pre- and post-irradiation samples are examined with selected area electron diffraction (SAED), scanning transmission electron microscopy (STEM) and Energy Dispersive Spectroscopy (EDS). Before the irradiation, B2 NiAl precipitates are uniformly distributed in matrix with increased sizes of 2.5, 4.9 and 8.1 nm. After the irradiation, the intensity of SAED superlattice pattern of B2 NiAl with 8.1 nm diminishes rather than disappeared in the remaining samples, indicating that the ordered B2 structure of NiAl precipitates of smaller size are mostly destroyed. EDS results proves that no elemental diffusion took place between the precipitates and matrix. Moiré fringes are found to be located beside dissolved precipitates attributed to radiation-enhanced diffusion. This work will provide advice for the material design of other intermetallic strengthened alloys especially in nuclear applications.

This study employs in situ transmission electron microscopy (TEM) to investigate the dynamic evolution of radiation-induced defects in gallium nitride (GaN) under high temperature (800 °C). The results demonstrate that defect cluster size increases progressively with irradiation dose (up to 2.48 displacements per atom, dpa), while cluster density exhibits a non-monotonic trend, peaking at intermediate doses (0.31–0.62 dpa) before declining due to coalescence of smaller clusters. Aberration-corrected scanning TEM reveals that irradiation generates dislocations, stacking faults, and cavities. Besides, N2 bubbles nucleate even at ultralow doses (0.02 dpa), driven by interstitial N aggregation and vacancy capture. Despite significant radiation damage, GaN maintains its crystalline structure without amorphization at high doses. Besides, there is negligible aggregation of defects around intrinsic dislocations—a behavior attributed to the high migration energy barriers of vacancies and interstitials in GaN. These findings elucidate the intrinsic radiation resistance mechanisms of GaN through atomic-level defect dynamics, providing critical guidance for designing next-generation radiation-tolerant power electronics and radiation detectors in extreme environments such as nuclear reactors and space applications.