A deuterium-tritium (D-T) fusion neutron generator produces high-intensity monoenergetic neutrons vital for nuclear technology development, where the target temperature is a critical parameter. Excessive temperature can impair nuclear reaction efficiency and cause target damage. This study established a dynamic in-situ temperature measurement system for rotating targets under vacuum using infrared thermometry. Based on this system, the rotating target thermometry experiment was conducted to verify the effectiveness of this method in evaluating the thermal performance of the target. Before the rotating target thermometry experiment, a calibration platform was designed to analyze and compensate for influencing factors like surface emissivity after treatment and window transmittance. Results indicated these factors significantly affect accuracy, but after calibration, the temperature error was reduced to within 5%. The rotating target thermometry experiment data were compared with conjugate heat transfer CFD simulations under corresponding conditions. The comparison demonstrated that the dynamic in-situ measurement method reliably tracks transient temperature changes during heating and effectively verifies the heat-carrying capacity of the rotating target. This ensures the target plate temperature meets neutron source requirements, guaranteeing operational stability and safety for the facility.

The Super Tau-Charm Facility (STCF) is a new-generation electron-positron collider proposed in China. It will operate in a center-of-mass energy range from 2 to 7GeV with a luminosity of 0.5×1035 cm−2⋅ s−1 at 4GeV, serving as a powerful tool for studying the tau-charm physics. An electromagnetic calorimeter (ECAL) based on pure CsI crystals is a crucial sub-detector of the STCF detector, playing a key role in precise measurement of photon energy and position. A prototype of the STCF ECAL, consisting of an array of 5 × 5 pure CsI crystals coupled to avalanche photodiodes, was developed and tested with electron beams with energies ranging from 0.5 to 3.5GeV at CERN. This paper presents the composition of the calorimeter prototype and a comprehensive performance evaluation of the prototype with test beam data. The performance evaluation of the prototype with 1GeV electrons showed an energy resolution of approximately 2.4%, a position resolution of approximately 5.4 mm, and a time resolution of approximately 286ps. These results demonstrate that the prototype meets the performance requirements for the STCF ECAL and support the feasibility of the current design and technical approach for the full detector.

68Ge is produced through the proton irradiation of a Ga–Ni alloy target, where the gallium content directly influences the 68Ge yield. However, increasing the gallium content compromises the thermal stability of the target. TG-DSC combined with in-situ XRD demonstrated that when the gallium content exceeds 70

High-power space reactors utilizing liquid lithium as a coolant exhibit significant potential due to the high specific power, extended operational life, and reduced environmental dependence. A significant issue is that liquid lithium generates helium under core irradiation. Such phenomenon provokes challenges on separating and storing helium in a microgravity environment. To solve this problem, the current work proposes a specific design for a passive centrifugal Gas-Liquid Separator (GLS). The performance of the designed GLS was verified and validated by parametric investigations using computational fluid dynamics (CFD) techniques. The performance parameters, i.e., flow, separation, and gas-storage were analyzed in detail. The results confirmed that the stable separation and storage of helium can be achieved successfully by the GLS. The mechanisms of separation and gasstorage were revealed through dynamic gas-liquid interface variations, static pressure distribution, threedimensional streamlines, axial and tangential velocities, and velocity magnitudes. The characteristics of flow, separation, and gas-storage within the GLS were precisely identified. According to the analysis of the threedimensional flow field, gas within the gas-storage zone of the GLS exhibited stable and slow internal circulation, which was the critical indicator for maintaining effective gas-storage. Flow rate, helix angle (theta s) and height to diameter ratio (H/Ds) were critical parameters influencing the separation and gas-storage performance of GLS. Notably, with varying flow rates, separation efficiency and maximum gas storage mass exhibited opposite variation trends. Decreasing theta s can significantly enhance the separation and gas storage capabilities of the GLS. When the volume of gas-storage zone remains constant, variations in H/Ds lead to non-monotonic changes in tangential velocity and axial velocity, which lead to opposite effects on maximum gas storage mass and separation efficiency.

The utilization of a lithium-cooled nuclear power supply system in conjunction with the He-Xe Brayton power system has great potential for providing power for space exploration missions. This is primarily attributed to its notable characteristics, such as high energy density, substantial output power, long-duration operation cycle, and little vulnerability to environmental factors. One of the salient concerns that necessitates attention is the phenomenon of heat transfer occurring between liquid lithium and a mixture of helium and xenon (He-Xe). The Vertical Cross-Flow Corrugated Plate Heat Exchanger (VC-CPHE) constructed from W-alloy possesses several advantages in space reactor applications compared to other heat exchangers. These include its compact design, which allows for a large heat exchange surface, as well as its ability to shield gamma-ray radiation. This paper investigates the thermal hydraulic properties of the VC-CPHE internal heat transfer medium using Computational Fluid Dynamics (CFD) techniques. The results indicate that, due to the similar flow channel structure of Li and He-Xe, there are similarities in terms of flow direction and periodic distribution of parameters. Nevertheless, due to the distinct thermophysical properties and operational parameters, these materials demonstrate notable disparities in temperature boundary layers, local thermal resistance, and other relevant factors. Furthermore, the optimization of VC-CPHE involves a balancing act between enhancing heat transfer efficacy and minimizing flow resistance. The VC-CPHE demonstrates optimal balanced performance when the inlet cross-angle is set at 45 degrees. In comparison to Li, He-Xe exhibits elevated levels of thermal resistance and pressure loss. Hence, in the investigation of optimizing the corrugation pitch and inlet cross-angle, the optimal balanced size of corrugation pitch is 12 mm and inlet cross-angle is 45 degrees on He-Xe side is used as the final result. An increase in the inlet temperature difference of the heat exchanger leads to a slight decrease in the heat transfer coefficient, but an overall improvement in heat transfer. On the basis of obtaining the flow and heat transfer characteristics inside VC-CPHE, the effects of inlet cross-angle, corrugation pitch, and inlet temperature difference on the performance of VC-CPHE are discussed. The findings derived from the present study provide valuable insights for the future design and optimization of VC-CPHE systems in megawatt-class nuclear power deep space exploration spacecraft, particularly in relation to internal heat transfer.

The technology of nuclear reactors is evolving rapidly, driven by the pursuit of more powerful and efficient systems. The Small Lead-based Reactor (SLR) represents an advanced nuclear reactor design that holds great promise for delivering enhanced power and efficiency. In the context of the SLR's fuel rod, the high-speed coolant flow within the reactor can induce vibration, potentially causing fretting wear and damage to the cladding. This study utilized the Burgreen correlation to establish an equivalence relationship between water and Lead-Bismuth Eutectic (LBE). An experiment was then conducted to simulate axial flow-induced vibration (FIV) of a simply supported fuel rod, employing an equivalent water loop. Flow-induced vibration characteristics in both the time and frequency domains were investigated at different flow speeds. The experimental results revealed a positive correlation between flow velocity and amplitude. The fuel rod exhibited low-frequency vibrations with a random pattern, registering frequencies around 14 Hz. These experimental findings can be leveraged to enhance the accuracy of numerical simulations for axial flow-induced vibration (FIV) of the fuel rod. Subsequently, the revised numerical model was applied to simulate FIV in the LBE environment using computational fluid dynamics (CFD), and the numerical results were found to be in agreement with the experimental data.

The Super Tau-Charm Facility (STCF) is a significant initiative for accelerator-based particle physics in China. Electromagnetic Calorimeter (ECAL) is one of the important detectors of STCF, which is tasked with the accurate measurement of photons. STCF ECAL employs pure Cesium iodide (pCsI) as its scintillation crystal and uses a large-area avalanche photodiode (APD) as a photoelectric conversion device. High luminosity of STCF results in significant background levels, leading to pileups challenging conventional signal processing. In this paper, a pile-up correction algorithm called “pipeline optimal filtering” is proposed, and a background simulation platform is built to verify the measurement effect of the algorithm on energy and time.

Mobile micro-reactors, which used the liquid lead–bismuth eutectic (LBE) as coolants, providing energy to remote regions had become a popular topic in nuclear energy due to their desirable characteristics, including inherent safety and modularity. However, the liquid sloshing effect in a reactor may exhibit fluid–structure interaction (FSI) coupling effects, which could have a significant impact on the relevant internal systems. And the ratio of coolant in liquid to solid form was correlated with the duration of heat dissipation. This paper aimed to investigate the liquid sloshing effect in a micro-reactor that was subject to vehicle vibrations, the objective was to provide recommendations for transportation scenarios involving various liquid sloshing. To achieve this, a full-vehicle dynamic model of the system was developed using multi-body dynamics. Additionally, MATLAB simulation software was utilized to simulate the road roughness loadings that the micro-reactor may encounter during transportation. Moreover, a finite element numerical model of the Mobile Micro-reactor had been developed in order to simulate the sloshing effect that occurred during transportation, the numerical models presented in this study were validated by comparing them with a previously-verified Housner model that involved a cylindrical tank. This study investigated the sloshing effects of the Mobile Micro-reactor under different liquid–solid ratios of coolant, internal component lengths, and liquid surface heights. The results indicated that the internal components within the reactor vessel can alleviate the sloshing effect. The solid ratios of liquid lead–bismuth coolant and the liquid surface height during transportation had an impact on the sloshing effect. These findings provided valuable insights for studying the sloshing response of on-board reactors during liquid sloshing transportation.

A deuterium-tritium fusion neutron generator can produce high-intensity monoenergetic neutrons, which is important for the research and development of nuclear technology, and the neutron target is one of the crucial components of a neutron generator. For the neutron target, the most important technical index is the temperature of the target. Excessive temperature could impact the efficiency of nuclear reactions on the target surface and lead to target damage. Consequently, the thermal-hydraulic performance of the neutron target is significant for the performance of the neutron generator.In this paper, a curved channel with surface grooves was designed for the neutron target of a high-intensity neutron generator under design. The influence and mechanism of the curved angle and groove angle on the thermal-hydraulic performance of the minichannel were studied with the computational fluid dynamics method. The results indicated that a 45-deg curved channel with 135-deg surface grooves could enhance the turbulence within the minichannel, effectively improving the heat transfer performance of the neutron target with less pressure loss. Thus, the neutron target could withstand a higher-energy deuterium beam bombardment, increase neutron yield, and ease the pressure requirements on the cooling water pumps and sealing components.

The intricate internal structure of fuel rods results in a non-uniform mass distribution, making it imperative to employ analytical methods for accurate assessment. The study utilizes Euler beam theory to derive the transverse vibration equation for beams with varying mass distribution. The approach involves transforming the non-uniform mass beam into a multi-segment beam with concentrated mass points. Modal function relationships between adjacent uniform segments are established based on continuous conditions at connection points. This transformation leads to the conversion of the variable coefficient differential equation into a nonlinear matrix equation. The Newton-Raphson method is then applied to calculate the characteristic equation and mode shapes, essential for determining natural frequencies. To validate precision, the results obtained are compared with those derived from the finite element method. Furthermore, the developed method is employed to assess the impact of gas plenum location and length on the natural frequency of fuel rods. The proposed methodology serves as a rapid design tool, particularly beneficial during the design phase of fuel rods with non-uniform mass distribution, aiding in configuring structural aspects effectively.

Super Tau-Charm Facility (STCF) is a next-generation high luminosity electron–positron collider facility and is currently one of the major options for accelerator-based particle physics experiment in China. The crystal-based electromagnetic calorimeter (EMC) with undoped CsI is a major sub-system of the STCF spectrometer. To fulfill the increasing physics requirements on measurement precision and the suffering of radiation, improving the detected light yield is an important task of STCF EMC R&D. This paper studies a “wavelength shifting in propagation” scheme for STCF EMC using the nanostructured organosilicon luminophore (NOL). The studies are performed by both Monte Carlo simulation and experimental tests. The light yield is proved to be improved by 159% in the experiment. Meanwhile, a study of the NOL’s radiation hardness is carried out to verify the reliability of the NOL. No obvious degradation in the performance is observed with the total ionization dose up to 100krad, far beyond the total radiation dose of STCF with ten years of operation.

针对工业检测中越来越复杂的检测对象,单一无损检测手段难以得到全面信息,很难满足检测需求.为了解决以上问题,本文基于两种不同的射线成像无损检测装置,设计并实现了一套高精度双模式射线融合成像智能控制系统.提出了基于PLC(可编程逻辑控制器)与智能仪器的三级分布式控制系统架构,提高了系统的双向数据通信稳定性;利用WinCC平台开发了人机友好的操作界面,可对现场多设备进行远程参数调节与状态监测;设计了带反馈校正的定位精度自调节控制系统,实现了被检品高精度定位功能.经被检品重复定位实验验证,控制系统在两个射线成像装置间的重复定位精度为±0.06 mm,符合工业自动化领域±0.05～0.08 mm的定位精度要求,为双模式射线融合成像的高精度自动控制系统设计提供参考.

The mobile micro-reactors, as advanced nuclear systems, had the capability to provide energy to remote areas and islands. However, the non-uniform mass distribution characteristic of Liquid Lead-Bismuth Eutectic (LBE), which possessed a high density, substantial mass, and compact volume, mobile micro-reactors required special attention during transportation when mounted on trucks and passing through rough roads. This paper aimed to investigate the vibration responses of the mobile micro-reactor with non-uniform mass distribution during transportation. To achieve this, a separated model was developed using the Lagrange multi-body dynamic equations, the recorded responses data were evaluated using MATLAB, a numerical simulation software. Furthermore, a parametric study was conducted to examine the influence of the mass of LBE mass and the positions of the micro-reactor on the vibration responses during transportation. The results indicated that the mass of the micro-reactor was directly proportional to the vibration responses, and the responses could be different with the moveable situation of the reactor. This study demonstrated that the separated model could evaluate the transportation vibration responses of both the mobile micro-reactors and the truck more accurately, thereby facilitating the safe transportation of mobile micro-reactors with non-uniform mass distribution.

CuCrZr合金作为一种性能优异的高强高导合金,是强流氘氚中子源中子靶散热基底材料的最佳选择之一.中子靶的制备需要经过长时间的高温处理,工作时需要承受高能束流轰击产生很高的热载荷,对靶基底的散热性能和力学性能提出了很高的要求.本文研究了预时效对提高CuCrZr合金高温环境下组织和性能稳定性的作用及机制.结果表明,经过预时效处理,CuCrZr合金中析出了细小、弥散的富Cr相和Cu-Zr金属间化合物,提高材料热导率的同时有效抑制了第二相的长大,从而保证了CuCrZr合金具有良好的导热性能及高温力学性能,进而为中子靶散热基底的性能及寿命提供了保障.

半悬臂式燃料元件为上端固定、下端间隙限制的结构形式,该结构可节省使用和安装空间,具有在小型反应堆应用的潜力.相较于传统的两端固定结构,半悬臂式燃料元件下端呈现弱约束特性,在振动工况下存在碰撞接触非线性行为.针对间隙引起的非线性问题,采用弹支梁等效方法,将底端间隙配合等效为弹簧结构.本文将半悬臂式燃料元件的非线性振动过程通过单摆—悬臂梁模型进行等效,推导出半悬臂式燃料元件振动周期公式,结合弹支梁振动方程,可快速准确得到等效弹簧刚度,从而建立半悬臂式燃料元件在间隙限制约束下非线性振动的等效方法.通过半悬臂式燃料元件抗震分析,对本文方法与传统有限元方法进行对比,结果显示:该案例计算时间大幅度减少,本文计算方法所用时间仅为传统有限元方法的 1/74;两种方法的结果表明:在关键部位的振动响应基本一致,初步验证了本方法可快速有效求解具有间隙约束的半悬臂式燃料元件振动问题,为小型反应堆提供了快速设计工具.

Lead-Bismuth Eutectic (LBE) alloy is chosen as the one of the most promising coolants for Generation IV (GIV) nuclear system and accelerator-driven system (ADS) based on its good nuclear and thermal-physical properties. Due to the high thermal expansion performance, LBE has a significant natural circulation (NC) capability for the passive safety system, such as delay heat remove system. In this paper, LBE NC experiments under a transient state were carried out to study the following issues in KYLIN-II natural circulation loop: 1) Flow resistance rising suddenly; 2) loss of heat sink (LOHS). Analysis with the RELAP5 code was also performed to simulate the transient thermal-hydraulics characteristics under the above two issues. The calculated results agreed well with experimental data for the two transient experiments. The results also showed that the RELAP5 code’s feasibility for the analysis of the LBE system.

Space nuclear reactor power,with the advantages of high energy density,high output power,long duration,and minimal influence from the external environment,is the preferred route for energy supply for future high-power long-life space missions and deep space exploration missions.Based on the developmental requirements and characteristics of different design options for megawatt-class space nuclear reactors,a technical scheme for a megawatt-class small lithium-cooled space reactor is designed.This scheme uses a lithium-cooled reactor coupled with a Brayton power conversion system that is lightweight and durable.The key technologies involved in the design are reviewed.Developmental progress of technical analysis and demonstration,verification prototype systems,and experimental platforms is presented.Suggestions and comments for developing high-power space nuclear power in China in the future are presented.

The Super Tau-Charm Facility (STCF) is a high-luminosity electron-positron collider proposed in China. It will operate in the energy region of 2–7 GeV with a peak luminosity of at least 0.5×1035 cm−2 s−1, providing an excellent platform for studying the tau-charm physics. The STCF detector includes an electromagnetic calorimeter (EMC), which plays a crucial role in the accurate measurement of photon energy. To address the challenge of achieving superior photon energy resolution in the high-rate environment caused by the high luminosity, a fast-response EMC based on pure CsI crystals is proposed for the STCF experiment. In this paper, we present the conceptual design of a pure CsI EMC for STCF. The light yield of a pure CsI unit designed for the STCF EMC was measured using cosmic rays. Without considering the mechanical structures of the EMC and the sub-detectors in front of the EMC, the performance of the pure CsI based EMC was studied through Geant4 simulations incorporating the measured light yield, and the EMC design was optimized based on the results. The simulation was carried out under the condition of 100 p.e./MeV light yield and the high background environment anticipated in the STCF experiment. By employing a waveform fitting method, an energy resolution of better than 2.5% for 1 GeV photons was achieved, which satisfies the major performance requirement for the STCF EMC. However, validation studies should be conducted, including the contribution of different types of experimental backgrounds and the accuracy of the background counting rate.

Due to compact size, high power density, low cost and short construction time, the small modular reactors are considered as one of the candidate reactors, in which the power generation system is important with a compact heat exchanger for modular construction. Therefore, the effect of plate structure and nature of the working fluid on the thermal performance of plate heat exchanger are analyzed for the design of compact and efficient heat exchanger. The heat transfer rate, temperature counters, velocity vectors, and pressure drop have been optimized and investigated using FLUENT. The Nusselt number has been calculated for the corrugated and flat plate heat exchanger to validate the convective heat transfer. The numerical results are agreed well with correlation within deviation of ~5-7%. The performance of heat exchanger can be improved by controlling the mass-flow rate, and temperature of working fluid. The corrugation plate heat ex-changer increases the heat transfer rate 20% and effectiveness 23%, respectively, as compare to flat plate heat exchanger when the working fluid is water. In the case of air, heat transfer rate, and effectiveness are about 10% and 9%, respectively. The results show that the corrugated plate heat exchanger is more effective than the flat plate heat exchanger because corrugation pattern enhances the turbulence of fluids, which further increase heat transfer rate and coefficient. The selection of the working fluid and structure of the plate must be considered carefully for efficient and compact design of heat exchanger.