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Effect of grain size on gas bubble evolution in nuclear fuel:Phase-field investigations

Chinese Physics B 2024年第1期33卷 563-572页

作者：孙丹杨青峰赵家珺高士鑫辛勇周毅尹春雨陈平赵纪军王园园 Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China Key Laboratory of Materials Modification by Laser Ionand Electron BeamsDalian University of TechnologyDalian 116024China

Numerous irradiation-induced gas bubbles are created in the nuclear fuel during irradiation, leading to the change of microstructure and the degradation of mechanical and thermal properties. The grain size of fuel is one of the important factors affecting bubble evolution. In current study, we first predict the thermodynamic behaviors of point defects as well as the interplay between vacancy and gas atom in both UO_(2) and U_(3)Si_(2) according to ab initio approach. Then, we establish the irradiation-induced bubble phase-field model to investigate the formation and evolution of intra-and inter-granular gas bubbles. The effects of fission rate and temperature on the evolutions of bubble morphologies in UO_(2) and U_(3)Si_(2) have been revealed. Especially, a comparison of porosities under different grain sizes is examined and analyzed. To understand the thermal conductivity as functions of grain size and porosity, the heat transfer capability of U_(3)Si_(2) is evaluated.

关键词： grain size point defects fission gas bubble

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Development and verification of the higher-order mode neutron flux calculation code HARMONY2.0

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Nuclear Science and Techniques 2025年第1期36卷 207-225页

作者： Er-Pin Zhang Zi-Ning Ni Nian-Biao Deng Jin-Sen Xie Yong Liu Tao Yu School of Nuclear Science and Technology University of South ChinaHengyang 421000China Key Laboratory of Advanced Nuclear Energy Design and Safety Ministry of EducationHengyang 421000China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

Higher-order modes of the neutron diffusion/transport equation can be used to study the temporal behavior of nuclear reactors and can be applied in modal analysis, transient analysis, and online monitoring of the reactor core. Both the deterministic method and the Monte Carlo(MC) method can be used to solve the higher-order modes. However, MC method, compared to the deterministic method, faces challenges in terms of computational efficiency and α mode calculation stability, whereas the deterministic method encounters issues arising from homogenization-related geometric and energy spectra *** on the higher-order mode diffusion calculation code HARMONY, we developed a new higher-order mode calculation code, HARMONY2.0, which retains the functionality of computing λ and α higher-order modes from HARMONY1.0, but enhances the ability to treat complex geometries and arbitrary energy spectra using the MC-deterministic hybrid two-step strategy. In HARMONY2.0, the mesh homogenized multigroup constants were obtained using OpenMC in the first step,and higher-order modes were then calculated with the mesh homogenized core diffusion model using the implicitly restarted Arnoldi method(IRAM), which was also adopted in the HARMONY1.0 code. In addition, to improve the calculation efficiency, particularly in large higher-order modes, event-driven parallelization/domain decomposition methods are embedded in the HARMONY2.0 code to accelerate the inner iteration of λ∕α mode using OpenMP. Furthermore, the higher-order modes of complex geometric models, such as Hoogenboom and ATR reactors for λ mode and the MUSE-4 experiment facility for the prompt α mode, were computed using diffusion theory.

关键词： Neutron diffusion equation Higher-order modes Global homogenization Two-step method Domain

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Atomistic study on the microscopic mechanism of grain boundary embrittlement induced by small dense helium bubbles in iron

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Nuclear Science and Techniques 2024年第3期35卷 84-95页

作者： Lei Peng Yong-Jie Sun Jing-Yi Shi Yi-Fei Liu Shang-Ming Chen Liu-Liu Li State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230027China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

The helium bubbles induced by 14 MeV neutron irradiation can cause intergranular fractures in reduced activation ferritic martensitic steel,which is a candidate structural material for fusion *** order to elucidate the susceptibility of different grain boundaries(GBs)to helium-induced embrittlement,the tensile fracture processes of 10 types of GBs with and without helium bubbles in body-centered cubic(bcc)iron at the relevant service temperature of 600 K were investigated via molecular dynamics *** results indicate that in the absence of helium bubbles,the GBs studied here can be classified into two distinct categories:brittle GBs and ductile *** atomic scale analysis shows that the plastic deformation of ductile GB at high temperatures originates from complex plastic deformation mechanisms,including the Bain/Burgers path phase transition and deformation twinning,in which the Bain path phase transition is the most dominant plastic deformation ***,the presence of helium bubbles severely inhibits the plastic deformation channels of the GBs,resulting in a significant decrease in elongation at *** bubble-decorated GBs,the ultimate tensile strength increases with the increase in the misorientation ***,the coherent twin boundary∑3{112}was found to maintain relatively high fracture strength and maximum failure strain under the influence of helium bubbles.

关键词： Helium bubble Grain boundary Embrittlement Reduced activation ferritic martensitic steel Molecular dynamics Bain path

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Surface-PMSM Sensorless Control Strategy Based on Reduced-Order Linear Kalman Filter Cooperating with Prediction Error Rolling Compensation

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IEEE Transactions on Power Electronics 2025年第8期40卷 10804-10815页

作者： Xu, Sang Shen, Anwen Tang, Qipeng Wang, Miaomiao Luo, Pan Luo, Xin Xu, Jinbang National Key Laboratory of Science and Technology on Multispectral Information Processing Key Laboratory of Image Processing and Intelligent Control School of Artificial Intelligence and Automation Wuhan430074 China Science and Technology on Reactor System Design Technology Laboratory Chengdu China

Kalman filter (KF) is increasingly attracted for sensorless control of surface permanent magnet synchronous motors (SPMSMs) due to its strong robustness against measurement and system noise. However, conventional method suffers from poor position and speed estimation accuracy under dynamic conditions, and high computational cost. In order to solve these problems, an enhanced sensorless control strategy based on reduced-order linear Kalman filter (RLKF) cooperating with prediction error rolling compensation is introduced in this paper. Differing from conventional method, a reduced-order linear state equation encompassing rotor position, speed and torque disturbance is constructed. Then, by obtaining the prediction error of system output using the motor current equation in the predictive reference frame, the optimal estimation of rotor position and speed in KF algorithm is achieved based on the reduced-order model. This not only simplifies the calculation process, but also enhances the position and speed estimation accuracy under dynamic conditions. Meanwhile, a prediction error rolling compensation algorithm is developed to minimize the estimation deviations caused by motor parameters variations. Additionally, the system's dynamic performance is further improved with an adopted speed controller based on torque disturbance feedforward and acceleration feedback. Finally, experimental results verify the effectiveness and feasibility of the proposed strategy.1 © 1986-2012 IEEE.

关键词： Permanent magnets

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MAHTD-DDPG-Based Multi-Objective Resource Allocation for UAV-Assisted Wireless Network

IEEE Journal on Miniaturization for Air and Space Systems

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IEEE Journal on Miniaturization for Air and Space systems 2024年第2期6卷 1-1页

作者： Sun, Wentao Li, Zan Shi, Jia Bai, Zixuan Wang, Feng Quek, Tony Q. S. School of Telecommunications Engineering State Key Laboratory of Integrated ServiceNetworks Xidian University Xi’an China Information System Technology and Design Pillar University of Technology and Design Singapore

As an aerial base station (BS), unmanned aerial vehicle (UAV) has been considered as a promising platform to provide wireless data service in future networks due to its flexible, swift and low cost features. However, since the suddenness and randomness of ground users’ (GUs’) data requirements, it is challenging for the UAV BSs to dynamically make decisions to provide real-time data services to GUs. In a multi-mode UAV-assisted wireless network, we formulate a multi-objective optimization problem to minimize the average peak age of information (APAoI) and energy consumption of UAVs, and to maximize the accumulated service data (ASD) for GUs. Therefore, this paper proposes the multi-agent hybrid twin delayed deep deterministic policy gradient (MAHTDDDPG) algorithm with hybrid action space design, which is empowered by centralized training and distributed execution (CTDE) framework. In the proposed algorithm, the UAVs can cooperatively make decisions by sharing the GU status information, in a result of jointly optimizing the UAV trajectory, mode selection and transmit power. Simulation results demonstrate that our proposed approach achieves 79.6% and 120.4% higher reward than MADDPG algorithm and HTD-DDPG algorithm respectively. IEEE

关键词： Heuristic algorithms

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RESEARCH ON INTEGRATED VIBRATION ISOLATION AND VIBRATION ABSORPTION FOR PUMP EQUIPMENT 30

RESEARCH ON INTEGRATED VIBRATION ISOLATION AND VIBRATION ABS...

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30th International Congress on Sound and Vibration, ICSV 2024

作者： Zhaowen, Li Longqi, Cai Yu, Wang Lizhi, Liu Jianyong, Lai National Key Laboratory of Reactor System Design Technology Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9789090390581

Pump equipment is the main source of vibration and noise during ship operation, and there are distinct characteristic line spectra at various transmission paths, which is not conducive to vibration reduction and noise control of ship system. Therefore, this paper focuses on a type of pump with significant vibration and prominent 50Hz characteristic line spectrum. It conducts research on integrated vibration isolation and vibration absorption based on floating raft isolation and dynamic vibration absorbers. The feasibility of above scheme was verified by the research on floating raft structure design, research on dynamic vibration absorber parameters, and analysis of vibration reduction and absorption effects. This paper provides a great measure to reduce the delivery of vibration and control line spectrum feature of one frequency of pump equipment. © 2024 Proceedings of the International Congress on Sound and Vibration. All rights reserved.

关键词： Vibration analysis

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Annealing-induced gradient nanostructured FeCrAlTiMo high-entropy alloy coatings with significantly enhanced wear resistance

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Tungsten 2024年第3期6卷 544-548页

作者： Jian Yang Ming-Yang Zhou Ji-Jun Yang Key Laboratory of Radiation Physics and Technology of Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

Recently,the amorphous high-entropy alloy(HEA)coatings exhibit an impressive resistance to the lead–bismuth eutectic(LBE)corrosion and ion irradiation,showing great application potential for lead-cooled fast reactors... 详细信息

关键词： alloy resistance wear

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Microstructure and Mechanical Properties of B-Bearing Austenitic Stainless Steel Fabricated by Laser Metal Deposition In-Situ Alloying

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Acta Metallurgica Sinica(English Letters) 2022年第3期35卷 453-465页

作者： Sheng Huang Xiaoyu Zhang Dichen Li Qingyu Li State Key Laboratory for Manufacturing Systems Engineering Xian Jiaotong UniversityXian 710049China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

In the field repair application of laser metal deposition(LMD),the kinds of powder materials that can be used are limited,while the equipment components are made of various *** many components have to be repaired with heterogeneous ***,it is difficult to match the mechanical properties between the repaired layer and the substrate due to the diff erent *** on the high flexibility of raw materials and processes in LMD,an in-situ alloying method is proposed herein for tailoring the mechanical properties of LMDed *** diff erent mixing ratios of Fe314 and 316 L stainless steel powders as the control parameter,the microstructure and mechanical properties of B-bearing austenitic stainless steel fabricated by LMD in-situ alloying with diff erent proportions of Fe314 and 316 L particles were *** the increase in the concentration of 316 L steel,the volume fraction of the eutectic phase in deposited B-bearing austenitic stainless steel reduced,the size of the austenite dendrite increased,the yield strength and ultimate tensile strength decreased monotonically,while the elongation increased ***,the fracture mode changed from quasi-cleavage fracture to ductile *** adding 316 L powder,the yield strength,tensile strength,and elongation of deposited B-bearing austenitic stainless steel could be adjusted within the range of 712 MPa–257 MPa,1325 MPa–509 MPa,and 8.7%–59.3%,***,this work provides a new method and idea for solving the performance matching problem of equipment components in the field repair.

关键词： Additive manufacturing Laser metal deposition In-situ alloying B-bearing austenitic stainless steel Mechanical properties

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Research and development of helium-xenon Brayton cycle technology:A review

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National Science Open 2024年第6期3卷 188-218页

作者： Weixiong Chen Meihui Song Yiran Qian Hongxing Yu Junjie Yan State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China Key Laboratory of Nuclear Reactor System Design Technology Nuclear Power Institute of ChinaChengdu 610200China

Helium-xenon Brayton cycle systems have significant potential as the energy conversion system for small-scale reactors in remote land,deep-sea,and space applications due to a range of advantages,including high cycle efficiency,compact system structures,and chemical *** objective of this review is to provide a comprehensive understanding of the helium-xenon Brayton cycle system based on the projects and ***,the basic information and development history are introduced,and a series of typical designs are ***,the system configurations,cycle parameter analysis and optimization are ***,the key components are classified,such as turbine,compressor,and heat ***,the dynamic processes and control strategies are introduced in different ***,the deficiency and prospect of current research are *** review covers the representative helium-xenon Brayton cycle systems,which could provide a reference for promoting the development of energy conversion systems.

关键词： helium-xenon Brayton cycle cycle analysis heat exchanger dynamic research

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Fretting Wear Characteristics of Nuclear Fuel Cladding in High-Temperature Pressurized Water

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Chinese Journal of Mechanical Engineering 2023年第4期36卷 326-338页

作者： Jun Wang Haojie Li Zhengyang Li Yujie Lei Quanyao Ren Yongjun Jiao Zhenbing Cai Key Lab of Advanced Technologies of Materials Tribology Research InstituteSouthwest Jiaotong UniversityChengdu 610031China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

In pressurized water reactor(PWR),fretting wear is one of the main causes of fuel assembly ***,the operation condition of cladding is complex and harsh.A unique fretting damage test equipment was developed and tested to simulate the fretting damage evolution process of cladding in the PWR *** can simulate the fretting wear experiment of PWR under different temperatures(maximum temperature is 350℃),displacement amplitude,vibration frequency,and normal *** fretting wear behavior of Zr-4 alloy under different temperature environments was *** addition,the evolution of wear scar morphology,profile,and wear volume was studied using an optical microscope(OM),scanning electron microscopy(SEM),and a 3D white light *** show that higher water temperature evidently decreased the cladding wear volume,the wear mechanism of Zr-4 cladding changed from abrasive wear to adhesive wear and the formation of an oxide layer on the wear scar reduced the wear volume and maximum wear depth.

关键词： Fretting wear Cladding High temperature and high pressure Zirconium alloy

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