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Research on perturbation of neutron fluence rate in a closed thermal neutron field due to medium materials

nuclear Science and Techniques 2024年第10期35卷 222-232页

作者： Jun-Kai Yang Ping-Quan Wang Zhi-Meng Hu Fan Li Jun-Mei Zeng Lin Xiao Hong-Yu Guo Jian Zhang Giuseppe Gorini Hui Zhang Chungming Paul Chu College of Engineering and Applied Sciences Nanjing UniversityNanjing 210093China National Institute of Metrology Beijing 100029China Department of Nuclear Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210093China Department of Physics University of Milan-Bicocca20126 MilanItaly

The neutron radiation field has vital applications in areas such as biomedicine,geology,radiation safety,and many others for neutron detection and neutron *** neutron fluence rate perturbation accurately is an important yet challenging *** study proposes a correction method that analyzes three physical *** method,which transforms the detection process from point detection to area detection,is based on a novel physical model and has been validated through theoretical analyses,experiments,and *** to the average differences between the calculated and experimental results,the new method(1.67%)demonstrated better accuracy than the traditional simulation(2.17%).In a closed thermal neutron radiation field,the detector or strong neutron absorption material significantly perturbs the neutron fluence rate,whereas its impact on the energy spectrum shape and neutron directionality is relatively ***,based on the calculation results of the perturbation rate formula for medium materials with different compositions and sizes,the larger the volume and capture cross section of the medium,the higher the perturbation rate generated in the closed radiation field.

关键词： Perturbation rate Area detection Three-dimensional neutron energy spectrum Closed radiation field

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Research on Generation Mechanism and Variation Characteristics of Single-phase Ground Overvoltage in Medium Voltage Transmission Line

Research on Generation Mechanism and Variation Characteristi...

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2022 IEEE International Conference on High Voltage engineering and Applications, ICHVE 2022

作者： Zhao, Shenyuan Chen, Tianxiang Ren, Xinyue Xu, Huikai Yang, Bowen College of Nuclear Technology and Automation Engineering Chengdu University of Technology Sichuan Chengdu China

ISBN: (纸本)9781665407502

In the experimental research on the impact of 10-35kV wildfire and tree line faults on transmission lines, it was found that are grounding overvoltage were generated. This paper studies and analyzes the mechanism of overvoltage generation. The research analyzes the three-phase voltage and zero sequence voltage caused by overvoltage. Variation characteristics, when resonance occurs, the random voltage of one phase is less than the voltage of the other two phases, and the magnitude of this voltage is determined by the neutral point displacement voltage;the moment of arc overvoltage will cause the amplitude of the zero sequence voltage and the non-fault phase voltage to be rapid within 0.6ms, the fault phase voltage is lower than the rated voltage, and presents a power frequency cycle change trend. Modeling and simulation were carried out by PSCAD/EMPTC simulation software, and the variation characteristics of arc overvoltage between metal and high resistance grounding were verified. © 2022 IEEE.

关键词： Electric lines

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STARTUP ANALYSES OF A HELIUM-XENON GAS-COOLED REACTOR 30

STARTUP ANALYSES OF A HELIUM-XENON GAS-COOLED REACTOR

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30th International Conference on nuclear engineering, ICONE 2023

作者： Ma, Yugao Bao, Hui Lu, Jiahao Ding, Shuhua Zhang, Meng Yang, Xiaolong Deng, Jian Zhang, Muhao Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu610059 China

ISBN: (纸本)9784888982566

The Helium-Xenon (He-Xe) gas-cooled reactor uses a He-Xe gas mixture to remove the heat from the reactor core. It has the characteristics of a long life-cycle, simple operation, and high power-mass ratio, which has an excellent application prospect in the field of Space Reactors Power Systems. The high operation temperature distinguishes the He-Xe gas-cooled reactor from the traditional reactor in reactivity feedback characteristics. Except for the Doppler effect of the fuel and monolith, the thermal expansion also introduces reactivity feedback during reactor operation. In this work, reactivity feedback characteristics, steady-state characteristics, and transient characteristics of a hundred-kilowatt-level He-Xe gas-cooled reactor (Submersion-Subcritical Safe Space reactor, S4) were analyzed. The Doppler feedback characteristics and thermal expansion feedback coefficients of fuel, matrix, and reflector from the cold to the hot state of the S4 reactor core were calculated based on the reactor Monte Carlo code (RMC). The results show that the S4 reactor core is mainly affected by the fuel Doppler effect and the matrix thermal expansion effect. Furthermore, the temperature distributions of fuel and He-Xe gas of the S4 reactor were calculated using the He-Xe reactor transient analysis code (HXRTRAN). The transient characteristics of the S4 reactor core when different reactivity was introduced were analyzed. This study may provide a reference for the operation state of the He-Xe gas-cooled reactor. © 2023 by JSME.

关键词： Helium

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Research on the Influence of Different Wiring Methods on the Conversion Results of Transformer Low-Voltage no-Load Test 4

Research on the Influence of Different Wiring Methods on the...

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4th International Conference on Power and Energy technology, ICPET 2022

作者： Ren, Xinyue Zhao, Shenyuan Li, Weijia Chen, Tianxiang Chengdu University of Technology College of Nuclear Technology and Automation Engineering Chengdu Sichuan China

ISBN: (数字)9781665480796

ISBN: (纸本)9781665480796

The no-load test of the transformer is an important item of the power transformer insulation preventive test, but due to the limitation of the test conditions, the field test cannot reach the rated voltage. Usually, the no-load test data measured at low voltage is converted into the no-load loss under the rated voltage. Determine the transformer condition. In this paper, the no-load test of S7-50/35 three-phase oil-immersed power transformer through five different wiring methods, the no-load loss measured under low voltage is converted to the no-load loss under rated voltage, and the experimental research and analysis are carried out. The measurement error of no-load loss under six wiring methods is discussed, and the influence of different wiring methods on the conversion result of no-load loss is discussed. The research results show that the test is carried out under the rated voltage of 22.5%~32.5%, and when the wiring method is not connected to the neutral point or only connected to the neutral point of the power supply side, the no-load loss conversion error is the smallest, and the maximum error is 3%. © 2022 IEEE.

关键词： Electric transformer testing

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Analysis on Insulation Fault of Capacitor in 10kV Reactive Power Compensation Device 2

Analysis on Insulation Fault of Capacitor in 10kV Reactive P...

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2nd Asia Power and Electrical technology Conference, APET 2023

作者： Zeng, Chaoxu Yang, Bowen Chen, Tianxiang Yang, Longshan Wang, Meng Chen, Long Yang, Sen College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu China Jianyang Power Supply Company State Grid Chengdu China

ISBN: (纸本)9798350359428

Capacitor reactive power compensation plays an important role in improving system voltage stability, reducing transmission line losses and substation losses. In this paper, for the 10kV system of a 220kV substation, the capacitor external fuse protection all melted and the body burned accident, based on the faulty capacitor deconstruction, analyzed the main reasons for the capacitor insulation damage and the reasons for the expansion of the fault, calculation and analysis of the capacitor imbalance protection found that the setting value is unreasonable. Through the simulation software PSCAD/EMTDC to reproduce the fault process, the cause of the fault is verified, and finally to avoid the recurrence of the fault puts forward the corresponding processing recommendations. © 2023 IEEE.

关键词： Electric power transmission

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Verification of a self-developed CFD-based multi-physics coupled code MPC-LBE for LBE-cooled reactor

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nuclear Science and Techniques 2021年第5期32卷 84-100页

作者： Zhi-Xing Gu Qing-Xian Zhang Yi Gu Liang-Quan Ge Guo-Qiang Zeng Mu-Hao Zhang Bao-Jie Nie College of Nuclear Technology and Automation Engineering Chengdu University of TechnologyChengdu 610059China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China

To perform an integral simulation of a pool-type reactor using CFD code,a multi-physics coupled code MPC-LBE for an LBE-cooled reactor was proposed by integrating a point kinetics model and a fuel pin heat transfer model into self-developed CFD *** code verification,a code-to-code comparison was employed to validate the CFD ***,a typical BT transient benchmark on the LBE-cooled XADS reactor was selected for verification in terms of the integral or system *** on the verification results,it was demonstrated that the MPC-LBE coupled code can perform thermal-hydraulics or safety analyses for analysis for processes involved in LBE-cooled pool-type reactors.

关键词： LBE-cooled pool-type reactor Computational fluid dynamics Multi-physics coupling code Safety analysis code Verification

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Enhanced Brain Tumor Detection Using Transfer Learning with Fine-Tuned Efficientnet-B3 Blocks and Graph-Based Spatial Attention Capsule Networks 21

Enhanced Brain Tumor Detection Using Transfer Learning with ...

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21st International Computer Conference on Wavelet Active Media technology and Information Processing, ICCWAMTIP 2024

作者： Aggrey, Esther Stacy E.B Zhen, Qin Kodjiku, Seth Larweh Fiasem, Delali Linda Sey, Collins Ejiyi, Chukwuebuka Joseph Ntia, Nsikakabasi Williamson School of Information and Software Engineering University of Electronic Science and Technology of China Chengdu China School of Computer Science and Technology Zhejiang Gongshang University Hangzhou China College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu China

ISBN: (纸本)9798331519254

Brain tumors are critical medical conditions that require timely and accurate diagnosis to improve survival outcomes. This research proposes a cutting-edge framework for brain tumor classification, combining fine-tuned EfficientNet-B3 blocks with graph-based spatial attention capsule networks. By addressing challenges such as limited data availability, overfitting, and the complex nature of tumor structures, the framework employs partial transfer learning, advanced feature extraction, and attention mechanisms to effectively model spatial relationships in MRI images. Evaluated on a dataset of 3,064 contrast-enhanced brain MRI images, the model demonstrated exceptional performance, achieving 99.85% classification accuracy and notable improvements in precision, recall, and F1 scores for glioma, meningioma, and pituitary tumours. The use of advanced data augmentation techniques significantly improved the model's ability to generalize, while its computational efficiency makes it well-suited for clinical diagnostic applications. © 2024 IEEE.

关键词： Dynamic contrast enhanced MRI

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Experimental Investigations of Quasi-Coherent Micro-Instabilities in J-TEXT Ohmic Plasmas

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Chinese Physics Letters 2024年第5期41卷 47-52页

作者：石鹏庄革程芝峰高丽周乙楠刘永罗景庭李景春 Institute of Plasma Physics Chinese Academy of SciencesHefei 230031China International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China Department of Engineering and Applied Physics School of Physical Sciences University of Science and Technology of ChinaHefei 230026China Shenzhen Key Laboratory of Nuclear and Radiation Safety Institute for Advanced Study in Nuclear Energy&SafetyCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 510640China

Quasi-coherent micro-instabilities is one of the key topics of magnetic confinement fusion. This work focuses on the quasi-coherent spectra of ion temperature gradient(ITG) and trapped-electron-mode instabilities using newly developed far-forward collective scattering measurements within ohmic plasmas in the J-TEXT *** ITG mode is characterized by frequencies ranging from 30 to 100 k Hz and wavenumbers(k_(θρs)) less than 0.3. Beyond a critical plasma density threshold, the ITG mode undergoes a bifurcation, which is marked by a reduction in frequency and an enhancement in amplitude. Concurrently, enhancements in ion energy loss and degradation in confinement are observed. This ground-breaking discovery represents the first instance of direct experimental evidence that establishes a clear link between ITG instability and ion thermal transport.

关键词： ITG mode collective

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Research on Performance Computer Evaluation Model of Low-Temperature Protective Clothing Based on Explicit Difference Method 2

Research on Performance Computer Evaluation Model of Low-Tem...

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2nd IEEE International Conference on Data Science and Computer Application, ICDSCA 2022

作者： Deng, Hui Sun, Yiqing The College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu Sichuan610059 China

ISBN: (数字)9781665472005

ISBN: (纸本)9781665472005

At present, the research institute has developed a three-layer low-temperature protection composite material. Low-temperature protective materials are mainly used for short-term low-temperature protection, effectively reducing the harm of the external environment to the human body. In this paper, considering that the heat release capacity of the phase change layer is different at different temperatures, according to the data of heat release capacity and temperature of protective materials, the change of heat release capacity Q and field temperature T is fitted by Fourier function, and the functional relationship of material heat release is obtained. Therefore, the model is divided into three stages and calculated separately. In the first stage, there is no self-heating or internal heat source in the three-layer materials, so according to the law of conservation of energy and Fourier law, the unsteady heat conduction formula is deduced and solved. In the second stage, the phase change layer begins to release heat, and the first stage model is added to each layer's heat conduction control equation with heat release capability. The third stage is similar to the first stage. With the help of the explicit difference method, the model is discretized, and the cooling model of materials is solved to effectively evaluate the protective ability of low-temperature protective composites. © 2022 IEEE.

关键词： Phase change materials

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Automated Production Line Control System based on Industrial Cloud Platform

Automated Production Line Control System based on Industrial...

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2022 International Conference on Intelligent Manufacturing and Industrial automation, CIMIA 2022

作者： Liu, JianQin Li, LinLin Qu, Tao He, HuiDong The College of Nuclear Technology and Automation Engineering Chengdu University of Technology Sichuan Chengdu610059 China

ISBN: (纸本)9781510655966

With the rapid development of modern industry, enterprises have an increasing demand for data monitoring and automated control of multiple production outlets and production lines. This paper first analyses the structure of the production line, completes the control system model design, establishes the network framework of the system, designs the human-machine interaction interface, gives the SFC flow chart of the workstations and the communication scheme of the PLC between each station, and finally realises the real-time interaction of the monitoring data in the industrial cloud platform. The research contributes new ideas to related research in this field. © 2022 SPIE.

关键词： Control systems

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