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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Zhang, Xiaolong Yu, Jiyang Huang, Tao Jiang, Guangming Zou, Zhiqiang Department of Engineering Physics Tsinghua University Beijing100084 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9784888983051

This paper presents the hydrogen risk analysis of a large Pressurized Water reactor (PWR) undergoing a severe accident using the HYDRAGON code. The code has been developed by the Department of Engineering Physics, Tsinghua University, as a hydrogen risk analysis software specialized for containment building of nuclear reactor power plants. The chemical interaction between zirconium cladding of the fuel rods and overheated coolant may release hydrogen when severe accidents occur in PWRs. The hydrogen mixed with air existing in containment may jeopardize the integrity of containment building if the flammable mixture explodes. In order to mitigate the hydrogen risk, many nuclear power plants install the Passive Autocatalytic Recombiners (PARs) that allow hydrogen and oxygen react chemically at low temperature without any sights of flame. Recombiners remove hydrogen and thereby prevent explosions. This work simulated the gas diffusion behaviors during the accident in the containment of a large PWR. The simulations obtained spatial concentration distribution of various gas species including hydrogen, oxygen, steam and nitrogen and several key parameters that are required to complete hydrogen burning and explosion investigation. Sensitivity analyses of recombiners' quantity and positions and hydrogen discharge intensity provides the reference for hydrogen mitigation measure design in the containment. The results demonstrate that the number of recombiners rather than positions has stronger influences on hydrogen mitigation. Since the installation position reflects less sensitivity, the recombiners could be arranged as higher as possible if necessary. Copyright © 2018-2019 by JSME

关键词： Hydrogen

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High-accuracy time synchronization method in highly reliable fiber-channel communication system 27

High-accuracy time synchronization method in highly reliable...

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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Chen, Qi Jiang, Wei Tu, Xiaodong Yu, Bo Liu, Mingxing Zhang, Xu Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China School of Information and Communication Engineering University of Electronic Science and Technology of China Chengdu Sichuan China

ISBN: (纸本)9784888983051

Accompanied with strict requirements on accuracy and determinacy in nuclear power industrial safety Digital Control system (DCS), time-triggered technology has been used in Ethernet widely, while another network protocol, Fiber-Channel (FC) protocol which is popular in avionic electronic systems with hyper reliability in port to port communication stands still, even though the optical fiber cable is quite adopted by other protocols like Ethernet. One important reason is the lack of the capability to handling time sensitive tasks in FC protocol itself. In order to bring Fiber-Channel protocol into real-time applications, like safety DCS for nuclear industry, with the situation that there are pretty few researches on the time synchronization in FC protocol, this paper makes fundamental research on the solution to achieve high-accuracy time synchronization in FC protocol networks, which has been proved a vital important step to realize real time communication according to Time-Triggered Ethernet (TTE)(H. Kopetz al, 2005). By analyzing current Fiber-Channel network time communication strategies and demo-boards testing, this paper designs a method to achieve the same level or better synchronization accuracy in FC network with that in TTE, which figures out a new direction in this blank field of time synchronization in FC protocol. Furthermore, this method only asks for few resources and slight modifications on current communications for future development and improvement. Copyright © 2018-2019 by JSME

关键词： Accident prevention

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A comprehensive comparison of micro heterojunction thermoelectric generators based on a carrier transport model

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International Journal of Heat and Mass Transfer 2023年 217卷

作者： Lin, Lin Jing, Zhen-Hua Zheng, Shao-Fei Chen, Wei-Hsin Lee, Duu-Jong Wang, Xiao-Dong School of Energy and Environmental Engineering University of Science and Technology Beijing Beijing100083 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing102206 China Researcher Center of Engineering Thermophysics North China Electric Power University Beijing102202 China Department of Aeronautics and Astronautics National Cheng Kung University Tainan701 Taiwan Department of Mechanical Engineering City University of Hong Kong Kowloon Tong999077 Hong Kong Department of Chemical Engineering & Materials Science Yuan Ze University Chung-Li32003 Taiwan

To be a crucial aspect in the performance of thermoelectric generators, carrier transport in thermoelectric materials cannot be captured by existing multiphysics models. In this work, a carrier transport model for heterojunction thermoelectric generators (TEG) is developed with the drift-diffusion equation comprehensively considering the effect of carrier mobility on the current density. Subsequently, based on the concept of inverse- and homo-heterojunction, three micro TEG are designed considering Si and Si0.7Ge0.3 bases with the doped boron and arsenic and compared with the original design for revealing the effects of load resistance and temperature difference on the thermoelectric performance. It has been demonstrated that for homo-heterojunction, the thermoelectric power and conversion efficiency are significantly improved at hot temperatures from 600 to 1000 K, with a maximum improvement of 18.09% compared to the conventional TEG. For inverse-heterojunction, the optimal temperature of the thermoelectric performance is 1100–1300 K, and its efficiency is 23.50% higher than that of the conventional TEG. Both the doping impurity ionization and intrinsic carrier excitation contribute to a high density of majority carriers and are responsible for the better performance of homo-heterojunction at low working temperatures. For inverse-heterojunction, a high working temperature can significantly promote the excitation of minority carriers because of the built-in electric field and leads to better performance. Finally, we propose a novel heterojunction by combining both homo- and inverse-heterojunction which can improve thermoelectric efficiency by up to 27.72%. © 2023 Elsevier Ltd

关键词： Thermoelectric equipment

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Effects of heaving condition on characteristics of system under forced circulation and natural circulation 27

Effects of heaving condition on characteristics of system un...

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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Cai, Rong Mi, Zhengpeng Yue, Nina Fang, Hongyu Qiu, Suizheng Wang, Kai Qiu, Zhifang Science and Technology on Reactor System Design Technology Laboratory Chengdu China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Chengdu China Xi'an Jiaotong University Xi'an Shaanxi China Department of Nuclear Engineering and Management School of Engineering University of Tokyo Tokyo Japan

ISBN: (纸本)9784888983051

Under ocean conditions, the nuclear power plants have complex movements due to the effects of wind and wave. The thermal-hydraulic characteristics of the nuclear power plants under ocean conditions are influenced by its various motions. To ensure the safety of the reactor, the research on the effects of various motions on its thermal-hydraulic characteristics are necessary. The previous research has shown that heaving condition has more serious effects on the thermal-hydraulic characteristics of the nuclear power plants. In this paper, a thermal-hydraulic system code for ocean conditions named STAC was developed, and the STAC code was validated by test data. The effects of heaving conditions on the thermal-hydraulic characteristics of the system under forced circulation and natural circulation are studied with the STAC code. The simulation results show that the thermal parameters of the reactor system under heaving condition fluctuate periodically, and the fluctuation period is the same as the heaving period. The delay of the variation of circuit flow and the thermal inertia of the fuel material cause a phase difference between the fluctuations of the thermal parameters of reactor core. Heaving motion has less effect on the nuclear power system under forced circulation than that under natural circulation. As the amplitude of the acceleration increases, the fluctuation amplitudes of thermal-hydraulic parameters in the nuclear power system increase. Under heaving condition with short period, the fluctuation amplitudes of thermal-hydraulic parameters are affected by the heaving period. With the increase of the fluctuation period, the fluctuation amplitudes of thermal-hydraulic parameters increase gradually, and finally approach certain values. Copyright © 2018-2019 by JSME

关键词： Nuclear power plants

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Global Dynamics and Optimal design of a New Highly Efficient Nonlinear Energy Sink Based on Magnetic-Elastic Impacts with Negative Stiffness

Research Square

引用

Research Square 2021年

作者： Li, Shuangbao Wang, Tingting Chen, Jianen Research Institute of Science and Technology Innovation Civil Aviation University of China Tianjin300300 China College of Science Civil Aviation University of China Tianjin300300 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

A new highly efficient elastic-impact bistable nonlinear energy sink (EI-BNES) based on magnetic-elastic impacts with negative stiffness and bistability is proposed and optimized through global dynamical analysis. The EI-BNES has better robustness and higher energy dissipation rates with nearly more than 96.5% for broadband impulsive excitations than the traditional cubic NESs and single bistable NESs. The structure of negative stiffness impacts is realized by reasonable layout of permanent ring magnets and springs. A two-degree-of-freedom (two-DOF) elastic-impact system is established to describe the coupled nonlinear interaction between the main structure and the attached EI-BNES. A global Melnikov reduction analysis (GMRA) is proposed to study global dynamics and homoclinic bifurcations of the reduced two-dimensional subsystem, which is used to explain the mechanism of nonlinear targeted energy transfer (TET) and detect the threshold of impulsive amplitudes of EI-BNES for in-well and compound motions between in-well and cross-well resonance responses. A special type of saddle-center equilibrium points is also found in the non-smooth system of the EI-BNES and can be used to effectively increase the energy dissipation rates. The optimal design criterion of the tuned EI-BNES for better dissipation performance is also first discussed based on the GMRA and numerical techniques for calculating the Melnikov function of the non-smooth systems. The effectiveness of the analytical GMRA is also verified by numerical simulations. © 2021, CC BY.

关键词： Stiffness

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The Qitai Radio Telescope

arXiv

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arXiv 2023年

作者： Wang, Na Xu, Qian Ma, Jun Liu, Zhiyong Liu, Qi Zhang, Hailong Pei, Xin Chen, Maozheng Manchester, Richard N. Lee, Kejia Zheng, Xingwu Kärcher, Hans J. Zhao, Wulin Li, Hongwei Li, Dongwei Süss, Martin Reichert, Matthias Zhu, Zhongyi Wang, Congsi Li, Mingshuai Li, Rui Li, Ning Kazezkhan, Guljaina Yan, Wenming Wu, Gang Cui, Lang Zhang, Ming Li, Haitao Xinjiang Astronomical Observatory Chinese Academy of Sciences Urumqi830011 China Key Laboratory of Radio Astronomy Chinese Academy of Sciences Nanjing210008 China Xinjiang Key Laboratory of Radio Astrophysics Urumqi830011 China Xinjiang Key Laboratory of Microwave Technology Urumqi830011 China Australia Telescope National Facility CSIRO Space and Astronomy PO Box 76 EppingNSW1710 Australia Department of Astronomy Peking University Beijing100871 China School of Astronomy and Space Science Nanjing University Nanjing210093 China Dr. Hans Jürgen Kärcher Engineering Office Karben61184 Germany Northwest China Research Institute of Electronic Equipment Xi’an710065 China Mainz55130 Germany Beijing Institute of Architectural Design Beijing100045 China Xidian University Guangzhou Institute of Technology Guangzhou510555 China

This study presents a general outline of the Qitai radio telescope (QTT) project. Qitai, the site of the telescope, is a county of Xinjiang Uygur Autonomous Region of china, located in the east Tianshan Mountains at an elevation of about 1800 m. The QTT is a fully steerable, Gregorian-type telescope with a standard parabolic main reflector of 110 m diameter. The QTT has adopted an umbrella support, homology-symmetric lightweight design. The main reflector is active so that the deformation caused by gravity can be corrected. The structural design aims to ultimately allow high-sensitivity observations from 150 MHz up to 115 GHz. To satisfy the requirements for early scientific goals, the QTT will be equipped with ultra-wideband receivers and large field-of-view multi-beam receivers. A multi-function signal-processing system based on RFSoC and GPU processor chips will be developed. These will enable the QTT to operate in pulsar, spectral line, continuum and Very Long Baseline Interferometer (VLBI) observing modes. Electromagnetic compatibility (EMC) and radio frequency interference (RFI) control techniques are adopted throughout the system design. The QTT will form a world-class observational platform for the detection of low-frequency (nanoHertz) gravitational waves through pulsar timing array (PTA) techniques, pulsar surveys, the discovery of binary black-hole systems, and exploring dark matter and the origin of life in the universe. The QTT will also play an important role in improving the Chinese and international VLBI networks, allowing high-sensitivity and high-resolution observations of the nuclei of distant galaxies and gravitational lensing systems. Deep astrometric observations will also contribute to improving the accuracy of the celestial reference frame. Potentially, the QTT will be able to support future space activities such as planetary exploration in the solar system and to contribute to the search for extraterrestrial intelligence. © 2023, CC BY.

关键词： Ultra-wideband (UWB)

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Reform and Practice in Experimental Teaching from the View of "Emerging Engineering": Case Study on the Field of Energy and Power Engineering

Reform and Practice in Experimental Teaching from the View o...

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Information Communication Technologies Conference (ICTC)

作者： He Tian Lijian Liu Miao Tian Shimin Zhou Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) School of Mechanical Engineering Tianjin University of Technology Tianjin China Tianjin Academy of Educational Science Tianjin China Tianjin Newborn New Energy Technology Co. Ltd Tianjin China

According to the idea of "Emerging Engineering Education" talent training model of Ministry of Education, students should be trained to have "metaphysical" concept, connection, imagination, macro thinking. Project-driven experiment teaching focuses on a project, and the goal is the completion of the project; the student is the center of teaching activities, which is supported by the inquiry process. This study analyzes the significance of the project-driven method in experimental teaching. This paper describes the implementation process of experimental teaching in the field of energy and power engineering in terms of project design, teaching system construction and so on under the project-driven method. By analyzing the results of a questionnaire survey distributed to students of energy and power in the College of Mechanical Engineering at the Tianjin University of technology, it is found that the students are satisfied with the effects of project-driven experimental teaching, and the use of experimental teaching has greatly aroused the students' enthusiasm for learning. The ability of the students to engage in autonomous learning, engineering practice and innovation has been greatly improved, and a good teaching effect has been achieved.

关键词： Training Power engineering Technological innovation Education Solids Communications technology Mechanical engineering

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An Approach on Visual Detecting Multi-Targets in the Unstructured and Complex Scenes Based on RGB-D Images 5

An Approach on Visual Detecting Multi-Targets in the Unstruc...

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5th International Conference on Automation, Control and Robotics Engineering, CACRE 2020

作者： Tan, Qimeng Sun, Yikun Xin, Pengfei Lin, Yimin Ma, Chao Wang, Xinyu Beijing Institute of Spacecraft System Engineering Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing China Beijing Special Engineering Design and Research Institute Propellant Injection Laboratory Beijing China Beijing University of Posts Telecommunications Institute of Optical Communication Optoelectronics Beijing China Beijing Information Science and Technology University School of Instrument Science and Optoelectronic Engineering Beijing China

ISBN: (纸本)9781728198880

The technology of detecting and identifying multitarget is of significance for robotic visual navigation within the unknown, unstructured, complex scenes, whose result could be considered as important references of 3D map building and path planning for mobile robot. Traditional algorithms of target detection can be applied to 2D images without depth information generally, which is disturbed by few factors such as illumination, view and scale easily. Therefore, an approach on visual detecting multi-target of unstructured and complex scenes based on RGBD images is proposed in this article to solve the above problem, which is composed of extracting descriptor of rotation and scale invariance feature, local encoding of targets, random ferns classifier training, Hough map generation, Hough voting theoretical model and local maximum search. Experimental results have shown that the proposed approach reduce the calculation of extracting and matching local feature, improve the accuracy of object recognition and detection in unknown complex environments, be capable of well robust against few disturbing factors i.e. rotation, scale, illumination, occlusion and non-rigid body deformation. © 2020 IEEE.

关键词： Motion planning

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Comparison of SGTR accident with two different passive residual heat removal systems 27

Comparison of SGTR accident with two different passive resid...

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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Wu, Yirui Shan, Jianqiang Xu, Tao Ma, Haifu Yang, Junyun Yu, Hong Wang, Junlong Deng, Yaxin School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an Shaanxi Province China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan Province China

ISBN: (纸本)9784888983051

Since the passive safety system turns out to be a desirable method to achieve simplification and increase the reliability of the performance of essential safety functions, passive technology has been generally applied to the design of advanced nuclear power plant. The traditional generation II+ nuclearpower plant is proposed to be improved with some passive systems to enhance safety performance. There are two series of passive safety systems for this kind of nuclear power plant in this paper, one of them contains: (1) the RMT (reactor makeup tank);(2) the A-ACC (advanced accumulators);(3) the IRWST (in-containment refueling water storage tank);(4) the PDS (passive depressurization system);and (5) the PRHRS (passive residual heat removal system), which is installed on the reactor coolant system (RCS) loop;the other contains:(1) the RMT (reactor makeup tank);(2) the A-ACC (advanced accumulators);(3) the IRWST (in-containment refueling water storage tank);(4) the PDS (passive depressurization system);(5) the PEFS(passive emergency feed water system), which is installed on the secondary side of SGs. In this research, the transient characteristics of SGTR accident with the two different passive residual heat removal systems which are PRHRS and PEFS is investigated using the best-estimate transient simulation code Relap5/MOD3.3. The calculation results show that both of PRHRS and PEFS could remove the decay heat from the primary loop efficiently to ensure the reactor safety and reduce the radioactive leakage to mitigate the accident impact during the SGTR accident. Due to the significant cooling effect of PRHRS and PEFS, the water level of broken SG would not be overfilled in both conditions, which is different with the SGTR accident of traditionalgeneration II+nuclear power plant. Compared with the PEFS, the PRHRS performed better in cooling efficiency, long-term cooling performance, reducing radioactive leakage capacity and mitigating accident effect. Copyright © 2018-2

关键词： Nuclear power plants

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Research about the influence of passive residual heat removal system on SGTR accident 27

Research about the influence of passive residual heat remova...

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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Wu, Yirui Shan, Jianqiang Xu, Tao Ma, Haifu Yang, Junyun Yu, Hong Wang, Junlong School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an Shaanxi Province China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan Province China

ISBN: (纸本)9784888983051

Since the passive safety system turns out to be a desirable method to achieve simplification and increase the reliability of the performance of essential safety functions, passive technology with inherent safety features has been generally applied to the design of advanced nuclear power plant. The PWR (pressurized water reactor) NPP (nuclear power plant) in this paper is a kind of mature pressurized water plants in china, and is proposed to be improved with some passive systems to enhance safety performance. The proposed and adapted passive safety systems for this PWR power plant in this paper contain: (1) the RMT (reactor makeup tank);(2) the A-ACC (advanced accumulators);(3) the IRWST (in-containment refueling water storage tank);(4) the PDS (passive depressurization system);(5) the PRHRS (passive residual heat removal system), which is installed on the reactor coolant system (RCS) loop. In this research, the behaviors of passive safety systems are studied and transient characteristics of the primary and secondary side of the reactor during the Steam Generator Tube Rupture (SGTR) accident are investigated using the best-estimate transient simulation code Relap5/MOD3.3. Results reported in this paper indicate that making use of passive safety systems especially the PRHRS could ensure reactor safety during the SGTR accident. Copyright © 2018-2019 by JSME

关键词： Pressurized water reactors

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