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SSRN 2022年

作者： Ma, Yugao Wang, Xueqing Yu, Hongxing Huang, Shanfang Zhang, Yingnan Huang, Jian Su, Guanghui Deng, Jian Chai, Xiaoming Hu, Wenzhen School of Nuclear Science and Technology Xi’an Jiaotong University Shanxi Xi’an710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Department of Engineering Physics Tsinghua University Beijing100084 China State Key Laboratory of Multiphase Flow in Power Engineering China

High-temperature alkali-metal heat pipes are passive heat transfer devices, where the capillary pressure created by the menisci in the wick pumps the condensed fluid back to the evaporator. Thus, the heat pipe heat transfer capacity is limited by the maximum capillary pressure at high heat fluxes. This work presents a two-dimensional heat and mass transfer model that includes the capillary and gravitational forces that are used to predict the capillary limit which is then validated by experimental data. The predicted critical heat flux temperature has an error of less than 20℃ and a relative error of 6%. The predicted transient sequences are consistent with the measurements. The model shows that capillary limit is affected by inclination angle, heat flux, and wick structure. For inclinations, the critical heat flux at the capillary limit is linearly related to the inclination angle with the predicted temperature rising 2 ~10℃/s during the early stage of the capillary limit critical heat flux condition. The evaporator temperature oscillates before the capillary limit with positive inclinations. For heat fluxes, increasing the heat flux by 17% increases the temperature increase rate 10 fold with a longer dryout length. The evaporator exhibits hysteresis after the capillary limit due to partial dryout of evaporator. For wick structures, reducing the mesh screen pitch from 80 μm to 15 μm reduces the critical heat flux to 10% of the CHF at 80 μm. This model can accurately predict the heat pipe temperature variations at the capillary limit and can explain the physical mechanisms for the dryout oscillations and recovery hysteresis at the capillary limit. Thus, the measurements and model provide analytical guidelines for designing heat pipe cooling systems. © 2022, The Authors. All rights reserved.

关键词： Heat flux

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Numerical study of fuel melting and molten migration based on the mps method

Numerical study of fuel melting and molten migration based o...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Lei, Zhong Deng, Jian Li, Wei Wu, Xiaoli Deng, Chunrui Nuclear Power Institute of China Chengdu Sichuan China Science and Technology on Reactor System Design Technology Laboratory Chengdu Sichuan China

ISBN: (纸本)9780791883785

Core melting and molten migration behavior are hot and difficult issues in the field of nuclear reactor severe accident research. The Moving Particle Semi-implicit (MPS) meshless method has potential to simulate free-surface and multiphase flows. In this study, the MPS method was utilized to simulate the melting process of UO2-Zr rod-type fuel elements. The models of heat conduction with phase change, simplified UO2-Zr eutectic reaction, viscous flow and surface tension were implemented with the framework of standard MPS method. Then, the improved MPS code was used to simulate and analyze the process of high-temperature melting and characteristics of molten migration and solidification in the coolant channel, aiming at revealing the severe accidents for light water reactors (LWR), particularly the early core damage. The results showed that compared with the case of higher initial temperature, when the initial temperature of molten UO2 is lower, more molten UO2 will solidify on the surface of rod cluster, and the blockage of upper flow channel caused by molten UO2 is more serious. In addition, this study also demonstrated the potential of the MPS method for the study of complicated severe accident phenomena in not only traditional LWR but also advanced nuclear reactors in the future. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Solidification

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design of an Online Operational Task Reliability Analysis system in Nuclear Power Plant

Design of an Online Operational Task Reliability Analysis Sy...

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system Reliability and Safety Engineering (SRSE), International Conference on

作者： Wei Li Ming Yang Zhengxi He Zhao Gao Yan Xiong Zhongyue Zhang Dehang Jiang Jipu Wang Fundamental Science on Nuclear Safety and Simulation Technology Laboratory College of Nuclear Science and Technology Harbin Engineering University Harbin China Nuclear Reactor System Design Technology Key Laboratory China Nuclear Power Research and Design Institute Chendu China Institute for Advanced Study in Nuclear Energy & Safety College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen China

Human factors play an important role in human- computer interaction systems such as nuclear power plants (NPPs). Especially for the human-computer interaction process in unknown scenarios, incorrect personnel actions will affect the operation of equipment and systems, and finally the achievement of safety goals of NPPs. This paper presents a design of an online operational task reliability analysis (OOTRA) system which provides early warnings to operations in a timely manner by monitoring the states of plant systems and equipment, and operator actions. For any wrong action of operators, the OOTRA system can online evaluate the impact of the wrong action on the operational task and the goals of NPPs.

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Optically transparent Millimeter-Wave metasurface for frequency-spatial multiplexed holographic imaging

Optically transparent Millimeter-Wave metasurface for freque...

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IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP)

作者： Zhiyun Zhang Guang Zhang Yulong Zhou Sijia Li Jianghao Tian Zexu Guo Xiangyu Cao Information and Navigation College Air Force Engineering University Xi’an China Shaanxi Changling Electronic Technology Co. Ltd. Baoji China National Key Laboratory of Science and Technology on Vessel Integrated Power System PLA Naval University of Engineering Wuhan China

ISBN: (数字)9798350351019

ISBN: (纸本)9798350351026

Restricted by the physical properties of materials, most traditional electromagnetic (EM) metasurfaces cannot achieve transparent stealth in visible spectrum. Although some metasurfaces for holography have been designed, there is no standard method for evaluating the advancement of wavefront manipulation, metasurface design, and algorithms. Here, a novel full space control the complex amplitude of a metasurface with optical transparency (OT) is presented in the millimeter-wave (mmWave) band. Through frequency-multiplexing, two distinct holographic images “HOLO” and “GRAM” with high quality are designed, achieving signal-to-noise ratios (SNR) of 14.6 dB and 14.4 dB, respectively. The $\mathbf{6 4 \times 6 4}$ bi-layered metasurface is composed of glass and PET substrates and three silver mesh layers. By changing the opening size and rotating angle of split rings, phase and amplitude modulations are simultaneously and independently realized at 26.6 GHz and 44.0 GHz.

关键词： Optical polarization Frequency modulation Holography Metasurfaces Optical imaging Holographic optical components Optical reflection Frequency division multiplexing Frequency control Signal to noise ratio

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Study on the liquid seal discharge process in an over-pressurized accident

Study on the liquid seal discharge process in an over-pressu...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Wu, Dan Deng, Jian Du, Sijia Qian, Libo Nuclear Power Institute of China Chengdu Sichuan China Science and Technology on Reactor System Design Technology Laboratory Chengdu Sichuan China

ISBN: (纸本)9780791883785

In an over pressure accident, one or more pressurizer safety(or relief) valves will open due to the rapid pressure rise process. Once the safety(or relief) valves are open, the liquid seal will be discharged, and this will generate great discharge force to the downstream pipes. Multi-level protection is chosen using pressurizer safety(or relief) valves with different setpoint in most of Nuclear Power Plant, especially in the self-designed Generation-III Nuclear Power Plants. As the over pressure accident progresses, one or more safety(or relief) valves will be open. The downstream pipes will experience one or more times of impacts, which will influence the arrangement of the pipes. The whole discharge process is very complex, and the key influence factors are the pressure rise rate, safety(or relief) valve opening time, liquid seal temperature and volume, and the arrangement of the downstream discharge pipes. In present paper, liquid seal discharge process in an over pressure accident is studied. The pressure rise rate is so fast that three safety(or relief) valves will open one after another, which will generate three impacts on the downstream discharge pipes. It is found that for a specific design of Nuclear Power Plant, well design of the safety(or relief) valve setpoint is very important to the discharge force analysis results. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Liquids

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KYLIN-V2.0 code calculation ability verification based on VERA benchmark

KYLIN-V2.0 code calculation ability verification based on VE...

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2020 International Conference on Physics of reactors: Transition to a Scalable Nuclear Future, PHYSOR 2020

作者： Wang, Dongyong Yu, Yingrui Peng, Xingjie Wang, Chenlin Liu, Kun Chai, Xiaoming Science and Technology on Reactor System Design Technology Laboratory Chengdu610213 China Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9781713827245

Virtual Environmental for reactor Analysis (VERA) benchmark was released by the Consortium for Advanced Simulation of Light water reactors (CASL) project in 2012. VERA benchmark includes more than ten problems at different levels, from 2D fuel pin case to 2D fuel assembly case to 3D core refuelling case, in addition, reference results and experimental measured data of some problems were provided by CASL. Fuel assemblies in VERA benchmark are various, including control rod assemblies, Pyrex assembly, IFBA assembly, WABA assembly and gadolinium poison assembly, and so on. In this paper, various fuel assembly models in the VERA benchmark have been built by using KYIIN-V2.0 code to verify its calculation ability from 2D fuel pin case to 2D fuel assembly case to 2D 3x3 fuel assembly case, and making a comparative analysis on the reference results in VERA benchmark, as well as the calculation results of the Monte Carlo code RMC. KYLIN-V2.0 is an advanced neutron transport lattice code developed by Nuclear Power Institute of china (NPIC). The subgroup resonance calculation method is used in KYIIN-V2.0 to obtain effective resonance self-shielding cross section, method of modular characteristics (MOC) is adopted to solve the neutron transport equation, and CRAM method and PPC method is adopted to solve the depletion equation. The numerical results show that KYLIN-V2.0 code has the reliable capability of direct heterogeneous calculation of 2D fuel assembly, and the effective multiplication factor, assembly power distribution, rod power distribution and control rod reactivity worths of various fuel assemblies that are calculated by KYLIN-V2.0 are in better agreement with the reference. © The Authors, published by EDP sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://***/licenses/by/4.0/).

关键词： Control rods

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High-Fidelity Neutronic/Thermal-Hydraulic Coupling Analysis of Plate-Type reactor based on MOOSE and cosRMC

SSRN

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SSRN 2023年

作者： Chen, Junyi Liu, Guodong Huang, Shanfang He, Ying Qiu, Meiming Wang, Kan Lu, Chuan Li, Zhigang Quan, Guoping Wang, Xing Department of Engineering Physics Tsinghua University Haidian district Beijing100084 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Shuangliu district Chengdu610213 China State Power Investment Corporation Research Institute Changping district Beijing102209 China

A full scale high-fidelity neutronic/thermal-hydraulic coupled analysis method for plate-type reactor is proposed based on the open-source Multiphysics Object-Oriented Simulation Environment (MOOSE) and Monte Carlo Code cosRMC. The two-dimensional heat transfer model and one-dimensional coolant subchannel model are established, and integrated into the thermalhydraulic analysis code SPhase. The code-to-code validations of SPhase show good agreement with that of CTF and Fluent. The detailed neutronics model and parameters schemes are verified through cosRMC to ensure accuracy of physics calculation. The criticality search is implented, and the full scale JRR-3M critical coupled simulation under steady state is realized through celllevel resolution. The thermal feedback introduces negative activity of about 400 pcm. The insertion of absorbers renders the complexity of power distribution. The reflection effect results in peak thermal neutrons flux and temperature at the edge of the core. This work provides reference for correlational studies on neutronic/thermal-hydraulic characteristics of plate-type reactor. © 2023, The Authors. All rights reserved.

关键词： Multiphysics

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Research on analysis and modeling methods for lbloca in nuclear power plants based on autonomous loca analysis platform arsac

Research on analysis and modeling methods for lbloca in nucl...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Zhou, Jiayue Wu, Dan Ding, Shuhua Jiang, Guangming Nuclear Power Institute of China Chengdu Sichuan China Science and Technology on Reactor System Design Technology Laboratory Chengdu Sichuan China

ISBN: (纸本)9780791883785

In order to meet the demand of continuous innovation of technologies and the general trend of autonomous nuclear power plants design and export of nuclear power plants, it is necessary to develop an autonomous LOCA analysis platform and corresponding analysis methods for the most complex design basis accidents. In this paper, the characteristics of LOCA analysis platform ARSAC, designed by Nuclear Power Institute of china, and the code ARSAC-K which meets the requirements of the US Federal Code 10 CFR 50.46 Appendix K model are introduced as well as a set of LOCA analysis methods and modeling methods. Based on the international advanced LOCA analysis code development concept, the code ARSAC has made new breakthroughs in matrix algorithms, key thermal hydraulic models and so on. Validation work has also been carried out in-depth. A set of advanced LOCA analysis methods has been developed using code ARSAC-K and advanced power plant parameter sampling methods. Analysis on LBLOCA of nuclear power plants with code ARSAC-K was performed, and the impact of different modeling methods on the LOCA analysis results was studied. To ensure the rationality and conservativeness of the analysis results, a set of reasonable and conservative modeling methods is fixed on the basis of a large number of sensitivity analyses for subsequent analysis and calculation. In the future, a lot of optimization work will be done to improve the LOCA code and corresponding methods. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Nuclear power plants

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Optimal Linear Crossover for Mitigating Negative Transfer in Evolutionary Multitasking

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IEEE Transactions on Evolutionary Computation 2024年

作者： Liu, Zhaobo Yuan, Jianhua Zhang, Haili Zeng, Tao Zhu, Zexuan Shenzhen University Institute for Advanced Study Shenzhen518060 China Shenzhen University College of Computer Science and Software Engineering Shenzhen518060 China Shenzhen Polytechnic University School of Undergraduate Education Shenzhen518055 China Shenzhen University National Engineering Laboratory for Big Data System Computing Technology Shenzhen518060 China Shenzhen University Shenzhen City Key Laboratory of Embedded System Design Shenzhen518060 China Chongqing University Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education of China Chongqing400044 China

Evolutionary multitasking algorithms use information exchange among individuals in a population to solve multiple optimization problems simultaneously. Negative transfer is a critical factor that affects the performance of evolutionary multitasking algorithms. In this study, we propose an innovative approach to mitigate negative transfer in evolutionary multitasking algorithms. The proposed approach is grounded in rigorous theoretical analysis, which provides valuable theoretical insights into the design of an optimal linear crossover operator for mitigating negative transfer. By identifying interpretable conditions, we establish a solid theoretical foundation to prevent negative transfer in diverse scenarios. Building upon these findings, we theoretically derive a closed-form expression for the optimal crossover operator and propose practical design methods based on approximations. Furthermore, we integrate the proposed optimal crossover operator into a fundamental evolutionary multitasking algorithm framework. The resultant algorithm is comparable or superior to other state-of-the-art methods. Empirical validation through comprehensive experiments confirms the effectiveness of our theoretical findings. © 1997-2012 IEEE.

关键词： Optimization algorithms

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Energy-Efficient Cell-Free Network Assisted by Hybrid RISs

arXiv

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arXiv 2022年

作者： Lyu, Wanting Xiu, Yue Yang, Songjie Yuen, Chau Zhang, Zhongpei National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China Chengdu61173 China Pillar Singapore University of Technology and Design Singapore487372 Singapore

In this letter, we investigate a cell-free network aided by hybrid reconfigurable intelligent surfaces (RISs), which consists of a mixture of passive and active elements that are capable of amplifying and reflecting the incident signal. To maximize the energy efficiency (EE) of the system, we formulate a joint transmit beamforming and RIS coefficients optimization problem. To deal with the fractional objective function, Dinkelbach transform, Lagrangian dual reformulation, and quadratic transform are utilized, with a block coordinate descent (BCD) based algorithm proposed to decouple the variables. In addition, successive convex approximation (SCA) method is applied to iteratively to tackle the non-convexity of the sub-problems. Simulation results illustrate the effectiveness and convergence of the proposed algorithm through analyzing the EE and sum rate performance with varying parameter settings. The proposed hybrid RISs schemes can achieve 92% of the sum rate but 188% of EE of active RISs schemes. As compared with passive RISs, 11% gain in sum rate can be achieved with comparable EE. Copyright © 2022, The Authors. All rights reserved.

关键词： Beamforming

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