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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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Secure State Estimation for Multi-Agent systems: On the Relationship between the Number of Agents and system Resilience

Secure State Estimation for Multi-Agent Systems: On the Rela...

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American Control Conference (ACC)

作者： Takumi Shinohara Toru Namerikawa Graduate School of Science and Technology Keio University Yokohama Japan Department of System Design Engineering Keio University Yokohama Japan

This paper addresses the problem of secure state estimation in multi-agent systems consisting of n agents. For the problem, the sparse observability index is a well-known measure of the system resilience. This index is defined as the largest integer δ for which the system observability is preserved even if any δ sensors are eliminated. The larger δ is, the more the system state can be reconstructed even if the system is subjected to more sensor attacks. In this paper, we analyze the relationship between the number of agents n and the sparse observability index δ especially when the network structure is path and cycle graphs. Intuitively, it is assumed that, as the number of agents n increases, the system resilience, i.e., δ, increases accordingly. However, as this study provides, δ does not monotonically increase with an increase in n. In path graphs, δ depends on whether n+1 is prime or composite, and the system resilience is enhanced when n+1 is prime. In cycle graphs, δ obeys whether n is prime or composite, and the system is more resilient when n is prime.

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Aerial Active STAR-RIS-assisted Satellite-Terrestrial Covert Communications

arXiv

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arXiv 2025年

作者： Zhang, Chuang Sun, Geng Li, Jiahui Wang, Jiacheng Zhang, Ruichen Niyato, Dusit Mao, Shiwen Quek, Tony Q.S. Computer Science and Technology Jilin University Changchun130012 China Singapore University of Technology and Design Singapore487372 Singapore College of Computer Science and Technology Jilin University Changchun130012 China College of Computing and Data Science Nanyang Technological University Singapore639798 Singapore Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun130012 China Department of Electrical and Computer Engineering Auburn University AuburnAL36849 United States Information System Technology and Design Pillar Singapore University of Technology and Design Singapore487372 Singapore

An integration of satellites and terrestrial networks is crucial for enhancing performance of next generation communication systems. However, the networks are hindered by the long-distance path loss and security risks in dense urban environments. In this work, we propose a satellite-terrestrial covert communication system assisted by the aerial active simultaneous transmitting and reflecting reconfigurable intelligent surface (AASTAR-RIS) to improve the channel capacity while ensuring the transmission covertness. Specifically, we first derive the minimal detection error probability (DEP) under the worst condition that the Warden has perfect channel state information (CSI). Then, we formulate an AASTAR-RIS-assisted satellite-terrestrial covert communication optimization problem (ASCCOP) to maximize the sum of the fair channel capacity for all ground users while meeting the strict covert constraint, by jointly optimizing the trajectory and active beamforming of the AASTAR-RIS. Due to the challenges posed by the complex and high-dimensional state-action spaces as well as the need for efficient exploration in dynamic environments, we propose a generative deterministic policy gradient (GDPG) algorithm, which is a generative deep reinforcement learning (DRL) method to solve the ASCCOP. Concretely, the generative diffusion model (GDM) is utilized as the policy representation of the algorithm to enhance the exploration process by generating diverse and high-quality samples through a series of denoising steps. Moreover, we incorporate an action gradient mechanism to accomplish the policy improvement of the algorithm, which refines the better state-action pairs through the gradient ascent. Simulation results demonstrate that the proposed approach significantly outperforms important benchmarks, and also validate the performance and practicality under different algorithm parameters and environment settings. Copyright © 2025, The Authors. All rights reserved.

关键词： Deep reinforcement learning

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The Grid Mapping for Pwr Core Pin-by-Pin Wise Coupling Calculation system

SSRN

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SSRN 2024年

作者： Li, Zhigang Pan, Junjie Xia, Bangyang Qiang, Shenglong Zeng, Wei Lu, Wei Feng, Ziliang Nuclear Power Institute of China 328 Huayang Changshun Avenue Section 1 Shuangliu County Chengdu China Science and Technology on Reactor System Design Technology Laboratory 328 Huayang Changshun Avenue Section 1 Shuangliu County Chengdu China Sichuan University No.24 South Section 1 Yihuan Road Chengdu China

Due to the possible cross between the fields during the neutronic/thermal-hydraulic coupling calculation at the pin-by-pin wise of reactor core, there is an urgent need for efficient mapping methods to improve the efficiency of large-scale grid mapping. This article combines the geometric characteristics of the pins in the reactor and proposes four acceleration strategies such as two-level grid search and OpenMP+MPI parallel based on the volume weight method. A mapping tool named MAP suitable for straight hexahedral grids has been developed. The evaluation based on 6 cases and 4 types mapping processes has been conducted, and compared with the open-source MEDCoupling. The results show that the four strategies proposed have achieved good acceleration effects. Compared with MEDCoupling, the average acceleration ratio of MPI-B reaches 21332.56, with an average relative deviation range of [0,1.57e-04]. The mapping time between millionth scale and million scale using MPI is less than 1.0s. © 2024, The Authors. All rights reserved.

关键词： Mapping

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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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Interactive Cloud Detection Based on Dynamic Mode Decomposition

Interactive Cloud Detection Based on Dynamic Mode Decomposit...

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2024 International Conference on Information technology, Data science, and Optimization, I-DO 2024

作者： Li, Yilong Yang, Lu Qiu, Xiaobin Bi, Chongke Tianjin Key Laboratory for Advanced Mechanical System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin China Tianjin Key Laboratory for Oceanic Meteorology and Tianjin Institute of Meteorological Science Tianjin China Tianjin University Tianjin China

ISBN: (纸本)9798400709180

Cloud detection can address data quality and analytical accuracy issues caused by cloud cover in satellite imagery, significantly enhancing image usability. Existing cloud detection methods still have the problem of detecting a certain amount of ground and sea surface as clouds, as well as some cloud regions that are missed, resulting in a decrease in the accuracy of cloud detection. Aiming at the above problems, an interactive cloud detection method based on Dynamic Mode Decomposition is proposed. Based on the fact that clouds are constantly moving, the dynamic mode decomposition can be utilized to detect the characteristics of moving objects, and the dynamic clouds are detected, avoiding the detection of the ground and sea surface as clouds. Although static clouds rarely appear, to ensure the robustness of the algorithm, we design an interactive static cloud detection algorithm for the users, which solve the problem of missed detection and further improves the accuracy of cloud detection. To assess the effectiveness of the algorithm, the four different types of clouds of floccus, undulatus, vortex clouds, and stratocumulus are detected, the experimental outcomes demonstrate the effectiveness and robustness of the algorithm. © 2024 Copyright held by the owner/author(s). Publication rights licensed to ACM.

关键词： Dynamic mode decomposition

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The Pure-quartic Bragg Soliton

The Pure-quartic Bragg Soliton

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CLEO: Fundamental science, CLEO:FS 2024 - Part of Conference on Lasers and Electro-Optics, CLEO 2024

作者： Choi, Ju Won Sohn, Byoung-Uk Sahin, Ezgi Chen, George F.R. Xing, Peng Ng, Doris K.T. Eggleton, Benjamin J. Tan, Dawn T.H. Photonics Devices and System Group Singapore University of Technology and Design 8 Somapah Rd Singapore487372 Singapore 2 Fusionopolis Way Innovis #08-02 Singapore138634 Singapore Institute of Photonics and Optical Science School of Physics The University of Sydney SydneyNSW2006 Australia The University of Sydney SydneyNSW2006 Australia

We report a new class of Bragg soliton, the pure-quartic Bragg soliton, which arises from the balance between self-phase modulation and the extraordinarily strong negative fourth-order dispersion induced by integrated... 详细信息

ISBN: (纸本)9781957171395

关键词： Self phase modulation

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Large Language Model for Multi-objective Evolutionary Optimization

arXiv

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arXiv 2023年

作者： Liu, Fei Lin, Xi Wang, Zhenkun Yao, Shunyu Tong, Xialiang Yuan, Mingxuan Zhang, Qingfu Department of Computer Science City University of Hong Kong Hong Kong School of System Design and Intelligent Manufacturing the Department of Computer Science and Engineering Southern University of Science and Technology Shenzhen518055 China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China Huawei Noah’s Ark Lab Canada

Multiobjective evolutionary algorithms (MOEAs) are major methods for solving multiobjective optimization problems (MOPs). Many MOEAs have been proposed in the past decades, of which the search operators need a carefully handcrafted design with domain knowledge. Recently, some attempts have been made to replace the manually designed operators in MOEAs with learning-based operators (e.g., neural network models). However, much effort is still required for designing and training such models, and the learned operators might not generalize well on new problems. To tackle the above challenges, this work investigates a novel approach that leverages the powerful large language model (LLM) to design MOEA operators. With proper prompt engineering, we successfully let a general LLM serve as a black-box search operator for decomposition-based MOEA (MOEA/D) in a zero-shot manner. In addition, by learning from the LLM behavior, we further design an explicit white-box operator with randomness and propose a new version of decomposition-based MOEA, termed MOEA/D-LO. Experimental studies on different test benchmarks show that our proposed method can achieve competitive performance with widely used MOEAs. It is also promising to see the operator only learned from a few instances can have robust generalization performance on unseen problems with quite different patterns and settings. The results reveal the potential benefits of using pre-trained LLMs in the design of MOEAs. To foster reproducibility and accessibility, the source code is https://***/FeiLiu36/LLM4MOEA. Copyright © 2023, The Authors. All rights reserved.

关键词： Multiobjective optimization

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Field-Harmonic-Oriented design of Vernier Permanent Magnet Machine Towards High Torque Density and Low Torque Ripple 26

Field-Harmonic-Oriented Design of Vernier Permanent Magnet M...

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26th International Conference on Electrical Machines and systems, ICEMS 2023

作者： Fang, Li Li, Dawei Zhang, Yuanzhi Wu, Jiewen Huazhong University of Science and Technology School of Electrical and Electronics Engineering Wuhan China Wuhan University School of Electricla Engineering and Automation Hubei Key Laboratory of Power Equipment and System Security for Integrated Energy Wuhan China National University of Singapore College of Design and Engineering Singapore

ISBN: (纸本)9798350317589

Vernier permanent magnet machine (VPMM) has been a promising candidate for low-speed large-torque applications owing to high torque density based on multiple-magnetic field-harmonics working principle However, rich field harmonics also cause large torque ripple, meanwhile the regular reducing methods will also undermine torque density. In this paper, the field-harmonic-oriented design approach is proposed for the VPMM towards high torque density and low torque ripple. Based on the permeance unit model, the mapping relationship between torque output and field harmonics is built. Explicit design regulations are established for the airgap structure so as to modulate the optimal field harmonics composition. Via the proposed method, a surface-mounted VPMM is purposely designed and the electromagnetic performance is verified by FEA. Finally, a prototype of the proposed machine has been manufactured and tested. Both analytical and experimental results validate the feasibility of the proposed design method. © 2023 IEEE.

关键词： Torque

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