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SSRN 2022年

作者： Wang, Zhiwei Duan, Zhongdi He, Yanping Huang, Chao Yuan, Yuchao Liu, Shiwen Li, Mingzhi State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China School of Naval Architecture Ocean & Civil Engineering Shanghai Jiao Tong University Shanghai200240 China Institute of Marine Equipment Shanghai Jiao Tong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The investigation of condensation-induced water hammer (CIWH) under ocean conditions is crucial to the system safety of the offshore floating nuclear plants (OFNPs). This paper establishes a CIWH numerical model under rolling conditions based on the computational fluid dynamics (CFD) code combined with user-defined functions (UDF). First, the numerical model is verified by published experimental data. Then, the transient behaviors of CIWH events under various rolling parameters are numerically investigated. The results show that the rolling motion causes a significant steam slug and enhances the steam-subcooled water contact area, which promotes the average condensation rate. The average condensation rate increases with an increase in rolling angle, decreases with an increase in rolling period. Due to the larger average condensation rate and reverse flow caused by rolling motion, the pressure peak generated by the CIWH significantly increases compared to static conditions. Similarly, the pressure peak increases as rolling angle increases, decreases as rolling period increase. Moreover, the pressure peak is proportional to steam inlet velocity, and the location of the pressure peak gradually moves back to the outlet direction as the steam velocity increases. These qualitative conclusions are useful to understand the effects of rolling motion on the CIWH and provide a reference for the CIWH simulations. © 2022, The Authors. All rights reserved.

关键词： Condensation

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Effect of Rolling Motion on Transient Behaviors of Condensation-Induced Water Hammer in an Equal-Height-Difference Passive Heat Removal system

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SSRN 2022年

作者： Duan, Zhongdi Wang, Zhiwei He, Yanping Huang, Chao Li, Mingzhi Yuan, Yuchao Liu, Shiwen State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China School of Naval Architecture Ocean & Civil Engineering Shanghai Jiao Tong University Shanghai200240 China Institute of Marine Equipment Shanghai Jiao Tong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The investigation of condensation-induced water hammer (CIWH) under ocean conditions is vital to the system safety of the offshore floating nuclear plants (OFNPs). This paper establishes a CIWH numerical model under rolling conditions based on the computational fluid dynamics (CFD) code combined with user-defined functions (UDF). First, the numerical model is validated with the experimental data. Then, the transient behaviors of the CIWH under various rolling parameters are numerically investigated. The results show that the rolling motion causes a significant steam slug and increases the steam-subcooled water contact area, which promotes the average condensation rate. The average condensation rate increases as the rolling angle increases and the rolling period decreases. Due to the larger average condensation rate and reverse flow induced by rolling motion, the pressure peak generated by the CIWH significantly increases compared to static conditions. Similarly, the pressure peak increases as the rolling angle increases and the rolling period decrease. Moreover, the pressure peak is proportional to the steam inlet velocity, and the location of the pressure peak gradually moves back to the outlet direction as the steam inlet velocity increases. These qualitative conclusions may serve as a reference for the CIWH simulations under ocean conditions. © 2022, The Authors. All rights reserved.

关键词： Condensation

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An Efficient Digital Twin Based on Machine Learning Svd Autoencoder and Generalised Latent Assimilation for Nuclear reactor Physics

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SSRN 2022年

作者： Gong, Helin Cheng, Sibo Chen, Zhang Li, Qing Quilodrán-Casas, César Xiao, Dunhui Arcucci, Rossella SJTU-ParisTech Elite Institute of Technology Shanghai 200240 China Data Science Institute Imperial College London LondonSW7 2AZ United Kingdom Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China Faculty of Sciences and Engineering Swansea University SwanseaSA1 8EN United Kingdom Department of Earth Science & Engineering Imperial College London LondonSW7 2AZ United Kingdom

This paper proposes an approach that combines reduced-order models with machine learning in order to create an digital twin to predict the power distribution over the core during the operation stage. The operational digital twin is designed to solve forward problems given input operation parameters, as well as to solve inverse problems given some observations of the power field. The forward model is realised using SVD autoencoder reduced order model and machine learning methods. The inverse model is based on a generalised latent assimilation method. The effectiveness in the sense of accuracy and real-time solver of the digital twin is illustrated through a real engineering problem in nuclear reactor physics - reactor core simulation in the life cycle of HPR1000 affected by control rod inserting step, burnup, power level and inlet temperature of the coolant, which shows potential applications for on-line monitoring purpose. © 2022, The Authors. All rights reserved.

关键词： Inverse problems

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Spatial Heterogeneity of Point Defect Properties in Refractory Multi-Principal Element Alloy with Short-Range Order: A First-Principles Study

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SSRN 2022年

作者： Shi, Tan Lyu, Sixin Su, Zhengxiong Wang, Yunpeng Qiu, Xi Sun, Dan Xin, Yong Li, Wenjie Cao, Jiang Peng, Qing Li, Yuanming Lu, Chenyang School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China Nuclear Power Institute of China Chengdu610213 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China School of Electronic and Optical Engineering Nanjing University of Science and Technology Nanjing210094 China State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing100190 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The short-range order is inherently present in the multi-principal element alloys and has a profound impact on the defect behaviour. The effect of short-range order on vacancy and interstitial formation and migration was studied in body-centered cubic multi-principal element alloy NbZrTi by first-principles calculations. Two short-range order structures created by density functional theory and Monte Carlo method at 500 K and 800 K were compared with the random solid solution structure. Both vacancy and interstitial formation energies increase with the degree of short-range order. Point defect formation energies tend to be higher in region enriched in Nb and lower in region enriched in Zr and Ti. Both vacancies and interstitials prefer to migrate towards Zr,Ti-rich regions and away from Nb-rich regions, suggesting that Zr,Ti-rich region can act as recombination center for point defect annihilation. Compared to the random solid solution, the short-range order increases the spatial heterogeneity of point defect energy landscape. Tuning the degree of short-range order can be a viable strategy to optimize the point defect behaviour to achieve enhanced radiation resistance in multi-principal element alloys. © 2022, The Authors. All rights reserved.

关键词： Monte Carlo methods

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Abnormal flow of α particles in heavy-ion collisions at intermediate energies

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Physical Review C 2021年第4期103卷 044607-044607页

作者： G. Qu (曲国峰) Y. Huang (黄宇) D. Peng (彭丹) Z. Xu (徐子虚) W. Lin (林炜平) H. Zheng (郑华) G. Tian (田国玉) R. Han (韩瑞) C. Ma (马春旺) M. Huang (黄美容) P. Ren (任培培) J. Han (韩纪锋 ) Z. Yang (杨振雷) X. Liu (刘星泉) R. Wada Key Laboratory of Radiation Physics and Technology of the Ministry of Education Institute of Nuclear Science and Technology Sichuan University Chengdu 610064China School of Physics Henan Normal University Xinxiang 453007 China School of Physics and Information Technology Shaanxi Normal University Xi'an 710119 China Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China College of Physics and Electronics information Inner Mongolia University for Nationalities Tongliao 028000 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China Cyclotron Institute Texas A&M University College Station Texas 77843 USA

The experimentally observed abnormal α flow behavior from heavy-ion collisions at intermediate energies is investigated using the events of Ca40+Ca40 at 35 MeV/nucleon simulated with an improved antisymmetrized molecular dynamics model with specific consideration of the Fermi motion in the nucleon-nucleon collision process. Its possible origins in the processes from the fragment formation to the experimental flow extraction, i.e., dynamical process, sequential decay, experimental detection, and data analysis, are closely examined. It is found that the observed abnormal α flow behavior originates from the reconstruction of reaction planes in the flow extraction. How the abnormal α flow behavior is generated from the reaction plane reconstruction procedure is discussed.

关键词： Collective flow Low & intermediate energy heavy-ion reactions Models & methods for nuclear reactions

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Correction to:Study on the resource utilization of high fluorine-containing organic waste through fluidized incineration

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Waste Disposal and Sustainable Energy 2023年第2期5卷 245-245页

作者： Wenhan Li Zengyi Ma Jianhua Yan Qianming Huang Xingjian Wen Zian Zhai Bochen Huang Shuang Wang Yongqiang Chen Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu610213China State Key Laboratory of Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou310027China Zhejiang Xianchuang Energy&Technology Co.Ltd Jinhua321000China

Correction to:Waste Disposal&Sustainable Energy(2022)4:117-129 https://***/10.1007/s42768-022-00101-7 The section Confict of interest'has been amended:'Jian-hua Yan is the Editor in-Chief of Waste Disposal&Sustain-able Energy.'The revised'Confict of interest'is as follows:Jianhua Yan is the Editor-in-Chief of Waste Disposal&Sustainable *** behalf of all authors,the corresponding author states that there is no conflict of interest.

关键词： Sustainable fluorine behalf

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A Reduced-order Extrapolation Model Based on Proper Orthogonal Decomposition Technique for Rayleigh-Bénard convection

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Journal of Physics: Conference Series 2019年第2期1176卷

作者： Jinghua Yang Dengfeng Lu Zhiguang Deng Xiang Guan Qing Shi Sichuan Electric Power Design & Consulting Co. Ltd Chengdu Sichuan 610041 China National Key Labortory of Science and Technology on Reactor System Design Technology Sichuan 610213 China

In order to quickly calculate the flow characteristics in the simulated two-dimensional Rayleigh-Bénard convection model, a reduced-order extrapolation difference model for solving two-dimensional Rayleigh-Bénard is established based on the Proper Orthogonal Decomposition (POD) method. Firstly, the classical difference format is used to calculate the flow field on the initial time span, the sample data is to construct the POD basis, and the truncation error generated in the process of constructing the POD base is analysed. Then, the two-dimensional reduced-order extrapolation Rayleigh-Bénard model is constructed by combining the SVD and POD methods. By numerical examples, the classical difference model and the reduced-order extrapolation model are numerically simulated under the given initial boundary value. The reliability and effective of the reduced-order method are verified by comparing the flow field temperature cloud maps in the two calculation stages.

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Experimental Study on the Characteristics of Annular Fluid Film in a Locally Deformed Narrow Rectangular Channel

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SSRN 2024年

作者： Wang, Fenze Ren, Quanyao Liu, Haidong Xiao, Yi Chen, Deqi Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing University Ministry of Education Chongqing400044 China Department of Nuclear Engineering and Technology School of Energy and Power Engineering Chongqing University Chongqing400044 China Science and Technology on Reactor System Design Technology Laboratory Chengdu610041 China Liangjiang International College Chongqing University of Technology Chongqing401135 China Chongqing Research Institute of HIT Chongqing401151 China School of Flight Technology Civil Aviation Flight University of China Sichuan618307 China China

The study of the characteristics of the annular flow film in the narrow rectangular channel under the localized deformation can provide a research basis for the heat and mass transfer and the hydrodynamic characteristics of the locally deformed narrow flow channel. In this study, the annular flow liquid film characterization experiments are carried out in a narrow rectangular channel without local deformation, ellipsoidal deformation and pillow-shaped deformation, and different annular flow liquid film parameters liquid film thickness, disturbance wave height, and disturbance wave wavelength are obtained by high-speed camera acquisition system and intelligent image processing technology. Analyze the effects of flow conditions and local deformation on the liquid film parameters of each annular flow. Local deformation impact factor functions for liquid film thickness, disturbance wave height, and disturbance wave wavelength are obtained. The error of the impact factor function is within ±30%. © 2024, The Authors. All rights reserved.

关键词： Liquid films

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Experimental Study on the Characteristics of Annular Fluid Film in a Locally Deformed Narrow Rectangular Channel

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SSRN 2024年

The local deformation of plate fuel assembly due to neutron irradiation will lead to the deterioration of heat transfer in the flow channel. Studying the characteristics of annular flow films in narrow rectangular channels under localized deformation provides a foundation for understanding the heat and mass transfer and the hydrodynamic characteristics of the locally deformed narrow flow channel. In this study, the annular flow liquid film characterization experiments were conducted in a narrow rectangular channel under three conditions: no local deformation, ellipsoidal deformation, and pillow-shaped deformation. Various parameters of the annular flow liquid films, including liquid film thickness, disturbance wave height, and disturbance wave wavelength, were obtained using a high-speed camera acquisition system and advanced image processing techniques. The effects of flow conditions and local deformation on the liquid film parameters of each annular flow were analyzed. As the radial size of the local deformation increases relative to the liquid film thickness, the viscous bottom layer of the liquid film disintegrates, resulting in a reduction of the total liquid film thickness. When the gas-phase velocity is low, the local deformation exerts a greater shear force on the disturbance wave, prolonging the action time and increasing the likelihood of wave disintegration. Under conditions of no channel deformation, the disturbance wave wavelength is negatively correlated with the gas-phase velocity;conversely, under localized channel deformation, the wavelength is positively correlated with the gas-phase velocity. Thus, the effect of localized deformation on wavelength is bidirectional. Local deformation impact factor functions for liquid film thickness, disturbance wave height, and disturbance wave wavelength have been derived, with the error of these impact factor functions maintained within ±30%. © 2024, The Authors. All rights reserved.

关键词： Neutron irradiation

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The application of Deep Reinforcement Learning in Coordinated Control of Nuclear reactors

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Journal of Physics: Conference Series 2021年第1期2113卷

作者： Jing Li Yanyang Liu Xianguo Qing Kai Xiao Ying Zhang Pengcheng Yang Yue (Marco) Yang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China Department of Engineering The University of Sydney Sydney 2006 Australia

The nuclear reactor control system plays a crucial role in the operation of nuclear power plants. The coordinated control of power control and steam generator level control has become one of the most important control problems in these systems. In this paper, we propose a mathematical model of the coordinated control system, and then transform it into a reinforcement learning model and develop a deep reinforcement learning control algorithm so-called DDPG algorithm to solve the problem. Through simulation experiments, our proposed algorithm has shown an extremely remarkable control performance.

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