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science China(Technological sciences) 2023年第9期66卷 2457-2480页

作者： XIANG HengGao CHEN Yang QI ZhiXiang ZHENG Gong CHEN FengRui CAO YueDe LIU Xu ZHOU Bing CHEN Guang National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China

Intermetallic TiAl alloys attract much attention in advanced engineering fields due to their low density(3.9–4.2 g/cm3) and excellent high-temperature properties. After more than half a century of research and development, TiAl alloys have found applications in aerospace, automotive, and related industries. However, as a kind of semi-brittle materials, intermetallic TiAl alloys exhibit different mechanical behavior from metallic and ceramic materials. Thus, it is necessary to systematically understand their mechanical behavior to ensure further developments and safe engineering applications. In this paper, the principal mechanical behavior of Ti Al alloys was reviewed comprehensively, including tension, creep, fatigue, and strengthening mechanisms. The mechanical performance and the corresponding deformation mechanisms are summarized and discussed in detail. The future directions of mechanical research on TiAl alloys are also overviewed to expedite their extensive utilization in engineering fields.

关键词： TiAl tension creep fatigue strengthening mechanisms

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Research on Imputation Method for Missing Values of Nuclear Power Plants' Operation Data 13

Research on Imputation Method for Missing Values of Nuclear ...

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13th International Conference on Electronics, Communications and Networks, CECNet 2023

作者： Liu, Jie Qi, Xiaodi Wu, Zhiqiang Jiang, Wei Chen, Zhi Jian, Yifan Wen, Juan School of Computer/Software University of South China China Laboratory of Nuclear Reactor System Design Technology China Nuclear Power Research and Design Institute China

ISBN: (纸本)9781643684802

The collection of nuclear power plants operating data is the basis for subsequent fault diagnosis and obtaining the operating status of nuclear power plants, but equipment failures and external interference will lead to missing operating monitoring data, which will reduce the quality of the data and thus reduce the accuracy of the subsequent analysis results. To solve this problem, this paper utilizes the fact that nuclear power plants have accumulated a large amount of operational data and researches the method of generating adversarial imputation network (GAIN)-based imputation method for missing values of nuclear power plants' operational data. The generator in the model estimates the missing values by learning the distribution of the true values, and the discriminator in the model discriminates which values are true and which are generated with the help of a hint matrix. The hint reveals partial information about the missing original samples to the discriminator, which the discriminator uses to focus its attention on the quality of the imputation of particular data values. Finally, a training set and a test set were constructed for comparative experiments on the PCTran simulation platform by simulating the operational data of the AP1000 as an example. The experimental results demonstrate that the investigated algorithm achieves lower root mean square error (RMSE), verifying the feasibility and accuracy of the method. © 2024 The authors and IOS Press.

关键词： Nuclear power plants

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Direct Contact Condensation Characteristics of Steam Injection into Cold-Water Pipe Under Rolling Condition 23rd

Direct Contact Condensation Characteristics of Steam Injecti...

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23rd Pacific Basin Nuclear Conference, PBNC 2022

作者： Wang, Zhiwei He, Yanping Duan, Zhongdi Huang, Chao Liu, Shiwen State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9789819910229

Direct contact condensation (DCC) is widely occurred in nuclear power systems and leads to undesired phenomena such as condensation-induced water hammer. For ocean nuclear power ships, DCC is inevitable in the passive heat removal system and influenced by sea conditions. In this paper, the characteristics of DCC under rolling conditions are analyzed. The numerical model of DCC is established based on computational fluid dynamics approach. The VOF model, SST k–ω turbulence model and the additional inertia force model are incorporated to describe the liquid-gas two-phase flow under the rolling motion. The condensation model based on surface renewal theory (SRT) is used to simulate steam-water DCC phenomenon. The simulation results are compared with the experimental data and show reasonable agreement. The effects of rolling motion on DCC for steam injection into a horizontal pipe filled with cold water are numerically investigated. The results show that the additional inertial forces and the average condensation rate increase with the increase of the rolling angle and frequency. The reverse flow of the seawater induced by rolling motion leads to the accumulation of the steam at the lower part of the pipe, resulting in a large pressure pulse. With the increase of rolling angle and frequency, the pressure pulse induced by DCC increases. © 2023, The Author(s).

关键词： Condensation

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Multi-conditioned controlled growth of CoBi nanostructures on SrTiO_(3)

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Frontiers of physics 2024年第6期19卷 107-113页

作者： Desheng Cai Yumin Xia Pengju Li Kun Xie Yuzhou Liu Yitong Gu Gan Yu Changgan Zeng Ping Cui Shengyong Qin International Center for Quantum Design of Functional Materials(ICQD) University of Science and Technologyof ChinaHefei 230026China CAS Key Laboratory of Strongly Coupled Quantum Matter Physics Department of PhysicsUniversity of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

Cobalt pnictides have been theoretically proposed to be attractive candi-dates for high-temperature ***,monolayered CoX(X=As,Sb,Bi)on SrTiO_(3) systems present a potential new platform for realizing topological superconductors in the two-dimensional limit,due to their nontrivial band *** this end,we have successfully fabricated high-quality CoBi nanoislands on SrTiO_(3)(001)substrates by molecular beam epitaxy followed by an investigation of their atomic struc-ture and electronic properties via in situ scanning tunneling microscopyl *** the previously predicted lattice with a=b=3.5 A,2×1 dimer row was observed in this ***,our results reveal that the topography of CoBi islands is strongly influenced by various growth conditions,such as substrate temperature,the flux ratio between Co and Bi,and the annealing *** study paves the way for further explorations of the superconductivity and topological properties of cobalt pnictidesystems.

关键词： CoBi/SrTiO_(3) molecular beam epitaxy scanning tunneling microscopy scanningtunneling spectroscopy nanostructure

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design of Code Generator for Safety Level I&C Software of NPPs 6th

Design of Code Generator for Safety Level I&C Software of NP...

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6th International Symposium on Software Reliability, Industrial Safety, Cyber Security and Physical Protection of Nuclear Power Plant, ISNPP 2021

作者： Wei, Jiang Lin, Lan Bin, Yang Hou, Rong-Bin Science and Technology On Reactor System Design Technology Laboratory Nuclear Power Institute of the China Sichuan Chengdu China

ISBN: (纸本)9789811911804

The function block diagram is used to design control algorithm of nuclear safety-level I&C (Instrumentation & Control) system. Then it is converted into C code by code generator. And the C code is downloaded into embedded software platform of NASPIC after compiled by a common C compiler. Therefore, the credibility of the code generator is directly related to the safety of nuclear power plant operation. At present, the methods which are used to guarantee the credibility of code generators mainly include test and V&V. However, the formal method describes the software system from a mathematical point of view and verifies its correctness of translation processes, which can improve the credibility of the code generator to the greatest extent. Based on the formal method and compilation technology, this paper introduces the design and implement of code generator for safety I&C software. A initial test has been performed to check the requirement of nuclear I&C software development. The test results show that the code generator can translate Lustre program into C program. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Nuclear power plants

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Research on Switch Signal Transmission System Based on Optical Fiber 1

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6th International Symposium on Software Reliability, Industrial Safety, Cyber Security and Physical Protection of Nuclear Power Plant, ISNPP 2021

作者： Xiang, Mei-Qiong Zhu, Jia-Liang He, Zheng-Xi Deng, Zhi-Guang Dong, Chen-Long Li, Zhuo-Yue Sun, Yong-Sheng Peng, Ye-Shun Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

ISBN: (数字)9789811911811

ISBN: (纸本)9789811911804

Nuclear power plants need to transmit a large number of switch signals, while traditional electrical transmission of switch signals requires a large number of cables, which makes it difficult to realize self-inspection of transmission path faults and is vulnerable to electromagnetic interference. In view of the needs of a large number of switch signal transmission and the shortcomings of traditional electrical methods, this paper developed two sets of switch signal transmission systems based on optical fiber, which realized the simultaneous transmission of 16 channels and 2 channels of switch signals on one optical fiber, and had the function of transmission path fault self-checking. It has the advantages of wide frequency response range, small transmission delay, high reliability and strong environmental tolerance, and has broad application prospects. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Optical fibers

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RESEARCH ON LOCA DYNAMIC ANALYSIS MODEL OF reactor SYSTEM 29

RESEARCH ON LOCA DYNAMIC ANALYSIS MODEL OF REACTOR SYSTEM

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2022 29th International Conference on Nuclear Engineering, ICONE 2022

作者： Liu, Shuai Harbin Engineering University Harbin China Science and Technology on Reactor System Design Technology Laboratory Chengdu China

ISBN: (纸本)9780791886472

The reactor system has a large scale of components. And the system dynamic analysis model for loss of coolant accidents(LOCA) contains many non-linear factors. The transient calculation analysis takes a long time and the convergence is difficult to guarantee. In this paper, two different analysis models (complete three-loop model and single-loop model) of the reactor loop system are established for comparative analysis. The analysis shows that the calculation error of the main position load in the two different model is within 10%. The decoupling influence of the surge tube and the reactor inlet and outlet on the system dynamic characteristics is within an acceptable range. When the single-loop model is used, it is necessary to decouple the reactor pressure vessel and pressurizer. And the simplified boundary is adapted to simulate its effect on the whole loop. The single-loop dynamic analysis model based on the decoupling criterion can greatly reduce the calculation scale and meet the calculation accuracy, which can be used to calculate the LOCA dynamic characteristics of the reactor system quickly. The model can also be used for seismic analysis of reactor system. And using this model for reactor system dynamic analysis can greatly improve the calculation efficiency. Copyright © 2022 by ASME.

关键词： Loss of coolant accidents

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Constructing Basic Probability Assignment Based on the Slope Correlation Degree 5

Constructing Basic Probability Assignment Based on the Slope...

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5th IEEE International Conference on Electronics technology, ICET 2022

作者： Chen, Jie Yang, Pengcheng Pu, Xiaofei Xie, Hao Wang, Jinxin Wu, Kunren Nuclear Power Institute of China Science and Technology on Reactor System Design Technology Laboratory Chengdu610213 China

ISBN: (纸本)9781665485081

DS evidence theory can be applied to deal with multi-sensor data and get reliable and accurate decision result of system's target or object due to its good measurement and reasonable description of system's uncertainty. In practical application field, DS evidence theory is achieved by two steps, one is the acquisition of the basic probability assignment function (BPA), and the other is the synthesis of multiple evidences that is obtained from multi-sensor data. The existing relevant literatures mainly solve the combination problem of conflict evidences, while lack of systematic research on the acquisition of BPA. In this paper, we focus on the discussion and innovation of the acquisition of BPA. BPA in DS evidence theory is the basic unit to describe the uncertainty of the system and evidences, which fundamentally determines its superiority with respect to probability theory and Bayesian reasoning. Getting a reasonable and effective BPA is the premise of the application of DS evidence theory. Traditional BPA acquisition methods have the limitations like absent priori knowledge and low acquisition accuracy. Aiming to solve the technical difficulties of traditional methods, we put forward a new BPA acquisition algorithm based on the slope correlative degree. The novel algorithm proposed in this paper successfully realizes the reliable descriptions of system's uncertainty, which is conducive to product the accurate BPAs and the precise fusion results. Experimental results and analyses demonstrate that the innovative algorithm can not only produce reasonable BPAs, which can better fit the sensors' monitoring data, but also expand the gap between the support degree of different propositions in BPA, which is more beneficial to the synthesis of evidences and the decision fusion of the system. Thus, the novel BPA acquisition algorithm has great application value and research significance. © 2022 IEEE.

关键词： Uncertainty analysis

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Hydrodynamic characteristics and noise reduction mechanism of a wave leading hydrofoil placed in the wake of a cylinder

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Journal of Hydrodynamics 2023年第6期35卷 1089-1100页

作者： Bing Zhu Yue Li Wen-jun Xu Wei Zhang School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai200093China National Key Laboratory of Marine Engine Science and Technology Shanghai201108China Marine Design and Research Institute of China Shanghai200011China

We have investigated the hydrodynamic and acoustic performance of a hydrofoil with a wave leading edge that is being ingested in a cylindrical wake,to explore the interaction and noise reduction mechanism with the use of near flow field and far field noise decoupled prediction methods of large eddy simulation(LES)and Ffowcs Williams-Hawkings(FW-H).Our results indicate that the wave leading edge has minimal effect on the hydrodynamic performance,however,it has demonstrated the ability to significantly improve the acoustic *** the comparison of sound pressure level(SPL)and acoustic directivity,we have observed that the wave leading edge can significantly reduce the broadband noise in the far *** is due to its ability to break the large-scale structure of the incoming flow,which weakens the direct impact and therefore reduces the tone ***,the interaction between the broken vortex and the boundary layer around the hydrofoil surface is weakened,leading to a reduction in surface pressure pulsation and broadband noise *** wave structure primarily affects the flow structure near the leading edge,resulting in a reduction in flow disturbance and sound source intensity,and an improvement in the acoustic feedback loop between the foil and the fore-cylinder.

关键词： Wave leading hydrofoil cylinder wake ingesting turbulence noise reduction large eddy simulation(LES)

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Effects of Inlet Conditions on the Two-Phase Flow Water Hammer Transients in Elastic Tube 23rd

Effects of Inlet Conditions on the Two-Phase Flow Water Hamm...

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23rd Pacific Basin Nuclear Conference, PBNC 2022

作者： Zhao, Zixiang Duan, Zhongdi Xue, Hongxiang Yuan, Yuchao Liu, Shiwen State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9789819910229

Two-phase flow water hammer events occur in the pipelines of the nuclear power systems and lead to transient and violent pressure shock to tube structures. For the sake of operation safety, the occurrence and severity of the two-phase water hammer should be carefully assessed. This paper presents a parameter analysis of the inlet conditions on the two-phase flow water hammer transients, with considering the elastic effect of the tube walls. A numerical model is established for the vapor-liquid two-phase flow based on the two-fluid six-equation modelling approach, with incorporating correlations and criterions for two-phase flow regime, interfacial interactions and heat transfer. The governing equations are transformed to matrix form expressed by characteristic variables, and solved using the splitting operator method and the total variation diminishing scheme. The accuracy of the model is verified against the experimental data in open literature. Then, the model is applied to investigate the effect of inlet velocity and inlet water temperature on the two-phase flow water hammer transients. The simulation results show that the increase of inlet velocity increases the pressure peak values and brings forward the onset of water hammer, and the increase of inlet temperature decreases the pressure shock. A comparison of the water hammer results between the elastic tube and rigid tube is further presented, and the effect of the elastic modulus on the water hammer is analyzed. The results also show that the pressure peak is largely affected by the tube diameter. © 2023, The Author(s).

关键词： Condensation

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