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Realization of quantum secure direct communication over 100 km fiber with time-bin and phase quantum states

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Light(science & Applications) 2022年第5期11卷 787-795页

作者： Haoran Zhang Zhen Sun Ruoyang Qi Liuguo Yin Gui-Lu Long Jianhua Lu State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua UniversityBeijingChina Beijing Academy of Quantum Information Science BeijingChina School of Information and Technology Tsinghua UniversityBeijingChina Beijing Institute of Spacecraft System Engineering BeijingChina Frontier Science Center for Quantum Information BeijingChina Beijing National Research Center for Information Science and Technology BeijingChina

Rapid progress has been made in quantum secure direct communication in recent *** practical application,it is important to improve the performances,such as the secure information rate and the communication *** this paper,we report an elaborate physical system design and protocol with much enhanced *** design increased the secrecy capacity greatly by achieving an ultra-low quantum bit error rate of<0.1%,one order of magnitude smaller than that of existing *** to previous systems,the proposed scheme uses photonic time-bin and phase states,operating at 50 MHz of repetition rate,which can be easily upgraded to over 1 GHz using current on-the-shelf *** results of our experimentation demonstrate that the proposed system can tolerate more channel loss,from 5.1 dB,which is about 28.3 km in fiber in the previous scheme,to 18.4 dB,which corresponds to fiber length of 102.2 ***,the experiment shows that intercity quantum secure direct communication through fiber is feasible with present-day technology.

关键词： fiber communication quantum

Realization of Low Crosstalk 8-Core Heterogeneous Fibre in C-Band with 125 μm Cladding Diameter 49

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Realization of Low Crosstalk 8-Core Heterogeneous Fibre in C...

49th European Conference on Optical Communications, ECOC 2023

作者： Song, Zhuoxuan Yang, Chen Du, Haoze Zhang, Fengming Yan, Siqi Zhao, Zhiyong Tang, Ming National Engineering Research Center of Next Generation Internet Access-system School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan430074 China National Engineering Laboratory for Next Generation Internet Access System School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan430074 China State Key Laboratory of Optical Fiber and Cable Manufacture Technology Yangtze Optical Fibre and Cable Joint Stock Limited Company China Optics Valley Laboratory Hubei China

A trench-Assisted heterogeneous 8-core fibre with cladding of 125 μm is designed using a genetic algorithm. The attenuation of the fibre is 0.3dB/km @1550nm, and the crosstalk is suppressed to-50 dB/10 km @1550nm, wh... 详细信息

ISBN: (纸本)9781839539954

关键词： Crosstalk

A Power Regulation Strategy for Heat Pipe Cooled reactors Based on Deep Learning and Hybrid Data-Driven Optimization Algorithm

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SSRN 2023年

作者： Huang, Mengqi Peng, Changhong Du, Zhengyu Liu, Yu School of Nuclear Science and Technology University of Science and Technology of China Anhui Hefei230027 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu610213 China

Heat pipe cooled reactors are suitable for deployment in remote or isolated areas as reliable small-scale power sources due to their good design characteristics. In order to cope with the real-time changing power demand in a dynamic environment, this study proposes a decision-making strategy for power regulation of heat pipe cooled reactors based on deep learning and hybrid data-driven optimization algorithm, which helps to achieve autonomous safe and efficient control of heat pipe cooled reactors under specific power demand. Firstly, an artificial neural network-based power prediction model for heat pipe cooled reactors is constructed;secondly, an evaluation criterion of power regulation schemes that integrates reactor safety and operational effectiveness is established based on utility theory, and finally, a hybrid data-driven optimization algorithm is proposed, which can quickly discover the power regulation scheme with the best utility under specific power demand. The strategy's effectiveness is verified by taking the power regulation process of the MegaPower heat pipe cooled reactor as an example. The results show that the strategy can make stable, accurate and near-optimal power regulation scheme decisions for arbitrary power demand within 20 seconds. © 2023, The Authors. All rights reserved.

关键词： Decision making

Thermal-Mechanical Influence Aspects and Evaluation of Helical Cruciform Single Rod in Fluoride-Salt-Cooled High-Temperature Advanced reactor

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SSRN 2024年

作者： Chen, Yiwen Zhang, Dalin Jiang, Dianqiang Li, Wei Wu, Xiaoli Tian, Wenxi Qiu, Suizheng Su, Guanghui Lu, Qi State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong University Xi’an710049 China Science Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China China

Helical cruciform fuels are novel in nuclear reactors, potential to increase reactor’s power density. However, the geometry is complicated so influence of it on the fuel performance is not identified yet. In this paper, impact of power density, cross-section parameters, and twist pitch on thermal and mechanical characteristics of fuel used in Fluoride-Salt-cooled high-Temperature Advanced reactor is discussed based on fluid-thermal-mechanical coupling. For thermal features, twist pitch is key while others have few effects. Increase in twist pitch leads to temperature uniformity and rise owing to weaker mixing effects. Fuel center temperature at middle plane of 300mm-pitch rod is 829.58℃, 54.66℃ higher than that of 100mm-pitch rod. Difference of maximum and minimum temperature at 45° cross section of 500mm-pitch rod is 153.62℃, while the figure is only 74.00℃ of 300mm-pitch rod. Besides, axial temperature of cladding outer surface increases wavelike due to complex geometry. For mechanical features, not geometry sizes but temperature affects stress distribution. Maximum Von-Mises stress appears at the elbow, where maximum temperature exists, 116.8MPa under normal conditions, lower than tensile strength of the material. After identifying the influence of these factors, five dimensionless parameters are proposed to evaluate and rate fuel performance based on Technique for Order Preference by Similarity to an Ideal Solution. As a result, an optimization comes up, scoring 0.310, twice more than the original design, owing to the thermal uniformity and mechanical safety. This study provides a reference for identifying and evaluating the performance of helical structure. © 2024, The Authors. All rights reserved.

关键词： Geometry

Quantitative Calculation of Bubble Pinning to Grain Boundaries in Uo2: A Phase-Field Study

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SSRN 2023年

作者： Liu, Wenbo La, Yongxiao Jiang, Yanbo Yun, Di Sun, Zhipeng Department of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

A phase-field model was established to simulate the pinning effect of fission bubbles on moving grain boundaries (GBs) in UO2 nuclear fuel. It was found that the average velocity of the GB at different positions was obviously different during the movement of the GB with the participation of bubbles. The simulation results also showed that the maximum pinning force of bubbles to the GBs is related to the GB energy and the ratio of bubble diameter to bubble spacing (2r/L). The maximum pinning force decreases with the reduction of the 2r/L, which is consistent with the theoretical analysis results. In addition, the logarithm of the average grain size R has a linear relationship with the logarithm of the bubble volume fraction fv. © 2023, The Authors. All rights reserved.

关键词： Grain boundaries

Research of the Neutronics Performance Improvement Based on the Small Lead-Based Fast reactor Slbr-50

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SSRN 2022年

作者： Zhao, Chen Lou, Lei Zhang, Bin Zhou, Bingyan Peng, Xingjie Wang, Lianjie Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

design of high-performance lead-based fast reactor has already become a hotspot in the advanced reactor system. Research of the neutronics performance improvement is presented based on the small lead-based fast reactor SLBR-50. Parameter sensitivity analyses are conducted, including height-diameter ratio(H/D), reflector assembly arrangement, pitch-diameter ratio(P/D) in fuel assembly, fuel material and fuel enrichment partition. Numerical results of eigenvalue in burnup procedure, assembly power distribution and energy spectrum are analyzed. These results provide influences of these design parameters in quantity and the neutronics performance can be improved with parameter optimization. © 2022, The Authors. All rights reserved.

关键词： Fast reactors

Study on Diffusion and Migration Characteristics of Impurities in Secondary Side of Simplified U-Tube Steam Generator

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SSRN 2023年

作者： Li, Meng Cheng, Kun Wen, Jiming Tian, Ruifeng Fundamental Science on Nuclear Safety Simulation Technology Laboratory Harbin Engineering University Harbin150001 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

In the operation process of nuclear power system, leakage accidents of main and auxiliary condensers are easy to occur, which leads to seawater entering the secondary loop from the condenser, and impurities such as Cl- enter the steam generator with the feed water of the secondary loop, and are enriched near the heat transfer tube. It is easy to cause wear and corrosion of steam generator heat transfer tube, which threatens the safety of nuclear power plant. In order to study the migration and diffusion process of impurity Cl- in the secondary side of steam generator, a multi-bundle three-dimensional physical model of fluid-solid coupling heat transfer in the primary and secondary loop of steam generator and heat transfer tube was established respectively. The fluid flow and heat transfer process between Ushaped tube bundles were simulated numerically to reveal the distribution law of key thermo-hydraulic parameters between Ushaped tube bundles, such as volume vapor fraction, temperature, velocity, etc. The diffusion and migration of Cl- in two-phase flow were also investigated. The influence of thermalhydraulic parameters on impurity migration, two-phase flow in the secondary side and effective diffusion coefficient of chloride ions on chloride ion concentration distribution were *** concentration of chloride ions changes with the change of effective diffusion coefficient of chloride ions. The effective diffusion coefficient of chloride ions is affected by the boiling intensity of coolant and the flow velocity of coolant. The synergistic effect of the boiling intensity of coolant and the flow velocity of coolant affects the migration and diffusion of chloride *** above phenomena may lead to impurity deposition and stress corrosion of heat transfer tubes near the surface. © 2023, The Authors. All rights reserved.

关键词： Steam generators

Numerical Study on Benchmark Analysis of NACIE-UP Facility with Uniform and Non-Uniform Power Distribution

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SSRN 2024年

作者： Li, Haoyang Zhang, Dalin Zhou, Lei Deng, Jian Tian, Wenxi Su, Guanghui Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China Nuclear Power Institute of China 328 Changshun Avenue Chengdu610213 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The NACIE-UP facility is located at the ENEA Brasimone Research Centre and is designed to investigate the thermo-hydraulic properties of LBE within a wire-spaced assembly under uniform and non-uniform power distribution conditions. In this study, the thermo-hydraulic characteristics of FPS are analyzed. ANSYS Fluent solver is applied with the COUPLE algorithm of RANS [[EQUATION]] model. Cheng&Tak correlation and computational conditions are implanted into Fluent in the form of UDFs. The results show that the RMSEs of ADP10SS1 and ADP10SS2 are 2.52 K and 3.69 K, 7.05 K and 8.48 K for ADP06SS1 and ADP06SS2, respectively, which indicate that the adopted models have good prediction ability for the temperature of the experimental conditions. Meanwhile, the heat transfer characteristics are investigated and compared with the correlations of Ushakov, Mikityuk, Kazimi and Carelli. Above all, this study provides quantitative and qualitative analysis for verification and validation of CFD/STH code and stand-alone CFD simulation. © 2024, The Authors. All rights reserved.

关键词： Heat transfer

POST-HOC INTERPRETABILITY BASED PARAMETER SELECTION for DATA ORIENTED NUCLEAR reactor ACCIDENT DIAGNOSIS system

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arXiv

arXiv 2022年

作者： Li, Chengyuan Li, Meifu Qiu, Zhifang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

During applying data-oriented diagnosis systems to distinguishing the type of and evaluating the severity of nuclear power plant initial events, it is of vital importance to decide which parameters to be used as the system input. However, although several diagnosis systems have already achieved acceptable performance in diagnosis precision and speed, hardly have the researchers discussed the method of monitoring point choosing and its layout. For this reason, redundant measuring data are used to train the diagnostic model, leading to high uncertainty of the classification, extra training time consumption, and higher probability of overfitting while training. In this study, a method of choosing thermal hydraulics parameters of a nuclear power plant is proposed, using the theory of post-hoc interpretability theory in deep learning. At the start, a novel Time-sequential Residual Convolutional Neural Network (TRES-CNN) diagnosis model is introduced to identify the position and hydrodynamic diameter of breaks in LOCA, using 38 parameters manually chosen on HPR1000 empirically. Afterwards, post-hoc interpretability methods are applied to evaluate the attributions of diagnosis model's outputs, deciding which 15 parameters to be more decisive in diagnosing LOCA details. The results show that the TRESCNN based diagnostic model successfully predicts the position and size of breaks in LOCA via selected 15 parameters of HPR1000, with 25% of time consumption while training the model compared the process using total 38 parameters. In addition, the relative diagnostic accuracy error is within 1.5% compared with the model using parameters chosen empirically, which can be regarded as the same amount of diagnostic reliability. Copyright © 2022, The Authors. All rights reserved.

关键词： Nuclear power plants