检索结果-内蒙古大学图书馆

SSRN 2024年

作者： Lin, Yue Zhang, Dalin Chen, Yutong Zhang, Xisi Deng, Jian Du, Peng Tian, Wenxi Qiu, Suizheng Su, Guanghui Department of Nuclear Science and Technology State Key Lab. of Multiphase Flow in Power Engineering Shaanxi Key Lab. of Advanced Nuclear Energy and Technology Xi’an Jiaotong University No.28 Xianningxilu Beilinqu Shaanxi Xi’an710049 China Institute of Reactor Engineering Technology China Institute of Atomic Energy Beijing102413 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu610213 China

As an important link in the possible occurrence of steam explosions, the interaction between molten materials and coolant is of great significance for safety analysis in severe accidents of nuclear reactors. This study is based on the two-dimensional multiphase and multi-component fluid dynamics code ACENA to model the process of single molten lead bismuth droplet impacting a water tank and obtain the velocity changes of the molten droplet as it moves through the water tank. Furthermore, a sensitivity analysis of relevant factors such as the heat transfer area fraction and drag coefficient of the droplet is carried out. To verify models in ACENA, the computation results are compared to experimental data. It is demonstrated that the overall trend of the velocity curve acquired by the ACENA code during the interaction between a molten lead bismuth droplet and water is consistent with the experimental results. The droplet falling velocity increases with the increase in droplet temperature when the temperature of water is the same, and the droplet falling velocity increases with the increase of water temperature at the same droplet temperature. The simulation results by ACENA code for MFCI are in good agreement with experiments which verifies the accuracy of relevant models in ACENA. It can provide an effective means for safety analysis of nuclear reactors in China. © 2024, The Authors. All rights reserved.

关键词： Drops

来源：评论

学校读者我要写书评

暂无评论

Experimental Study on Flow Resistance and Phase Distribution of Gas-Liquid Flow in Helical Cruciform Fuel Assembly

SSRN

引用

SSRN 2024年

作者： Zhang, Qi Wang, Haoyu Li, Junlong Ren, Quanyao Zhou, Yi Zheng, LeLe Zhang, Yile Li, Dongyang Gu, Hanyang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China School of Nuclear Science and Engineering Shanghai Jiao Tong University Shanghai200240 China Harbin Engineering University China

The helical cruciform fuel (HCF) is characterized by self-supporting and enhanced transverse mixing, which may replace the cylindrical fuel of the light water reactor (LWR). In this work, the flow resistance and phase distribution of a 4×4 HCF assembly was investigated by experimental method. The experimental system of air-water two-phase flow was established, and the void fraction was gained by wire-mesh sensor (WMS). The dummy HCF elements produced by additive manufacturing technology were assembled with the locating plates. The evolution of the flow regime and the void fraction of the central and peripheral were paid particular attention. The correlations for the two-phase friction multiplier and void fraction were proposed based on the experimental data. © 2024, The Authors. All rights reserved.

关键词： Two phase flow

来源：评论

学校读者我要写书评

暂无评论

Residual resampling-based physics-informed neural network for neutron diffusion equations

arXiv

引用

arXiv 2024年

作者： Zhang, Heng He, Yun-Ling Liu, Dong Hang, Qin Yao, He-Min Xiang, Di Chongqing University of Posts and Telecommunications Chongqing400065 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China CNNC Engineering Research Center of Nuclear Energy Software and Digital Reactor Chengdu610213 China

The neutron diffusion equation plays a pivotal role in the analysis of nuclear reactors. Nevertheless, employing the Physics-Informed Neural Network (PINN) method for its solution entails certain limitations. Traditional PINN approaches often utilize fully connected network (FCN) architecture, which is susceptible to overfitting, training instability, and gradient vanishing issues as the network depth increases. These challenges result in accuracy bottlenecks in the solution. In response to these issues, the Residual-based Resample Physics-Informed Neural Network(R2-PINN) is proposed, which proposes an improved PINN architecture that replaces the FCN with a Convolutional Neural Network with a shortcut(S-CNN), incorporating skip connections to facilitate gradient propagation between network layers. Additionally, the incorporation of the Residual Adaptive Resampling (RAR) mechanism dynamically increases sampling points, enhancing the spatial representation capabilities and overall predictive accuracy of the model. The experimental results illustrate that our approach significantly improves the model’s convergence capability, achieving high-precision predictions of physical fields. In comparison to traditional FCN-based PINN methods, R2-PINN effectively overcomes the limitations inherent in current methods, providing more accurate and robust solutions for neutron diffusion equations. Copyright © 2024, The Authors. All rights reserved.

关键词： Network architecture

来源：评论

学校读者我要写书评

暂无评论

Electrolytic Failure Modeling of Aluminum Electrolytic Capacitor by Finite Element Method

Electrolytic Failure Modeling of Aluminum Electrolytic Capac...

引用

Power Electronics and Application Symposium (PEAS), IEEE International

作者： Xinrui Chen Ran Yao Hui Li Wei Lai Yuan Min Cheng Yang Zeyu Duan Siyu Chen State Key Laboratory of Power Transmission Equipment Technology Chongqing University Chongqing China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

The failure rate of aluminum electrolytic capacitor (AEC) is high in power electronic systems. Due to the complex structure of AEC, it is difficult to establish an actual model, so experiments are the common way to analyze the failure of AEC. Thus, this paper proposes a finite element method (FEM) for AEC considering electrolytic failure. Firstly, the mechanism of electrolytic failure and changes of characteristic parameters in the AEC are elucidated. Secondly, an equivalent finite element model is established to simulate and analyze the electrolytic failure of AEC. Finally, the effectiveness of the proposed AEC FEM method is verified through capacitor aging experiments.

关键词：

来源：评论

学校读者我要写书评

暂无评论

AN UNSUPERVISED LEARNING-BASED FRAMEWORK FOR EFFECTIVE REPRESENTATION EXTRACTION OF reactor ACCIDENTS

arXiv

引用

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 Sichuan China

Compared to knowledge-based diagnostic systems, data-based methods tend to perform better in terms of speed and accuracy in diagnosing reactor accidents, and have significant advantages in terms of scalability of models. With the increasing use of high-precision system analysis programs in nuclear engineering, the number of high-fidelity computational data for accident simulation is exploding. Therefore, an algorithm that can achieve both automatic extraction of low-dimensional features from the data and guarantee the validity of the features is needed to improve the performance and confidence of the accident diagnosis system. This study proposes an autoencoder-based autonomous learning framework, namely Padded Auto-Encoder (PAE), which is able to automatically encode accident monitoring data that has been noise-added and with partially missing data into low-dimensional feature vectors via a Vision Transformer-based encoder, and to decode the feature vectors into noise-free and complete reconstructed monitoring data. Thus, the encoder part of the framework is able to automatically infer valid representations from partially missing and noisy monitoring data that reflect the complete and noise-free original data, and the representation vectors can be used for downstream tasks for accident diagnosis or else. In this paper, LOCA of HPR1000 was used as the study object, and the PAE was trained by an unsupervised method using cases with different break locations and sizes as the dataset. The encoder part of the pre-trained PAE was subsequently used as the feature extractor for the monitoring data, and several basic statistical learning algorithms for predicting the break locations and sizes. The results of the study show that the pre-trained diagnostic model with two stages has a better performance in break location and size diagnostic capability with an improvement of 41.62% and 80.86% in the metrics respectively, compared to the diagnostic model with end-to-end model st

关键词： Extraction

来源：评论

学校读者我要写书评

暂无评论

Corrosion Behavior of Alumina-Forming Austenitic Steel in Supercritical Carbon Dioxide Conditions: Effects of Nb Content and Temperature

SSRN

引用

SSRN 2023年

作者： Ma, Zhaodandan Cong, Shuo Chen, Huan Liu, Zhu Dong, Yuanyuan Tang, Rui Chen, Yong Guo, Xianglong Science and Technology on Reactor System Design Technology Laboratory Chengdu610041 China Science and Technology on Reactor Fuel and Materials Laboratory Chengdu610041 China Nuclear Power Institute of China Chengdu610041 China Shanghai Jiao Tong University Shanghai200030 China

The corrosion behavior of alumina-forming austenitic (AFA) stainless steels with different Nb additions in supercritical carbon dioxide environment at 500℃, 600℃ and 20 MPa were investigated. A novel structure with a double oxide was identified as outer Cr2O3 oxide film and inner Al2O3 oxide scale with discontinuous Fe-Cr spinel outermost in the steels with low Nb content and a transitional layer, consisting of Cr spinel and γ`-Ni3Al phase was distributed randomly below the oxide scale. The oxidation resistance was improved by decreasing diffusion of oxygen after adding 0.6wt.% Nb. However, the corrosion resistance ability degraded significantly at higher Nb level due to the accelerated diffusion rate of ions through the refined grain boundaries, which resulted in the formation of a continuous thick outer FeCr2O4 layer on the surface and an internal oxide zone. Fe2(Mo, Nb) Laves phase were discovered as well with high Nb addition, which promoted the production of cracks inside the oxide film. Fewer spinel and thinner oxide scales were found after exposure at 500℃. The specific mechanism was discussed. © 2023, The Authors. All rights reserved.

关键词： Alumina

来源：评论

学校读者我要写书评

暂无评论

A Novel Model for Dynamic Process Study of reactor Control Rod Drive Mechanism

A Novel Model for Dynamic Process Study of Reactor Control R...

引用

International Conference on Electrical Machines and systems (ICEMS)

作者： Yun Yang Qiwei Xu Xuefeng Zhang Tianda Yu Xinan Chen Yizhou Zhao National Key Laboratory of Power Transmission Equipment Technology Chongqing University Chongqing China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

The magnetic jack type control rod drive mechanism (CRDM) is a critical electromagnetic actuator utilized in reactors, with its movable components subject to the combined effects of electromagnetic force, liquid resistance, spring force, and other factors, resulting in highly nonlinear and uncertain motion characteristics. This article establishes a novel model for the dynamic process analysis of the CRDM. The dynamic electromagnetic force and inductance of the CRDM are analyzed based on the equivalent magnetic network (EMN) model, taking into account mesh reconstruction and magnetic saturation. Through kinematic analysis and parameter coupling analysis, electromagnetic and kinematic parameters during the CRDM lifting process are obtained. Finally, finite element analysis (FEA) and experimentation are conducted to validate the accuracy of the proposed model.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Simulation Method for Multiscale Failure of Optocoupler Based on Aging of Solder Layer in Photovoltaic MOSFET

Simulation Method for Multiscale Failure of Optocoupler Base...

引用

Power Electronics and Application Symposium (PEAS), IEEE International

作者： Xuan Chen Ran Yao Hui Li Wei Lai Yuan Min Cheng Yang Zeyu Duan Siyu Chen Zhen Xing State Key Laboratory of Power Transmission Equipment Technology Chongqing University Chongqing China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

This paper presents a simulation method for investigating the failure of optocoupler equipment (OCEP) in multi-physical fields. The method is based on the aging of the solder layer of the photosensitive field-effect tube (PFET) and aims to analyze the performance degradation of the PFET. Firstly, a comprehensive multi-physical field model of the OCEP is developed using the actual structure of the CT test OCEP, taking into account the conductivity of the chip. Next, an OCEP failure simulation method is proposed, which takes into account the shedding of the PFET solder layer caused by the failure mechanism of the OCEP. Finally, the simulation results demonstrate that the degree of solder layer shedding reaches 70%, resulting in the failure of the OCEP.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A Long-term Dependent and Trustworthy Approach to reactor Accident Prognosis based on Temporal Fusion Transformer

arXiv

引用

arXiv 2022年

作者： Li, Chengyuan Qiu, Zhifang Ma, Yugao Li, Meifu Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

Prognosis of the reactor accident is a crucial way to ensure appropriate strategies are adopted to avoid radioactive releases. However, there is very limited research in the field of nuclear industry. In this paper, we propose a method for accident prognosis based on the Temporal Fusion Transformer (TFT) model with multi-headed self-attention and gating mechanisms. The method utilizes multiple covariates to improve prediction accuracy on the one hand, and quantile regression methods for uncertainty assessment on the other. The method proposed in this paper is applied to the prognosis after loss of coolant accidents (LOCAs) in HPR1000 reactor. Extensive experimental results show that the method surpasses novel deep learning-based prediction methods in terms of prediction accuracy and confidence. Furthermore, the interference experiments with different signal-to-noise ratios and the ablation experiments for static covariates further illustrate that the robustness comes from the ability to extract the features of static and historical covariates. In summary, this work for the first time applies the novel composite deep learning model TFT to the prognosis of key parameters after a reactor accident, and makes a positive contribution to the establishment of a more intelligent and staff-light maintenance method for reactor systems. Copyright © 2022, The Authors. All rights reserved.

关键词： Nuclear industry

来源：评论

学校读者我要写书评

暂无评论

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

SSRN

引用

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

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：