bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corrosion Behavior of a Novel Alumina Forming Austenitic Steel Exposed to Supercritical Water
Authors: Sun Dayun , Gao Yang , Cong Shuo , Guo Xianglong 
Published: November 2022

Abstract
The corrosion behavior of novel alumina-forming austenitic steel Fe-26Ni-19Cr-2.5Al-1Nb-0.5Si and 310S steel in aerated supercritical water (SCW) at 550 °C/25 MPa was investigated. The AFA and 310S steels has been exposed in supercritical water for up to 1000h. The results show that both the weight gain curves of AFA and 310S steels follow near-parabolic law. Although the weight gain of 310S steel exposed in supercritical water after 1000h was up to 37 mg/dm2, the weight gain of AFA steel exposed in supercritical water after 1000h was near 18 mg/dm2, which was only half of that of 310S steel. The weight gain curves indicating that the AFA steel has better corrosion resistance than 310S steel. Besides, microstructure characterization of two steels has been conducted by SEM, EDS and XRD. SEM images shows that there are some differences between surface morphology of 310S steel and AFA steel. The microstructure results show that 310S steel has a double oxide layer: a Fe-riched outer layer and a Cr-riched inner layer, while a multilayer structure mainly composed of Fe-riched oxide layer, Cr-riched oxide layer and Al-riched oxide layer was formed on AFA steel, indicating a different corrosion process from 310S steel. The corrosion mechanism of two steels based on the microstructure is discussed in detail.
Bubble Behaviors in Saturated Flow Boiling Based on the VOF Model
Authors: Gao Deyang , He Wen , Bo Hanliang 
Published: November 2022

Abstract
Flow boiling in vertical pipes widely exists in nuclear reactors. The bubble motion and behavior attract more and more attention due to their influence on the heat transfer capacity. However, the most used two-phase flow model in numerical simulation, called Eulerian two-fluid model, is not able to obtain parameters of phase interfaces and provide an observed image of bubble movements. Therefore, the present study aims to simulate the bubble behavior and trajectory in the saturated flow boiling in the vertical pipe using VOF model which can treat the deformation of interfaces. Firstly, the bubble parameters were calculated based on existing bubble dynamic models. Then, the random generation of bubbles was simulated by directly adding mass and momentum sources into the flow region by the User Defined Function (UDF). Finally, the deformation, collapse, and coalescence of bubbles were simulated and predicted in bubbly flow. The feasibility of the newly proposed model is proved by comparing with experimental data and other simulation results. The present study provides a new idea for simulating the movement of a large number of bubbles in the saturated flow boiling in vertical pipes, which adopts bubble parameters as boundary conditions directly, instead of heat and mass transfer models. In comparison, the present model can greatly improve the calculation efficiency.
Analysis of Contribution Degree of Vibration Transmission of Bolted Structure
Authors: Liu Shuai , Li Wanyou , Huang Xuan , Xiong Furui , Jiang Xiaozhou , Deng Liwei 
Published: November 2022

Abstract
In practical engineering, the vibration transmission between bolted structures supported by cantilever beams involves many factors, including the friction between plates and the bolt connection relationship. The vibration transmission effect is the embodiment of the coupling of various factors, so it is impossible to accurately and quantitatively evaluate the influence degree of various factors. In this paper, the influence factors of vibration between bolted plates in the form of cantilever beam are studied by numerical calculation method. The effects of friction coefficient, bolt preload, temperature and internal and external pressure on vibration characteristics are studied. Finally, the contribution of different influencing factors to vibration transmission is given. The preliminary research shows that the bolt connects the two plates into a whole structure, and its stiffness changes little with the friction coefficient, bolt preload, temperature and internal and external pressure. The natural frequency of each order increases with the increase of friction coefficient, bolt preload and internal and external pressure, decreases with the increase of temperature, and the overall trend changes little. At the same time, the bolt preload is verified by test, the difference of natural frequency under the same preload is compared and analyzed, the numerical calculation is compared with the test value, and the vibration contribution of preload is verified.
Experimental Studies and Mechanical Properties Analysis of Three-Dimensional Oblique Rotating Friction Seismic Isolators
Authors: Wu Saifeng , Liu Wenguang , He Wenfu 
Published: November 2022

Abstract
Traditional isolation devices widely provide protection only against the horizontal components of earthquake motions. The vertical ground motions are transmitted through the isolation system unchanged or even magnified. Thus, in this paper, a mechanical model of a novel three-dimensional oblique rotating friction seismic isolator is proposed. The device with oblique-torsion coupling deformation is designed by combining three inclined rubber bearings. The test results show that the device have asymmetric behavior and a plump hysteretic loop in a vertical direction. After three times cyclic loading, the slope of the curve for the device hardly changes, and there is no damage in the loading process. The error of vertical post-yield stiffness of the device between the experimental result and theoretical prediction is within 10%, and it is in good agreement with the theoretical model prediction. In addition, the effects of different parameters are highlighted based on the theoretical mechanical model. The results show that the inclination angle, the friction coefficient, radius of PTFE, distance from the center of the inclined LRB to the center of the rotating block, and the performance of the inclined LRBs strongly influence the vertical behavior of the proposed device and should be worthy of attention in the design of devices.
An Experimental Study on the Retention of Graphite Dust Aerosol in Pool Scrubbing and the Possible Application in HTGRs
Authors: Wang Yating , Zhang Yiyang , Fang Zhu , Wu Xinxin 
Published: November 2022

Abstract
Owing to the inherent safety, the modular high-temperature gas-cooled reactor (HTGR) eliminates the possibility of severe accidents in principle. Therefore, the source term is the main concern for HTGR accidents. Especially, the graphite dust problem, arising from the abrasion of fuel pebbles, complicates the evaluation of source terms. In the water ingress accidents, the graphite dust may be released to the containment during the overpressure discharge, which not only contributes to the source term but also makes trouble for post-accident measures. In this work, we consider the possibility to develop a pool scrubbing measure to retain graphite dust and fission products for the overpressure discharge of HTGR. A scrubber is set up with aerosol particle concentration measurement at both the inlet and outlet, which enables us to determine the decontamination factor (DF). By conducting a series of experiments for different submergence depth and particle size, it is demonstrated the DF value increases with the increase of submergence depth. When the submergence depth is 105 cm, the retention efficiency of graphite particles larger than 2 μm exceeds 96%. Our previous study has shown due to a fragmentation effect, most of the graphite particles released during the overpressure discharge are below 2 μm, while the DFs for these small particles fall below 20. The experimental results show that the pool scrubbing technology can efficiently retain the graphite particles for the overpressure discharge in HTRGs. More efforts are still needed to effectively improve the DF for graphite particles below 2 μm.
Simulation of Plasma Magnetic Confinement System Based on Modelica Language: Starting with a Single Particle
Authors: Lyu Hanyang , Wang Xiang 
Published: November 2022

Abstract
This article uses Modelica language to create a plasma magnetic confinement system with a single charged particle. The physics used in the article is basically the equations of a charged particle moving in a magnetic field. The Modelica language is an object-oriented component-based programming language that can easily modularize the system. The geometric part represented by the program can be processed automatically after the input of parameters. At last, the program simulates three different operating conditions for a magnetic confinement system. The initial velocities and initial positions that are different from the standard case, and the combination of the two are selected as the experimental objects. By comparing with the simulation with the case without magnetic confinement, the results show that the confinement system is effective.
Seismic Isolation Reliability Analysis of a Lead-Bismuth Small Modular Reactor
Authors: Huang Yi , Qi Min 
Published: November 2022

Abstract
Seismic isolation technology has been proven to significantly reduce the seismic response of the structures, systems and components (SSCs) in a nuclear power plant (NPP), improve the seismic reliability and safety of nuclear power plants, reduce construction costs, and shorten construction periods. Reliability analysis of a lead-bismuth small modular reactor (SMR) with a seismic isolation design was conducted: ANSYS APDL was used to establish a finite element model of the SMR, modal analysis was performed on the isolated SMR, and the dynamic characteristics of the SMR was obtained; seismic design spectrum proposed by Newmark-Hall was used as input for seismic spectrum analysis, and the seismic response evaluation of SMR was carried out; ANSYS PDS (Probability design system) module was used to carry out probabilistic calculation of the above process, and the calculation considers the uncertainties in the physical parameters of structure materials and isolation bearings, geometric dimensions and seismic response spectrum, the random variables were sampled by the Latin hypercube sampling method in the Monte Carlo method, and failure probability of isolated SMR and non-isolated SMR were obtained through mathematical statistics. The calculation results show that the seismic isolation design can significantly reduce the failure probability under earthquakes and improve the safety of lead-bismuth SMR.
The Reconstruction of 3d Radiation Field Based on Sparse Measurement Data
Authors: Xie Xingwen , Cai Jiejin , Tang Zhihong 
Published: November 2022

Abstract
With the development of nuclear technology, more and more occupational workers work in radioactive environments. The three-dimensional (3D) dose rate field is of great significance in the radiation protection field. Many researchers focus on the reconstruction of 2D radiation fields but few of them paid attention to the reconstruction of the 3D radiation field based on sparse measurement data. In this work, an interpolation method is introduced to reconstruct 3D radiation field using sparse sampling nodes. The proposed method includes interpolation on sampling grid lines, interpolation on sampling grid plane and interpolation in the three-dimensional space. Additionally, two simulation cases are conducted in MATLAB to prove the effectiveness and accuracy of the proposed method. Case1 and Case 2 are 3D radiation fields with a single radioactive source and two radioactive sources respectively. The reconstruction radiation field is compared to the dose rate field simulated by the Monte Carlo method. By using less than 1% of measurement data, the proposed method precisely reconstructs radiation fields with an average relative error of 0.82% and 1.71% respectively. What’s more, the accuracy of the proposed method was studied at different sampling node ratios. As the ratio of sampling nodes decreases, the average error and maximum of the relative error increase obviously. The proposed method is an interpolation method suitable for the radiation field and it can reconstruct the 3D radiation field accurately with sparse data.
Research on Cold End Optimization of Water Supply Mode of Expanded Unit System of Circulating Water System in Coastal Nuclear Power Plant
Authors: Lin Fang , Jian Jiale , Wang Fang , Yang Jia 
Published: November 2022

Abstract
A typical northern nuclear power plant and a typical southern nuclear power plant are selected to optimize the cold end of the circulating water system with one machine and two pumps in an expanded unit system. And study the optimal operation mode of the circulating pump and the cold end configuration scheme with the minimum annual cost in this water supply mode. It is discussed how to combine the site conditions of the nuclear power plant, the price of raw materials and the main cold-end equipment of the steam turbine, the cost of the main structures of the water supply and drainage system and the related annual operating costs, power generation income and other factors, to seek the optimal solution through economic and technical comparison of multiple schemes. That is to select the optimal matching combination scheme of the configuration of the cooling water system such as the configuration scheme of the low-pressure cylinder of the steam turbine, the area of the condenser, the flow rate of the cooling water pump, and the cooling water pipe trench, and determine the economical and reasonable design parameters of the equipment at the cold end. By comparing the cold end optimization results of the constant speed scheme of 1 machine with 2 pumps, the frequency conversion scheme of 1 machine with 2 pumps and the expansion unit system scheme of 1 machine with 2 pumps, the frequency conversion scheme of 1 machine with 2 pumps is superior in terms of technology and economy and has a great advantage for the northern site. For the southern site, due to the higher water temperature and smaller variation, the advantage is less.
Study on Technology and Application for Health Assessment of Electronic Equipment
Authors: Guilian Shi , Xiaojin Huang , Xiaopeng Zhao 
Published: November 2022

Abstract
Electronic equipment is an indispensable part of high reliability equipment such as aerospace and nuclear power plant (NPP). It is difficult to evaluate the health condition of the electronic equipment because of its complex structure and uncertain fault behavior. This paper firstly classifies the health assessment methods of electronic equipment, introduces in detail the main technical methods under the three categories of classical assessment methods, data-based assessment methods and physical model-based assessment methods, and analyzes the advantages and disadvantages of each method. In addition, considering the increasingly complex functional structure of electronic equipment, its physical failure mechanism is more difficult to grasp. From the perspective of application potential, this paper focuses on the research of data-based health assessment strategy, proposes a multi-model health assessment method based on working conditions, gives a general model of electronic equipment health assessment, and gives a way to obtain model parameters through the local optimal least square method. Finally, the above strategy is applied to study the degradation condition of DCDC power module aging test data of nuclear power board, and the validity of the proposed algorithm is verified based on the degradation data of board aging test, which provides a reference for electronic equipment health evaluation.
Seismic Behavior Study of a new Isolated Structure System With Damping Supporter for Nuclear Power Plants in a Cave or Underground
Authors: Feng Yixin , Xu Hao , Liu Wenguang , Zhang Qiang 
Published: November 2022

Abstract
There have been heated discussions on how to reduce the earthquake response of NPPs. Generally, isolation technology is one of the most efficient methods but researches on traditional isolated structure and 3D isolated structure for NPPs, to some extent, have deficiencies. Therefore, in this paper, a new structural system which included base isolation system and lateral damping supporters for NPPs (hereinafter referred to as DISO) in a cave or underground was proposed to obtain a positive seismic response, aiming to protect the nuclear island. The motion characteristics of the system have been studied and a simplified mathematical model has been set up. The dynamic equation was deduced and solved. The theoretical analysis results that there is an optimal range of parameter β, the ratio of the damping coefficient of the additional damping support to the equivalent linear damping coefficient of isolation layer, to get a positive response of DISO system. The seismic response of the DISO structural system was analyzed and the correlation that the parameters including damping arrangement coefficient, damping index and damping coefficient have with the seismic response of the structure were discussed. The results show that the acceleration response of the DISO system decreases to minimum value with the increasing of damping coefficient, along with whiplash effect, and then increases regularly. There is a positive correlation between the damping coefficient and displacement decline rate. A case study has been completed. The numerical results show that the DISO system performs more effectively than the ISO system (refer to the traditional isolated structural system). Given that the equipment and pipelines in NPPs are sensitive to large isolation displacement, the displacement response of DISO system is less than that of the traditional isolated structural system without acceleration amplifying. Moreover, both acceleration of superstructure and displacement get decreased. And IDA-based (Incremental Dynamic Analysis) seismic fragility analysis of ISO and DISO system has been performed. DISO system has the smaller probability of failure compared with the ISO system.
Measurement of Unbalance Vibration Phase for Active Magnetic Bearing in High Temperature Gas-Cooled Reactor
Authors: Bian Xiaoyu , Shi Zhengang , Zheng Yangbo , Mo Ni , Shi Lei 
Published: November 2022

Abstract
In high temperature gas-cooled reactor (HTGR), the primary helium circulator (PHC) is the key component of the reactor. The active magnetic bearing (AMB) has some outstanding advantages such as micro-friction, no need of lubrication, high temperature resistance, extended life and so on. It is the ideal support device for the rotor of the PHC because it can ensure a clean helium environment. Generally, due to the existence of mass imbalance of the rotor, the AMB system will generate unbalance vibrations during operation. Accurate measurement of the unbalance vibration phase is of great significance to the analyses of dynamic balance and speed up and down of the AMB system. In this work, the principle of the unbalance vibrations and the incidental problems are analyzed in great detail. And a simple and practical unbalance vibration phase measurement algorithm is proposed by combining hardware structure with software programing. This algorithm consists of real-time peak detection and phase calculation, which can realize real-time and accurate measurement of the unbalance vibration phase. In addition, the proposed method can reduce the effect of the noises of the AMB system. The experiment results demonstrate that the proposed algorithm effectively revises the conventional phase measurement methods, improves the accuracy and reduces the inherent error of the system.
Study on the Fallback Time Analysis Method for Loss of Ultimate Heat Sink Under Normal Power Operation of Nuclear Power Unit
Authors: Zhang Zhao , Yan Jun-Jie , Li Gen , Chong Dao-Tong , Liu Ming , Wang Zi-Chun , Shen Rong-Fa 
Published: November 2022

Abstract
For the beyond design basis accident, loss of ultimate heat sink under normal power operation of CPR1000 nuclear power unit, an analytical model is proposed to evaluate the process during which the component cooling system is cooled by the Refueling Water Storage Tank, which is very important for the accident treatment. The results of the analytical model agree well with that provided by EDF. Based on the according strategies of State-oriented Procedure, a fallback time analysis method is carried out, the result is in accordance with the simulation time on the full-scope simulator. These indicate that the analytical model for the cooling process and the fallback time analysis method are correct.
A Novel PID Self-Tuning Method Based on Closed-Loop Identification Used in Nuclear Power Plants
Authors: Zhang Pengbin , Xing Kunpeng , Zou Tao , Yang Zhijia , Wang Jingyang , Wang Hongrui 
Published: November 2022

Abstract
Nuclear power is one of several significant clean energy and its production capacity is increasing rapidly. This paper proposed a novel PID self-tuning method based on closed-loop identification used in nuclear power plants to deal with the turbine’s load tracking problem. A setpoint-shifting method is adopted to achieve the informativity of the closed-loop system, and the PID parameters are designed through an optimization method. For validating the proposed method, this paper modeled a pressurized-water reactor (PWR) nuclear power plant, a complex system consisting of three circuits, through the first principle. The primary circuit contains three main devices: a nuclear reactor, a pressurizer, and a steam generator. The models of these three devices are provided by previous literature separately. The whole model is generated through mass and energy balance. This mechanism model is used as the plant model, while the identified model is used as the control model. The initial PID parameters are set through open-loop identification using an external excitation. Then the proposed method works online to track the turbine’s load in time. The effectiveness of the proposed method is illustrated by simulations.
Investigation on the Inspection Technology of GH3535 Alloy Butt Weld With Linear Array Probe
Authors: Yuan Xiaodan , Li Zhijun 
Published: November 2022

Abstract
The critical problem to accurately characterizing defects in GH3535 alloy weld is the deflection of the acoustic beam and scattering due to the coarse columnar grains. Signal-to-noise ratio is an important index to indicate whether the grain scattering is severe in the ultrasonic inspection. In this paper, the phased array ultrasonic testing of GH3535 alloy butt weld with the thickness of 46mm was studied using sector scan mode with linear array (LA) probe with 64 channels. The center frequency is 2.25MHz, and the incident angle is 19.87°. The sound field characteristics of the linear array probe with different focusing parameters were analyzed, and the signal-to-noise ratio (SNR) in the detection was calculated. The results show that: the grain size of butt weld ranges from 40um to 500um. The acoustic beam of the linear array probe can cover the weld thickness range of 5–39mm, based on the removal of weld reinforcement. The signal-to-noise ratio of transverse hole with φ3mm located at the weld-fusion line is more than 15dB, when the front end of the probe is located directly above the transverse hole of weld-fusion line.