Hydrodynamic noise in water-supply systems for nuclear power plants

The results of vibro-acoustic investigation of laboratory model of the fourth circuit of nuclear power plant are presented. It is shown that the spectrogram of hydrodynamic noises is the solid spectrum, on the background of which there are the pronounced discrete components. The centrifugal pump and the throttling orifice are the main reasons of vibrations and noise. The recommendations of how to minimize the hydrodynamic noise in such systems are given. The results of investigation can be used for stationary and floating nuclear power plants and also for other types of power plants.     

电力系统不同过程仿真中的核电机组数学模型研究

针对“核电机组单机容量普遍比火电机组大、运行特性不同于火电机组且在电力系统中比例不断升高从而给电力系统稳定运行造成影响”的问题,在前人建立的详细核电机组数学模型的基础上,建立了适用于电力系统中长期稳定性分析的核电机组数学模型,并在Simulink平台上,通过对单机无穷大系统的暂态稳定性仿真测试,考察了在暂态稳定性仿真中核电机组机械出力以及其他相关变量的变化.研究结果表明,在电力系统暂态稳定性分析中,核电机组机械出力和其他核电机组内部的相关变量变化很小,因此核电机组的机械功率可以当作恒功率来处理,这样可以极大地简化核电机组在电力系统暂态稳定性研究中的数学模型.     

Slip-bearing operation in dense liquid-metal coolants at nuclear power plants

It is presented the results of experimental and numerical investigations in respect to wearing processes occurring in different steel and iron sliding bearing supports of vertical shafts (of pumps and engagements) operating in lead medium, and in the mediums of lead-bismuth and lead-lithium eutectic alloys, if the temperature is less than 510°C, the admixture of thermodynamically active oxygen in molten metal is from 10 up to 10, and there is the solid phase of coolant oxides.     

核电起重机的抗震计算

以核电环行起重机为例,阐述了基于美国ASMENOG-1—2004标准有限元反应谱分析方法在核电起重机抗震计算中的应用,为类似起重机的抗震计算提供借鉴。     

Local fracture properties and dissimilar weld integrity in nuclear power plants

In this paper, the local fracture properties in a Alloy52M dissimilar metal welded joint (DMWJ) between A508 ferritic steel and 316 L stainless steel in nuclear power plants were investigated by using the single-edge notched bend (SENB) specimens, and their use in integrity assessment of DMWJ structures was analyzed. The results show that the local fracture resistance in the DMWJ is determined by local fracture mechanism, and which is mainly related to the microstructures and local strength mismatches of materials at the crack locations. The initial cracks always grow towards the materials with lower strength, and the crack path deviation is mainly controlled by the local strength mismatch. If the local fracture properties could not be used for cracks in the heat affected zones (HAZs), interface and near interface zones, the use of the fracture properties (J-resistance curves) of base metals or weld metals following present codes will unavoidably produce non-conservative (unsafe) or excessive conservative assessment results. In most cases, the assessment results will be potentially unsafe. Therefore, it is recommended to obtain and use local mechanical and fracture properties in the integrity assessment of DMWJs.     

Tribological problems in electrical contacts

Electrical contacts are considered from the point of view of tribological behaviour, and their classification is presented. The main problems in friction, wear and lubrication in connection with the field of application are examined. Contact resistance of electrical contacts is evaluated as a function of surface topography, load and mechanical properties of materials. The interrelation of electrical performances with friction and wear is discussed taking into account material properties and lubricant effects.     

核电阀门鉴定标准的探讨

介绍了核电厂能动机械设备的鉴定标准（ASME QME-1-2002）对于核电厂能动阀门装置的功能鉴定要求,提出了建立我国核电阀门鉴定国家标准的建议。     

核电厂闸阀锅炉效应的危害与防治

论述了核电站用阀门锅炉效应的危害及其产生的机理。结合阀门的功能结构、核电厂的运行以及事故工况、概率安全分析和利益代价比分析等因素,给出待改进阀门的判断方法。针对阀门的不同情况,提出了相应的改进方案。以大亚湾核电厂和岭澳核电厂为实例,介绍了防治阀门锅炉效应的良好实践。     

Tribological problems of mineral comminution

A laboratory method has been developed which involves the use of three new rigs simulating the grinding action in the majority of existing types of mills. All three rigs combine abrasion and erosion with comminution processes. The object of this investigation was to develop a test procedure that would be suitable for general use in estimating the abrasiveness of particular minerals, and to study abrasive wear in various grinding systems. Three separate industrial problems involving coal grinding have been investigated by means of the novel apparatus. The results from the relatively simple laboratory procedures, designed and operated according to the principles of similarity, may be used to predict the service life of grinding machine elements. The tribo-testing procedure and apparatus can be used to evaluate the abrasiveness of any granular mineral, and for testing the wear resistance of any material in abrasive or erosive action. A second paper (see p. 257) publishes results obtained using the apparatus.     

核电站起重机面临的问题及其对策

介绍了核电站起重机的特点,论述加强核电站建造期间、运营检修期间、应急抢险期间所使用的各类起重机安全监管的重要性,探讨了国内核电站起重机在安全监管、检验检测、设计制造、安装维修、使用单位安全管理等方面在法律层面、技术层面和管理层面存在的部分问题,并提出了一些解决的办法,供相关单位参考。     

Structural integrity evaluation for interference-fit flywheels in reactor coolant pumps of nuclear power plants

This study is concerned with structural integrity evaluations for the interference-fit flywheels in reactor coolant pumps (RCPs) of nuclear power plants. Stresses in the flywheel due to the shrinkage loads and centrifugal loads at the RCP normal operation speed, design overspeed and joint-release speed are obtained using the finite element method (FEM), where release of the deformation-controlled stresses as a result of structural interactions during rotation is considered. Fracture mechanics evaluations for a series of cracks assumed to exist in the flywheel are conducted, considering ductile (fatigue) and non-ductile fracture, and stress intensity factors are obtained for the cracks using the finite element alternating method (FEAM). From analysis results, it is found that fatigue crack growth rates calculated are negligible for smaller cracks. Meanwhile, the material resistance to non-ductile fracture in terms of the critical stress intensity factor(K _IC) and the nil-ductility transition reference temperature RTinNDT are governing factors for larger cracks.     

Benchmark analysis on PFM analysis codes for aged piping of nuclear power plants

Probabilistic fracture mechanics is a rational methodology in structural reliability evaluation and risk assessment for aged piping in nuclear power plants. Several probabilistic fracture mechanical analysis codes have been improved or developed in Japan. To verify the reliability and applicability of two of these codes, we did a benchmark analysis using their basic functions in consideration of representative piping systems in nuclear power plants and typical aging mechanisms. Based on the analysis results, we concluded that the analysis results of these two codes are in good agreement.     

小转矩多回转核级阀门电动装置的研制

介绍了核级阀门电动装置在设计、材料选用、鉴定试验等过程中需要考虑的问题。     

AP1000核电厂环吊国产化技术要求分析

由于核电厂总设计理念以及起重机标准的差异,AP1000环吊的技术要求与二代核电厂环吊之间存在显著差异。通过对AP1000环吊的主要技术参数、安全分级、抗震分类、使用工况、抗震分析方法、起升机构强度设计、起升机构布置形式等方面的要求进行梳理和分析,明确了AP1000环吊国产化的主要技术要求,为AP1000环吊的设备国产化作了有益的尝试和探索。     

核电站常规岛和电站配套设施压力管道安全管理

压力管道是核电站常规岛和电站配套设施的重要设备之一,加强对它们的管理和检查是一项重要的工作,为此首先应对核电站常规岛和电站配套设施的压力管道进行普查与信息收集。由于核电站压力管道系统有其自身的特点,因此首先对核电站压力管道的普查范围、选管分类原则、信息收集内容进行了阐述,其中重点介绍了压力管道的选管分类原则。最后对核电站压力管道数据库开发以及完善压力管道的检验制度进行了初步的探讨。     

Tribology in coal-fired power plants

Material wear and degradation is of great importance to the economy of South Africa especially within the mining, agriculture, manufacturing and power generation fields. It has been found that unexpected and high rates of fly-ash erosion occur at certain sections of power plants, this is particularly evident at the Majuba power station. The loss of small amounts of material due to erosion can be enough to cause serious damage and significantly reduce the working lifetime of, for, e.g. hopper liners.This study investigated the long-term solid particle erosion of a range of oxide and nitride-fired SiC-based ceramics and alumina with the aim of reducing erosive wear damage in power plants. This entailed carrying out experimental tests on an in-house built erosion testing machine that simulate the problems encountered in the industry. The target materials were eroded with 125–180 μm silica sand at shallow and high impact angles. The surface wear characteristics were studied using both light and scanning electron microscopy (SEM).The results obtained indicate that the erosion rates of the materials remain fairly constant from the onset. It was found that prolonged exposure to erosion results in the progressive removal of the matrix and subsequent loss of unsupported SiC particulates. The fact that the particles were relatively small did not have a significant effect on the erosion rate. This would explain the observed constant rates of erosion for longer periods. These behaviours can be further explained in terms of the composition and mechanical properties of the erodents and target ceramics.     

Application of super-resolution techniques to expert testing of welded joints in pipelines of nuclear power plants

Utilization of super-resolution techniques in processing reflected signals in ultrasonic testing has proved to be useful with a view to improve expert estimates of defect dimensions and shapes with the help of theAvgur holographic facility. In particular, the improvements in the image quality mostly due to athree-fold increase in the beam coordinate resolution has allowed more accurate determination of defect dimensions and more reliable classification of defects.A lower intensity of the speckle noise due to the broader frequency band can also be considered as a favorable feature of the extrapolation techniques. The signal-to-noise ratio in the images of flaws in materials with an intense structural noise isa factor of about 1.7 higher when super-resolution techniques are used. The paper describes some results of practical utilization of super-resolution techniques in estimating dimensions of flaws detected in welded joints of DU-300 pipelines (an effective diameter of 300 mm) of nuclear power plants.     

Wear problems in nuclear industry

In nuclear industry, several kinds of components or materials are subjected to wear phenomena. As the real system cannot be fully instrumented parameters regarding contact kinematics are not perfectly known. Mock up scale 1 and parametric tribometers are used to approach these phenomena. Initially, it is essential to be able to observe worn parts taken from reality or very similar system. It is then considered essential to research on the exact conditions of the encountered and to isolate them. To be representative of the effectively activated wear mode, the tests will have to feature similar wear kinetics and aspects (including shape and dimension). The damage survey is the key point in order to be realistic for improving solutions.     

Tribology in nuclear power generation

A prerequisite for the efficient production of electricity from nuclear power reactors is a high degree of reliability and predictability of performance in engineering components and plant. This can only be achieved if engineering designs are based on sound tribological principles and incorporate the best available data from well planned back-up research and development programmes.The approaches being adopted to tackle the specifically nuclear orientated (ie non-conventional) engineering problems in nuclear power generation are discussed and examples given of successful solutions at all of the various stages of the nuclear fuel cycle ranging from uranium enrichment to power station operation, spent fuel reprocessing and, finally, disposal of waste products. The paper is not intended to be a comprehensive review and does not cover all the areas in great detail.     

Wave mixing in oscillatory-type power plants

We have investigated processes of wave mixing in oscillatory-type power plants and presented the results in the paper. The flow in the power plant has been simulated by solving a set of 2D nonstationary Navier–Stokes equations for viscous uncompressible liquid. The flow field was formed by blade vibration and, as a result, the triangle deformed mesh has been used. The marker method has been used as the basic method for calculating the evolution of the admixture. The information of computations is processed using special criteria of the mixture quality. The influence of frequency and amplitude on the mixing intensity has been investigated. The consumed power has been estimated. The obtained information forms a basis for determining optimal modes of power plant operation in terms of power consumption–mixing efficiency.