“华龙一号”ZH-65型蒸汽发生器研发

"华龙一号"是我国自主研发的具有完全自主知识产权的第三代压水堆核电技术。介绍了"华龙一号"核电机组反应堆冷却剂系统关键设备ZH-65型蒸汽发生器(SG)的自主研发情况,主要包括SG的设计、设计软件研发、设计验证试验和关键材料研制。ZH-65型SG在技术上达到第三代PWR核电站SG的水平,具有完全自主知识产权,是"华龙一号"头上的一颗璀璨明珠。该型SG的研发成果已用于出口巴基斯坦的K2K3工程项目和福建福清核电站第5、6号机组工程项目。K2机组的3台ZH-65型SG已于2017年7月12日验收出厂,必将创造良好的经济效益和显著的社会效益。     

蒸汽发生器完整性评估的现状及展望

本文阐述了核电厂蒸汽发生器完整性评估的三个发展阶段,分析了不同国家SG完整性评估技术的现状及异同,并从技术层面、核电厂层面和核安全监管机构层面展望建立适用于国内的SG完整性评估技术体系需进行的工作。     

防振条对蒸汽发生器传热管完整性的影响分析

以二代加压水堆核电厂蒸汽发生器(SG)为例,分析了防振条组件对SG传热管完整性可能产生的影响。分析表明:发现防振条自身扭转、防振条与传热管之间的间隙、防振条的下插深度等对传热管的完整性影响较大。为提高传热管在役运行的可靠性,防振条的设计中对防振条组件(AVB)与SG传热管之间的设计间隙应作充分的考虑,避免在装配时对管束和AVB施加异常外力并确保同组AVB的下插深度一致。     

核电厂全厂断电工况下蒸汽发生器自然循环特性的比例分析

试验验证是支撑新型先进压水堆核电技术的设计和核安全审评的重要手段,考虑到建设1∶1尺度的试验装置会导致高昂的建造成本,通常会开展比例试验研究。为了保证比例试验装置的重要现象与原型核电厂的现象具有相似性,试验获得的数据可以支撑原型电厂的设计,需要开展充分的比例分析工作。基于比例分析的重要性,文章以非能动核电厂AP1000的全厂断电事故为研究背景,采用H2TS方法开展了比例分析,重点关注了主回路自然循环阶段蒸汽发生器(SG)内的热工水力学行为,获得了相应的相似准则,并进行了失真分析,得出以下结论:当SG的高度比和流通面积比与系统级的高度比和流通面积比一致时,SG装置的关键现象与原型SG的关键现象之间存在相似关系;采用等物性模拟全厂断电事故情况下,蒸汽发生器换热能力远大于堆芯衰变功率,能够满足堆芯冷却的功能需求,蒸汽发生器换热量不存在失真。     

EPRI《蒸汽发生器完整性评估导则》解读

《蒸汽发生器完整性评估导则》是美国电力研究院发布的用于评估蒸汽发生器(Steam Generator,简称SG)完整性的导则。该导则通过SG传热管结构完整性评估、一次侧—二次侧泄漏完整性评估以及二次侧完整性维护进行SG完整性评估。基于导则及相关文献调研与分析,从历史背景、发展历程、内容框架三个方面较为详细地介绍了《SG完整性评估导则》的基本信息,并对我国建立SG完整性评估技术体系的必要性和需开展的工作进行了初步讨论。《SG完整性评估导则》的全面解读对于推动我国核电厂开展SG完整性评估工作具有重要意义。     

AP1000蒸汽发生器环焊缝局部热处理防DING分析及监造措施

AP1000蒸汽发生器(SG)的环焊缝局部热处理防永久变形(DING)技术是有别于二代核电SG焊缝局部热处理的一项新工艺,文章从DING产生的原因、影响因素、工艺预防措施进行简单介绍,提出在质量监督过程中需要关注的重要检查点。     

AP1000核电厂乏燃料贮存安全性分析

福岛事故暴露出了二代沸水堆乏燃料组件贮存的安全问题。本文比较了三代AP1000核电技术与二代沸水堆技术在乏燃料贮存方面的差异。AP1000核电厂乏燃料水池冷却系统运用先进的非能动设计,通过多种补水方式和补水水源以及沸水蒸汽排放控制等措施可有效地解决福岛事故中存在的问题,保障了乏燃料组件贮存的安全性。     

民用小堆SGTR防满溢设计改进

民用小堆因单位功率下的蒸汽发生器（SG）汽空间偏小,稳压器容积和SG传热管内径偏大等特点,会引起蒸汽发生器传热管破裂（SGTR）事故快速满溢。本文采用RELAP5程序对民用小堆SGTR事故开展了优化措施研究,并提出极限单一故障下防止SG发生满溢的工程可行方案,即增加SG高水位排放液体的溢流管线或提高二次侧设计压力且同时增加自动的安注闭锁信号,保证在事故过程中蒸汽发生器不满溢和放射性排放满足限值要求。在民用小堆专设设备基本不变的前提下,针对系统进行了优化,极大地提升了安全性,为民用小堆设计改进提出了工程可行方案。     

蒸汽发生器水位全程控制系统数字化及仿真实现

采用单冲量和三冲量的水位控制方案设计了蒸汽发生器(SG)水位的全程数字化控制系统,提出一套利用软件模块组态的方法,实现了水位控制策略。并将此方案应用于核电仿真机的运行。仿真结果曲线表明,设计的控制方案能使SG水位在稳定工况时保持恒定;变负荷时,水位能随着负荷的变化而产生变化并最终保持在恒定值上。     

蒸汽发生器二次侧下部流场与排污试验

位于核电厂蒸汽发生器（SG）管板内的下部排污结构能吸出管板二次侧表面的泥渣并将其排出。为了能合理设计该排污结构并提升排污效率,本文基于非能动大型先进压水堆（CAP1400）的SG设计原型结构,按照1∶4比例设计了排污试验体,以模拟SG下部的管板、传热管等部件。通过对下部流场进行计算流体动力学（CFD）计算并与排污试验的结果进行对比,进一步掌握近管板表面区域的流体流动特征。本试验通过研究SG近管板区域流体流动特征及泥渣分布规律、测量试验体各部件压降、对比SG单边和双边排污结构的设计,为减少淤泥集结、改进设计提供依据。研究发现,单/双边排污结构排污性能基本相同,单边排污结构即可将试验体内泥渣颗粒有效排出。     

Life prediction of steam generator tubing due to stress corrosion crack using Monte Carlo Simulation

The failure of steam generator tubing is one of the main accidents that seriously affects the availability and safety of a nuclear power plant. In order to estimate the probability of the failure, a probabilistic model was established to predict the whole life-span and residual life of steam generator (SG) tubing. The failure investigated was stress corrosion cracking (SCC) after the generation of one through-wall axial crack. Two failure modes called rupture mode and leak mode based on probabilistic fracture mechanics were considered in this proposed model. It took into account the variance in tube geometry and material properties, and the variance in residual stresses and operating conditions, all of which govern the propagations of cracks. The proposed model was numerically calculated by using Monte Carlo Simulation (MCS). The plugging criteria were first verified and then the whole life-span and residual life of the SG tubing were obtained. Finally, important sensitivity analysis was also carried out to identify the most important parameters affecting the life of SG tubing. The results will be useful in developing optimum strategies for life-cycle management of the feedwater system in nuclear power plants.     

Prediction of SG Tube Support Plate Flow Area Blockage Rate Using SG Wide Range Level Measurements and Hydrodynamic Analysis

Some nuclear power plants have recently experienced hydrodynamic instability in steam generators (SGs). Instability, if present in the SG of a pressurized water reactor, results in the periodic oscillation of the water level, steam flow, feedwater flow, and the flow through the circulation loop. In this instability analysis, the major parameters are the power level and flow area of the tube support plate (TSP). The threshold power above which instability may occur is generated by variations in TSP flow area. The current method of estimating the blockage rate is the visual inspection of the SG interior. This type of visual inspection, however, requires many resources. To improve this method, we focus on measurements of the SG level. The measurements of the level change because the SG downcomer flow rate varies due to the blockage of the TSP flow area. To quantify this effect, we calculate the circulation ratio in relation to changes in TSP flow area. In addition, we evaluate the pressure drops that affect the SG water level. Sensor drift analyses of the level measurements are performed to confirm that the level variance is derived from system characteristics rather than sensor drift. Finally, the blockage rates of the TSP flow area are generated by using measurements of the SG water level.     

AP1000核岛主设备锻件性能提高对制造的影响

为了满足AP1000核电站设计寿命60年的需求,核岛设备蒸汽发生器锻件的强度和韧性要求比CPR1000核岛主设备都有所提高,加之尺寸增大,使得AP1000蒸汽发生器锻件的制造难度加大,对其变化认识不够,不仅锻件的产品质量不稳定,而且后序的焊接也可能出现质量问题,文章通过对比分析AP1000核电蒸汽发生器锻件与CPR1000锻件的变化,提出了采取措施的方向。     

Adaptive estimator-based dynamic sliding mode control for the water level of nuclear steam generators

Steam Generator (SG) is a crucial component of nuclear power plant. The proper water level control of a nuclear steam generator is of great importance in order to secure the sufficient cooling source of the nuclear reactor and to prevent damage of turbine blades. The water level control problem of steam generators has been a main cause of unexpected shutdowns of nuclear power plants which must be considered for plant safety and availability. The control problem is challenging, especially at low power levels due to shrink and swell phenomena and flow measurement errors. Moreover, the dynamics of steam generator vary as the power level changes. Therefore, it is necessary to improve the water level control system of SG. In this paper, an adaptive estimator-based dynamic sliding mode control method is developed for the level control problem. The proposed method exhibits the desired dynamic properties during the entire output tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness and stability. Simulation results confirm the improvement in transient response obtained by using the proposed controller.     

PGV-1500 steam generator. New problems and solutions

The basic questions concerning the development of a steam generator for a nuclear power plant with a VVé R-1500 reactor are presented. The basic design requirements which follow for steam generators from experience in operating analogs at nuclear power plants and taking account of the requirements for a reactor system are presented. The special features inherent to horizontal-type steam generators, which have been mastered and are used in nuclear power plants in our country, are noted. The domestic and world operating experience is taken into account in the development of the design. It is concluded that the design of the PGV-1500 steam generator satisfies the requirements for the concept of a VVéR reactor facility for a 1500 MW(e) unit of a nuclear power plant and is competitive on the world market for power-generating equipment for nuclear power plants. __________ Translated from Atomnaya énergiya, Vol. 99, No. 6, pp. 416–425, December, 2005. An erratum to this article is availabel at .     

AP1000核岛主设备用SA508-3钢锻件的监造

ASME SA508-3钢具有优越的可焊性、较好的抗中子辐照脆化性能和非常好的断裂韧性以及冲击韧性,因此被广泛应用于压水堆核电站核岛压力容器的制造中。AP1000三代核电机组的一些主设备,如反应堆压力容器、蒸汽发生器、稳压器的全部大锻件及一些重要部件均采用了这一钢种。通过对SA508-3钢锻件制造过程中的技术要点的分析,指出了该钢种的锻件在制造过程中的质量关注重点,提出了对该钢种锻件实施监造过程中的监督方法和监督重点。     

Evaluation of the burst characteristics for axial notches on SG tubings

Some events of steam generator tubes have been reported in some nuclear power plants around the world. Main causes of the leakage are from various types of corrosion in the steam generator (SG) tubing. Primary water stress corrosion cracking (PWSCC) of steam generator tubing have occurred in many tubes in Korean plants, and they were repaired using sleeves or plugs. In order to develop proper repair criteria, it is necessary to ascertain the leak behavior of the tubings. A high-pressure leak and burst testing system was manufactured. Various types of electro-discharged-machined (EDM) notches having different lengths were machined on the o.d. of test tubes to study SG tube behavior. Leak rate and ligament rupture pressure as well as the burst pressure were measured for the tubes at room temperature. Rupture pressure of the part through-wall defect tubes depends on the defect depth and length. Water flow rates after the rupture were independent of the flaw types; tubes having 20–60 mm long EDM notches showed similar flow rates regardless of the initial defect depth. A fast pressurization rate generated a lower burst pressure than the case of a slow pressurization.     

Numerical model for estimation of corrosion location in nuclear power plant steam generators

Deposition of dissolved impurities and corrosion in steam generators is a significant problem in the operation of nuclear power plants. Impurities and corrosion products usually accumulate in the secondary sides of steam generators (SG) and form deposits on the SG surfaces. A high level of impurity concentration close to the SG heating surface causes the corrosion process to occur with more intensity. The aim of this study is to estimate the most probable locations of impurity concentration and deposition in a SG. Equations representing the convection and diffusion in the liquid phase close to the heated surface (the viscous sub layer) are derived. Based on the mass balance of impurities in the viscous sub layer as the boundary condition, the derived differential equations are solved by the finite volume (upwind) methods. The distribution of impurities, sediment formation rate and the location of the depositions in the viscous sub layer at different heat flux values are studied in steady and unsteady states.     

核电厂主蒸汽隔离阀控制系统故障分析及可靠性提升

主蒸汽隔离阀是核电厂核岛与常规岛间主蒸汽管线上最重要的隔离设备,主要介绍了秦山第二核电厂1/2号机组主蒸汽隔离阀控制系统功能及控制原理、故障模式分析。结合历史故障统计得出系统的薄弱点—限位开关,并对限位开关故障失效机理和根本原因分析进行了重点阐述,最后针对系统的可靠性提升从人、机、料、法、环5方面提出了改进措施,对国内其他在役核电厂主蒸汽隔离控制系统维护和改进有一定的借鉴和参考意义。      

新型蒸汽发生器综合性能实验研究

由于蒸汽发生器中流动及传热的复杂性,目前华龙一号ZH-65型蒸汽发生器不能完全通过理论计算进行设计,其性能是否满足设计要求必须通过开展相应的实验予以确认。本文利用中国核动力研究设计院的蒸汽发生器综合实验装置对新型蒸汽发生器开展综合性能实验研究,以验证ZH-65型蒸汽发生器二次侧自然循环性能和总体性能。通过稳态实验研究,获得了蒸汽发生器不同功率负荷下二次侧出口蒸汽压力、蒸汽产量、出口蒸汽湿度、循环倍率、给水组件阻力、汽水分离器压降等关键热工参数,全面验证了蒸汽发生器静态工作特性。本文还对蒸汽发生器瞬态工作特性进行了深入研究,获得了蒸汽发生器阶跃条件下的运行特性,获得的实验数据表明,华龙一号ZH-65型蒸汽发生器完全满足设计要求。