秦山核电厂蒸汽发生器水位控制试验

简要介绍了蒸汽发生器水位控制系统的运行方式和试验方法。试验项目包括旁通阀控制试验、主给水阀控制试验和旁通阀与主给水阀的切换试验。文中给出了试验结果,即在液位扰动和核动率扰动时,蒸汽发生器液位的变化过程。经过两个月的运行和瞬态试验,证明蒸汽发生器水位控制系统满足设计要求。     

阳江核电厂1号机组旁路阀优化策略研究

阳江核电厂1号机组给水调节阀均由FISHER换型为MASONEILAN后,由于旁路给水控制系统参数与实际情况不符,直接造成蒸汽发生器液位剧烈波动,进而触发跳堆事件。优化主给水控制系统(ARE)控制逻辑中ARE407/408/409RG(小阀控制曲线函数)曲线函数,通过优化控制函数的方式来弥补现场设备与控制逻辑不符的情况,实现蒸汽负荷与给水流量的匹配。优化后与参考机组对比可发现,机组正常升功率经过大小阀切换点与30%FP(FP为满功率)平台大小阀切换试验过程中蒸汽发生器液位扰动情况,阳江1号机组试验结果明显优于参考机组。     

自然循环蒸汽发生器瞬态热工水力建模与分析

应用瞬态分析专用程序建立了CPR1000蒸汽发生器几何模型,对CPR1000蒸汽发生器在功率运行期间停运一台主泵时的热工水力瞬态响应、主蒸汽管道破裂和蒸汽/主给水流量同时+10%阶跃扰动工况下的瞬态响应进行了模拟与分析,获得了蒸汽发生器内部热工水力参数如流量、温度、换热系数的响应特性,分析结果表明,瞬态分析模型满足蒸汽发生器设计瞬态分析的要求。     

基于模糊控制的核电蒸汽发生器水位的串级自抗扰控制

针对核电站蒸汽发生器所存在的非线性,时变性,大时滞等特点,本文提出了基于模糊控制的蒸汽发生器水位的串级自抗扰控制方案。该方案采用双闭环控制,内环采用带前馈的一阶线性自抗扰控制调节阀,并分别前馈补偿蒸汽扰动和给水扰动,外环采用二阶模糊自抗扰,设计了新型的幂次控制率。仿真结果表明,该控制方案对蒸汽发生器水位具有良好的控制效果,与串级ADRC-PID控制系统相比,不仅具有优良的鲁棒性和抗干扰能力,而且具有可行性。     

ACPR1000核电厂SG水位控制调试方法研究

针对改进型压水堆核电机组(ACPR1000)蒸汽发生器(SG)水位控制的难点,从水位控制原理和工艺系统耦合问题进行分析,找出调试的关键点。对传递函数进行差分化推导,计算并设置PID控制系统各参数。在首次升功率到30%FP(FP:满功率)期间完成小阀的调试、二回路蒸汽负荷映像(411ZO)系数调试、大小阀切换点设置等重要调试工作。在RRC(Reactor Control)瞬态试验过程中验证控制效果,结果表明该调试方法效果良好,在各瞬态试验中SG水位控制稳定。     

压水堆蒸发器水位调节失控跳堆分析及在线诊断调整

分析了核电站引发蒸发器给水控制系统(ARE)水位跳堆的主要原因和薄弱环节,建立了在功率运行状态下进行ARE主阀调节偏差在线调整和旁路阀调节偏差在线调整技术,提出并实施处理方案,解决了压水堆机组在启停过程中水位容易发生失控的技术难题.     

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。     

AP1000核电机组凝结水精处理设计特点及调试经验反馈

AP1000核电机组60 a的设计寿命对二回路水质提出了更高要求。为保证水质并提高系统固有安全性,海阳核电站凝结水精处理采用无阀旁路工艺,通过增加后置过滤器、改进再生设备、优化再生工艺来控制硫酸根的生成,防止蒸汽发生器不锈钢腐蚀;凝结水精处理系统调试时按照西屋分包模式进行,对调试过程中出现的一些情况进行了经验反馈。     

CPR1000新项目DCS手自动无扰切换实现研究

无扰切换是调节系统设计时要考虑的主要问题之一。调节控制中自动切向手动后,在施加手动作用前,阀位保持在切换前自动信号决定的位置,不存在扰动问题;但由手动切向自动时,原决定于手动作用的阀位一般与自动装置计算出的阀位不完全一致,如果在实现上未采取措施,将产生扰动问题。本文主要论述CPR1000新项目DCS平台手自动无扰切换的实现方法。     

CPR1000堆型主给水隔离措施改进分析

CPR1000机组主给水流量控制系统(ARE)的调节阀站位于常规岛厂房,由于其所在的常规岛厂房是按非核级抗震等级设计,故在叠加地震事件的工况下,ARE系统给水调节阀和隔离阀有可能被破坏,导致主给水不可控地注入蒸汽发生器,进而可能通过安全壳内蒸汽管道破口进入反应堆厂房,引起安全壳超压风险。文章主要是针对此问题提出改进方案,并从确定论和概率论两方面保证改进方案的可行性,以期能开展对主给水隔离措施的专题研究。     

钠冷快堆一回路主循环泵在厂外主辅电源切换工况下的运行特性研究

在厂外主辅电源切换时,为避免因一回路主循环泵（简称主泵）运行引起反应堆保护停堆或电机辅助绕组启动,对主泵惰转特性及转速控制进行分析,分别对快切和慢切工况下主泵的快速飞车启动和搜频飞车启动模式进行研究,给出了不同模式下主泵的最低转速预测模型,分析出了快切工况（断电1.5 s）下主泵最低转速为708.3 r/min,慢切工况（断电10 s）下最低转速为341.2 r/min。在主泵水台架上,用1.5 s和10 s断电试验来模拟厂外主辅电源快切和慢切工况,试验结果表明,快切工况下主泵最低转速为689r/min;慢切工况下主泵最低转速为346.7 r/min。最低转速预测值与试验值吻合较好,偏差小于3%。试验验证了主泵在主辅电源切换工况下的运行特性,可实现快切不导致反应堆保护停堆,慢切不导致辅助绕组启动,对反应堆安全运行具有指导意义。     

大亚湾核电站闸阀锅炉效应状况及其改进

基于国际上相关的闸阀锅炉效应的试验和研究结果,利用甄别方法及概率安全分析(PSA)方法对大亚湾/岭澳核电站每个机组的闸阀锅炉效应进行了分析.结果表明,大亚湾/岭澳核电站每个机组的闸阀RIS063/064VP及PTR022VB需要改进.为了防止阀腔超压,改进的措施分别为:RIS063/064VP增加带有双向逆止阀的的旁路,PTR022VB则在高压侧的闸板上钻孔.     

旁路阀调节对高温气冷堆闭式布雷顿循环瞬态特性影响研究

闭式布雷顿循环是第4代高温堆核能系统的关键技术之一,其典型的动态过程是旁路阀调节。为分析这一过程,建立了循环中关键部件的动态模型,其中压气机在径向平衡模型基础上耦合了对附面层发展的预测,兼顾了计算效率与准确性;换热部件模型基于双曲型守恒律方程,对工质的热物性和参数的快速变化有较好的适应性。在此基础上根据回路的质量守恒和压力平衡原则将各部件的模型耦合,建立了系统的动态模型。由于旁路阀调节是氦气透平发电系统主要的功率快速调节手段,瞬态效应较为显著,以模块式高温气冷堆（HTR-10GT）旁路阀开启后的过渡过程作为算例,分析了主要循环参数的响应特性,并通过分析,给出了降低输出功率的机制。计算结果表明：系统的容积惯性对旁路阀调节的响应速度影响较大,而阀门的开度则决定了系统在末态的输出功率;回热器的温度冲击现象可能发生在调节过程中,但可通过两旁路阀联动的方式缓解;反应堆出口温度变化幅度很小,因此反应堆模型的准确程度对结果基本无影响。     

蒸汽发生器液位控制系统手自动切换的前馈补偿研究

当前蒸汽发生器（SG）液位控制系统手自动切换信号复制回路的设计中,液位控制器运算基准为切换时的汽水失配信号,主给水流量调节阀由手动模式切到自动模式后导致SG液位控制系统失去快速调节给水流量的前馈作用。针对该问题,结合阳江核电厂4号机组SG液位高高跳堆事件,提出了针对手自动切换操作方式和系统设计的2种优化方案。针对操作方式的优化,在主给水流量调节阀投自动前,手动平衡汽水流量;针对系统设计的优化,增加汽水失配判断环节和前馈自动补偿环节。通过SG液位扰动试验证明,所提出的优化方案能有效提高手自动切换后控制系统的调节速度、减小超调量,对核电机组安全运行水平提升有重要贡献。      

Design and control of coaxial switching system for ion cyclotron wave resonance heating system of EAST

Ion cyclotron wave resonance heating system(ICRH) which is one of the most important auxiliary system in EAST provides conditions for heating the plasma. In order to make the whole transmission network of ICRH form the required state, the coaxial switching system was developed, which mainly consists of 11 same coaxial switches. Each coaxial switch has a controller with an RS485 communication interface and is able to switch between two states. All controllers are integrated to an RS485 hub which connects to the computer. A master computer software is developed to control the coaxial switching system so as to achieve the state needs of ICRH. Moreover, several rounds of experiments show that the coaxial switching system operates reliably. The coaxial switching system has already been applied to normal use currently.     

Model development and simulation of transient behavior of helium turbine system

This paper describes a performance model for the transient analysis of helium turbine system. Governing equations have been derived from integral forms of unsteady basic conservation equations. The one-dimensional model is employed for flow-paths except turbine and compressor, which are considered as zero-dimensional components and volume-less treatment is employed. Component mathematical model results in a set of ordinary differential equations and algebraic equations. The simulation code is established on MATLAB, and the ordinary differential equations are solved a variable order solver of MATLAB, ode15s. The accidents of loss of load and loss of feedwater to precooler and intercooler, the transients of recuperator and the decreasing heat transfer capacity of intermediate heat exchanger are simulated respectively. The analysis of calculated results verifies the present model. The effects of bypass valve size and thermal inertia of the recuperator wall are also studied. The simulation results show that throttle size of bypass valve has important influence on the characteristics of turbine system and should be carefully selected to satisfy the requirement of system control and safety.     

Development of diagnosis algorithm for the check valve with spectral estimations and neural network models using acoustic signals

We have developed a method for detecting and diagnosing a disk wear failure and a foreign object failure among the various failure modes of check valves. The method is based on the acoustic emission sensors which can detect the sound wave of the leakage flow and the estimation of the power spectral densities with an auto-regressive model. For validating the method, we implemented a hydraulic test loop with an artificially failed check valve. We have found that the frequency spectrums from the acoustic signals are strongly dependent on the failure modes of the check valve and that they are nearly independent of the failure size and operating pressure through an estimation of the power spectral density with an auto-regressive signal processing model. In addition, the root mean square values of the acoustic signal and the amplitudes of the power spectral density as well as the loop pressure have a strong dependency on the failure size in each failure mode of the check valve. We developed a diagnosis algorithm by using neural network models in order to identify the type and size of the failure in the check valve. The diagnosis algorithm consists of a hierarchical model composed of three back-propagation neural networks. The results of our research and the experiments show that the diagnosis algorithm is proven to be a good solution for identifying the failures of the check valves without any disassembling work.     

An efficient static correction algorithm with application to the hydrodynamic loading of thin shell structures

This paper treats the problem of correctly accounting for the quasi-static component of the response of a thin-shell structure to a dynamic loading which originates from a pressure disturbance within the body of a contained fluid. The importance of quasi-static structure response has been observed in BWR safety/relief valve (SRV) actuation tests which produce a pressure oscillation in the suppression pool as a consequence of the expansion and contraction of bubbles formed from air expelled from the SRV pipeline. The problem is treated within the context of a finite-element methodology which has been previously developed for the coupled analysis of a linear elastic structure in contact with a linear acoustic fluid. For problems involving a large number of degrees of freedom, the efficient application of this method requires reduction to a set of normal modes approximating the response of the coupled fluid-structure system. The coupled modes are synthesized from the fluid properties and a set of normal modes describing the behavior of the structure in the absence of the fluid. The proposed solution to the problem is to append a shape function, representing the quasi-static component of the structural response, to the set of modes computed by standard eigenvalue extraction. The success of the method is demonstrated by comparison of calculated results with measured structural response from a typical SRV test.