Development and Application of Maintenance Template in Pressurized Water Reactor Nuclear Power Plant

Good practices of maintenance optimization in nuclear power field need to be effectively consolidated and inherited,and maintenance optimization can provide technology support to create a long-term reliable and economic operation for nuclear power plants( NPPs) especially for a large number of nuclear powers under construction. Based on the development and application of maintenance template in developed countries,and combining with reliability-centered maintenance( RCM) analysis results and maintenance experience data over the past ten years in domestic NPPs, the development process of maintenance template was presented for Chinese pressurized water reactor( PWR) NPP,and the application of maintenance template to maintenance program development and maintenance optimization combined with cases were demonstrated. A shortcut was provided for improving the efficiency of maintenance optimization in domestic PWR NPP,and help to realize a safe,reliable,and economic operation for domestic NPPs.

A Novel Computerized Water Level Control System of PWR Steam Generator of Nuclear Power Plant

This paper presents a novel method to solve old problem of water level control system of pressurized water reactor (PWR) steam generator (SG) of nuclear power plant (NPP) .The level control system of SG plays an important role which effects the reliablity,safty,cost of SG and its mathematical models have been solved.A model of the conventional controller is presented and the existing problems are discussed. A novel rule based realtime control technique is designed with a computerized water level control (CWLC) system for SG of PWR NPP.The performance of this is evaluated for full power reactor operating conditions by applying different transient conditions of SG′s data of Qinshan Nuclear Power Plant (QNPP).

Research on Monitoring and Earlywarning System of Marine Organisms for the Intake of Nuclear PowerPlants

An monitoring and earlywarning system is proposed for marine organisms and the cause of water intake blockage is analyzed. Based onthe intelligent sensing technology, computer software and hardware technology and digital signal processing technology, the buoy monitoring platformsystem is developed by internet of things technology, cloud computing and the application of large data. Remote realtime monitoring of aquatic organisms and foreign bodies is realized based on underwater acoustic detection and low light imaging technology. Data processing center is established to store, analyze and process monitoring information and display it in real time, and provide emergency decision support. Through development and test of relevant key equipments, the reliability of cold source system of nuclear power plants is improved, which effectively reduces theinfluence of marine biological invasion on security and economic operation of the units.

Project Construction and Important Technical Innovation for Qinshan Phase Ⅲ (PHWR) Nuclear Power Plant

Qinshan Phase Ⅲ(PHWR)Nuclear Power Plant,the first commercial heavy water reactor nuclear power plant in China,was the biggest trade project performed between the governments of China and Canada.As the owner,the Third Qinshan Nuclear Power Company(TQNPC)persisted in independent innovation management during the project construction,commissioning and self-dependent operation,efficiently realizing the three controls of the project,i.e.quality control,schedule control and investment control,and persisted in technical improvement on the basis of digestion and absorption of CANDU-6 technology to improve the unit safety and reliability.The project construction practice has helped China's nuclear power project management to becomeprogrammed,computerized,standardized and internationalized management from the existing basis.After completion of the project,with unit safe and steady operation as the prerequisite,TQNPC performed several technical modifications and innovations to continuously improve the unit performance.In the area of staff development,TQNPC paid much attention to cultivation of corporate culture,strengthed staff training and built up a good circulating mechanism with staff training and project construction promoting each other.Further to "Zero Breakthrough" and a new step forward of locolization successfully realized in Qinshan Nuclear Power Plant and Nuclear Power Qinshan Joint Venture Company,the improvement and developemnt of nuclear power project management level in Qinshan Phase Ⅲ(PHWR)Nuclear Power Plant provided reference for promotion of nuclear power development in China and standardized management of introducing large imported project.

Assessment of fuel-rod meltdown in a severe accident at Bushehr nuclear power plant(BNPP)

After the Fukushima disaster, interest in the evaluation of severe accidents in nuclear power plants and off-site consequences has significantly increased. Because experimental studies are difficult to conduct, computational methods play a substantial role in accident analysis. In this study, a severe accident in the Bushehr pressurized water reactor power plant caused by a station blackout with a total loss of alternating current power supply has been evaluated. This analysis presents the in-core damage of fuel rods and the release of fission products as well as the thermal hydraulic response of the station components during the loss of active emergency cooling systems. In this manner, a perfect model of the Bushehr nuclear power plant using the MELCOR code is prepared. The accident progression is simulated, and the thermal responses of the fuels and hydraulic components are presented. It is shown that, without operator intervention, steam generators will become dry in approximately 3000 s, and the heat sink of the reactor will be lost. The simulation results show that at approximately 8600 s, the upper parts of the core start melting. This model calculates the shortest available time for accident prevention and proves that the time available is sufficient for operator manual action to prevent a nuclear disaster.

Modeling the Effect of Thermal Diffusion Process from Nuclear Power Plants in Vietnam

In this study, we evaluate the ecological impact of effluent cooling water from the Ninh Thuan nuclear power plant II, using a two-dimensional hydraulic model to simulate thermal diffusion from the effluent outfall. Sites selected for this study were Ninh Thuan nuclear power plant and Vinh Hai seawater in four different scenarios. This paper utilized the relationship between surface water temperature and the water temperature at a depth of -15 m to calculate the water temperature at intake and outlet at a depth of -14 m. A combination between the results of interpolated and results of model showed that effluent cooling water from Ninh Thuan plant affected the largest incidence about 2450 m in the North, 880 m in the South and 960 m in the West. It can be considered as safe distance to not to affect the coral reefs ecosystem in the North and sea turtle conservation area in the South. This study was first in this region to have an integrated approach using two-dimensional model.

Feasibility Study for Self-Sustained Wastewater Treatment Plants—Using Biogas CHP Fuel Cell, Micro-Turbine, PV and Wind Turbine Systems

This paper studies the application of renewable energy sources in wastewater treatment plants to achieve self-sustain- ability of power. The data of wastewater treatment plant in the rural city of Toukh-EGYPT are presented as a case-study. The primary objective is to provide an entirely renewable standalone power system, which satisfies lowest possible emissions with the minimum lifecycle cost. Mass balance principle is applied on the biodegradable components in the wastewater to evaluate the volume of digester gas that is produced from sludge through anaerobic digestion process. Using digester gas as a fuel lead to study combined-heat-and-power technologies, where fuel cell is selected in order to abide by the low emissions constraint. The study assessed the electrical power obtained from fuel cell and the utilization of the exhausted heat energy for additional electrical power production using a micro-turbine. After covering the major part of load demand, the use of other renewable energy sources was studied. The strength of both solar and wind energy was determined by the case-study location. Hybrid optimization model for electric renewable (HOMER) software was used to simulate the hybrid system composed of combined-heat-and-power units, wind turbines and photovoltaic systems. Simulation results gave the best system configuration and optimum size of each component beside the detailed electrical and cost analysis of the model.

混合式抽水蓄能电站对下泄水温影响的数值模拟研究

【目的】混合式抽水蓄能电站运行特性与常规电站相比存在差异,本文旨在掌握抽水蓄能电站水温的变化规律,为水库管理调度提供参考。【方法】以紧水滩水库为研究对象,采用MIKE3水温模型模拟不同进/出水口高程以及不同抽水流量工况的下泄水温,据此探讨混合式抽水蓄能电站对下泄水温的影响。【结果】抽蓄水流会对下泄水温产生影响,相对于现状无抽水工况的下泄水温,抽蓄工况下的下泄水温基本表现为5—9月略有下降,其余月份略有升高,下泄水温的最大降幅不超过0.7℃,最大升幅不超过0.8℃。【结论】进/出水口高程对于下泄水温影响较大,且高程越低,下泄水温差异越大。然而抽水流量对于下泄水温差异影响并不显著,但整体上也呈现出随着抽水流量增加,水温差异增大的趋势。

基于过热蒸汽干燥开式制粉燃褐煤发电技术研究

针对高水分褐煤燃烧发电中存在的热效率低和低负荷稳燃困难等问题,提出了基于过热蒸汽干燥开式制粉系统的新型高效燃褐煤发电技术,该技术采用基于汽轮机抽汽加热的过热蒸汽干燥开式制粉系统,保证了制粉系统的运行安全性,提高了燃烧系统的运行灵活性,实现了制粉系统与锅炉主机的运行解耦,并综合解决了褐煤锅炉炉温低、热效率低的等问题。以600 MW超临界燃褐煤机组为例,对采用该技术的热力系统进行了仿真,分析了其节能与环保效益。研究结果表明,该技术通过对锅炉与汽轮机整体热力系统的综合优化,将汽轮机回热系统扩大至高水分煤的干燥过程,同时梯级回收锅炉排烟废热和制粉乏汽废热至汽轮机回热系统,可获得较为显著的节煤效益。同时,该技术不仅可由节煤相应减少各类污染物及CO_(2)排放,还可回收大量水资源,有望实现零水耗电厂。

发电厂冷却工艺用水发展现状与展望

冷却工艺用水是发电厂总用水量的主要部分。随着全球淡水资源持续紧缺,改进冷却工艺系统、提高冷却水使用效率的必要性和迫切性日益凸显。从多个方面对发电厂冷却工艺节约用水进行了论述,概述了现有冷却工艺的局限性;介绍了对发电厂冷却系统进行改进和优化以实现节水、降耗的新工艺;探讨了以海水和再生水为代表的非传统水源应用于冷却系统的可能性,以及将其应用于冷却工艺时可能面临的复杂性和挑战;介绍了冷却水处理和水质监测的关键技术,阐述了相关技术改进所能带来的节水效果;最后提出了冷却水管理方面存在的机遇与挑战。

核电厂消防水管道的腐蚀与防护研究

针对核电厂消防水管道的腐蚀问题,系统地分析了核电厂消防水系统的组成、运行情况、水质特点等,综述了核电厂消防水管道常见的均匀腐蚀、腐蚀瘤、空泡腐蚀等问题,并阐述了消防水管道腐蚀造成的阀门卡涩、喷淋头堵塞等问题。此外,从消防水系统水质改善、管道材料替换、管道内壁吹扫、定期试验工艺优化等方面,介绍了消防水管道的防护方法,以期为核电厂消防水管道防腐蚀管理提供指导和借鉴。

2023年冬季宁德核电冷源海域棘头梅童鱼(Collichthys lucidus)资源声学评估

滨海核电厂冷却水源的取水安全正受到海洋生物暴发引起的堵塞威胁,鱼类堵塞核电冷源的事件时有发生。声学技术在海洋生物探测方面具有高效、实时的优势,因此,被广泛应用于海洋生态系统研究。为了解冬季宁德核电厂冷却水源取水海域棘头梅童鱼(Collichthys lucidus)的密度和运动规律,利用声学技术对相关海域冷却水源生物量进行了测量和评估。研究结果显示,棘头梅童鱼为研究海域的优势种,拖网调查显示平均尾数密度为1964尾·km^(-2),平均质量密度为0.483 kg·km^(-2)。棘头梅童鱼丰度在研究海域向核电厂方向减少,质量密度以核电厂温排水区域站点最高。通过对鱼类回波特征和个体轨迹的追踪统计,分析了该海域冬季内单体目标强度检测及其空间结构分布、资源现存量和资源丰度密度的时空分布变化。声学走航海域鱼类平均密度为2.78×10^(5)尾·n mile^(-2),生物量密度均值为1.41×10^(4) kg·n mile^(-2),棘头梅童鱼资源总量为7.47×10^(5) kg。研究表明,声学技术在宁德核电厂取水海域冬季冷却水源生物量测量中具有明显优势。通过不断改进和优化方法,声学技术将能更好地支持核电厂取水海域的生态环境监测与资源管理,为冷却水源取水安全提供科学依据。

火电厂再生水中的微生物对管道的腐蚀行为研究

为探究火电厂以再生水为水源时供水管道的微生物腐蚀行为,采用环状生物膜挂片反应器,动态模拟了再生水管道运行状况,通过测定溶液pH值、电导率,试片失重,电化学参数(如氧化还原电位、极化曲线、交流阻抗)、细菌数量并结合SEM、EDS、XRD等手段研究了铁细菌(IOB)、硫酸盐还原菌(SRB)及这2种混合菌对Q235钢腐蚀的影响过程和机理。结果表明,2种细菌数量随时间的延长而增长,再生水的pH值先降后升、电导率则稳步增长,环境中的细菌数与此时管材的腐蚀速率呈正相关性,SRB是影响微生物腐蚀的主要菌种;通过EDS和XRD分析发现不同环境下的腐蚀产物主要成分:IOB时腐蚀产物以FeOOH为主,存在少量Fe_(2)O_(3)、Fe_(3)O_(4);SRB时腐蚀产物主要为氧化铁和硫化铁;而SRB+IOB共存时主要腐蚀产物为Fe_(2)O_(3)、Fe_(3)O_(4)和FeS;同时管道前期表面产生的微生物膜和腐蚀产物会抑制Q235的腐蚀,后期微生物膜失活、覆盖的腐蚀产物脱落,又会使腐蚀加速。

大型直流冷却火电厂用水特征分析

直流冷却火电厂是我国工业用水大户,随着水资源短缺问题日益严重、节水要求日益提高,开展直流冷却火电厂用水特征分析研究,为节水改造提供技术支撑,愈发紧迫。文章以中山嘉明电厂为例,对其开展水平衡测试工作,确定电厂用水结构,推演用水参数及各系统用水指标,进行节水潜力分析并提出节水措施。分析结果显示,直流冷却是该类电厂主要的用水、退水环节,电厂用水指标满足相关定额要求,但在除盐水回用等方面仍有一定的节水潜力。测试及分析的开展为大型直流冷却火电行业节水改造、节水企业创建提供了一定的参考和借鉴。

RCS高硼含硅水处理技术研究进展

目前,国内核电站一回路(RCS)普遍存在水中硅含量上升明显的问题,为寻求解决该问题的合理方法与思路,系统调研了RCS水中硅的主要来源,总结了普通含硅水的处理手段与目前核电站RCS中应用的硅处理方法。调研表明,目前RCS中硅主要来源于Boraflex材料制备的燃料架以及RCS玻璃纤维过滤芯。应用于普通含硅水的处理技术很多,但由于核电站RCS水的高硼特性,在核电站RCS中仅有树脂法和膜法得到了应用和实践,其中离子交换树脂法因成本较高,适合以移动装置的形式应用于对突发状况的应急处理中,NF与RO是用于RCS除硅的典型膜分离工艺,但该工艺对硼的回收率低,需开发新的技术以提高硼的回收率。

核电厂便携式低放废水在线监测设备关键技术探讨

结合核电厂的实际情况和需求,梳理了低放废水的特点,明确了其对便携式在线监测设备的技术要求,其中最关键是能同时满足低探测下限(MDAC≤8 Bq/L)和便携性(设备总重≤50 kg)的限制。讨论了测量方式、探测器选型和校准方式等在线监测设备的关键技术,对低放废水进行了放射性在线监测,测量方式选择取样式,探测器选择大体积NaI晶体,校准方式选择代表点法。调研了低放废水在线监测设备的研究现状,现有的在线监测设备重量都在200 kg以上,与核电厂的要求之间存在较大的差距,有必要开展同时具备低探测下限和优异便携性的新型在线监测设备的研制。对新型探测器的应用、结构和新型测量方式的发展这三个研究方向给出了建议。最后,从提高探测效率的角度,提出了一种基于环形NaI晶体的新型探测器结构,初步论证了其探测下限和设备总重指标有望满足核电厂的要求。

燃煤机组废水资源化利用方案研究

为解决天津A厂1 000 MW燃煤机组废水排放率高、回用率低的问题,通过对废水的基本特征加以明确并对废水收集问题开展深入调查分析,提出了全厂废水资源化利用方案,指导全厂废水高效回用,同时针对终端废水处理系统现存不足进行剖析并提出合理化建议,目的是提高企业的用水水平,真正实现废水梯级利用,并最终达到零排放。

基于经验模态分解的火力发电厂锅炉给水泵振动故障监测

常规的给水泵振动故障监测方法以振动故障分布特征分析为主,受到给水泵运行环境的影响,故障监测存在失误的问题。因此,文章设计了基于经验模态分解的火力发电厂锅炉给水泵振动故障监测方法。提取火力发电厂锅炉给水泵振动信号特征,采集锅炉给水泵的振动信号,反映水泵在不同频率的故障状态。基于经验模态分解构建给水泵振动故障监测模型,利用经验模态分析处理给水泵振动信号,得到IMFs幅值、频率、能量分布等参数,进一步表征给水泵振动故障状态。在线监测发电厂锅炉给水泵振动效率,设置给水泵振动效率阈值,评估给水泵的振动异常情况,从而避免故障监测失误的问题。采用对比实验,验证了设计方法的故障监测准确性更高,能够应用于实际生产中。