蒸汽发生器二次侧pH分布的模型研究  

Distribution of pH values in a model simulating the secondary side of a steam generator

作　　者：肖发亮 钟婷婷 付威伶 康晓言 邓水全 XIAO Faliang;ZHONG Tingting;FU Weiling;KANG Xiaoyan;DENG Shuiquan(College of Chemistry,Fuzhou University,Fuzhou 350108,China;State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,China;College of Chemistry and Materials Science,Fujian Normal University,Fuzhou 350007,China;Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China,Fuzhou 350108,China)

机构地区：[1]福州大学化学学院,福州350108 [2]中国科学院福建物质结构研究所结构化学国家重点实验室,福州350002 [3]福建师范大学化学与材料学院,福州350007 [4]中国福建光电信息科学与技术创新实验室(闽都创新实验室),福州350108

出　　处：《核技术》2022年第11期87-98,共12页Nuclear Techniques

基　　金：国家自然科学基金(No.22031009、No.21921001、No.22075282、No.61874122);国家重点研发计划(No.2021YFB3601501);中国科学院青年创新促进会(No.2019302);中国福建光电信息科学与技术创新实验室(闽都创新实验室)(No.2021ZR123)资助。

摘　　要：核电站二回路的腐蚀问题一直是影响其安全和效率的重要原因之一。实际运行中通过加入碱化剂调控二回路水的pH可以有效减缓管道腐蚀。然而,二回路实际工况的复杂性使pH的分布存在显著的非均匀性而难于获得。目前,对于一些关键部位的pH大多采用外部实验或用国外的商用软件进行模拟,但这些模拟很难考虑实际的工况条件。本文首先建立含有碱化剂的二回路水中重要离子之间温度相关的平衡关系,并进一步通过有限元方法研究了二回路模型系统中水的温度场分布,据此计算了相应的pH分布,研究了不同总浓度条件下,复合碱化剂摩尔浓度比、支撑板等对pH分布的影响;研究了乙醇胺(Ethanolamine,ETA)对pH更好的提升效应并发现了有关的饱和效应。这些结果对解决核电站二回路的腐蚀问题及降低其运行成本提供了有价值的参考。[Background]The corrosion of the secondary circuit has remained a challenging problem influencing the security and efficiency of a nuclear power plant.In an actual operation,an amount of alkalizer is usually added into the secondary circuit water to adjust its pH value to alleviate the corrosion of the pipelines.However,the very complex real working condition results in a significantly inhomogeneous distribution of the pH values,and the enclosed nature of the secondary circuit have frustrated various efforts to control the precise pH values at some key sites inside the circuit.So far,pH values around such key locations have been roughly estimated by either external simulating experiments or by using patented commercial software of foreign companies.However,it is difficult for such external simulations to take into account the various important working conditions.[Purpose]This study aims to develop a method without specific assumptions or uncontrolled approximations to calculate the distribution of pH values in the secondary circuit under its working conditions.[Methods]Firstly,the complex and repeated structure inside the steam generator was simplified and simulated by using one direct tube model.Except for the length,the other geometrical dimensions,support plates as well as the tube material etc.were chosen to be as similar as possible to the actual ones.Then,all temperature-dependent equilibriums involving H+in water solution of the secondary circuit were considered with additional consideration of the equilibriums of the alkalizers in the gas and liquid phases.As an essentially field quantity defined on the space of the secondary circuit,these pH values together with other relevant parameters,such as temperature,fluid velocity etc.were depended on the position coordinates,and were calculated by using the finite element method coded in the COMSOL package.Finally,the boundary conditions of flowing rate and temperature of the water at the inlet were set as 1.0 m·s−1 and 543.2 K,respectively,and the pressure a

关 键 词：PH 碱化剂 有限元模拟 腐蚀 二回路 

分 类 号：TG174[金属学及工艺—金属表面处理] TM623.7[金属学及工艺—金属学]