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首页> 外文会议>NPC 2010;International radiolysis, electrochemistry and materials performance workshop;Nuclear plant chemistry conference;Internaional conference on water chemistry of nuclear reactor systems >DISPERSANT APPLICATION: (1) DURING STEAM GENERATOR WET LAYUP FOR REMOVAL OF EXISTING DEPOSITS, AND (2) DURING THE LONG-PATH RECICRULATION CLEANUP PROCESS OF THE CONDENSATE/FEEDWATER SYSTEM TO REDUCE STARTUP CORROSION PRODUCT TRANSPORT TO THE STEAM GENERATORS
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DISPERSANT APPLICATION: (1) DURING STEAM GENERATOR WET LAYUP FOR REMOVAL OF EXISTING DEPOSITS, AND (2) DURING THE LONG-PATH RECICRULATION CLEANUP PROCESS OF THE CONDENSATE/FEEDWATER SYSTEM TO REDUCE STARTUP CORROSION PRODUCT TRANSPORT TO THE STEAM GENERATORS

机译：分散应用：（1）在蒸汽发生器湿敷以去除现有沉积物期间，以及（2）在冷凝水/给水系统的长途回收清洁过程中，以减少腐蚀产物向蒸汽发生器的传输

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During the last few decades, utilities have spent considerable resources minimizing corrosion product deposition within steam generators (SGs). In the past, two basic approaches have been used: 1. Reducing the corrosion product ingress rate (e.g., by replacing secondary components containing corrosion-susceptible materials, implementing favorable chemistry changes, etc.) 2. Removing corrosion products which have accumulated in the SGs through top-of-tubesheet (TTS) sludge lancing and other chemical and mechanical methods Despite the success of these methods, there are limitations, including practical lower limits on the feedwater iron concentration and the high cost and effectiveness limits of cleaning techniques (particularly for crevices). A third approach is the online addition of a polymeric dispersant to promote suspension of corrosion iron, thereby reducing deposition onto SG surfaces and facilitating more efficient removal via blowdown. More than a decade of qualification work and two full-scale plant trials-at ANO-2 in 2000 and at McGuire Unit 2 from 2005 to 2007-addressed initial technical concerns, paving the way for routine use in nuclear SGs. Online application of dispersant at the four Exelon plants with recirculating SGs is the focus of another paper at this conference. This paper is focused on the additional benefits that could be gained from similar dispersant applications during: 1. normal SG wet layup to remove some of the existing deposit inventory 2. routine long-path recirculation cleanup of the PWR secondary side prior to startup The addition of dispersant to the SGs during full wet layup periods could provide additional benefit by dispersing loose sludge powder that has accumulated, thereby facilitating its removal. Routine dispersant-assisted wet layup applications could be performed in conjunction with normal layup protocols without affecting the planned outage schedule, and could potentially reduce the frequency of more costly deposit management operations (e.g., sludge lancing, chemical cleaning, etc.). In 2009 EPRI worked with Exelon Corporation to develop and implement a plan for a trial dispersant application during the SG wet layup at Three Mile Island Unit 1 (TMI-1). Because the SGs were scheduled for replacement during the Fall 2009 outage, this trial represented a unique opportunity to evaluate the efficacy of a dispersant wet layup application with minimal risk to the SGs. This paper discusses the technical bases supporting the addition of dispersant during wet layup at TMI-1 and the results of the Fall 2009 trial application. Additional applications, under EPRI sponsorship, have either just taken place (Doel 3 in Summer 2010) or are planned (Braidwood 1 in Fall 2010). It is anticipated that addition of a dispersant during the long-path recirculation cleanup process will more readily clean up transportable corrosion products from the system and increase their retention time in solution, thereby increasing the amount of iron removed from the condensate and feedwater systems prior to initiation of flow to the SGs. Evaluations preparing for applications of this type include: 1. Reviews of the procedure and general characteristics of the long-path recirculation cleanup process at three plants: Byron Unit 1, Millstone Unit 2 and Three Mile Island (TMI)Unit 1. 2. A laboratory test program to assess dispersant efficacy under the conditions present during the long-path recirculation cleanup process. A number of different dispersant chemicals, including the polyacrylic acid (PAA) used in online applications, were investigated. 3. Generic and plant-specific evaluations (for the above three units) of the compatibility of PAA with the secondary system components anticipated to be wetted during the long-path recirculation cleanup process. Based on the results of this study, inputs concerning the recommended dispersant chemical, concentration, application schedule, and cleanup criteria were generated to aid interested utilities in the development of a plant-specific application plan for an initial industry trial. An application is planned at Byron 1 in Spring 2011 under EPRI sponsorship.
机译：在过去的几十年中，公用事业机构已花费大量资源来最大程度地减少腐蚀在蒸汽发生器（SGs）中的沉积。过去，已经使用了两种基本方法：1.降低腐蚀产物的进入速率（例如，通过更换包含易腐蚀材料的次要成分，进行有利的化学变化等）。2.清除积累在腐蚀产物中的腐蚀产物。通过管顶污泥（TTS）污泥喷枪和其他化学和机械方法进行的SG尽管这些方法取得了成功，但仍然存在一些局限性，包括实际对给水铁浓度的下限以及清洁技术的高成本和有效性的限制（特别是缝隙）。第三种方法是在线添加聚合物分散剂以促进腐蚀铁的悬浮，从而减少沉积在SG表面上，并有助于通过排污更有效地去除。 2000年在ANO-2以及2005年至2007年在McGuire 2号机组进行了十多年的资格认证工作和两次全面的工厂试验，解决了最初的技术问题，为核SG的常规使用铺平了道路。本次会议的另一篇论文的重点是在四个具有再循环SG的Exelon工厂中在线应用分散剂。本文着重于在以下期间可从类似的分散剂应用中获得的其他好处：1.常规SG湿法沉积以去除一些现有的沉积物库存2.启动前对PWR二次侧进行常规的长路径再循环清理在整个湿法上浆期间向SGs分散剂可通过分散已累积的疏松污泥粉末，从而促进其去除而提供额外的好处。常规的分散剂辅助湿法堆肥应用程序可以与常规的堆肥协议结合使用，而不会影响计划的停机计划，并且可以潜在地减少更昂贵的沉积物管理操作（例如，污泥清理，化学清洗等）的频率。 2009年，EPRI与Exelon Corporation合作制定并实施了在三英里岛1号机组（TMI-1）的SG湿法铺设过程中试验分散剂应用计划。由于SG已计划在2009年秋季停运期间更换，因此该试验提供了一个独特的机会来评估分散剂湿法铺层应用的功效，而对SG的风险却最小。本文讨论了支持在TMI-1湿式铺网过程中添加分散剂的技术基础，以及2009年秋季试用申请的结果。在EPRI的赞助下，其他申请已经开始（2010年夏季的第3阶段）或已计划中（2010年秋季的第1布莱德伍德）。可以预料的是，在长程循环净化过程中添加分散剂将更容易地从系统中净化出可运输的腐蚀产物，并增加其在溶液中的停留时间，从而增加了从冷凝水和给水系统中去除铁的数量开始流向SG。为这种类型的应用做准备的评估包括：1.审查以下三个工厂的长程再循环净化过程的程序和一般特征：拜伦1号机组，密尔斯顿2号机组和三英里岛（TMI）1号机组。2. A实验室测试程序，以评估长途再循环净化过程中存在的条件下的分散剂功效。研究了许多不同的分散剂化学品，包括在线应用中使用的聚丙烯酸（PAA）。 3.对PAA与预期在长路径再循环净化过程中被润湿的次级系统组件的相容性的通用和特定于工厂的评估（针对上述三个单元）。根据这项研究的结果，生成了有关推荐的分散剂化学物质，浓度，应用时间表和清除标准的输入，以帮助感兴趣的公用事业公司制定针对特定工厂的应用计划，以进行初步的工业试验。计划在EPRI赞助下于2011年春季在拜伦1号进行申请。

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