Lifetime and ageing management of nuclear power plants: A brief overview of some light water reactor component ageing degradation problems and ways of mitigation

The susceptibility and tendency for nuclear power plant (NPP) components to undergo changes in their mechanical and physical properties in the course of the NPP lifetime is generally termed as “ageing”. The light water reactor (LWR) nuclear environment is not a begnign one; it is characterized not only by fast neutrons, which can degrade metallic structures, but also relatively high temperatures of coolant water (around 300°C) which may contain impurities (e.g. sulphate, chloride, peroxides) which can cause corrosion. The hydrodynamical conditions of the coolant in steam generators, for example, can cause thermal fatigue, erosion and corrosion; suspended particulate matter can accelerate erosion processes which can lead to wall thinning and lowering of safety margins. Ageing is, therefore, a very complex mixture of factors concerned with materials, temperatures, times of exposure to environments which vary with time and with respect to chemical composition and flow charactertistics.

The paper describes a few ageing phenomena which can be considered important due to their impact on nuclear safety issues; their influence on economic aspects (availability) of NPP is outlined. Mitigation measures for NPP component ageing problems are given together with recommendations for addressing such issues in NPP now and in the future.     

Effects of processing conditions on the curing of a vinyl ester resin

The effects of temperature, initiator, and accelerator levels on the curing of an epoxy bisphenol‐A vinyl ester resin Derakane® 411‐45 (formulated with styrene) were investigated by gel‐time and exotherm‐peak measurements on bulk samples. It was observed that the gel time was reduced as the initiator or accelerator ratio increased. Except at higher contents of the accelerator, a small kinetic plateau was seen in the gel curve and a shift of the maximum exotherm toward high temperatures in the DSC curves. This was explained by the dual role played by the accelerator species. A regression analysis of all gel‐time data showed a dependence of 3/2 order in the accelerator and first order in the initiator concentrations. Thus, for this polymerization initiation system, the gel time can be predicted for any initiator and cobalt levels and at any temperature within the ranges studied. The effect of the initiator on the unreacted styrene and vinyl ester was also examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1146–1154, 2002; DOI 10.1002/app.10403     

Convective drying of wood-waste in air and superheated steam

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钛酸酯催化环氧树脂固化动力学研究

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曙—区超稠油间歇蒸汽吞吐技术探讨

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联合循环机组汽封系统的设计改进

介绍了联合循环汽轮机原汽封系统存在的问题以及改进后汽封系统的工作原理和运行控制过程。     

220t/h高压蒸汽锅炉过热器的吊装技术

220t/h高温高压蒸汽锅炉过热器为大体积，大吨位，且锅炉工程与土建安装施工处于交叉作用状态，场地又狭窄，基于上述原因，提出了分部倒钩吊装方法，介绍了该方案的实施过程，对过热器的扳倒，倒钩，吊装的每道工序均进行了阐述，在不增加成本的前提下，安装，可靠，高效地完成吊装任务。     

改性己二胺制备TG301环氧树脂室温固化剂

已二胺经与环氧树脂进行羟烷基化及与丙烯腈进行氰乙基化反应达到改善低熔点低毒性．低脆性的综合效果．文中介绍了改性乙二胶固化剂的制备方法，质量指标和有关固化特性等．