Cast iron is primarily used in buried piping to transport water in the fire protection system of nuclear power plants; ductile cast iron is generally used for domestic nuclear power plants. In general, the fluid used as fire-extinguishing water in such fire protection systems is tap water, and corrosion inhibitors are not currently added. In this study, the synergistic effect of an adsorption barrier (monoethanolamine) and oxidized film in an environment with a corrosion inhibitor (tungstate) is examined, and the corresponding passivation properties are presented. An immersion corrosion test and electrochemical test in tap water to which only tungstate was added showed suppression of corrosion compared to molybdate at the same concentration. The polarization resistance value of a passivation film in tap water mixed with monoethanolamine and tungstate showed better results than that of the molybdate control. A surface analysis in mixed addition tap water also demonstrated that oxygen ions were sufficiently distributed, including at some spheroidized graphite sites, when tungstate was added compared to molybdate. In addition, the amount of tungsten ions adsorbed on the surface was larger than that of molybdenum ions, and it was confirmed that tungsten ions were evenly distributed over the entire surface.

中文翻译：

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自来水中添加的钨酸盐和乙醇胺对核电厂球墨铸铁管的缓蚀作用

铸铁主要用于地下管道中，以输送核电站消防系统中的水；球墨铸铁通常用于家用核电站。通常，在这样的消防系统中用作灭火水的流体是自来水，并且目前不添加腐蚀抑制剂。在这项研究中，研究了在具有缓蚀剂（钨酸盐）的环境中吸附势垒（单乙醇胺）和氧化膜的协同作用，并提出了相应的钝化性能。与相同浓度的钼酸盐相比，在仅添加钨酸盐的自来水中的浸没腐蚀试验和电化学试验显示出对腐蚀的抑制作用。在自来水中混有单乙醇胺和钨酸盐的钝化膜的极化电阻值显示出比钼酸盐对照更好的结果。在混合添加自来水中的表面分析还表明，与钼酸盐相比，添加钨酸盐时，氧离子已充分分布，包括在一些球形石墨位置。另外，钨离子在表面上的吸附量比钼离子大，并且证实了钨离子均匀地分布在整个表面上。