最近从核电厂，尤其是位于美国的核电厂的运行经验（其中许多电厂的运行年限在30至40年之间）表明，至少在一些电厂中，埋地管道正在发生退化，这是一个需要核工业关注的问题。在管道的外表面和内表面都观察到了各种形式的降解。到目前为止，在大多数情况下，直到发现泄漏后才检测到降解。其中一些泄漏导致放射性同位素（通常为氚）和可能对环境有害的材料（以下简称“环境敏感材料”）的释放。这些事件（a）未导致任何部件或系统的预期安全功能丧失；（b） 未导致场外辐射暴露超过监管限制；（c） 仅占泄漏到环境中的含氚水的10%左右； （d）引起了公众的极大关注。本NACE国际技术委员会报告旨在概述可能适用于全球的埋地管道相关问题。然而，本报告是从美国的经验角度撰写的。采取这种做法主要是因为缺乏有关这一主题的公开国际信息。本报告介绍了上述运行经验的一部分。它只包括与埋地管道的外部腐蚀有关的主题，即与土壤或混凝土直接接触的管道。它不包括与埋地管道内部腐蚀相关的主题。此外，它不包括与埋地储罐腐蚀相关的主题，例如与土壤、混凝土或地下管道和储罐接触的储罐，即封闭在拱顶或沟槽中的储罐。 与所有NACE最新报告一样，本报告的目的并不是对埋地管道的退化、防腐或缓蚀问题进行完整论述。更确切地说，本报告的目的是确定在核电站埋地管道退化时腐蚀专业人员应考虑的问题。该报告介绍了受试者，并确定了有关该受试者的适用参考资料。当发现与埋地管道退化有关的特定问题是核电厂独有的，且没有足够的参考材料时，本报告提供了有关该问题的补充文本。本报告各章节的长度与核电厂埋地管道相关主题的独特性而非重要性相关。

Recent operating experience from nuclear power plants, particularly those located in the United States, many of which are between 30 and 40 years old, indicates that degradation of buried piping is occurring in at least some plants and represents an issue requiring the attention of the nuclear industry. Degradation in a variety of forms has been observed on both the external and internal surfaces of the pipe. In most cases to date, the degradation was not detected until a leak was identified. Some of these leaks have resulted in the release of radioisotopes (normally tritium) and materials that may be harmful to the environment (hereafter, 'environmentally sensitive material'). These events (a) have not resulted in the loss of the intended safety function of any component or system; (b) have not resulted in off-site exposure to radiation in excess of regulatory limits; (c) constitute only about 10% of the leaks of tritium containing water into the environment; and (d) have attracted significant public attention.It is the intent of this NACE International technical committee report to provide an overview of issues associated with buried piping that might be applicable worldwide. This report, however, is written from the perspective of experiences in the United States. This approach was taken primarily because of a lack of publicly available international information concerning this topic.This report addresses a subset of the operating experience described above. It includes only topics related to the external corrosion of buried piping, i.e., piping that is in direct contact with soil or concrete. It does not include topics related to internal corrosion of buried piping. Additionally, it does not include topics related to the corrosion of buried tanks, such as those in contact with soil, concrete, or underground piping and tanks, i.e., those enclosed in a vault or trench.As with all NACE state-of-the-art reports, it is not the intent of this report to be a complete treatise on the subject of degradation, corrosion prevention, or corrosion mitigation of buried piping. Rather, it is the intent of this report to identify issues for corrosion professionals to consider when addressing degradation of buried piping in nuclear power plants. The report introduces subjects and identifies applicable reference material on the subject. When a specific issue related to buried piping degradation is found to be unique to nuclear power plants, and when ample reference material is not available, this report provides additional text concerning the issue. The length of the sections of this report correlate with the uniqueness, not the importance, of the topic considered with respect to buried piping at nuclear power plants.