Flow accelerated corrosion in piping components under single and two phase flow conditions

流动加速腐蚀（FAC）是老化发电厂，特别是核电厂面临的严重安全性和可靠性问题。这种现象会导致大面积的管道磨损，从而导致突然和灾难性的故障。有两种机制负责FAC：（i）取决于工作流体的化学性质的电化学现象，以及（ii）由于工作流体和金属表面的相对运动引起的金属腐蚀。该项目的目的是研究管道部件的流动加速腐蚀（FAC）。特别地，在一系列流动条件下，将评估两个背靠背布置的90度弯管中单相和两相流对FAC的水动力效应。之所以选择这种配置，是因为在大多数电厂中，通过对管道系统的在线监测，弯头已被确定为最容易发生FAC。实验将进行不同的背靠背弯头分离距离和弯头安排的一系列进口流速和两相流制度。弯管中的流量和磨损率将被表征，以引出负责FAC的主要流动机制。该项目将与加拿大原子能有限公司（AECL）合作进行。本研究项目的结果将提供信息，可用于更好地管理在线监测的核电厂FAC通过确定流动条件和管道配置，最容易发生FAC。根据双方的设想，该项目将是更全面研究计划的开始，以更好地了解NPP中的FAC，从而提高核电厂的安全性，可靠性和经济性。

Flow Accelerated Corrosion (FAC) is a serious safety and reliability problem facing aging power generation plants, especially nuclear power plants. This phenomenon results in the wear of large areas of piping that can lead to sudden and catastrophic failure. There are two mechanisms responsible for FAC: (i) an electrochemical phenomenon which depends on the chemical properties of the working fluid, and (ii) erosion of metal due to the relative motion of the working fluid and the metal surface. The objective of the proposed project is to investigate flow accelerated corrosion (FAC) in piping components. In particular, the hydrodynamic effects of single and two phase flow on FAC in two 90-degree elbows arranged back-to-back will be evaluated under a range of flow conditions. This configuration was chosen because elbows have been identified as most prone to FAC through on-line monitoring of piping systems in most power plants. Experiments will be performed for different back-to-back elbow separation distances and elbow arrangements for a range of inlet flow velocities and two-phase flow regimes. Both the flow and wear rates in the elbows will be characterized to elicit the principal flow mechanisms responsible for FAC. The project will be performed in collaboration with Atomic Energy of Canada Limited (AECL). The results from this research project will provide information that can be used for better management of on-line monitoring of nulcear power plants for FAC by identifying the flow conditions and piping configurations that are most prone to FAC. It is envisaged by both partners that this project will be the start of a more comprehensive reserach program to better understand FAC in NPP that will lead to enhanced safety, reliability and economics of nuclear power plants.