Abstract
Evaluation of wastage rate for nuclear power plant piping is important in maintaining plant reliability and safety. The two commonly well known causes of pipe wastage are liquid droplet impingement erosion (LDIE) and flow accelerated corrosion (FAC). This study is to evaluate the wastage rate of pipe wall and to measure the loss of mass caused by LDIE. LDIE often occurs at downstream of corner of pipe or orifice. A high speed rotating disk and water jet is used to perform LDIE phenomena. In this study, the liquid droplet impinging tests were conducted with the test piece mounted on the high speed rotating disk which crosses thin water jet. The amount of the wastage by LDIE was evaluated by changing the impingement speed, the impingement angle, and test piece materials. After the experiment, the result of erosion was investigated by observing the surface of the test piece using a digital microscope, and photo was taken. Software is used to convert the photo into data. An erosion rate and volume decreasing rate measurement method is designed to evaluate the maximum erosion rate and volume decreasing rate caused by LDIE. Besides, two-phase flow in piping in the power plant was analyzed by using analytical code TRAC.
