Life Prediction Of The Main Steam Pipe Based On The Theory Of Reliability

In this paper, several factors which affect the service life of main steam pipe were analyzed. Finite element analysis has been carried out for straight pipe and 90°pipe elbows. The effect of the ovality and the different initial thickness asymmetry of steam pipe elbows on the stress distribution variation in the elbow is confirmed. And an analytical model to calculate equivalent stress of elbow from straight pipe stress is presented. Based on the analysis above, considering the ovality, the different initial thickness and the steam pressure as random variables, the theory of reliability was employed to calculate remain life reliability degree(the unfailing probability of the pipe in remaining service life)of the elbows using probability method. The reliability-based approach considers the aforementioned random factors, thus it predict the life of the elbow more objectively. In addition, the main steam pipe remain life on-line assessment system was developed and be used well.