A sensitivity study in probabilistic fracture mechanics analysis of light water reactor carbon steel pipe

Through the efforts in leak-before-break research for light water reactor pipings based on deterministic fracture mechanics analysis, simple models which evaluate pipe fracture behavior are being established. Using these models it is also becoming possible to apply probabilistic fracture mechanics analysis. This paper describes an example of such an analysis, using these proposed models.

Since the authors' interests are in the range of uncertainty of the calculated failure probability, the effects of changes in the input parameters or the analytical conditions are also estimated by a sensitivity analysis. The results show that the calculated failure probability may be influenced significantly by changes in parameters concerning initial crack size distributions, and that effects due to a change in the leak detection model may appear after long operation of the plant.