Validation of a Leak-Before-Break Criterion Using Limit Load Solution

摘要

The assessment of risk of crack-like defects in pipes and pressure vessels is a challenging task for the power plant operator and the designer. Leak-Before-Break phenomenon is an important requirement for the safe design and re-assessment of pressure vessels. In this paper, early basic concepts have been verified with the available literature test data and the reason for their non-compliance has been discussed. In order to predict the leak and break behavior of the crack in a cylindrical pressure vessel or pipe, a simple limit load solution is utilized. Using the limit load solution, failure boundary is successfully created for cylindrical vessel made of high-strength steels including 4134 V steel and 4130 X steel. The boundary distinctly separates the leak and break cases. It is a handy tool for the operator or designer of the Nuclear and Thermal Power Plants to check the fitness of the cracked pressure vessels or pipes.