Abstract
It is important to prevent the buckling of thin pipes caused by an external pressure in the heat-exchanger system of a pressurized water reactor. The design code in ASME Sec. III NB considers this point. However, the thickness of pipes is partially thinned down by steam-liquid flow in service, and in design step no consideration is being paid to such a partially thinned down pipe, though much attention should be paid on this point.
In this paper, the pressure at failure of a partially thinned pipe under an external pressure was studied. The experimental results show that the failure occurs at unexpectedly small pressure, if the thinned part has some expansion in area, and that the pressure at failure does not follow with the buckling equation given by elastic theory for thin cylinders.
