LAUSR

Abstract The article discusses a case of a fractured support bearing plate of a pipeline in a pumped-storage power station; the failure made it necessary to shut the power station down temporarily. Brittle fracture of the plate occurred fifty years after the pipeline was built. On the basis of the analysis of the operating conditions of the pipeline as well as the results of the analysis of the chemical composition, tensile, impact and fracture toughness tests, along with fractographic examination of the cracks of the fractured plate, it was discovered that it was the stresses whose value had temporarily become critical in the course of repair works that constituted the direct cause of the bearing failure. A number of factors that were conducive to the appearance of the fracture at a given stress level were also pointed out. These included, for example, factors connected with dynamic load of the pipeline, dimensions, shape and structure of the plate, as well as long-standing operation and ageing of the plate material.