Quantifiable destructive and non-destructive methods for lifetime assessments of Eskom's high temperature plant

Over long exposure periods high temperature and high pressure components suffer degradation of their properties and this accumulated damage subsequently leads to cracking and failure. State-of-the-art quantifiable destructive and non-destructive methods for lifetime assessment of reliability and maintainability of Eskom's plant are used. Geometry, strain rate, mode of load, materials, fabrication technique and history are all important factors affecting the component life and material microstructure. Novel cost-effective techniques have been developed by Eskom for the assessment of the effective temperature of components operating in the creep regime. Accumulated creep strain is measured directly on the component during a certain service interval. This information is then used to calculate the remanent life of a component. A library of more than 30 000 metallographic replicas representative of approximately 6000 components exists and these ‘fingerprints’ are of great value in the overall life predictions.