THE CARE AND MAINTENANCE OF HIGH-TEMPERATURE, HIGH-PRESSURE PIPEWORK SYSTEMS

This paper describes the routine inspections carried out on the high-temperature, high-pressure steam pipework associated with large electricity generating units owned by PowerGen. The early implementation of the Pressure Systems and Transportable Gas Container Regulations, 1989, has allowed power stations more flexibility to set intervals between outages for inspection compared to the fixed intervals required under the Factories Act, 1961. Part of these inspections includes a detailed examination of high-temperature, high-pressure steam pipework welds and support systems. The method of inspection and analysis carried out to contain the risk of failure at welds due to high system stresses is described in the paper. Details are also included of how pipework flexibility analyses have been used to redesign some systems that have exhibited significant problems.