The High Temperature Life Assessment System For P91 Key Components Containing Defect In Supercritical Unit

In order to improve thermal efficiency and reduce CO2 emissions, clean and efficient ultra-supercritical(USC) thermal power units are being developed all over the world. However, the elevated temperatures and pressure exposes the power plant steam pipes to severe service conditions. This may have a critical impact on the safe operation of such structures, especially for pipes that may contain some defects(e.g., cracks, lack of penetration, cavities, and solid inclusions). Based on the high temperature structural integrity assessment theory, the high temperature life assessment system for P91 key components containing defect in supercritical unit was developed in order to maintain safety.The tensile properties, creep properties and creep crack growth data of P91 steel were obtained by a wide range of query literature, reports, meeting and test at home and abroad. After calculating the stress of the piping, the finite element method was used to calculate the stress distribution of each part of the pipeline, including the typical welded joint, T-junction and elbow in both main steam pipe and heat pipe.The high temperature life assessment system for P91 key components containing defect in supercritical unit consisted of three main modules, material property module, stress module and the assessment module. The programmed stress state data calculated by the finite element method were embedded into the stress module.