Life Prediction of Power Plant Components

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Over the years, significant development has been made on the 9-12%Cr creep strength enhanced ferritic (CSEF) steels. Traditionally, in material development for power plant components, creep ductility, which can be treated as resistance to damage, has received much less attention. However, the risk of catastrophic failure due to low damage tolerance is a real challenge, in particular, in the situation where mechanical and metallurgical constraints are present. In addition, due to the increasing frequency of cyclic operations, i.e. starts up and shut downs for main steam pipelines of power plants, low cycle creep fatigue failure due to low ductility of the materials has become an important concern.The aim of the PhD project is to investigate creep and creep fatigue behaviour which takes into account the variable ductility for CSEF power plant steels subject to realistic plant loading cycles, through a comprehensive theoretical, experimental and computational programme. Predicting the useful life of components will align with the research area of automating existing electricity, gas and other energy vectors advanced controls, and instrumentation.Specific objectives include:1. Data acquisition and analysis and literature review on the currently available models and assessment procedure.2. Experimental investigation of LCF behaviour and microstructure characterization of the candidate power plant steel/weld (possibly MARBN).3. Development of a cyclic visco-plasticity model for PM, WM and HAZ which takes into account the cyclic softening and damage.4. Application of the model for component assessment using plant operational data and considering typical plant component geometries and plant operator requirements for condition assessment.5. Exploring early life contributors to damage such as severe plant operation, impact of poor design and creep brittle properties.High temperature mechanical testing and physical characterization will be carried out using well-established facility. The theoretical and modelling work will be carried out using finite element package ABAQUS through user defined subroutines.