Research Objectives and Approach

Most current efforts focus on predicting the remaining life of nuclear power plants since this topic is of major international interest. Key-components are the reactor vessel, the primary and secondary circuits, plastics and polymeric material used for electric cables and coating of components as well as the concrete structures of the plant. Picture: copyright MAI/EDF R&D.

Objectives:

• to understand, model, predict and anticipate the ageing of materials used in the electricity generating plants, whether nuclear, fossil fuel or hydroelectric;
• to develop knowledge about the behavior of materials which shall be used in the future generating facilities in order to make recommendations to the members of the institute, as to the choices offered by the manufactures;
• to capitalize on, maintain and share knowledge and skills in order to help plant owners and operators throughout the world to safely operate their facilities and reinforce the cohesion among stakeholders within a structure made up of industrial and scientific partners.

Approach:

Research at the MAI is characterized by three specific pillars, i.e. experiments, modeling and operational experience. Experimental research is based on observation and tests on specimen specifically developed by and for the MAI. The tests include thermal ageing (months or years of thermal stress) for which the Institute has numerous furnaces which can reach temperatures of up to 650 °C.

Modeling is one of the central topics of the MAI. Mathematical models not only allow to verify our understanding of the fundamental processes such as stress corrosion cracking, corrosion fatigue and creep – they also enable to capitalize our knowledge in terms of parameter databases. Furthermore, they are of key-importance in assessing the durability of components and materials for periods and under conditions that are beyond experimental reach. The Institute has therefore heavily invested in computer facilities, among them the IBM Blue Gene/L computer with 32000 CPUs. The Institute has expertise in numerical simulation of dislocation dynamics, molecular dynamics, ab initio modeling, generation of complex 3D structures of materials and much more.

Operational feedback data is obtained using samples of material that are made available by EDF after replacement of specific components. The Institute utilizes non-destructive testing techniques based on ultrasonics and associated scientific software (e.g. Athena). Moreover, the 30 years operating history of some materials provides useful insight in irradiation assisted stress corrosion under real exposure conditions.