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International school on modelling of irradiation damage
Course: October 1-5, 2007
Background
The design of materials with properties adequate for their use in nuclear reactor environments requires an in-depth understanding of radiation (particularly neutron) effects on their physical and mechanical properties. Over the last few decades and particularly over the last few years, substantial progress has been made in identifying and understanding the basic mechanisms governing the response to irradiation of some structural materials, especially those that are widely used in the existing nuclear power plants. Nonetheless, open fundamental questions regarding the microstructure evolution induced by irradiation and the consequent mechanical property changes, particularly in the technical alloys, remain.
It is recognised that a precise and quantitative understanding of the fundamental physical mechanisms driving the microstructural changes due to irradiation are of primary importance to predict the behaviour of the materials in operating conditions. For this purpose, physical, rather than empirical, models need to be developed.
Since radiation effects start from energetic particles that hit atoms of the crystal and go up to changes in the mechanical properties, such as hardening and embrittlement, it is widely recognised that physical models dealing with these effects can only be multiscale, multiphysics models. These models rely largely on the current capabilities of computers, which allow very complex systems composed by a large number of elemental units (atoms, defects, dislocations, finite elements, …) to be treated. Nonetheless, these computer models must be and are based on a firm physical and theoretical background and further theoretical developments are needed in order to cleverly deal with all scales of interest, by extracting from more fundamental levels all and solely the strictly needed physical information required for a coarser-grained model to work beyond empiricism. In addition, specific computational problems need to be solved in order to integrate different models into the same platform, aimed at becoming eventually a tool suitable for industrial use.
The FP6-EU-PERFECT integrated project (IP), as well as other projects in Europe and worlwide, are currently devoted to this endeavour.