Abstract
Energy production uses equipment and structures with specific features: their physical dimension (a hydroelectric dam, a nuclear power plant or an 8MW offshore wind turbine are very large structures), their lifespan (over 100 years for some dams) and great physical complexity (multi-physical, multi-scale phenomena), with variable and partially known input data. Numerical simulation provides a major source of information for building, operating and deconstructing them, as this industrial sector is subject to the same efficiency constraints (economic and technical) as any other. Whether for numerical reasons (problem size too large for current techniques, curse of dimensionality) or sobriety, it is necessary to control and reduce the complexity of numerical simulations. In this presentation, we illustrate these issues of complexity and sobriety through the lens of two particular physics: solid mechanics and neutronics. We show the obstacles still present and the research and development directions envisaged in terms of complexity reduction for numerical simulation