3D thermo-mechanical analysis of the ITER limiter small scale specimen

This analysis describes in part, the design activity related to the small scale limiter specimen for ITER. Steady state heat fluxes of 3 MW/m² are expected. A 3D finite element model has been created to represent the beryllium-copper-steel layered construction of the limiter small scale specimen. The boundary conditions are chosen to simulate the actual conditions of the entire limiter. The Cu block has a 1 cm thick castellated layer of Be armor facing the plasma on one side and is attached to a 5 cm thick cooled SS backing on the other. The interface between the various layers assumes no inter-layer compositions and the analysis is elastic. These two rather severe assumptions tend to give higher stresses at the SS/Cu/Be interface. The maximum Be temperature is 586°C at the coolant exit. The maximum von-Mises stresses at the Cu/Be interface corners are 445 MPa. These stresses are superficially high due to the singularity at the interface and the assumption of no plastic deformation. It is proposed that any additional analysis should include the plastic deformation at the interfaces between different layers and also include an interface layer of materials to more closely simulate actual conditions