IFMIF lithium target backplate design integration and thermo-mechanical analysis

In the framework of the IFMIF R&D program, a design-integration and a thermo-mechanical analysis of the Li target backplate has been carried out. The stress and displacement fields, due to the heating induced by the neutron flux, have been computed with the aim to check if the stress remains below the materialʹs allowable values and the induced displacement field leads to an acceptable deformation of the surface where the lithium flows, so that no flux instabilities are induced in the lithium jet. The analysis has been performed for two different backplate geometries, namely a thick and a thin option, for two different thermal and mechanical constraint cases and for different materials: austenitic steel 316L, IEA F82H steel and Mod 9Cr1Mo steel (T91). The results, obtained by means of ABAQUS code, show that AISI 316L steel might be not suitable as black-plate material, conversely, both the F82H and the T91 steels satisfy ASME requirements. The thin plate solution appears preferable in order to reduce the stress field.