RESIDUAL STRAIN IN A FUSION-REACTOR 1ST-WALL COMPONENT SUBJECTED TO THERMAL FATIGUE

The residual strain in a mock-up of a first wall for nuclear fusion reactors is investigated. An AISI 316L steel component was subjected to 27 000 thermal cycles simulating the heat flux variations during reactor operations, in an experimental station built for this purpose at the JCR Ispra. The residual strain map was obtained theoretically by using finite element analysis. The numerical results are compared with the strain values measured along two lines, using neutron diffraction. Although the theoretical computation does not consider the actual state of the component, including the effects of undesirable thermal variations connected to preparation and handling, good agreement was obtained between theoretical prediction and measured values, indicating that neutron diffraction is a refined tool for studying residual strains.