Preliminary theoretical and experimental study of the effects of plasma disruptions on the thermal fatigue lifetime of the ITER/NET first wall

In this work the research programme regarding the possible interaction between plasma disruptions and the thermal fatigue lifetime of a bare fusion reactor first wall is shown. The analysis of the peculiar scenario in which a short surface crack propagates under a purely thermal stress driving force, leads to some doubts regarding the real possibility of a catastrophic failure of the FW structure during the planned lifetime. In order to investigate if and how such a crack propagates an experimental activity is in progress at the JRC ispra. The most pessimistic reactor relevant plasma disruption is simulated on a first wall mock-up by means of an electron beam gun. A description of the choice criteria for the reference disruption is given. Then its thermal effects on a bare first wall component are investigated and a characterization of the shape and size of the largest induced crack is performed on a statistical basis. Subsequently, the component will be thermal fatigue cycled and the experimental results will be then compared with existing theoretical models. (orig.)