Thermal fatigue crack growth: modelling and experimental verification

The first wall of tokamak type fusion reactors suffers from thermal fatigue damage as the result of discontinuous loading due to plasma disruptions. The Institute for Advanced Materials launched a generic thermal fatigue research project aimed at the numerical modelling, and at its experimental validation, of the lives spent in growing a crack to failure in components subjected to cyclic temperature gradients typical of NET. The experimental testing facilities consist of an out-of-pile and an in-pile rig for measuring the crack growth rate in tubular components exposed to thermal fatigue conditions in a neutron free condition and under neutron irradiation in the HFR reactor, respectively. Test results in the neutron free environment on 316L steel considered for first wall application in NET serve as a thermal fatigue life data base, and as a basis for the verification of the model prediction of crack growth rates under LEFM conditions. ((orig.))