Fatigue of neutron irradiated austenitic steel below the creep range

In the present design of the Next European Torus fatigue with strain amplitudes in stainless steel as high as 0.3% are anticipated in the first wall operating at temperatures up to 700 K. Fatigue and tensile test results of the European type 316 reference heated irradiated up to 5 dpa and up to 40 appm helium are presented. In the test frequency range from 0.5 mHz to 0.5 mHz it was observed that the fatigue endurance is dependent on the frequency, though the test temperatures 10-3 s-1 the number of cycles to failure is hardly affected by radiation which can be explained on the basis of tensile test results. (author). 9 refs.; 5 figs