Very high cycle fatigue in pulsed high power spallation neutron source

Xiong, Z.*; Futakawa, Masatoshi  ; Naoe, Takashi   ; Maekawa, Katsuhiro*

Very high cycle fatigue degradation of type 316L austenitic stainless steel, which is used as the structural material of neutron spallation sources under intensive neutron irradiation environment, is investigated by using an ultrasonic fatigue testing machine. The strain rate imposed on the structure of neutron spallation source is almost equivalent to that produced in the testing machine. The temperature on the surface was controlled by the air-cooling. The effect of strain rate on the fatigue strength is recognized to increase the fatigue limit.