Environmental effect on fatigue strength of stainless steel in PWR primary water – Role of crack growth acceleration in fatigue life reduction

The influence of the pressurized water reactor (PWR) water environment on fatigue life and fatigue crack growth rate was discussed. The fatigue lives of Type 316 stainless steel in the PWR water environment were investigated using cylindrical hollow specimens. The acceleration in the crack growth due to the environment was quantified by investigating spacing of striations and crack growth tests using compact tension specimens. The growth rates obtained could be represented by the strain intensity factor. It was shown that the fatigue lives estimated by crack growth prediction agreed with those obtained by the tests. Then, it was concluded that the reduction in the fatigue life due to the PWR water environment was brought about not by enhancement of crack initiation but by the acceleration of the crack growth.