An analysis of the effects of sulphur content and potential on corrosion fatigue crack growth in reactor pressure vessel steels

The present work characterizes the effects of sulphur content and applied potential on the corrosion fatigue crack propagation rate in nuclear reactor pressure vessel steels. The data for the characterization were achieved by conducting the tests on A533B type steels, subjected to a sine-waveform loading at 0.0167 Hz in stagnant PWR Primary (Li/B dosed) water at 290oC. Data analyses reveal that both plateau corrosion fatigue crack propagation rate, da/dNp, and threshold stress intensity factor, ΔKthp, are closely proportional to the square root value of bulk sulphur concentration in the range 0.003-0.019%. These relationships have been supported by other sources of data obtained under similar testing conditions. Available experimental results also show that both da/dNp and ΔKthp are linear functions of the difference between externally applied potential and open circuit potential, ΔE. An equation has been proposed to predict the synergistic effect of sulphur content and applied potential on the plateau corrosion fatigue crack growth rate of A533B steels. (Author)