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Prediction of environmental crack growth in nuclear power plant components. Volume 3: Fatigue crack growth of A533B steel in high-temperature hydrogen gas: Final report

Technical Report ·
OSTI ID:10193404
 [1]
  1. Westinghouse Electric Corp., Pittsburgh, PA (United States). Power Systems Div.

Fatigue crack growth rate tests of A533 Grade B Class 1 steel were performed in high purity hydrogen gas as a function of temperature, pressure and cyclic frequency. Highly accelerated fatigue crack growth rates were observed at 200{degrees}F in 1,500 psig hydrogen. The acceleration factor decreased as the test temperature increased until reaching unity between 375{degrees}F and 550{degrees}F as the hydrogen enhancement effect disappeared. Accelerated fatigue crack growth rates were accompanied by a dramatic change in the microscopic fracture appearance. Current results, together with a review of the phenomenology of fatigue crack growth rate behavior in hydrogen gas and in reactor coolant water, fractographic observations, hydrogen diffusion rates, trap binding enthalpies, and measured effective hydrogen fugacities provide a compelling argument that hydrogen is the principal actor in accelerated fatigue cracking of pressure vessel steels in reactor coolant water at temperatures below 400{degrees}F, and that the film rupture-anodic dissolution process is the dominant factor above 400{degrees}F. Theoretical support for empirically determined upper limits to fatigue crack growth rates in reactor coolant water remains unchanged at steady state operating temperatures. Arguments are presented in support of these same limits at lower temperatures where a different accelerating mechanism is operative.

Research Organization:
Electric Power Research Inst., Palo Alto, CA (United States); Westinghouse Electric Corp., Pittsburgh, PA (United States). Power Systems Div.
Sponsoring Organization:
Electric Power Research Inst., Palo Alto, CA (United States)
OSTI ID:
10193404
Report Number(s):
EPRI-TR--102797-Vol.3; ON: UN94002559
Country of Publication:
United States
Language:
English