Keywords: crack growth, fatigue, nuclear pressure vessels, structural reliability, nuclear energy, nuclear power, failure probability
Deterministic and probabilistic approaches to fatigue crack growth in nuclear pressure vessels
This paper presents some approaches to the fatigue crack growth in nuclear pressure vessels for failure probability calculation. According to the Thomson methodology, the crack growth is the physical process in which the time is explicitly involved in the structural failure of the pressure vessel. Since the crack growth laws are of deterministic nature, we first obtain the failure probability considering a deterministic approach. Next, probabilistic approaches are applied to calculate the failure probability based on the fact that the fatigue crack growth is a random process. Here, we use a probability distribution function to represent the failure process if the random behaviour is due only to the variability of experimental data. Next, we propose a stochastic approach for the failure probability calculation when the random nature of the crack growth along the time must be taken into account. The result of a simple problem shows that the stochastic approach is the most accurate one.