Monte Carlo simulation for evaluating the creep crack growth rate of type 316LN stainless steel

Type 316LN stainless steel (SS) is widely used as the structural material for liquid metal reactor (LMR) components. The components may be subjected to a non-uniform stress and temperature distribution during a high temperature service. These conditions generate localized creep damage and propagate the cracks and ultimately cause a fracture. A significant portion of the components' life can be spent in crack propagation. Thus, it is very important to evaluate the creep crack growth rate (CCGR) from a design concern and in predicting the residual life of the components. However, so far, the design and/or evaluation of the components have been mostly conducted by deterministic fracture mechanics. This method may bring about overly conservative evaluation by applying highly upper limit values in material properties. So, using probabilistic fracture mechanics, the crack propagation should be evaluated probabilistically. In this paper, the CCGR data was dealt with from probabilistic viewpoints in order to logically evaluate the CCGR in type 316LN SS. Using Monte Carlo simulation (MCS), a number of random variables were generated, and the CCGR lines are predicted probabilistically. For application of the MCS, in the case of a standard deviation of 1σ for the probability variables, P (B, q), the CCGR lines were predicted, and the results were discussed