A Probabilistic Fracture Mechanics Approach to Weld Stability in Nuclear Power Plant Piping | November 19, 2015 |
Scott Sanborn In order to ensure safe continuing operation of nuclear power plants, comprehensive understanding of the aging and degradation mechanisms of piping components is necessary. However, traditional deterministic methods may not adequately address the complexities and uncertainties associated with active degradation mechanisms known to be of concern. This talk will focus on the recent development of the extremely Low Probability of Rupture (xLPR) code. xLPR was developed as a cooperative effort between the US Nuclear Regulatory Commission and the Electric Power Research Institute as a tool to probabilistically simulate degradation within pressurized water reactor primary loop piping and evaluate failure frequencies for extremely low probability events. . The code leverages existing fracture mechanics-based models to simulate initiation and growth of cracks within piping systems. Additionally, inspection, leak detection, and physical and chemical mitigation techniques are included in the code to evaluate the effect of methods employed by plant operators to reduce the probability of a pipe rupture. A number of sampling options are allowed to characterize, categorize, and propagate the problem uncertainties. Rupture probabilities and other results for a particular weld will be discussed. Additionally, the critical parameters and uncertainties contributing to the rupture probabilities will be discussed. |