A probabilistic assessment of the primary coolant loop pipe fracture due to fatigue crack growth for a PWR plant

Abstract

The work reported herein assesses the probability of a double-ended quillotine break of the hot leg, cold leg and cross-over line (for the purpose of this paper we defined it as a large LOCA) of a PWR plant subjected to the loads caused by plant transients and earthquakes. The work employs a fracture mechanics bases fatigue model to propagate cracks from an initial flaw distribution. Flaw size and aspect ratio, material properties, operating transient and seismic stress histories, pre-service and in-service inspections as well as leak detections are considered random variables to be input into the fatigue crack growth fracture mechanics model. A brief description of the model and interrelationship between various steps are also given.