Failure probability evaluation for a weld of the heat pipe in the Mega-Power heat pipe cooled reactor

Heat pipe cooled reactor, featuring using heat pipes as passive cooling, has received renewed interest. A Monte-Carlo-based probabilistic fracture mechanics analysis code, including crack initiation and propa-gation model, is developed to estimate the probability of failure at a weld in the heat pipe due to stress corrosion cracking (SCC), fatigue, and high temperature creep. The application of this code is demon-strated on the heat pipe of the Mega-Power rector. The results show that SCC is more important in accel-erating heat pipe failure than fatigue and high temperature creep. Failure probabilities under the condition of one or two adjacent failed heat pipes are abnormally close. Uncertainty analysis for input parameters proves initial crack size is more sensitive than temperature. This also provides a reference for heat pipe design and safety assessment of whole reactor. (c) 2022 Elsevier Ltd. All rights reserved.