CNA U-I Cooling Channel Replacement Strategy

Abstract

The coolant channels are structural components of the reactor core of CNA UI that undergo dimensional changes when subjected to neutron flux, temperature, pressure, and mechanical stresses. Such changes can impact reactor availability, making their monitoring a matter of critical importance. Through the Reactor Internals Surveillance Program, the dimensional evolution of the channels is systematically monitored over time. At present, the plant is undergoing a planned outage for life-extension activities for a period of 20.25 EFPY, during which channel replacement tasks will be performed with the objective of minimizing post–life-extension interventions and maximizing reactor operational availability. In this study, the NASA01-R2021 model is employed to predict the behavior of critical channels during the 2028–2046 period. Based on the model outcomes, alternative strategies for channel replacement and exchange to be implemented during the life-extension outage are proposed.