Abstract
The Critical Heat Flux (CHF) is one of the fundamental safety parameters in the design of Light Water Reactors (LWRs). However, due to the limited knowledge of this phenomenon, current reactors are designed based on conservative approximations, which compromise their efficiency. Despite the numerous methods developed to observe the two-phase flow behavior, no technique has successfully captured real-time high-speed images of boiling at reactor operational conditions. Hence, the purpose of this thesis is to propose the design of a non-invasive advanced visual inspection system to record high-speed video of nucleate boiling. The system consists of a borescope apparatus and light source, designed and tested to operate at high-pressure high-temperature environments, providing acceptable factors of safety and clear images. Posterior tests will use this monitoring system to record and study transient boiling, void fraction, and the onset of film boiling in an out-of-pile setup