Continuous and real time health monitoring of structural components has become of paramount importance in nuclear facilities to proactively address potential failures that result in the shutdown of operation and/or health and environmental. Subsequently, there has been an intense interest in fiber optic sensing technologies because of their relative tolerance to radiation exposure and elevated temperatures. Nonetheless, challenges remain prevalent with respect to reliability and cost. To address these concerns, while also taking advantage of the fiber optic materials, an acoustic based sensing technique has been developed to monitor phenomena such as temperature to better evaluate the aging and degradation of critical structures such as nuclear containment components, cable insulation, and metal pressure boundaries. Recently, a unique single mode acoustic waveguide design with strong power confinement and relatively low loss was demonstrated in an all-silica acoustic fiber. The “suspended core” acoustic waveguide consists of a pure silica glass core with an inner air cladding and outer silica cladding. In addition, a temperature sensor was demonstrated by monitoring the time of flight in the suspended core. The first-of-its-kind acoustic waveguide structure and sensor represents the first step in the development of a low-cost, reliable sensing system for the deployment of the fiber sensor arrays for the next generation of 3D network monitoring solutions.