Demonstrating Distributed Fiber-Optic Temperature Sensors in a Simulated Gas-Cooled Reactor Outlet

Gas-cooled reactors operate with a large temperature variation across the core due to the low heat capacity of gaseous coolants such as helium. There are also significant variations in local power generation and coolant flow rates through many parallel flow channels that ultimately combine and mix at the core outlet. These complexities make it difficult to identify and/or predict the hot channel within the core, which ultimately limits the total reactor power. In addition, the complex mixing that occurs at the core outlet can make it difficult to accurately monitor the mixed mean core outlet temperature, which is used for calorimetry and periodic calibration of the reactor power. Finally, large core outlet temperatures could potentially damage downstream components due to alternating thermal loads.