Sensors for Small Modular Reactors Powered by Thermoelectric Generators

The aim of this work is to develop thermoelectrically powered sensing and actuating devices for normal and off-normal conditions in Small Modular Reactors (SMRs). This is realized using thermoelectric generators (TEGs) placed on key reactor components such as pipes, pump housings, heat exchangers or reactor vessels to capture waste heat and produce usable electric power. The electrical power generated is used to drive sensors, signal conditioning, and wireless communication to relay critical plant information to operators and emergency crew. Surplus power can be stored in batteries and/or super capacitors for actuation and other high-current, short-duration power needs. A review of key SMR reactor types and candidate locations for installing these devices is presented. The design and manufacturing process of an integrated TEG assembly that attaches to a schedule 40 steam pipe and preliminary test data of the system from an installation performed on a conventionally-fueled cogeneration power plant located on site are presented. The nominal pipe temperature is 350°C, and the assembly is designed to reduce the temperature to 230°C on the hot side of the TEG. A cold side temperature of 70°C was obtained using a large heat sink cooled by natural convection to the ambient. Designs for an enclosure system are also presented to protect the electrical components from fire and radiation.