The goal of this collaborative research between Idaho National Laboratory, University of Notre Dame, Boise State University, and University of Houston under the Nuclear Energy Enabling Technologies Program's Advanced Sensors and Instrumentation Pathway is aimed at developing efficient and reliable thermoelectric (TE) generators for self-powered wireless sensor nodes (WSNs) for nuclear applications. This power harvesting technology has crosscutting significance to all U. S. Department of Energy

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... ffice of Nuclear Energy research and development programs, as it will enable self-powered WSNs in multiple nuclear reactor designs and spent fuel storage facilities using thermal energy available in a nuclear power plant or spent fuel storage facility. This project will address the technology gap that exists in realizing truly WSNs due to the need for cables to connect to external power supplies by developing TE power harvesting devices to deliver sufficient power to drive the WSNs. The outcomes of the project will lead to significant advancement in sensor and instrumentation technologies, resulting in reduced costs, improved monitoring reliability, and therefore enhancing safety. The self-powered WSNs could support the long-term safe and economical operation of all reactor designs and fuel cycle concepts, as well as spent fuel storage and many other nuclear science and engineering applications. Most wireless sensor network applications require operation over extended periods of time beginning with their deployment. Network lifetime is extremely critical for most applications and is one of the limiting factors for energyconstrained networks. A battery is traditionally used to power WSNs, however there is a wide range of different energy sources suitable for use depending on the application. The deployed WSN is required to last for a long time. Due to the finite amount of energy present in batteries, it is not feasible to replace batteries. Recently there has been a new surge in the area of energy harvesting where ambient energy in the environment can be utilized to prolong the lifetime of WSNs. Some of the sources of ambient energies are solar power, thermal gradient, human motion and body heat, vibrations, and ambient radio frequency energy. This report presents the development of a TEG-powered WSN prototype that could be used in nuclear applications. Different design considerations that are important in assembling different components of a WSN were carefully taken into consideration. The designed WSN is compatible to operate with low-power generating TEG and high-power generating TEG based on application requirements. Also, to maintain appropriate power levels across different sensor node components, a direct current-to-direct current converter with maximum peak power tracking algorithm is implemented. A storage device with a real-time clock is embedded to enable local data storage and real-time time stamping. The wireless communication module selected and implemented is Zig Bee protocol. To accommodate different operating conditions and any loss of power from the TEG due to unforeseen reasons, a backup battery system is also implemented. The entire assembly was built on a 2-layer printed circuit board and tested for operation. The outcome was successful and provided enough data to validate the mathematical model developed to estimate average power consumption of a WSN under different operating conditions.