Printed Sensors for Monitoring Reactor Health

Innovative sensors and measurement technologies are needed to characterize parameters that directly support existing power reactors, materials test reactors, and transient test reactors that improve monitoring and control of nuclear energy systems. These advances should demonstrate greater accuracy, reliability, resilience, higher resolution, and ease of replacement/upgrade capability for applications in the nuclear environment, reduce operations and maintenance costs and address regulatory concerns. Fuel and cladding temperature and fuel thermal properties (e.g. thermal conductivity) and strain sensors were desired in-pile parameters selected for monitoring by a blue-ribbon panel in a DOE-supported workshop. Applied Nanotech (ANI) is collaborating with researchers from Boise State University (BSU), a DOE SBIR/STTR underrepresented institution, and Idaho National Laboratory (INL, in Phase II) to demonstrate the use of Additive Manufacturing (AM) for the fabrication of low-cost, durable sensors used for health monitoring of nuclear power plants. We will focus efforts in AM techniques to develop printable and high-temperature irradiation-resistant thermocouples (HTIR-TCs) for temperature and heat flux (and indirectly thermal conductivity) monitoring of thermal fields inside nuclear power plants. Using the same or similar inks materials, we can print a capacitive strain sensor with a slight change of the design. The incorporation of these technologies within the nuclear industry would enable the development of advanced sensor and instrument technologies necessary to address critical technology gaps for monitoring and controlling reactors and fuel cycle facilities. The ability to print such sensors enables direct writing of sensors onto fuel, cladding, and structural components. Additive Manufacturing materials will be developed for printing multimodal sensors compatible with the nuclear plant environment sensors to measure temperature and thermal flux. The developed materials will be used to print HTIR-TCs devices. Heat flux sensors are made with thermocouples connected in series. We will demonstrate temperature stability at 1100ºC for minimum 100 hrs with less than 10% shift. We will demonstrate heat flux sensor and capacitive strain sensor functionality to 500ºC. In Phase 2, we will characterize printed sensors at higher temperatures and in high neutron flux environments for extended periods to demonstrate in-pile stability. The direct commercial application of this technology will be advanced monitoring of new and existing nuclear energy systems. The true value will be in the cost savings, efficiency gains and improved reliability that will be realized from using these sensors in nuclear power reactors. Other benefits will include new additive manufacturing materials and sensors for automotive, aerospace, renewable energy and manufacturing sensors and components for extreme environments.