Printed Sensors for Monitoring Reactor Health

Statement of the Problem or Situation that is Being Addressed – Innovative sensors and measurement technologies are needed to characterize parameters that directly support existing power reactors, materials test reactors, transient test reactors and the next generation fast reactors. These sensors 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 and strain sensors were desired in-pile parameters selected for monitoring by a blue-ribbon panel in a DOE-supported workshop. Statement of How this Problem or Situation is Being Addressed – 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 on 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 for current and future generations of nuclear reactors. The ability to print such sensors enables direct writing of sensors onto fuel, cladding, and structural components. What is done in Phase I – 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 to 300ºC. In Phase 2, we will characterize printed sensors at higher temperatures and with proton beam irradiation to simulate extended periods in high neutron flux environments to demonstrate in-pile stability. Commercial Applications and Other Benefits – 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 additive manufacturing materials for protecting nuclear components against corrosive reactions such as fuel cladding chemical interaction (FCCI) and other structural and heat exchanger materials.