Radiation monitoring: ORNL builds sensors to detect nuclear material in fuel facilities

Oak Ridge National Laboratory (ORNL) has developed a compact, low-cost radiation detector for continuous, real-time monitoring of nuclear material buildup in facility air ducts. It has been designed to replace slow, manual inspection methods with an affordable, automated system. The device is basically an automated cylinder that straps directly onto ventilation ducts to provide continuous, real-time radiation monitoring. This monitoring method could help nuclear facilities enhance safety, environmental protection, and national security. Continuous vetting in vents In nuclear fuel processing facilities, air ducts serve as overhead ventilation channels designed to continually circulate, filter, and exhaust indoor air. Although these facilities handle radioactive materials inside strictly sealed processing zones protected by high-efficiency particulate filters, microscopic dust particles like uranium can still escape into the airflow. Over long periods, these tiny radioactive specks settle along the interior walls of the metal ductwork. Allowing unmonitored nuclear dust to accumulate inside these overhead vents creates an unshielded radiation source that endangers worker health and poses a serious national security risk if unaccounted material is stolen or diverted. This new monitor provides continuous surveillance by scanning ventilation ducts every minute to detect accumulating nuclear material and enforce peak safety and security standards. The 12-inch device operates in two simple modes depending on facility needs. It operates on battery power for up to a month, capturing and storing data samples once per minute. When connected via Power over Ethernet, it streams and saves data every second for real-time tracking. Ethernet replaces older USB connections, allowing longer cable runs between overhead air ducts and central monitoring hubs. To make the system truly seamless, researchers are pairing the hardware with advanced software. An AI-enhanced algorithm is trained on real facility data collected during live testing at ORNL. Once integrated, the smart software will automatically analyze radiation signatures and trigger instantaneous alerts the second dangerous material builds up to unsafe levels. Low-cost setup Overall, the system is also low-cost. Typical detection components cost upwards of $10,000. ORNL team created the device around a cheap plastic scintillating crystal that costs just a dollar or two. When radiation strikes the detector, a low-cost plastic crystal emits light flashes in the form of photons. A silicon photomultiplier then converts these light pulses into electrical signals. Materials like uranium produce distinct energy signatures. Therefore, the system is programmed to tally specific electrical pulses and immediately flag unsafe radiation levels. Project lead Brett Witherspoon explains that the device merges low-power, historical analog processing with secure, modern digital microcontrollers. Replacing bulky vacuum tubes with compact silicon photomultipliers gives the detector superior temperature resistance and reduces its overall size and cost. Using a plastic crystal priced at just one or two dollars instead of other $1,000 to $10,000 alternatives enables nuclear facilities to deploy widespread radiation monitoring far more affordably. “This is a thousand times more affordable than current technology, while the purpose-built design offers a more accurate, user-friendly, and financially beneficial alternative for nuclear facilities,” said Callie Goetz, who is the overall project lead. “These devices will make nuclear facilities safer and more efficient as it reduce their regulatory burden.” Apart from safeguarding from unshielded radiation, the monitor addresses a major national security concern: preventing illicit actors from secretly harvesting unaccounted-for nuclear material trapped in ductwork. The application doesn’t stop at just fuel plants, either. Researchers are currently stress-testing the electronics to handle extreme heat, aiming to deploy the monitors in next-generation molten salt reactors, small modular reactors (SMRs), and even outdoor perimeter portals to prevent theft in harsh environments.Get the latest in engineering, tech, space & science - delivered daily to your inbox.Mrigakshi is a science journalist who enjoys writing about space exploration, biology, and technological innovations. Her work has been featured in well-known publications including Nature India, Supercluster, The Weather Channel and Astronomy magazine. If you have pitches in mind, please do not hesitate to email her.