Lightbridge advances next-gen nuclear fuel to irradiation testing at Idaho National Lab

Lightbridge Corporation is advancing its next-generation nuclear fuel technology into a new testing phase at Idaho National Laboratory (INL), where fuel samples will be irradiated under conditions designed to replicate those inside a commercial nuclear reactor. The U.S. advanced nuclear fuel developer has secured access to the Advanced Test Reactor (ATR) loop testing facility under a new project task statement with Battelle Energy Alliance, the U.S. Department of Energy contractor that operates INL. The testing will expose clad Lightbridge Fuel rodlets to controlled coolant conditions, providing data the company needs as it works toward potential qualification for existing light-water reactors. Testing fuel under commercial reactor conditions The new work represents a step beyond Lightbridge’s previous efforts in fuel fabrication and materials development. Rather than placing fuel samples in a static reactor position, the ATR loop lets researchers test fuel in a separately controlled environment. According to Lightbridge, the loop can reproduce key conditions that fuel would experience in a commercial light-water reactor, including coolant chemistry, temperature, pressure, and flow. That makes the resulting data particularly important for evaluating how the company’s fuel performs under realistic operating conditions. Under the project, Lightbridge will test fuel rodlets made from an enriched uranium-zirconium alloy with cladding. The experiments will include both cylindrical and multi-lobe fuel geometries. The work is expected to cover experiment design, material provision, assembly, irradiation, shipment, and eventual disposition of the materials over approximately 60 months. The company describes the irradiation program as the next stage in moving its technology from laboratory development toward fuel qualification. Lightbridge CEO Seth Grae said the irradiation data is intended to address a key question from utilities considering new nuclear fuel technologies: how the fuel performs under reactor conditions. What Lightbridge is trying to develop Lightbridge is developing Lightbridge Fuel, a proprietary advanced fuel technology intended for existing light-water and pressurized heavy-water reactors, as well as future small modular reactors. The company says its fuel is designed to improve reactor safety and economics while also providing proliferation-resistance benefits. For SMRs, Lightbridge is additionally targeting the ability to adjust reactor output more readily alongside renewable energy on a low-carbon grid. However, the company has not yet demonstrated commercial deployment of the fuel. The new ATR testing is part of the process needed to generate performance data for further evaluation. Lightbridge says data from the irradiation will be used to confirm the performance of its fuel rod design and materials and to benchmark its computer models. The company also plans to use samples from the ATR irradiation in a later testing campaign at INL’s Transient Reactor Test Facility (TREAT). That facility is intended to examine fuel behavior under transient conditions, giving researchers another way to study how the material responds when reactor conditions change rapidly. The progression from fabrication to steady-state irradiation and eventually transient testing is important because advanced nuclear fuels must demonstrate predictable behavior under a range of operating conditions before they can be considered for use in commercial reactors.For Lightbridge, the ATR program therefore represents more than another laboratory experiment. It moves the technology into a testing environment intended to closely reproduce the conditions its fuel would face in an operating reactor. It also provides the performance data that will be needed for the next stages of development and eventual regulatory consideration.Get the latest in engineering, tech, space & science - delivered daily to your inbox.Kaif Shaikh is a journalist and writer passionate about turning complex information into clear, impactful stories. His writing covers technology, sustainability, geopolitics, and occasionally fiction. A graduate in Journalism and Mass Communication, his work has appeared in the Times of India and beyond. After a near-fatal experience, Kaif began seeing both stories and silences differently. Outside work, he juggles far too many projects and passions, but always makes time to read, reflect, and hold onto the thread of wonder.