Lightbridge completed its final design review for the ATR irradiation experiment in June 2025 and began irradiation of 26–30% enriched uranium-zirconium alloy samples at INL’s Advanced Test Reactor using the FAST method in November 2025. Initial samples are scheduled for discharge in April–May 2026, with post-irradiation examinations set to assess structural integrity, thermal conductivity, and fission gas behavior later this year.

At the TopFuel 2025 conference, Lightbridge presented three technical papers demonstrating that its metallic fuel design maintains safe temperature margins during simulated locked rotor accidents, offers larger safety margins than conventional UO2 in OECD NEA transient simulations, and supports accurate modeling of its proprietary co-extrusion fabrication process.

The company ended fiscal 2025 with $201.9 million in cash—up from $40.0 million a year earlier—after raising approximately $176 million through its at-the-market equity program. The debt-free balance sheet and $3.6 million in annual interest income are expected to fund extended fuel development and regulatory qualification efforts.

Lightbridge has expanded its internal team across neutronics, thermal hydraulics, mechanical engineering, materials science, and regulatory licensing to support next-phase fuel qualification. Engagement with the NRC is planned for this year, focused on post-irradiation examination, co-extrusion process scale-up, and initial deployment planning for an expandable fuel facility.