South Korea grants Lightbridge patent allowance for mixed-grid nuclear fuel assembly design, expanding IP protection in key reactor market
Lightbridge Corporation (Nasdaq: LTBR) announced October 30 that it received a Notification of Patent Grant from South Korea’s Ministry of Intellectual Property for Korean Patent Application No. 10-2025-7001591, titled “Nuclear Fuel Assembly.” The patent covers 17 claims directed to the company’s mixed-grid nuclear fuel assembly design — broadening its intellectual property position in one of the world’s more active nuclear energy markets.
South Korea grants Lightbridge patent allowance for mixed-grid fuel design
The Notification of Patent Grant arrived October 30, 2026, from South Korea’s Ministry of Intellectual Property — formally the Korean Intellectual Property Office. Once Lightbridge pays the registration fee, Patent Application No. 10-2025-7001591 becomes an enforceable Korean patent. Its 17 claims describe a fuel assembly where fuel elements are arranged in a mixed-grid pattern combining two different grid configurations.
That detail matters. A mixed-grid arrangement is central to how Lightbridge organizes its fuel elements within a bundle, and locking in patent rights over that arrangement in South Korea means real IP protection in a market running a meaningful share of the world’s nuclear capacity.
South Korea’s growing nuclear ambitions — and its rare combination of reactor types — make that protection strategically significant.
Why the new claims offer broader protection than the 2022 Korean patent
This isn’t Lightbridge’s first Korean patent on mixed-grid fuel. Back in August 2022, the company announced a patent in the same Korean patent family — but that earlier grant had a narrower scope, requiring the mixed grid to pair a rectangular pattern specifically with a triangular one.
The newly allowed application is a divisional of that 2022 patent. Divisional applications let companies pursue additional claims from the same original filing. Here, the new claims cover the mixed-grid concept itself, without tying protection to any particular combination of grid shapes. Lightbridge now holds broader protection in South Korea over how its fuel elements can be arranged within a bundle — not just one specific rectangular-triangular pairing, but the mixed-grid approach more generally.
Technical details: Fuel element design and reactor compatibility
The allowed claims describe a fuel assembly whose outermost fuel elements form a substantially circular perimeter. That circular bundle shape is characteristic of pressurized heavy water reactors, including CANDU-type designs — which happen to be among the reactors South Korea operates.
Each fuel element features a multi-lobed profile with spiral ribs. The ribs of neighboring elements touch at intervals along the assembly length, holding elements in position without additional hardware — a structural solution built directly into the fuel geometry itself.
Dependent claims extend coverage further, addressing bundles of 19 and 61 fuel elements housed inside circular or twelve-sided shrouds, with grid patterns alternating along concentric circles. Assemblies can also mix different rod types: four-lobe Lightbridge fuel rods, conventional pelleted fuel rods, or burnable poison rods. That gives operators real flexibility in how they configure a bundle.
South Korea’s nuclear sector and significance of the market
South Korea isn’t a peripheral nuclear market. The country runs 26 reactors supplying roughly one-third of its electricity, according to the World Nuclear Association. Three of those reactors are CANDU 6 pressurized heavy water units located at the Wolsong site.
That mix of reactor types is unusual. South Korea is one of only a handful of countries operating both pressurized water reactors and pressurized heavy water reactors simultaneously, and it designs and exports its own reactor technology — giving it influence well beyond its domestic fleet. The government is doubling down: South Korea’s 11th Basic Plan for Electricity Supply and Demand targets nuclear’s share rising from 30.7% in 2023 to 35.2% by 2038, backed by two new large reactors.
CEO Seth Grae highlighted why that combination matters for Lightbridge specifically. “South Korea is one of the few countries that operates both pressurized water and pressurized heavy water reactors, and it builds and exports its own reactor designs,” he said, “so patent coverage there supports both our light water and CANDU fuel designs.”
Lightbridge’s broader patent portfolio and fuel development program
South Korea is one piece of a larger IP strategy. Lightbridge’s fuel technology is backed by a worldwide patent portfolio spanning jurisdictions that represent the majority of global nuclear generating capacity, built steadily across key reactor markets over several years.
On the development side, the company is working toward commercializing its fuel for existing light-water and pressurized heavy-water reactors, as well as for new small modular reactors. The SMR application is designed to support load-following alongside renewables on zero-carbon grids — a capability that’s increasingly relevant as electricity systems integrate more variable generation. Lightbridge has two long-term framework agreements with Battelle Energy Alliance, the Department of Energy’s operating contractor for Idaho National Laboratory, and DOE’s Gateway for Accelerated Innovation in Nuclear program has awarded the company twice to support fuel development work.
What this patent grant means for Lightbridge
Lightbridge now holds stronger and wider IP protection in South Korea than it did before. The new patent covers the mixed-grid arrangement broadly, building on the narrower 2022 patent in the same family. South Korea’s growing nuclear ambitions — and its rare combination of reactor types — make that protection strategically significant.
The patent becomes formally registered once Lightbridge pays the registration fee, at which point it joins a portfolio designed to protect the company’s fuel technology across the markets where nuclear power is most active.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
