Lightbridge secures South Korean patent allowance for its mixed-grid nuclear fuel assembly design, expanding IP protection in a key reactor market
Lightbridge Corporation (Nasdaq: LTBR) announced on October 30, 2026, that South Korea’s Ministry of Intellectual Property has issued a Notification of Patent Grant for a patent application covering the company’s mixed-grid nuclear fuel assembly design. The application, titled “Nuclear Fuel Assembly,” covers 17 claims related to how fuel elements can be arranged within a bundle — and it extends Lightbridge’s IP foothold in one of the world’s most active nuclear energy markets.
Lightbridge receives South Korean patent allowance for mixed-grid fuel design
Korean Patent Application No. 10-2025-7001591 is the formal name behind the announcement. The title — “Nuclear Fuel Assembly” — sounds straightforward, but what it covers runs deeper. Its 17 allowed claims describe a fuel assembly where elements are arranged in a mixed-grid pattern, combining two different grid arrangements rather than relying on a single uniform design.
The patent isn’t in force yet. Lightbridge must pay the required registration fee before it takes legal effect in South Korea — a standard procedural step, but a necessary one.
According to the World Nuclear Association, the country operates 26 reactors supplying roughly one-third of its electricity — a substantial share by any measure.
What the allowed claims cover and why they represent broader protection
At the core of the allowed claims is a fuel bundle where the outermost fuel elements form a substantially circular perimeter. That circular-perimeter geometry is characteristic of pressurized heavy water reactors, including CANDU-type designs — a detail that turns out to be strategically important.
Each fuel element in the described assembly carries a multi-lobed profile with spiral ribs. Ribs of neighboring elements touch at intervals along the assembly’s length, keeping everything in position without extra mechanical supports.
Dependent claims push the protection further still. They cover bundles of 19 and 61 fuel elements housed inside a circular or twelve-sided shroud, grid patterns alternating along concentric circles, and assemblies that mix four-lobe Lightbridge fuel rods with conventional pelleted fuel rods or burnable poison rods. That’s a wide range of configurations under a single patent.
The comparison to Lightbridge’s earlier Korean patent is worth making. The 2022 patent — announced in August of that year — required the mixed grid to pair a rectangular grid pattern with a triangular one specifically. The newly allowed claims drop that requirement entirely, covering the mixed-grid concept itself regardless of which grid shapes are combined. That’s a meaningful expansion: it closes off design-arounds that might’ve worked under the narrower 2022 claims.
South Korea’s nuclear sector makes patent coverage strategically significant
South Korea isn’t a peripheral nuclear market. According to the World Nuclear Association, the country operates 26 reactors supplying roughly one-third of its electricity — a substantial share by any measure.
Three of those reactors are CANDU 6 pressurized heavy water reactors, located at the Wolsong site. That’s directly relevant to the newly allowed patent, which describes the circular-perimeter fuel bundle geometry used in exactly that reactor type.
South Korea also builds and exports its own reactor designs, operating both pressurized water reactors and pressurized heavy water reactors. That dual-reactor profile is uncommon globally. For Lightbridge, it means a single patent jurisdiction can cover IP relevant to two distinct reactor technologies simultaneously — something few markets offer.
Seth Grae, Chairman and CEO of Lightbridge, made that point directly in the announcement: “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, so patent coverage there supports both our light water and CANDU fuel designs.”
South Korea’s nuclear expansion plans and Lightbridge’s global IP portfolio
South Korea isn’t standing still. The government’s 11th Basic Plan for Electricity Supply and Demand targets an increase in nuclear’s share of generation from 30.7% in 2023 to 35.2% in 2038, with two new large reactors planned to support that growth. A market actively expanding is one where IP protection carries real long-term weight.
The new Korean patent sits within the same patent family as the 2022 Korean patent — a divisional application, branching off from that earlier filing while covering distinct claims. The relationship between the two is additive: the 2022 patent protects a specific rectangular-triangular grid pairing, while the new one covers the broader mixed-grid approach. Together, they give Lightbridge layered protection in South Korea.
Lightbridge’s worldwide patent portfolio extends well beyond South Korea, spanning jurisdictions that represent the majority of global nuclear generating capacity. The company has also built operational ties with the U.S. national laboratory system, holding two long-term framework agreements with Battelle Energy Alliance — the Department of Energy’s operating contractor for Idaho National Laboratory. The DOE’s Gateway for Accelerated Innovation in Nuclear (GAIN) program has awarded Lightbridge twice in support of its fuel development work.
What this patent allowance means for Lightbridge’s position in South Korea
The October 30 announcement adds a meaningful layer to Lightbridge’s IP position in a market that’s both active today and growing. Broader than the company’s existing Korean patent, the allowed claims cover the mixed-grid concept without locking it to specific grid shapes — which matters in a country running both CANDU and light-water reactors. Once the registration fee is paid and the patent formally issues, Lightbridge will hold two complementary patents in the same Korean family: one specific, one broader, covering a fuel assembly design it’s working to commercialize globally.
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.
