The US Nuclear Regulatory Commission’s (NRC) has approved the topical report High Burnup for Pressurised Water Reactors submitted in 2024 by Framatome. The report was based on nearly six years of work supporting increased fuel burn-up limits for the GAIA and HTP fuel designs that enhance operational efficiency, competitiveness and flexibility for nuclear plant operators.
These advanced fuel solutions will be manufactured at the company’s facility in Richland, Washington. With more than 55 years of fuel manufacturing excellence, this upgraded facility plays a key role in delivering the most advanced nuclear fuel solutions.
GAIA is Framatome’s most advanced pressurised water reactor (PWR) fuel, specifically engineered for high burn-up and high-enrichment cycles. It uses mixing vane grids MVGs) to improve the Critical Heat Flux (CHF) performance, allowing reactors to operate with greater safety margins MVGs are specialised structural components within a nuclear fuel assembly designed to actively stir the coolant as it flows past fuel rods. While standard spacer grids primarily provide mechanical support and maintain proper rod spacing, mixing vane grids feature integrated “vanes” or tabs that extend into the coolant flow.
GAIA also features Monobloc Guide tubes made of Q12 alloy, which significantly increases resistance to fuel assembly bowing and lateral deformation. It is specifically designed to accommodate NRC’s higher burn-up limits and can utilise Chromia-doped pellets (typically UO2 with 500–1600 ppm Cr2O3) to better manage fission gas release at end-of-life.
The High Thermal Performance (HTP) design is a globally established platform known for its extreme mechanical reliability. Its signature feature is the HTP spacer grid, which uses an “8-line” fuel rod support concept that is exceptionally resistant to grid-to-rod fretting (GTRF) wear. The HTP platform is available for nearly every PWR lattice type and has a vast operating history across the US and Europe. Much of the GAIA design is built upon technologies first proven in the HTP line.
The submittal is part of Framatome’s Advanced Fuel Management (AFM) programme, which focuses on bringing innovative nuclear fuel technologies that include uranium oxide (UO2) pellets with higher enrichment levels and advanced codes and methods, which support higher fuel burn-ups for the existing US nuclear fleet.
These innovative solutions provide safe, reliable and economical fuel cycles and support cycle length extensions from 18 to 24 months for a large segment of the US reactor fleet. By extending fuel burn-up capabilities, plant operators can optimise fuel utilisation, reduce waste and support the continued generation of competitive, clean and sustainable energy.
This submittal and acceptance complement Framatome’s other recent advancements to deliver higher enriched fuel to the nuclear industry. NRC recently approved the application of the company’s suite of PWR advanced codes and methods to operating conditions with U-235 enrichments exceeding the standard of 5%. NRC also approved a licence amendment allowing Framatome to transport fresh PWR and BWR fuel assemblies within the US with U-235 enrichments up to 8%.
