Testing and performance simulation of Advanced Technology Fuels (ATF) (ATF- HBU)

The proposed CRP will support interested IAEA Member States in advancing the development and qualification of Accident Tolerant and Advanced Technology Fuels (ATFs) for existing water-cooled reactors and water-cooled small modular reactors (WC-SMRs). Following the Fukushima Daiichi accident, international efforts have focused on fuel and cladding concepts that can better withstand loss of cooling and other accident conditions, reduce hydrogen generation, and improve the time available for operators to respond. Among the most promising cladding options are chromium-coated zirconium alloys, FeCrAl claddings, and silicon carbide (SiC) composites, which offer improved high-temperature oxidation resistance and the potential for enhanced safety margins combined with traditional or advanced fuels such as doped fuel, microcell fuel, or uranium nitride-based fuels. Building on the IAEA CRP T12032 on Testing and Simulation for Advanced Technology and Accident Tolerant Fuels (ATF-TS), completed in May 2025, and which generated key experimental data and code benchmarks for ATF behaviour under accident conditions, this new CRP will focus on their performance at high burnup and under realistic operational and transient scenarios including the operation of SMRs. It will combine targeted experiments with advanced computer simulations and methodologies to study advanced fuel and cladding behaviour, including coating integrity, fission gas release, pellet–cladding mechanical interactions (PCMI), and response to Loss-of-Coolant Accident (LOCA) and Reactivity-Initiated Accident (RIA) conditions. The work will also promote harmonized test procedures, data processing and expand the IAEA's fuels and materials databases to further support code verification and validation (V&V) and licensing. The CRP will bring together research organizations, regulators, technical support organizations, and industry from interested Member States to share data, models, and best practices, and coordinated experimental evaluations, benchmark exercises using coupled fuel-performance and thermal-hydraulic codes. By improving the understanding and prediction of ATF behavior up to high burnups, the project will help quantify the potential economic benefits of these fuels, particularly for near-term deployment in existing water-cooled reactors and water-cooled SMR designs. In doing so, it will strengthen the technical basis for safer, more resilient, and more sustainable nuclear power, contributing to global efforts to enhance nuclear safety and support low-carbon energy systems.