Advancing TRISO Fuel Manufacturing for Next Generation Reactors in France

by Erica Marchand
Paris, France (SPX) Nov 06, 2025

Framatome has launched a new pilot line to produce TRISO fuel at its Romans-sur-Isere facility in France. This development increases Framatome's capacity for advanced nuclear fuel manufacturing in Europe and adds to its efforts in the United States.

TRISO, which stands for Tri-structural Isotropic particle fuel, features uranium (or thorium) fuel kernels encapsulated in layers of pyrolytic carbon and silicon carbide, each particle less than a millimeter wide. These particles are embedded within a graphite matrix, then formed into either cylindrical blocks or spherical pebbles for use in high-temperature gas-cooled reactors.

Unlike conventional nuclear fuel, TRISO particles do not melt in commercial reactor conditions and withstand temperatures above 1,600 degrees Celsius. Each miniaturized particle acts as its own containment system, offering high resistance to irradiation, corrosion, and physical damage. The subdivided design ensures that even if individual particles are breached, surrounding materials continue to retain radioactive products, strengthening reactor safety.

First developed in the 1960s, TRISO's robust performance has supported applications in research and commercial demonstration reactors across several countries. Its architecture enables longer operating cycles, high fuel burnup, and decreases risks associated with meltdown, supporting streamlined containment requirements in advanced reactors.

The Romans-sur-Isere pilot line will manufacture TRISO fuel enriched up to 20 percent, supporting specification, qualification, and quality control processes necessary for advanced reactor projects. The initiative aims to enable future large-scale industrialization of TRISO fuel in France.

"We are proud to reinforce our expertise in France and support innovation in advanced nuclear fuels," said Lionel Gaiffe, Senior Executive Vice President of the Fuel Business Unit at Framatome. "With more than 65 years of experience, Framatome is well positioned to develop TRISO fuel programs tailored to the needs of our customers and partners, including start-ups."

As part of France's 2030 Innovative Nuclear Reactors project, Framatome and Blue Capsule Technology, a French start-up, have formalized cooperation to advance qualification of TRISO fuel particles and the production of fuel elements for high-temperature reactors.