Otrera
Updated: August 28, 2026
Frédéric Varaine - Founder & CEO
Country: France | Funding: €19.5M (+)
Founded: 2023
Website: https://otrera.fr/en/
Otrera is making modern fast neutron reactor (FNR) rethinking its core design decisions to make it simple, safe, and cost-competitive. Its concept is based on a compact, modular loop-type architecture, drawing inspiration from proven LWR principles. It features three alternating reactor vessels: two in operation and one in cooling. This configuration allows for in-vessel fuel cooling, eliminating the need for separate storage pools—a major cost-saving innovation. The project is designed to reduce or even eliminate the traditional limitations of sodium technology and allows to simplify the reactor’s overall architecture, shrink the size of components and supporting infrastructure. Otrera’s modular design relies on standardized components, enabling a range of reactors from 30 to 450 MWe while significantly cutting costs and qualification timelines.
Founded: 2023
Website: https://otrera.fr/en/
Otrera is making modern fast neutron reactor (FNR) rethinking its core design decisions to make it simple, safe, and cost-competitive. Its concept is based on a compact, modular loop-type architecture, drawing inspiration from proven LWR principles. It features three alternating reactor vessels: two in operation and one in cooling. This configuration allows for in-vessel fuel cooling, eliminating the need for separate storage pools—a major cost-saving innovation. The project is designed to reduce or even eliminate the traditional limitations of sodium technology and allows to simplify the reactor’s overall architecture, shrink the size of components and supporting infrastructure. Otrera’s modular design relies on standardized components, enabling a range of reactors from 30 to 450 MWe while significantly cutting costs and qualification timelines.
