Exosens equipped the first two reactors of the DOE program to achieve criticality
Exosens announced in a press release published on October 8, 2026, that it had supplied neutron detectors to Antares Nuclear and Valar Atomics. These two designers operated the first two reactor models to achieve criticality under the Reactor Pilot Program of the U.S. Department of Energy (DOE).
The DOE program exceeded its criticality objective
In August 2025, the DOE's Reactor Pilot Program selected 11 advanced reactor projects. Its objective was to bring at least three reactor models to criticality by July 4, 2026. According to the press release, this objective was exceeded: four projects achieved criticality within the set timeframe.
Exosens specified that it provided Antares Nuclear and Valar Atomics with neutron detectors as well as associated technical expertise. These detectors are integrated into neutron flux monitoring systems contributing to safety. They provide the measurements necessary for monitoring reactor power and the approach to criticality during startup and testing phases.
The company presents these advances as a "decisive step" toward the commercial deployment of next-generation nuclear technologies in the United States, particularly for small modular reactors (SMR).
Exosens present in seven SMR projects in the United States and Europe
According to the group, these achievements should result in the short term in pre-series orders and, in the long term, support demand for its nuclear instrumentation solutions in the American market.
Chief Executive Officer Jérôme Cerisier linked this direction to demand for reliable and decarbonized energy, "in particular to meet the unprecedented energy needs of data centers dedicated to artificial intelligence". He indicated that Exosens already provides nuclear detection solutions as part of seven projects related to SMRs in the United States and Europe. Cyril Barre, director of nuclear instrumentation, discussed supporting reactor designers in their transition from first-of-a-kind testing to commercial deployment.
The company, which claims more than 2,000 employees and 13 sites in Europe and North America, will publish on October 27, 2026 its revenue and adjusted gross margin for the first nine months of 2026, then its full-year 2026 results on February 22, 2027.
