Westinghouse Electric Company reached a key milestone earlier this month when it successfully completed criticality testing for its eVinci microreactor. The work was completed by Los Alamos National Laboratory in collaboration with Idaho National Laboratory, the Nevada National Security Site, and the DOE/NRC Collaboration for Criticality Safety Support for Commercial-Scale HALEU Fuel Cycles and Transportation. The eVinci microreactor criticality testing was conducted at the National Critical Experiments Research Center (NCERC), a National Nuclear Security Administration facility located in Nevada. Testing eVinci at core temperatures upward of 1,000 degrees Celsius yielded invaluable data about the reactor’s performance as Westinghouse works to move this advanced nuclear design toward commercialisation. The eVinci test brings the system one step closer to real-world conditions On September 3, 2026, the eVinci test reached criticality at 663 degrees Celsius. Westinghouse researchers measured a peak core temperature of 1,011 degrees Celsius, a record-high temperature for a reactivity measurement at NCERC. The tests generated high-quality temperature data that Westinghouse will use to strengthen its analytical models and accelerate the eVinci reactor prototype design. This continues …