Westinghouse has completed high-temperature, zero-power criticality testing of its eVinci microreactor at a US nuclear testing facility, generating experimental data on reactor behaviour at temperatures approaching its proposed operating conditions.
The test was carried out at the National Criticality Experiments Research Center (NCERC) in Nevada, in cooperation with Los Alamos National Laboratory and the Nevada National Security Site. The eVinci test reached criticality at 663°C, while a subcritical reactivity measurement was conducted at a peak core temperature of 1,011°C.
Westinghouse said the latter was the highest-temperature reactivity measurement carried out at NCERC. The measurements provide temperature-dependent data that can be used to validate computational models and inform further development of the reactor core and prototype design.
The test follows earlier zero-power criticality work on eVinci and forms part of Westinghouse’s development approach, in which experimental results are used to refine the design before subsequent testing and deployment stages.
The eVinci concept is a compact heat-pipe-cooled reactor using TRISO fuel and a graphite core. Heat pipes transfer heat from the reactor core to a power conversion system without relying on conventional primary coolant circulation. The architecture is intended for applications where a compact and relatively autonomous power source is required, including remote locations and potential defence and space applications.
Westinghouse says the proposed reactor is designed to operate continuously for up to eight years without refuelling, although commercial deployment will depend on further development, testing and regulatory approval.
The latest experiment provides data at temperatures substantially above the 663°C criticality point, allowing engineers to examine changes in reactivity as representative reactor materials heat towards anticipated operating conditions.
The work is being conducted with support from US national laboratories and the National Nuclear Security Administration’s testing infrastructure. For Westinghouse, the results represent another step in moving eVinci from analytical and zero-power testing towards prototype development.
The company is continuing to use simulation and experimental testing to refine the design, with the latest measurements intended to reduce uncertainty in the reactor’s thermal and neutronic models ahead of subsequent development stages.
