eVinci sets temperature record during zero-power criticality tests

Westinghouse has completed zero-power criticality testing of its eVinci microreactor, achieving criticality at 663 degrees Celsius and a reactivity measurement at 1,011 degrees Celsius. The work was conducted at the National Criticality Experiments Research Center in Nevada in partnership with Los Alamos National Laboratory. The eVinci is a heat pipe-cooled reactor producing up to 5 megawatts electric, designed to run for eight or more years per fuel load before refuelling, and shipped as a factory-built unit. The testing generated temperature-dependent data to inform the prototype design.

Where this fits

This is validation work on a firm, energy-dense generation source that requires minimal on-site assembly and no refuelling for years. It bears directly on the reliability and sovereignty case: Australia's grid is being built on weather-dependent renewables that need firming capacity, transmission overbuild, and a supply chain (panels, batteries, inverters) owned by China. Small modular reactors like eVinci offer firm dispatchable power with a low material footprint per megawatt-hour and no weather risk. Australia has banned nuclear generation by law; this milestone happens in Nevada, not here.

What it means

As the US and its allies advance designs that can be factory-built and deployed quickly, Australia remains locked out of the technology by statute while committing to a grid architecture that will require decades of gas-fired firming and new transmission to manage renewable intermittency. The eVinci programme shows what firm, scalable, low-emission power looks like when the legal and regulatory path exists to build it. Australia has chosen a different path: one that is costlier in whole-system terms, materially intensive, and dependent on supply chains it does not control.