The prototype of the 190kA generator circuit breaker (GCB) of the Hualong One’s first overseas project K-2/K-3 has passed its short-circuit breaking test, marking the successful development of the large-capacity GCB for China's first million-kilowatt nuclear power unit. This achievement means China can independently produce critical equipment for the million-kilowatt nuclear power units and resolves the technical challenges of the generator circuit breaker for the Hualong One. It provides solutions for China's nuclear power units and ensures the self-reliance and controllability of China's export supply chain of China National Nuclear Corporation Overseas.

The 190kA GCB is primarily applied in large million-kilowatt nuclear power units and is a critical piece of equipment for ensuring the safety of nuclear power plants. The process of arc breaking involves a complex and transient evolution of multiple parameters, including electromagnetism, thermal, and mechanical interactions. During the breaking of ultra-high short-circuit currents, a plasma arc with temperatures reaching tens of thousands of degrees Kelvin will be instantly generated. And when the circuit breaker opens, the temperature at the contact point needs to be reduced within microseconds, which is a huge challenge. It places high demands on the anti-erosion performance of components in the arc-extinguishing chamber.