China's first nuclear power unit using Hualong One technology, a domestically developed third-generation reactor design, achieved criticality in Fuqing, east China's Fujian on Wednesday. This means that the No. 5 nuclear power unit is in a normal state of nuclear power generation, a step closer to commercial operation. Hualong One reactors were jointly designed by two nuclear power giants, China General Nuclear Power Group and China National Nuclear Corporation, and passed inspection by a national panel in August 2014. The nuclear power unit began construction in 2015 and is expected to start operation this year.