The first Hualong One nuclear power unit in south China's Hainan Province was connected to the power grid on Saturday, marking a key milestone before the reactor enters commercial operation.

The unit, officially Unit 3 of the Phase II Changjiang Nuclear Power Plant, uses China's domestically developed third-generation Hualong One nuclear reactor technology. Following grid connection, the unit will undergo a series of commissioning, efficiency optimization and performance tests before being put into full commercial service.

The second phase of the Changjiang project consists of two 1.2-gigawatt nuclear power units. Once both reactors are operational, they are expected to generate about 18 billion kilowatt-hours of electricity annually, according to He Qingwei, a senior operator at the Changjiang Nuclear Power Plant.

The project is expected to save around 6.3 million tonnes of standard coal each year while reducing carbon dioxide emissions by approximately 11.6 million tonnes, contributing to energy security and China's climate goals, He said.

China has pledged to peak carbon dioxide emissions before 2030 and achieve carbon neutrality before 2060.

Multiple innovations

The Hualong One reactor incorporates several safety features developed with independent Chinese intellectual property.

One of its most notable designs is a double containment structure. Unlike earlier-generation reactors that used a single containment shell, this Hualong One features both an inner and an outer protective barrier.

The inner containment consists of 1.3 meters of reinforced concrete lined with a 6-millimeter steel plate, designed to securely contain radioactive materials. The outer containment is built with 1.8 meters of high-strength concrete, providing additional protection against external impacts.

The reactor island contains approximately 230,000 tonnes of reinforcing steel, and the containment structure is designed to withstand the impact of extremely heavy external forces.

Another key safety feature is its passive emergency cooling system. A gravity-fed water tank capable of storing about 2,400 tonnes of water can automatically inject cooling water into the reactor without external electricity or human intervention if an emergency occurs. The system can continue cooling the reactor for up to 72 hours, helping maintain safe temperatures and providing operators with valuable time to respond.

The plant also uses a fully domestically developed digital management system integrating video surveillance, 5G communications and artificial intelligence to monitor nuclear power production throughout its entire lifecycle.

The platform enables closed-loop digital management and full operational traceability while providing compatibility with future fourth-generation nuclear reactors, supporting China's efforts to strengthen independent and intelligent nuclear power technologies.

Supporting local low-carbon transition

The project also aligns with Hainan Province's long-term climate strategy.

Under the Hainan Low-Carbon Island Construction Plan released last July, the province aims to peak carbon emissions by 2030, establish a comprehensive low-carbon island by 2045, reduce annual carbon dioxide emissions by 70% from peak levels, and build a zero-carbon, efficient, smart and resilient energy system. Hainan targets achieving carbon neutrality by 2060.