Hainan’s First Hualong One Nuclear Unit Connects to Grid

China Huaneng Group announced on August 1 that Unit 3 of the Huaneng Changjiang Nuclear Power Phase II project—Hainan Province’s first “Hualong One” nuclear power unit—has successfully connected to the power grid and begun generating electricity, according to Xinhua News Agency. The milestone marks a significant step forward for China’s self-developed third-generation nuclear technology and the island province’s clean energy transition.

A Key Milestone for Hainan’s Energy Future

The grid connection represents the culmination of a five-year construction effort. The Changjiang Phase II project, located in Changjiang Li Autonomous County in western Hainan, was officially launched on March 31, 2021, making it the first nuclear power project to begin construction during China’s 14th Five-Year Plan period (2021-2025), as People’s Daily reported at the time.

The project plans two 1.2 million kW nuclear power units equipped with the Hualong One (HPR1000) reactor—China’s fully self-developed third-generation pressurized water reactor technology with complete independent intellectual property rights. After both units are completed, the project’s annual power generation is expected to reach 18 billion kWh, enough to meet the annual electricity needs of approximately 1 million people.

The environmental impact is substantial. Once fully operational, the project will save more than 6.32 million tons of standard coal annually and reduce CO2 emissions by approximately 11.6 million tons per year, providing clean, safe, and efficient energy support for the construction of the Hainan Free Trade Port.

Advanced Safety Design

The Hualong One reactor incorporates a combined active and passive safety design approach, featuring several notable innovations. According to ITHome, the reactor features a double-layer containment shell—an inner shell of 1.3-meter concrete with a 6mm steel plate lining, and an outer shell of 1.8-meter high-strength concrete that is twice the strength of ordinary residential buildings.

Perhaps the most distinctive safety feature is the passive water tank. Storing 2,400 tons of water beneath the reactor dome, this tank requires no external power and no manual operation when a reactor anomaly occurs. It automatically injects more than 2,000 tons of water into the reactor through gravity alone, providing 72 hours of passive cooling—acting like a giant water-cooled air conditioner that buys critical time for repairs.

As Tencent News noted in its analysis, the reactor is designed to withstand magnitude 9 earthquakes, and the equipment localization rate exceeds 90 percent, reflecting China’s push for nuclear power design autonomy and manufacturing self-sufficiency.

Progress Toward Commercial Operation

The grid connection follows a series of key milestones. Unit 3 completed its non-nuclear steam turbine test in November 2025, and began loading its first nuclear fuel on April 30, 2026, entering the nuclear commissioning phase. After grid connection, the unit is operating well with all technical indicators meeting design requirements. It will now enter the load trial operation phase, conducting power ramp-up and various performance tests toward commercial operation, expected later this year.

Meanwhile, Unit 4’s outer dome was successfully hoisted into place on April 13, 2026, marking the basic completion of the Unit 4 nuclear island main structure, as China Power reported. Unit 4 is expected to begin commercial operation in 2027, completing the full project.

Part of a Broader Nuclear Expansion

The Changjiang project is part of China’s rapidly expanding nuclear energy program. According to CCTV News, China now has 60 commercial nuclear power units in operation, 36 under construction—more than half of global under-construction capacity—and 16 approved pending construction. Total installed nuclear capacity has reached 125 million kW, ranking first globally.

The Hualong One technology has entered the batch construction phase, with more than 40 units in operation, under construction, or approved for construction both domestically and internationally. The Changjiang Phase II project, with a total investment of approximately 39.45 billion yuan, is the largest power engineering investment since the Hainan Free Trade Port was established, as reported by ifeng.

The project is majority-owned by China Huaneng Group and jointly constructed with China National Nuclear Corporation. It represents Huaneng’s first pressurized water reactor nuclear project, complementing its portfolio that includes the world’s first fourth-generation high-temperature gas-cooled reactor at Shidao Bay in Shandong.

What to Watch

As Unit 3 progresses through its commissioning tests, attention will turn to the completion of Unit 4 and the full project’s contribution to Hainan’s “Clean Energy Island” strategy. With clean energy already accounting for more than 83 percent of Hainan’s installed capacity, the Changjiang project will provide stable base-load power to support the Free Trade Port’s industrial development. The successful grid connection of this Hualong One unit reinforces China’s position as a global leader in nuclear energy deployment and its commitment to carbon reduction goals.