China National Nuclear Corp's (CNNC) Fuqing nuclear power plant in East China's Fujian Province, the country's second nuclear unit using Hualong One technology, a domestically developed third-generation reactor design, reached criticality for the first time on Saturday, marking its official entry into operation and an important step toward commissioning.

Experts said that the unit will provide clean energy, boost the high-quality economic development, ensure power supplies and help the country reach its carbon emissions reduction goals.

Reactor criticality is an important step in the commissioning of a nuclear power plant. After criticality, the reactor will commence nuclear operations. According to CNNC, unit 5 underwent maintenance and fuel re-loading on December 6.

Unit 6, after a series of criticality-related tests, will carry out the first connection to the grid of the turbine generation unit.

CNNC said that after the full completion of the six units of the Fuqing Nuclear Power Plant, the total installed capacity will reach 6.678 million kilowatts, with annual generation capacity of 50 billion kilowatt hours, boosting clean energy supplies to power the country's high-quality development.

As China's "calling card" for its nuclear power industry, Hualong One has become one of the most widely recognized third-generation nuclear power models in the market.

In May 2015, construction began on the world's first Hualong One demonstration project in Fuqing. On January 30, the world's first nuclear power unit under Hualong One, unit 5 of CNNC's Fuqing nuclear power plant, entered commercial operation.

With Hualong One online, China is now at the world forefront of third-generation nuclear technology, alongside countries like the US, France and Russia, the Xinhua News Agency reported, citing CNNC Chairman Yu Jianfeng.

In April 2021, unit 3 of a Hualong One nuclear reactor at a plant in Karachi, Pakistan, CNNC's second overseas unit under Hualong One, entered the commissioning stage following installation.

According to CNNC, each Hualong One unit will generate about 10 gigawatt hours (GWh) of electricity, sufficient to support the needs of 1 million local people, which will deepen the China-Pakistan strategic partnership and promote nuclear energy cooperation.

"CNNC's Hualong One has fully independent intellectual property rights based on over 30 years of experience in nuclear power design, manufacturing and operation, which will not only benefit China's independent development of nuclear power, but also contribute to the world's clean-energy development, especially countries and regions along the Belt and Road Initiative," Han Xiaoping, chief analyst at energy industry website china5e.com, told the Global Times on Sunday.

China has accelerated its use of nuclear power and maintained high levels of safety. Han said that with the nuclear power unit equipped with several major passive emergency cooling water source systems, the safety level has been further improved.

From January to October, the country's nuclear power plants generated 336.6 billion kilowatt-hours of electricity, an increase of 12.7 percent compared with the same period in 2020, official data showed last month.