Hot testing of first San’ao unit completed

Tuesday, 17 June 2025

Hot functional tests involve increasing the temperature of the reactor coolant system and carrying out comprehensive tests to ensure that coolant circuits and safety systems are operating as they should. Carried out before the loading of nuclear fuel, such testing simulates the thermal working conditions of the power plant and verifies that nuclear island and conventional equipment and systems meet design requirements.

China General Nuclear (CGN) said the completion of hot test at San’ao unit 1 on 10 June “lays the foundation for subsequent reactor loading, grid-connected power generation and commercial operation”.

Cold functional tests – which are carried out to confirm whether components and systems important to safety are properly installed and ready to operate in a cold condition – were completed at San’ao 1 in November last year. The main purpose of those tests – which marked the first time the reactor systems were operated together with the auxiliary systems – was to verify the leak-tightness of the primary circuit.

_{The San’ao plant site (Image: CGN)}

In May 2015, the National Energy Administration approved the project to carry out site protection and related demonstration work at San’ao. On 2 September 2020, the executive meeting of the State Council approved the construction of units 1 and 2 as the first phase of the plant. China’s National Nuclear Safety Administration issued a construction permit for the two units on 30 December that year and first concrete for unit 1 was poured the following day. The first concrete for San’ao 2 was poured on 30 December 2021.

San’ao 1 and 2 are scheduled to begin supplying electricity in 2026 and 2027, respectively.

The San’ao plant is the first nuclear power project in China’s Yangtze River Delta region to adopt the Hualong One reactor design. A total of six Hualong One units are planned for the San’ao site. In August 2024, the State Council approved the construction of San’ao Phase II (units 3 and 4).

The San’ao project marks the first Chinese nuclear power project involving private capital, with Geely Technology Group taking a 2% stake in the plant. CGN holds 46% of the shares of the project company Cangnan Nuclear Power, with other state-owned enterprises holding the remainder.