Hot testing starts of second CGN Hualong One unit

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) announced that hot functional testing of the 1180 MWe (gross) pressurised water reactor began at 9.00am on 25 September.

Fangchenggang unit 4 (Image: CGN)

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 - have already been completed at Fangchenggang 4. The main purpose of those tests was to verify the leak-tightness of the primary circuit.

First concrete was poured for the nuclear island of unit 3 - 39% owned by Guangxi Investment Group and 61% by CGN - in December 2015, while that for unit 4 was poured a year later. Unit 3 was originally expected to start up in 2019, with unit 4 scheduled to start up in 2020. Both their start-ups were subsequently postponed until 2022.

In January 2022, CGN announced that the start-up of Fangchenggang 3 and 4 had been put back again due to delays caused by the COVID-19 pandemic. It said the start of operation of unit 3 had been put back to the second half of 2022, with that of unit 4 expected in the first half of 2024. However, in December, CGN announced Fangchenggang 3 would not begin operation until the first half of 2023.

Unit 3 achieved first criticality - a sustained chain reaction - on 27 December 2022 and was synchronised with the grid on 10 January this year. It entered commercial operation on 25 March.

The Fangchenggang site (Image: CGN)

The Fangchenggang plant is planned to house six 1000 MWe reactors. The first phase comprises two CPR-1000 units which were put into commercial operation in 2016.

The first two units of China National Nuclear Corporation's version of the Hualong One design at the Fuqing plant in Fujian province have both already started up. Unit 5 entered commercial operation on 30 January 2021, with unit 6 following on 25 March 2022.