Friday, 11 April 2025
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Cold functional tests are carried out to confirm whether components and systems important to safety are properly installed and ready to operate in a cold condition. The main purpose of these tests is to verify the leak-tightness of the primary circuit and components – such as pressure vessels, pipelines and valves of both the nuclear and conventional islands – and to clean the main circulation pipes.
Huaneng Hainan Changjiang Nuclear Power announced that the final test – in which the pressure in the primary loop is held at 22.3 MPa for 10 minutes – was successfully completed on 10 April. The tests confirmed that the primary circuit pressure boundary of the Hualong One unit was “intact and well sealed”, it said.
Cold testing will now be followed by hot functional tests, which 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.
First concrete was poured for the base slab of unit 3’s nuclear island in March 2021, with that of unit 4 being poured in the December of that year. Changjiang Phase II – units 3 and 4 – represents a total estimated investment of CNY40 billion (USD6.4 billion), according to China Huaneng, which holds a 51% share in the project, with China National Nuclear Corporation holding the remaining 49%. The construction period is expected to be 60 months. Both units are scheduled to be fully operational in early 2027.
The Changjiang nuclear site is already home to two operating CNP-600 pressurised water reactors (PWRs) – Changjiang 1 and 2 – which entered commercial operation in 2015 and 2016, respectively. In 2021, CNNC also began construction of a demonstration ACP100 small modular reactor at the site. The multi-purpose 125 MWe PWR – also referred to as the Linglong One – is designed for electricity production, heating, steam production or seawater desalination.
