Cold hydrostatic testing has been completed at unit 3 of China’s Changjiang NPP in Hainan province. Huaneng Hainan Changjiang Nuclear Power said the tests are the first time the reactor systems are operated together with the auxiliary systems.
Changjiang 3&4, both with Hualong One reactors, are planned to be fully operational in early 2027. First concrete was poured for the base slab of unit 3’s nuclear island in March 2021, and for unit 4 the following May. Changjiang Phase II (units 3&4) involved estimated investment of CNY40bn ($6.4bn), according to China Huaneng, which holds a 51% share in the project. China National Nuclear Corporation holds the remaining 49%. The construction period is expected to be 60 months. The site is already home to two operating CNP-600 pressurised water reactors (PWRs) – Changjiang 1&2 – which entered commercial operation in 2015 and 2016. In 2021, CNNC also began construction of a demonstration ACP100 small modular reactor (Linglong One) at the site.
The main purpose of the cold 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 as well as to clean the main circulation pipes. According to Huaneng Hainan Changjiang Nuclear Power, in the final test, the pressure in the primary loop was held at 22.3 MPa for 10 minutes. The tests confirmed that the primary circuit pressure boundary of the Hualong One unit was “intact and well sealed”, it said.
Cold testing paves the way for 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 properly. These tests, which simulate the thermal working conditions of the plant take place before the loading of nuclear fuel, and verify that nuclear island and conventional equipment and systems meet design requirements.
