Hot thermal 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. Such testing simulates the thermal working conditions of the power plant and verifies that nuclear island and conventional equipment and systems meet design requirements.

The tests verified the functioning of the unit's active and passive systems as well as non-nuclear components including steam turbines, CNNC said.

Four Hualong One units - Fuqing 5 and 6 in Fujian province and Fangchenggang units 3 and 4 in Guangxi province - are expected to be connected to the Chinese grid this year, while construction began on a unit at Zhangzhou in Fujian last September and at Taipingling in Gaungdong in late December. Two units - promoted on the international market as the HPR1000 - are under construction at Karachi in Pakistan.