Unit 2 of the Sanmen nuclear power plant in China's Zhejiang province has successfully completed pre-operational testing. Sanmen 1 is expected to be the first AP1000 to begin operating later this year, with Sanmen 2 also set to start up in 2018.

The hot tests - which were carried out over 77 days - aim to simulate the temperatures and pressures which the reactor's systems will be subjected to during normal operation. This important phase ensures coolant circuits and nuclear safety systems are functioning properly before fuel can be loaded.

Cold hydrostatic testing of Sanmen 2's primary circuit was completed on 2 September. Those tests involved filling the reactor's primary circuit with water, which is circulated at high pressure by the reactor coolant pumps to verify that the welds, joints, pipes and components of the reactor coolant system and associated high-pressure systems meet regulatory standards. The coolant pumps will help to maintain the reactor's internal temperature at a safe level during operation.