China Guangdong Nuclear Power Company has celebrated the achievement of criticality at the first reactor of the Ling Ao II nuclear power plant.

Control rods were withdrawn from the core of the pressurized water reactor on 9 June, while concentrations of boron in the coolant water were reduced to create conditions for a sustained chain reaction. CGNPC then undertook 35 hours of zero-power tests that helped it verify the performance of the reactor core as well as instrumentation and monitoring systems.

The commissioning milestone of criticality comes before start-ups and shutdowns at low power, connection to the grid and a stepped increase to full power and commercial operation in around October. At that point it would become the 12th nuclear reactor to supply power to China and take total generating capacity close to 10 GWe.

The reactor is the third CPR-1000 to be built, representing a development from a French 900 MWe design imported in the 1990s: The CPR-1000 can deliver 1080 MWe and has a design life of 60 years.

CGPC noted the increased involvement of Chinese designers and suppliers, which reached about 50% with this unit. A subsequent reactor at Ling Ao II should have 70% local content — including the first Chinese-made pressure vessel. The figure is rising beyond 80% for the 12 other CPR-1000s currently under construction and beyond those another 13 are firmly planned which should use Chinese suppliers for over 90% of parts.