Control rod drive mechanisms for Unit 6 of the Fuqing nuclear plant and Unit 3 of the Karachi nuclear power plant in Pakistan in the Hualong One (HPR 1000) demonstration project recently officially passed acceptance, officials said.

To date, all four control rod drive mechanisms for the nuclear power units for the HPR 1000 demonstration project -- both at home and abroad -- have been completed.

Officials said it reflects the maturity of the design, the procurement and manufacturing capabilities of China's third-generation nuclear power equipment, and was a major breakthrough in China's nuclear power key equipment.

They said it effectively guarantees the progress of the HPR 1000 demonstration project and lays a solid foundation for the project to "go global".

The control rod drive mechanism is the "gear switch" of a nuclear power plant reactor, which can realize the functions for a reactor startup, power adjustment, power maintenance, normal outage and accident outage. Its equipment performance is directly related to the safety of a reactor operation and is a key master device of the nuclear island.

Due to the harsh operating conditions, the precision of mechanical cooperation and the complexity of electromechanical cooperation, only a few countries in the world -- including the United States, France and China -- have mastered the key design and manufacturing technologies for the control rod drive mechanism.

As the independently developed third-generation nuclear power plant in China, the HPR 1000 places higher requirements on the reactor's main equipment.

The control rod drive mechanism of the HPR 1000 reactor is completely independently developed by the CNNC Nuclear Power Institute of China.

Officials said the key performance of this equipment has set a world record and reached international advanced levels. It is the control rod driving mechanism of the third generation nuclear power station with the longest life and highest reliability in the world, they said.

In response to design demands for a longer design life, higher earthquake resistance and higher reliability proposed by the third-generation nuclear power plant for the drive mechanism, the CNNC Nuclear Power Institute of China carried out the development of new drive mechanisms suitable for the third-generation nuclear power plant, which have passed stage acceptance.

The new control rod drive mechanism uses 440-level high temperature resistant electromagnetic coils, long-life and wear-resistant claw components, high temperature resistant integrated rod position detectors and an integrated all-nickel-based sealed shell. It is the new upgrade for the control rod drive mechanism of the HPR 1000.