The CNP Generation II nuclear reactors (and Generation III successor ACP) were a series of nuclear reactors developed by China National Nuclear Corporation (CNNC), and are predecessors of the more current Hualong One design.

The CNP-300 is a pressurized water nuclear reactor developed by the China National Nuclear Corporation (CNNC).

It is China's first domestic commercial nuclear reactor design, with development beginning in the 1970s based on a nuclear submarine reactor design.^[1][2]

The reactor has a thermal capacity of 999 MW and a gross electrical capacity of 325 MW, with a net output of about 300 MWe and a single-loop design and .^[3]

The first CNP-300 unit started operations in Qinshan Nuclear Power Plant in 1991.^[1]

The CNP-300 was the first Chinese nuclear reactor to be exported, with the installation of the first unit at Chashma Nuclear Power Plant in Pakistan.^[4] The unit began operation in 2000. Another unit was completed in 2011 and two more units began operation in 2016 and 2017 at the same plant.

The CNP-600 is a generation II reactor pressurized water nuclear reactor developed by the China National Nuclear Corporation (CNNC).

It is based both on China's first commercial domestic nuclear reactor design, the CNP-300^[2] and the M310 reactor design used in Daya Bay Nuclear Power Plant.^[5][6]

The reactor has a capacity of 650 MW, a 2-loop design and 121 fuel assemblies. Other features include single containment, 40-year design life and a 12-month fuel cycle.

The first CNP-600 unit began operation at Qinshan Nuclear Power Plant in 2002, with other 3 units coming online between 2004 and 2011. There have been built two further CNP-600 reactors at Changjiang Nuclear Power Plant, which went into regular operation in 2015 and 2016.

From the CNP-600, CNNC developed a Generation III successor named the ACP-600.

Similar to the CNP-600, the reactor will contain 121 fuel assemblies, but will be designed to operate on a longer 18-24 month fuel cycle. Other features include double containment, active and passive safety systems, improved response capability in the case of a station blackout event, digital instrumentation and control, and a 60-year design life.

No examples of this reactor type had been built.^[7]

CNNC's largest CNP development was a three-loop 1000 MW version of the design designated CNP-1000. Work on the project began in the 1990s with the help of vendors Westinghouse and Framatome (now AREVA).^[7]

The first CNP-1000 units were due to be built at Fangjiashan (the same site as Qinshan). However, the design was subsequently changed to CGN's CPR-1000. Later, 4 units of the CNP-1000 were later built at Fuqing NPP. Further work on the CNP-1000 was stopped in favour of the ACP-1000.^[7]

In 2013, CNNC announced that it had independently developed the ACP-1000, with Chinese authorities claiming full intellectual property rights over the design.

The reactor has a gross output of 1100MW, a 3-loop design and 177 fuel assemblies (12 ft active length), and is designed to operate on an 18-month refuelling cycle for economic competitiveness.^[7]

As a result of the success of the Hualong One project, no ACP-1000 reactors have been built to date. CNNC had originally planned to use the ACP-1000 in Fuqing reactor 5 and 6 but switched over to the Hualong One.^[7]

Since 2011, CNNC has been progressively merging its ACP-1000 nuclear power station design^[8] with the CGN ACPR-1000 design, while allowing some differences, under direction of the Chinese nuclear regulator. Both are three-loop designs originally based on the same French M310 design used in Daya Bay with 157 fuel assemblies, but went through different development processes (CNNC's ACP-1000 has a more domestic design with 177 fuel assemblies while CGN's ACPR-1000 is a closer copy with 157 fuel assemblies).^[9] In early 2014, it was announced that the merged design was moving from preliminary design to detailed design. Power output will be 1150 MWe, with a 60-year design life, and would use a combination of passive and active safety systems with a double containment. CNNC's 177 fuel assembly design was retained.

Initially the merged design was to be called the ACC-1000,^[10][11][12] but ultimately it was named Hualong One. In August 2014 the Chinese nuclear regulator review panel classified the design as a Generation III reactor design, with independently owned intellectual property rights.^[13][14] As a result of the success of the merger, ACP-1000 and ACPR-1000 designs are no longer being offered.

• CPR-1000 - Reactor design by the other state owned company China General Nuclear (CGN)
• Hualong One - Successor of the ACP-1000