18.3.1 Introduction of ACP100

Since 2010, one type of small and medium-size water-cooled pressurized reactor called ACP100 has been developed by China’s national nuclear corporation. ACP100 is an innovative reactor based on existing PWR technology, adapting a ‘passive’ safety system and ‘integrated’ reactor design technology. After 3 years’ development, its overall design was complete, including conceptual design and basic design. A number of testing facilities are under construction and R&D on safety-related experiments will be carried out in the following 2 years. The construction of the ACP100 will be started around the end of 2014.

18.3.2 Technical aspects

The ACP100 design has the following remarkable technical features:

• Primary system and equipment integrated layout. The maximum size of the connection pipe is 5-8 cm, whereas in a large NPP it is 80-90 cm.

• Large primary coolant inventory.

• Small radioactivity storage quantity. The total radioactivity of an SMR is one-tenth that of large NPPs, and meanwhile a multi-layer barrier is added to keep the accident source-term at a low level.

• The vessel and equipment layout is beneficial for natural circulation.

• The decay heat removal is more effective: two to four times the efficiency of large NPP heat removal from the vessel surface.

• Smaller decay thermal power: one-fifth to one-tenth times of decay thermal power compared with that of a large PWR after shutdown, and is easier to achieve safety by way of the ‘passive’ system.

• Reactor and spent fuel pool are under ground for better protection against exterior accident and for the reduction of radioactive material release.

• No operator intervention is needed for 72 hours after an accident.

• Passive severe accident prevention and mitigation action, such as for containment hydrogen eliminator, cavity flooding, etc. is built in to ensure the integrity of pressure containment.

• The modular design technique makes it easy to control the product quality and shorten the site construction period.