 Further builds in China will be based on the modified CAP1400 design.The AP1000 design traces its history to two previous designs, the AP600 and the System 80.The System 80 design was created by Combustion Engineering and featured a two-loop cooling system with a single steam generator paired with two reactor coolant pumps in each loop that makes it simpler and less expensive than systems which pair a single reactor coolant pump with a steam generator in each of two, three, or four loops.