System 80 is a pressurized water reactor design by Combustion Engineering (which was subsequently bought by Asea Brown Boveri and eventually merged into the Westinghouse Electric Company). Three System 80 reactors were built at Palo Verde Nuclear Generating Station.
System 80+
An updated version of the plant has been designed which was given a "+" at the end of the name. This indicates an evolutionary plant design - changes were made to improve costs and safety.
The control rods differ by using both 12 finger CEAs (control element assemblies) and 4 finger CEAs. The 12 finger ones are more reactive and only used for shutdown, while the 4 finger CEAs are used to control reactivity smoothly during operation.
The System 80+ was the design basis for the Korean Standardized Nuclear Plant, and contributed many features to the AP1000 as well. It has served as the basis for a number of evolutionary Generation III fission-electric reactors, including the APR-1400.
The NRC has certified the System 80+ for the U.S. market, but Westinghouse no longer actively promotes the design for domestic sale.