Three generations of commercial nuclear power plants have evolved over the last decades. Early “Generation 1” prototype reactors were constructed in the 1950s and early 1960s, primarily to see if fission could produce power economically.
Widespread Adoption of Gen 2
The first big wave of commercial nuclear power plants came online in the late 1960s through the mid-1990s. These are described as “Generation 2” plants (Gen 2, for short). Around the globe, 433 Gen 2 nuclear reactors are in operation, producing more than 371,000 megawatts of electricity. The U.S. is home to nearly one quarter of these plants, which produce almost 102,000 megawatts of electricity from nuclear power -- more than any other country in the world.
As of 2012, the number of Gen 2 plants operating in the U.S was 104. That total is expected to rise in 2013, when a final Gen 2 plant is scheduled to begin operations at Watts Bar in Tennessee.
Emergence of Gen 3
Apart from the Gen 2 plant underway in Tennessee, all commercial nuclear reactors to be built in the U.S. in the future will be designated “Generation 3” or Gen 3 plants.
Three new Gen 3 reactors have been approved for preliminary construction in the U.S. and are scheduled to start operations between 2016 and 2020. Thus far the NRC has approved two Gen 3 designs: the Westinghouse AP-600 and its slightly larger sibling, the Westinghouse AP-1000, both of which are pressurized water reactors.
The U.S. Nuclear Regulatory Commission (NRC) has received applications for another 23 licenses for new Gen 3 plants, but has not yet approved them. With some companies changing plans, it is impossible to know how many of these applications will actually lead to operating plants.
One of the primary goals for the new Gen 3 plants is to address the problems suffered by Gen 2 plants.