Over the last 30 years, almost no new nuclear power plants have been constructed within the U.S. The newest reactor to enter service is Tennessee's Watts Bar Unit 2, which began operation in June 2016. The next-youngest operating reactor is Watts Bar Unit 1, also in Tennessee, which entered service in May 1996.

Recently, the U.S. Nuclear Regulatory Commission (NRC) approved designs by Portland, OR-based NuScale Power for the use of a new type of reactor called a small modular reactor (SMR). SMRs are intended to be built quickly in a factory rather than on site, and have a lower cost, produce much less power, and tend to be safer than traditional nuclear reactors.