The renewed interest in nuclear power has resulted primarily from higher prices for natural gas, improved operation of existing reactors, and uncertainty about future restrictions on coal emissions. Nuclear power's relatively stable costs and low air emissions may now appear more attractive, particularly combined with a substantial tax credit for nuclear generation and other incentives provided by the Energy Policy Act of 2005 ( P.L. 109-58 ). New nuclear plant applications can also take advantage of amendments to the Atomic Energy Act made in the early 1990s to reduce licensing delays. As indicated in Figure 1 , although no new U.S. reactors have started up since 1996, U.S. nuclear electricity generation has since grown by more than 20%. Much of this additional output resulted from reduced downtime, notably through shorter refueling outages, which typically take place every 18 months. Licensed commercial reactors generated electricity at an average of 89.8% of their total capacity in 2006, after averaging around 75% in the mid-1990s and around 65% in the mid-1980s. Falling operating costs have improved the outlook for the nation's existing fleet of nuclear power plants. From 1989 to 1998, 12 commercial reactors were closed before reaching the end of their 40-year licenses—California's Rancho Seco plant and Oregon's Trojan plant after only 14 and 16 years of operation, respectively. By the late 1990s, there was real doubt about whether any reactors would make it to 40 years. Since 2000, however, 48 commercial reactors have received 20-year license extensions from NRC, giving them up to 60 years of operation. Without the production tax credit contained in the 2005 Energy Policy Act, a nuclear facility is not competitive with either coal-fired or natural gas-fired facilities under base case assumptions. Under base case conditions, it seems unlikely that a new nuclear power plant would be constructed in the United States, barring a sustained, long-term increase in natural gas prices and the creation of a substantial, mandatory greenhouse gas reduction program that would increase coal-fired and natural gas-fired generating costs. As indicated in Table 4 , the production tax credit contained in EPACT is sufficient to make nuclear power competitive with either natural gas-fired or coal-fired facilities. The advantage provided to nuclear power by the production tax credit is not definitive; however, it appears sufficient to allow a decision on constructing a nuclear power station to move beyond initial economic considerations to examining other relevant factors, such as fossil fuel prices and the regulatory environment for both nuclear power and future fossil fuel-fired generation. Greenhouse Gas Control

Any substantial mandatory greenhouse gas control program would probably affect the cost of new coal-fired and natural gas-fired generation. In all current proposals before the Congress, nuclear power is assumed to have no greenhouse gas emissions. Nuclear Waste

Highly radioactive spent fuel produced by nuclear reactors poses a disposal problem that could be a significant factor in the consideration of new nuclear plant construction. In the near term, continued storage at reactor sites and interim storage at central locations would be the most likely possibilities.
Nearly three decades after the most recent order was placed for a new nuclear power plant in the United States, several utilities are now expressing interest in building a total of up to 30 new reactors. The renewed interest in nuclear power has resulted primarily from higher prices for natural gas, improved operation of existing reactors, and uncertainty about future restrictions on coal emissions. A substantial tax credit and other incentives for nuclear generation provided by the Energy Policy Act of 2005 (P.L. 109-58) are also likely to improve the economic viability of qualifying new reactors. New nuclear plant applications can also take advantage of amendments to the Atomic Energy Act made in the early 1990s to reduce licensing delays.
Currently, there are 103 licensed and operable power reactors at 65 plant sites in 31 states, generating about one-fifth of U.S. electricity. Although no new U.S. reactors have started up since 1996, U.S. nuclear electricity generation has since grown by more than 20%. Much of this additional output resulted from reduced downtime, notably through shorter refueling outages. Licensed commercial reactors generated electricity at an average of 89.8% of their total capacity in 2006, after averaging about 75% in the mid-1990s and about 65% in the mid-1980s.
Falling operating costs have helped renew the economic viability of the nation's fleet of nuclear power plants. From 1989 to 1998, 12 commercial reactors were closed before reaching the end of their 40-year licenses. By the late 1990s, there was real doubt that any reactors would make it to 40 years. Since 2000, however, 44 commercial reactors have received 20-year license extensions from the Nuclear Regulatory Commission (NRC), giving them up to 60 years of operation, and more are pending.
The nuclear production tax credit in the Energy Policy Act could have a significant impact on the economic viability of new nuclear power plants. Under base case assumptions, new reactors are not competitive with either coal-fired or natural gas-fired facilities. However, if new reactors are able to take full advantage of the nuclear production tax credit, nuclear power appears competitive with either natural gas-fired or coal-fired facilities.
Other factors will also be important in the commercial decision to invest in new nuclear plants, such as fossil fuel prices and the regulatory environment for both nuclear power and future fossil fuel-fired generation. If natural gas prices remain at historically high levels, future nuclear plants will be more likely to be competitive without federal tax credits. However, natural gas prices have been highly cyclical in the past, raising the possibility that nuclear costs could be undercut in the future.
Any substantial mandatory greenhouse gas control program would probably affect the cost of new coal-fired and natural gas-fired generation relative to nuclear power, particularly if nuclear power is assumed to have no greenhouse gas emissions. Continued delays in nuclear waste disposal facilities—forcing spent fuel to be stored at plant sites—could also affect the decision to construct new reactors.