The US Energy Department is poised to approve $US6.
5 billion ($A7.22 billion) in federal loan guarantees for the first nuclear power plants built from scratch in the country in more than three decades.
Energy Secretary Ernest Moniz was expected to announce final approval of the deal at a speech on Wednesday, a day before he visits the $US14 billion Vogtle nuclear plant now under construction in eastern Georgia.
Three government officials familiar with the deal confirmed its details on Tuesday.
They asked not to be identified because the deal has not been made public.
Atlanta-based Southern Co is building the plant with several partners about 50km southeast of Augusta, Georgia.
The project is widely considered a major test of whether the industry can build nuclear plants without the endemic delays and cost overruns that plagued earlier rounds of building in the 1970s.
Vogtle was originally estimated to cost around $US14 billion, but government monitors have warned the final cost is likely to be higher.
The Energy Department tentatively approved an $US8.3 billion loan guarantee for the project in 2010 as part of President Barack Obama’s pledge to expand nuclear power and other energy sources.
Obama and other proponents say greater use of nuclear power could cut the country’s reliance on fossil fuels and create energy without producing greenhouse gas emissions.
More than two dozen nuclear reactors have been proposed in recent years, but experts now say it is likely that only five or six new reactors will be completed by the end of the decade.
The once-expected nuclear power boom has been plagued by a series of problems, from the prolonged economic downturn to a sharp drop in natural gas prices and the 2011 nuclear disaster in Fukushima, Japan.
Owners of at least four nuclear reactors have shuttered plants in recent months or announced plans to do so, including California’s troubled San Onofre nuclear plant.
Utilities have decided it is cheaper to close plants rather than spend big money fixing them and risk the uncertainty of safety reviews.