TerraPower's Natrium plant will be built in Kemmerer, a remote western Wyoming town where the Naughton coal plant is due to shut in 2025. Pending permits, the 345 megawatt plant will open in 2028, which is the timeline mandated by Congress.

The project will get about $1.9 billion from the federal government including $1.5 billion from the bipartisan infrastructure bill that President Joe Biden signed this week. The bill included about $2.5 billion for advanced nuclear reactors.

"It's a very serious government grant," said Chris Levesque, president and CEO of TerraPower, which is partnering with GE Hitachi Nuclear Energy. "This was necessary because the U.S. government and the U.S. nuclear industry was falling behind," he told reporters.

The United States has been competing with China and Russia which also hope to build advanced reactors and export them.

Advanced reactors are expected to be smaller than traditional ones and theoretically be built in remote locations. The Natrium reactor would be fueled by uranium enriched up to 20%, a far higher level than today's fuel.

Some nuclear power experts say the more highly enriched fuel could be an attractive target for militants looking to create a crude nuclear weapon.

Advanced reactor proponents say the plants are safer and create less waste.

Gates had initially hoped to build an experimental nuclear plant near Beijing with state-owned China National Nuclear Corp. But TerraPower was forced to seek new partners after the administration of Donald Trump restricted nuclear deals with China.

Energy Secretary Jennifer Granholm said the plant would give hope to a town where a coal plant will shut. "The energy communities that have powered us for generations have real opportunities to power our clean energy future through projects just like this one."

(Reporting by Timothy Gardner; Editing by Stephen Coates)

By Timothy Gardner