A nuclear power renaissance is underway in much of the world, but in the US you would hardly notice.

Shifting energy economics and public safety concerns have made new American nuclear reactors rare, even as China and others ramp up investment in the carbon-free power source.

But now, the US government is seeking to stay relevant in an evolving global nuclear industry, in part by proposing new ways to confront a decades-old challenge: handling mounting nuclear waste.

"If we want to continue to have low-cost, clean power from nuclear reactors, which today produce about 60 percent of our country's emission-free electricity, then we have to have a place to put the used nuclear fuel," Sen. Lamar Alexander (R) of Tennessee said in a statement Tuesday, after reintroducing a bill to create a nuclear waste management agency.