The opening of a new nuclear power plant reactor near Savannah, Ga., on July 31 was indicative of the challenges the industry has faced in recent years — and of the changes boosters say are being made to ensure that nuclear power can serve as a key component of a 21st century energy portfolio.

Amid the rapid growth of renewables like wind and solar, nuclear power may seem like a source of electricity from the past. But wind and solar are intermittent sources, which aren’t produced when the wind doesn’t blow or the sun doesn’t shine, meaning dirty old coal and natural gas are still widely used to provide a reliable, steady supply of power.

That reality has led experts and policymakers such as Secretary of Energy Jennifer Granholm to advocate for building up the nation’s nuclear energy portfolio as a cleaner source of base load power until renewables can meet a greater share of the demand.