For some, nuclear power may conjure images of mushroom clouds or bring back memories of disturbing nuclear disasters like Chernobyle and Fukushima. But despite public fear around nuclear power, the technology has proved to be an emission-free, reliable way to produce large amounts of electricity on a small footprint.

As a result, sentiments about the technology are beginning to change. Both the U.S. government and private companies including X Energy, NuScale and, Bill Gates-backed, TerraPower are pouring money into developing, what they say will be smaller, safer nuclear reactors. CNBC visited Idaho National Laboratory to see the Marvel microreactor firsthand and learn what such developments could mean for the future of nuclear power.

After humankind discovered nuclear fission, the first applied use was the atomic bomb. The study of fission for electricity production came later. In December 1953, President Dwight D. Eisenhower gave his fateful Atoms for Peace speech, an impassioned plea to reconstitute the power of the atomic bombs dropped in World War II for a more noble cause.

“Against the dark background of the atomic bomb, the United States does not wish merely to present strength, but also the desire and the hope for peace,” Eisenhower told the United Nations. Almost 70 years later, the tension between those end uses still underlies the space today. From the 1950s through the 1970s, the United States dramatically increased its nuclear energy generation.

But the Three Mile Island accident in 1979 and Chornobyl meltdown in 1986 changed the landscape, spurring fear that nuclear energy could not be controlled safely. Since the 1980s, nuclear energy capacity and generation in the U.S. has largely stayed flat. Today, the country’s fleet of nuclear power reactors produces only 19% of the country’s electricity, according to the government’s Energy Information Administration.

In more recent times, the Fukushima Daiichi accident in Japan in 2011 — and earlier this year the capture of nuclear power plants in Ukraine by invading Russian forces — have added to public concerns. But despite its fraught origin story and the psychological effect of high-profile accidents, nuclear energy is getting a second look. That’s largely because nuclear energy is clean energy, releasing no greenhouse gasses.

Meanwhile, the world is seeing more of the effects of climate change, including rising global temperatures, increased pollution, wildfires, and more intense and deadly storms. “We need to change course — now — and end our senseless and suicidal war against nature,” Antonio Guterres, the secretary-general of the United Nations, said in Stockholm on Thursday. “There is one thing that threatens all our progress. The climate crisis. Unless we act now, we will not have a livable planet,” Guterres said. “Scientists recently reported that there is a 50-50 chance that we could temporarily breach the Paris Agreement limit of 1.5 degrees Celsius in the next five years.”