President Trump signed executive orders last week to boost production of nuclear power,

an energy source with a complicated history in the U.S.

After World War II, nuclear was heralded as the future of American energy.

Then the partial meltdown at Three Mile Island in 1979 marked a turning point and solidified opposition.

In the last two decades, a dozen reactors in the U.S. have closed and only three new ones have come online.

But as William Brangham reports, the site of America's worst nuclear accident may now be the site of its rebirth.

It's part of our series, Tipping Point.

They sit quietly now, perched on an island in the middle of the Susquehanna River, four giant cooling towers, two nuclear reactors, and one terrifying chapter in American history.

Good evening. We're sorry to interrupt your regular programs, but we've been waiting all evening to go to Harrisburg, Pennsylvania. Back in 1979, a combination of mechanical failures

and human error caused the radioactive core of one of the site's nuclear reactors to start

overheating. For nearly a week, local communities around Harrisburg were on edge, fearing a full meltdown

or explosion.

While the worst-case scenarios didn't happen, small amounts of radioactive material were released.

According to the Nuclear Regulatory Commission, it had negligible effects on health and

the environment, but a lasting impact on the nation and the industry.

We learned so much from that particular incident.

And now we've got 45 plus years of operational excellence that showed what we've learned

and continue to operate.

Brian Hansen is Chief Generation Officer for Constellation, the energy company which owns

the other reactor on Three Mile Island, known as Unit 1.

We talked in its control room, which still looks very much like it did decades ago.

Unit 1 was closed at the time of the accident for refueling. And while Unit 2,

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