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We Are East Idaho: Arco

We Are East Idaho is spending the year introducing you to places and people that make east Idaho special. In our We Are East Idaho series, we're going on a road trip and sharing things you may not know about this beautiful place we call home.

ARCO — On a cold winter day in 1951, Walter Zinn and a group of scientists met in a small nuclear reactor 50 miles west of Idaho Falls to conduct an experiment that would change the modern world forever.

It was five days before Christmas, and Cold War tensions between the United States and the Soviet Union were at their height.

“At that time, the Soviets claimed everything the United States (did with nuclear power) was about weapons. We didn’t have a peaceful bone in our bodies,” INL spokesman Don Miley says of the Soviet’s mentality.

But this experiment would prove that the U.S. was about more than nuclear weapons and that atomic energy could be used for peaceful means.

That day, Zinn and his group of scientists conducted the world’s first usable electricity generated by a nuclear reactor.

“They lit four light bulbs, and the next day, lit the entire building,” says Miley.

That’s the story behind Experimental Breeder Reactor I, the first nuclear reactor built in Idaho on the National Reactor Testing Site. NRTS is the predecessor to what we know today as Idaho National Laboratory.

Experimental Breeder Reactor I off US Highway 20-26, about 20 minutes southeast of Arco | Rett Nelson,

Testing at EBR-I confirmed that a reactor could create more fuel than it consumes and it paved the way for an even bigger scientific breakthrough with a different reactor four years later.

In July of 1955, another group of scientists attempted to use nuclear energy to power an entire town.

“They tied the generator into the power grid and flipped a switch. They were not in phase with the utility and fried seven miles of power lines,” says Miley.

They tried it again several days later, and this time they succeeded.

“One or two nights later, they made sure they were in phase with the power company, switched over to BORAX-III, and for an hour in the middle of the night, they lit our central facilities area and Arco, Idaho.”

Arco, located 20 miles northwest of EBR-I, became the first city in the world lit by atomic power on July 17, 1955.


Carol Jardine, a resident of Arco, remembers what happened that day and says no one knew what was going on.

“It was very hush-hush, and we didn’t know what happened until it was over,” Jardine recalls.

She was in high school at the time. Her memory of that day is vague, but she does remember where she was when it happened. She was watching a movie at the old Walker movie theater and there was a power surge.

“The show went off, and then it came back on,” she says.

Though powering Arco with nuclear energy was groundbreaking, Miley says it was just a drop in the bucket given Arco’s small size.

“Lighting Arco with one reactor wasn’t that big of a deal. It did not require megawatts of electricity. It was pretty small at that point,” he says.

And that’s exactly what Jardine and others thought.

“To a 17-year-old kid, it wasn’t a big deal. Later on, I was secretary of the Chamber of Commerce and that’s when they started Atomic Days,” says Jardine.

Atomic Days

atomic days
Atomic Days parade in Arco several years ago. | Tara Parsons

As residents learned what had taken place that day, Arco’s fame spread. Today, a marquee above the city’s Visitor Center contains the words, “First city in the world to be lit by atomic power.” Despite its claim to fame, Arco remains a tiny town with a population of 880, as of 2017. But an annual event celebrating what happened brings people in from all over the world.

“Arco is pretty quiet throughout the year, but the third weekend in July, it’s a busy place with people, noise, and excitement,” Butte County Clerk Shelly Blackner tells

Atomic Days has been a staple in the community since 1982 and is always held on the third weekend in July.

The event typically kicks off with a softball tournament Friday evening. Saturday begins with a parade and ends with a rodeo. Food vendors and other businesses are on-hand in the park throughout the day.

“It’s a bunch of good people coming together for a good time,” Blackner says.

The number of people who attend fluctuates from year to year. Blackner says many people base their class or family reunions around Atomic Days. She attends with her family every year and has many fond memories of the celebration.

“In the rodeo, they do a stick horse race in memory of my good friend’s father. His name was Bob Sherman and he owned a jewelry store here,” says Blackner. “My children have all participated in that and now my grandchildren are participating in it.”

Blackner’s family moved to Arco in 1978 because her dad got a job at the site, known then as the INEL. She was only six years old and says the town was much bigger.

“It was probably triple the size it is now,” she says. “Main Street was filled. We had three to four clothing stores. There were three to four restaurants. There was a ski shop, gas stations. It was a booming town.”

Blackner’s first memory of Atomic Days centers around the rodeo, where her dad played a major role as a calf-roper. Several years later, when the rodeo was no longer part of the celebration, her dad served on a committee that helped bring it back.

Though there are very few original families left in Arco who grew up learning the history of Atomic Days, Blackner says the event has a theme every year that is geared toward teaching people what it’s all about.

“Last year, we had the American Solar Challenge come here.”

American Solar Challenge is a team of people who compete to design, build and drive solar-powered cars during a timed rally.

Regarding people’s attendance at Atomic Days each year, Blackner says its good, solid family fun that gives a good reflection of what Butte County and Arco are all about.

“Arco is about family, friends. We pride ourselves on doing the best we can with what we’ve got.”

Nuclear Pioneers

walter zinn ebr I scientist
Water Zinn, left, and another scientist working at EBR-I in 1951 | Courtesy INL

Years after the initial test that powered four light bulbs, EBR-I continued as a site for generating usable electricity for 12 more years. It was shut down in December 1963.

“They had done everything imaginable with this reactor. They didn’t build it with the ability to really modify anything,” says Miley. “After 12 years, they just couldn’t get any more out of it. They learned all they could.”

EBR-I was decommissioned the following year. President Lyndon B. Johnson and Glenn Seaborg, then chairman of the Atomic Energy Commission, dedicated EBR-I as a National Historic Landmark on Aug. 25, 1966.

“It had only been retired for two years when it was given that designation, which illustrates that what happened here was incredibly significant for the nation and the world,” says Miley.

Today, EBR-I is open as a museum between Memorial Day and Labor Day. Miley says more than 10,000 people from all over the world visit the site every year. One of the exhibits on display is a wall hanging that contains the names of the 18 men involved in that initial experiment 67 years ago.

“The gentlemen that signed the wall – I met quite a few of them throughout the years,” Miley says. “It was a real treat to walk through this building with them and see the pride they took in what they accomplished here.”

There are no surviving members of the EBR-I light bulb experiment, but Miley says the men considered themselves a team and were happy to be involved in whatever capacity they could.

“They truly felt like pioneers with what they were doing and they really were,” Miley says.

The end of an era

Arco’s close proximity to the INL continues to make it an attractive spot for those who work there. People also move here for outdoor recreation and the quiet.

Some folks, however, want more access to restaurants and places to shop. Blackner says people ultimately moved away so they could be closer to bigger cities like Idaho Falls and Blackfoot. But in recent years, Blackner says there’s been a resurgence of growth.

“Our real estate is moving. We’re making improvements all over the city and the county,” Blackner says. “I’ve seen individuals take more pride in being a resident here.”

After the shut down of EBR-I, EBR-II went online and from 1964 to 1986, was instrumental in refining the process for generating and breeding nuclear fuel. Miley says funding for the project came to a halt when the federal government decided to shut down this type of research in 1994.

“There are priorities politically, and the way it was seen in ’94 was that this was not a priority anymore. So we left it behind,” Miley says.

The future of nuclear research

Nuclear electricity research has started to pick up again in recent years. George Griffith, the deployment lead for a new nuclear project with the INL, says companies are starting to produce smaller reactors that are much safer, easier to construct and less expensive to deploy and operate than today’s conventional nuclear reactors.

One of the companies designing this concept is NuScale.

In 2014, the Carbon Free Power Project called for building the nation’s first small modular reactor power plant on the INL site using NuScale Power’s technology.

Construction could begin in the next few years. It’s going through the federal permitting process now, but if approved, the first of 12 modules is slated to begin operation in 2026.

If the plant goes up and all 12 units begin operation, Griffith says it would mean another 720 megawatts of electricity for the local energy market — enough to power about 540,000 homes.

“It will make Idaho power independent and stable,” Griffith says. “We would be able to have secure power at a fixed price for a long time.”

With these particular units, Griffith says the license lasts 40 years.

“They’ve got 12 individual reactors, so when they have to refuel one every couple of years, they take that one offline and the other 11 continue operating. You’d refuel it, put it back into service and go on to the next one. So this would provide power to the grid for 40 years.”

Miley says this project is attracting worldwide attention, and, if implemented, would put eastern Idaho on the world stage.

“For eastern Idaho in general, it raises the level of economic activity, which is always a good thing, but it also puts us on the map,” Miley says. “If east Idaho becomes the place for the first small modular reactor in the world, (this will) be the place (where people) want to come.”







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