Thousands of “Calutron Girls” helped build the atomic bombs of World War II—but were unaware of what they were doing.
Female high school graduates were recruited for positions as “cubicle operators” at Y-12, and have been more recently referred to as “Calutron Girls.” Ruth Huddleston is third back on the left, seated.
In early August 1945, as 19-year-old Ruth Huddleston perched on a stool, monitoring meters and dials on a mysterious upright machine in what is now the Y-12 National Security Complex in the newly formed city of Oak Ridge, Tennessee, her supervisor announced that the U.S. had dropped an atomic bomb on Hiroshima, Japan.
“And,” he told Huddleston and the other young female cubicle operators sitting side-by-side in the long, shot-gun style corridor, “you had a part in making that bomb.”
It was the first time anyone had acknowledged what Huddleston and her colleagues had been working on for the past year.
By the time she got home, news of the bombing had consumed the radio, and the local newspaper was running the headline “Oak Ridge Attacks Japan.”
“They told about all the people that had been killed,” recalls Huddleston, now 94. “It was horrible, but we knew that that would end the war. And my husband-to-be would have been over there soon if the war hadn’t ended.”
But that didn’t stop the rollercoaster of emotions that gripped Huddleston for weeks.
“I was happy and then I was sad and then I was happy, and then I got to thinking about it,” she says. “I got to thinking that I had a part in killing all of those people and it really bothered me. It bothered me for a long time after that, but there wasn’t anything I could do about it. There would have been a lot more killed if we hadn’t dropped the bomb. You just have to face reality, so that’s what I did. But I still don’t like to think about that part of it.”
The Making of a Bomb
As soon as Brigadier Gen. Leslie Groves of the U.S. Army Corps of Engineers was appointed commander of the Manhattan Project in 1942—three years into World War II—he knew just where he wanted to build the research and development site for production of the world’s first nuclear weapons. The property was secluded, landlocked and far from the coast where German and Japanese fighters could easily get to it. And the area’s small population would help keep the project a secret.
Following Groves’ orders, the government purchased 59,000 acres of rural land along the Clinch River in East Tennessee and designed a plant with nine buildings. Construction began in February 1943 and Tennessee Eastman, the for-profit company charged with running the facility, recruited job-hungry employees from the surrounding area, including Knoxville.
The sole purpose of the Y-12 plant was to house 1,152 massive bomb-building “calutrons” in a town that would later come to be known as Oak Ridge.
Ed Westcott
These women workers leaving Y-12 were photographed by Ed Westcott, famous Manhattan Project photographer; and the lady on the extreme left with her coat draped over her arm was “Miss Atomic Bomb” in 1945.
Invented by Ernest O. Lawrence, director of the Radiation Laboratory at the University of California, Berkeley, the simple mass spectrometer called the calutron—the name stood for “California University Cyclotron”—could separate and enrich uranium isotopes with two large magnets. (In 1940, Lawrence won the Nobel Prize for his creation and reportedly assigned patent rights to the U.S. government for $1.)
Ray Smith, historian for the City of Oak Ridge and Y-12 who worked at Y-12 for 48 years, retiring as the Y-12 Historian, describes the process this way: “If I had two rubber bands hanging down from my hand and I put a golf ball on one of them and a ping-pong ball on the other, then I held it down to my side and very quickly I spun it up so that it would make an arc, that golf ball, being heavier than the ping-pong ball would stretch that rubber band farther than the ping-pong ball.”
In the calutron, Smith says, the heavier Uranium-238 isotopes act like the golf balls, leaving the lighter, less plentiful Uranium-235 to be processed into atomic energy.
The operation was fairly simple, but it required humans—lots of them—to constantly monitor the equipment. Most of the area’s young men were fighting in the war overseas, so Tennessee Eastman started exploring the idea of hiring girls straight out of high school.
“They could be trained to do it,” Smith says. “You just turn the knob to keep a meter on a certain point. It didn’t require any technical training. They didn’t even know what they were reading.”
Before long, the company was recruiting young women by the thousands at the schools where they were about to graduate. Of the 22,482 people working at Y-12 in August of 1945, Smith indicates that many of them were 18-year-old girls.
Calling All Calutron Girls
Growing up in the small community of Oliver Springs, Tennessee, Huddleston had always wanted to teach. She was so good at tutoring both her younger and older classmates that the teacher let her skip seventh grade and go straight to high school. Huddleston graduated early, at age 16, and was soon instructing kids in grades 4-8 at a nearby mining camp. She was working at a hosiery mill in 1944, biding her time until she could go to college to get a bona fide teaching degree and waiting for her fiancé, Lawrence, who’d been drafted, to come home from Europe, when she heard about the job openings at Y-12.
Ruth Huddleston, 94, “still doesn’t like to think about that part of it.”
During the week-long training, Huddleston’s employer emphasized the strict rules of the plant. “What you learn here and what you do here stays here,” they said. “Don’t tell your family. Don’t tell your friends. All you need to know is that you’re working to help end the war.”
In 2004, during a visit to Y-12, a former Calutron operator named Gladys Owens told Smith that on the last day of training, a man in a suit entered the classroom and reiterated what the girls had already been told: “We can’t tell you what you’re going to be doing. We can only tell you how to do it.” Pausing, the man added, “All I can say is if our enemy gets it first, God help us.”
Working the swing shift eight hours a day, Huddleston sat at her “cubicle,” watching and adjusting meters and knobs and gauges on control panels connected to the giant calutrons in the next room.
“If the hand on those meters went too high, we had to get to work and get it back balanced,” she says. “If it went too low, we had to sit on that stool and watch it. And if it got to the point where we couldn’t control it, we had a person that we could call and they would come help us. And if they couldn’t control it, then they had to shut it down and call for help. I was always afraid to move.”
She was also careful to stay tight-lipped. “They told us that we could immediately be taken out of our position if we were caught talking about it,” she says. “A time or two, people disappeared, so we didn’t know whether they’d fired them or what had happened. I sure didn’t want to have to be one of those.”
One thing the women did know was that strange things happened in the calutron room, commonly called the “racetrack.”
“The building had silver electromagnets that pulled bobby pins out of your hair,” said former calutron operator Wynona Arrington Butner in an Oak Ridger article in 2016. “Screwdrivers would stand out in your pockets.”
Owens, too, shared her own magnet story with Smith during her 2004 visit to the Oak Ridge plant after he explained how the knobs she’d adjusted all day controlled the electrical current that separated the uranium. “She reached over and patted me on the arm,” Smith remembers. “She said, ‘I still don’t know what I was doing, but I know if I had any bobby pins in my hair, they’d just go pf-f-f-t and go stick to the walls.’”
Adds Huddleston: “If you had a ring on, it could remove it, so I just never did go out there. There wasn’t any use unless you just wanted to be nosy and see what was going on. But I did hear of a lot of people losing their watches and their belt buckles.”
Calutrons were named for CALifornia University CycloTRONS. Shown are Alpha Calutrons, the first stage. The second stage was smaller and called Beta Calutrons.
The fact that the calutron operators were kept in the dark didn’t detract from their efficiency. They were, by all accounts, exceptional workers. So when Lawrence’s Berkeley researchers protested that young women shouldn’t be assigned such an important role, Tennessee Eastman arranged a contest, with the male scientists and engineers sitting on one side, the girls on the other, monitoring their respective dials. There were, of course, no female STEM professionals back then.
“At the end of the week, the young girls had beat them hands down. They were making much more productivity than the scientists and engineers,” Smith says. “The reason was the young girls were doing what they were told. They were practicing statistical process control, just like they’d been trained. These scientists and engineers, they’d go trying to fix every little thing that was going wrong and the machine never took a set, so it never settled down.”
Leaving a Legacy
The term “Calutron Girl” came decades later, when Owens spotted an old photo of herself operating the machines at the American Museum of Science and Energy in Oak Ridge. When she pointed it out to the museum director, he called Smith, who was looking for original operators to interview for written archives and videos, and said, “I’ve got you a Calutron Girl.”
“So we initiated that ‘Calutron Girl’ name and it’s just taken off,” Smith says. “Those elderly ladies are just tickled to death.”
The calutrons still exist in two of the Y-12 structures. Building 9731 boasts the world’s only remaining Alpha magnet, which stands about 20 feet tall. At 10 feet, the smaller Beta Calutrons can be found in Building 9204-3. Both buildings are now a part of the Manhattan Project National Historical Park. The separate K-25 plant contained the modern gaseous diffusion uranium-separation process that started in 1944 and replaced the calutrons when they shut down in 1946.
Y-12 had nine large buildings which housed 1,152 Calutrons used to separate the Uranium-235 for Little Boy.
Huddleston went on to marry her sweetheart, who also worked at Y-12, three months after the bombs hit Hiroshima and Nagasaki. She earned her degree and taught first grade through college freshman courses before spending 29 years as a high school guidance counselor. She never spoke about what had happened at Y-12, not even to her own children.
Then one day about 20 years ago, her young granddaughter called with a special request. “Nanny, I’m writing a paper on Oak Ridge and I wonder if you know anything about the beginnings of it and the part it had in the war.”
Huddleston took a deep breath and proceeded to tell her shocked granddaughter what it was like to work at the place that made the bombs that ended World War II.
There are only a few Calutron Girls left, now in their 90s. Most have passed away; others have dementia or physical disabilities that prevent them from speaking publicly or granting media interviews. Huddleston, on the other hand, often shares her story alongside Smith at events that draw up to 500 audience members.
“They like the idea of how we could have kept such a good secret,” Huddleston says. “Every group I’ve been to, it just kind of amazes them.”
Children, especially, are hungry to learn about the Secret City and the Calutron Girls, Smith says. It is not uncommon for a teacher to show one of his self-produced, online documentaries in class and FaceTime him the next day so he can answer the students’ questions. Each year, he also visits about 40 schools around the country. At one of them, when the bell rang at the end of class, a little girl asked, “Mr. Smith, if we go get our lunch and bring it back here, will you keep talking?”
“The history is of interest to young people,” Smith notes. “They are just not getting it in any way that they can hold onto. They need stories. They need videos. They need something more than just a teacher reciting facts. Those don’t stick with them. The bobby pin story—they’ll remember that. The ping-pong ball and the golf ball—they’ll remember that. And that’s important.”
He also wants them to understand what a vital role the Calutron Girls played in saving American lives.
“Remember, 60 million people were killed during World War II,” he says. “That’s the most that’s ever been killed in such a short period of time, the awfullest war that we’ve ever had. And these calutrons helped end it because they provided the uranium for Little Boy that was dropped on Hiroshima, Japan, and Fat Man on Nagasaki, and that resulted in the end of all that killing. Without the Calutron Girls, they couldn’t have operated these machines.”
Coming Full Circle
About five years ago, Huddleston got an unexpected phone call from a Japanese reporter who was scouting possible people and places for a documentary about Y-12. The filmmakers later interviewed Huddleston and her family members and captured footage of them making dinner, at church and elsewhere.
“It was amazing. They were so nice,” Huddleston says. “They asked me how I felt about [what I did at Oak Ridge]. I told them that I’d like to see people love each other a little more and quit fighting and just accept people for who they are, and have more love in the world. And they liked that.”
The story above appears in our May/June, 2020 issue. For more subscribe today or log in to the digital edition with your active BRC+ subscription. Thank you for your support!