The Experimental Breeder Reactor-1 made history in 1951 when it generated electricity from nuclear energy for the first time.
So did the people who witnessed the event: Their 18 names are etched on the wall to this day.
Well, at least some of them.
Walter Zinn, leader of the team that built the reactor, told project personnel to sign the wall. But not support personnel, many of whom were women.
It wasn't until the early 1990s that a plaque was added bearing the names of the women present.
That's one example of what it was like for women working in a man's nuclear world. In those early days, women held mostly secretarial positions.
Today, employment of women at Idaho National Laboratory and the Idaho Cleanup Project stands at about 25 percent and 21 percent, respectively.
Women make up about 17 percent of employees at The Advanced Mixed Waste Treatment Project.
The numbers still aren't what they should be, said Frances Marshall, acting scientific director for the Advanced Test Reactor National Scientific User Facility.
As of 2011, about 18 percent of chemical engineers and just 4.5 percent of mechanical engineers were women, according to the U.S. Bureau of Labor Statistics.
But nuclear engineering tells a different story: So few of the 20,000 people employed in the field are women that it amounts to a blank spot in the data.
SHORTAGE IN SCHOOLS
Marshall's first work experience was similar to her college one: She was outnumbered.
After graduating from the University of Virginia with a degree in nuclear engineering in the 1980s, she landed a job at the Millstone Nuclear Power Station in Connecticut.
She was the only female engineer in a group of 60.
"I'd walk into the machine shop to talk to the mechanics or the maintenance engineers (and) work would stop (at the machines) and they'd watch me go," she said. "Then I'd go into the office and work would start up again."
Marshall doesn't think it was an act of scrutiny so much as curiosity.
She said she believes that has changed, but the number of women enrolling in school for science and engineering remains low. It's unclear exactly why.
About 33 percent of undergraduate freshmen women intended to major in science and engineering fields in 2010, according to the National Science Foundation.
In 2009, nearly 18 percent of undergraduates enrolled in engineering programs were female, according to the foundation.
Marshall thinks women are tougher on themselves than men and more likely to drop out if they receive a low grade. She encourages women to not give up so easily.
MANUEVERING INA MAN'S WORLD
Tammy Hobbes cried for three days when a shift-supervising job at the Naval Reactors Facility was handed to a man.
Hobbes arrived at the facility in the late 1980s. Soon after, she completed the rigorous qualifications to become a shift supervisor before the man who got the position. She said the plant manager wasn't sure how to handle the situation.
"He's like: 'Well, ya know, we've just never had a female in this position, and I'm not sure I can trust you,' " she said.
She shadowed a male supervisor for three or four months before getting the job.
"I realized you may be in some place where other women haven't been before, and you need to help people feel comfortable with it," she said.
Today, the 49-year-old is vice president of the waste management group at CH2M-WG Idaho LLC, also know as CWI, the contractor for the Idaho Cleanup Project.
Hobbes' experience is not unlike that of Susan Prestwich, the first female drilling engineer and geologist to work at the site.
In the 1970s, the then-National Reactor Testing Station began well drilling at Raft River. Prestwich was hired to examine cuttings during the drilling operation, but there was some hesitation.
In Susan's Stacy's history of the site, "Priving the Principle," she quotes physicist Jay Kunze saying of Prestwich: "Drilling crews are known to be roughnecks. I can't send a woman out there all night to work that well."
Prestwich assured him she could handle the guys. Her career eventually led her to a DOE job in Washington, D.C.
JUGGLING WORK AND FAMILY
As the INL bus bounced over roads on its way to the site more than 20 years ago, all Jamie Stuart could think about was the one place she'd rather be: home with her kids.
It was her first week back to work since her children were born.
"It was hard to go back after I had that break," Stuart said. "But I knew I could provide a better life for them if I had a job."
Looking back, the manager over Security and Emergency Management at Idaho Treatment Group is glad she worked as a single mom. But it was still difficult.
"When someone asks what you want for Christmas, you say eight hours of sleep," she said. "Occasionally, you get it."
Hobbes also worked while her kids, now 17 and 18, were growing up.
Without the help and support of her husband, Jeff, she said she wouldn't have been able to work and raise her children.
"Both people have to be willing to give and take," she said.
Hobbes' job and family life have intertwined nicely over the past 20 years, but she said it works because she realizes she can't do everything - no one can.
The problem is, women paving the way before her didn't set a good example, she said. Those women preached doing anything and everything.
"No person can do everything - you can't have everything," she said. "So setting that example is a bad thing to do. You have to remember to be balanced."