Ted Petry, last known witness to pioneering nuclear reaction at UChicago, 1924-2018

South Side teen saw history made when scientists conducted first nuclear chain reaction

In early 1942, Ted Petry was recruited out of high school to a secret government project at the University of Chicago, told only that it had “something to do with the war effort.” Little did the 17-year-old from the South Side of Chicago know that the $94-per-month job would be part of a groundbreaking experiment that ushered in the Atomic Age.

Working for Nobel-winning scientists Arthur Compton and Enrico Fermi, Petry played a small but important role in the first controlled, self-sustaining nuclear chain reaction. Working as a messenger and laborer, Petry was one of the people who worked day and night to build the 20-foot reactor of graphite and uranium known as Chicago Pile-1 where the landmark discovery happened.

The last known living person to witness one of the most important scientific experiments of the 20th century, Petry died July 28 at age 94.

Petry was one of 49 people present Dec. 2, 1942 on the squash racquets court under the west stands of Stagg Field for the reaction. He etched his name in history when he signed the wrapper of the jade-green bottle of Bertolli Chianti used to toast the achievement along with Fermi and other scientists.

“Ted Petry was a witness to history as part of the Chicago Pile-1 experiment at the University of Chicago. He saw a groundbreaking discovery first hand, playing a role in research that would change science, energy, medicine and the world,” said Angela Olinto, dean of Division of the Physical Sciences. “His presence at last year’s events commemorating the 75th anniversary of the experiment provided a unique and essential perspective on a historic moment in science.”

Petry was honored in December 2017 when the University of Chicago commemorated the 75th anniversary of the first nuclear reaction, and he was featured in The Washington Post and the Chicago Tribune, among others. Although he enjoyed the opportunity to rekindle the past, the ever-humble Petry never bragged about his unique place in history.

“My neighbors don’t know that I ever worked on the project. I just went ahead and lived a normal life and didn’t think about half this stuff,” Petry said at the time. “It was a way of life. It was just a job.”

‘You didn’t question too much’

Petry first got involved with the atomic project when a recruiter visited Tilden Technical High School, where he was a graduating senior. He became a self-described “go-fer” for the UChicago project, one of 30 or so young men hired as laborers. Day and night, they stacked the tons of wood that would support the atomic pile; cut and moved the 45,000 graphite blocks that formed its lattice structure; and used a hydraulic press to turn uranium powder into thousands of baseball-sized spheres that formed part of the reactor’s fuel.

All along, Petry said he never asked the intended use of all the construction work. “A lot of people worked there and left without any knowledge of what was going on,” he said. “You didn’t question too much.”

That included when Petry saw workers jackhammering doorways into the West Stands of Stagg large enough for people to walk through. “If the pile went critical, and they couldn’t control it,” Petry recalled, “they said: ‘Get out through those things and head for Indiana.’”

 ‘1, 2, 3, and it was over with’

When Petry arrived at Stagg Field on Wednesday, Dec. 2, 1942, he saw a large number of dignitaries and scientists gathered in the balcony of the squash racquets court. “When all these people came in,” he said, “you begin to wonder, ‘Hey, what’s going on?’

The night before, workers had finished assembling the final layer of Chicago-Pile 1. Petry remembered gathering with others in the balcony, while Fermi was next to the pile conducting the experiment.

History was made at 3:25 p.m., with the splitting of uranium nuclei into a sustained chain reaction.

“It worked out perfectly. It was a simple slide rule experiment—1, 2, 3, and it was over with,” Petry recalled. “Fermi said, ‘That’s it,’ and everyone rejoiced.”

Project scientist Eugene Wigner presented Fermi with the bottle of Chianti and some paper cups to toast the achievement. Those in the room signed the bottle’s straw wrapper to signify they were present for the reaction. He printed “Ted Petry 42” in block letters along the bottle’s side, not far from Fermi’s signature.

“Surprisingly, they just asked you to sign it. You knew these people, but you considered them workers alongside of you,” Petry said. “They didn’t feel like they were above you.”

‘Written in the history books’

Petry left UChicago soon after and worked a number of jobs in support of the war effort: He sailed on the USS Youngstown, an ore freighter in the Great Lakes; worked at the Dodge Chrysler plant, making engines for C-47 war planes; and served as a tool-and-die maker at the Pullman plant. In the years that followed, Petry worked in manufacturing and taught shop for 17 years in the Chicago Public Schools.

Petry attended UChicago’s 20th anniversary celebration of the first chain reaction in 1962. He also was part of the University contingent invited to Washington, D.C. to meet President John F. Kennedy in the Rose Garden, where his former colleagues referred to him as “the Baby of CP-1.”

According to Argonne National Laboratory records, more than a quarter of the 49 people who were present at the critical experiment on Dec. 2, 1942 lived into their 90s. When scientist Warren Nyer died in February 2016 at the age of 94, Petry was left as the only known witness to history—a distinction of which he was unaware.

“He was a kid that did a job. He worked on this pile that’s written in the history books,” said Petry’s daughter Laura Dowling. “A lot of people have their one claim to fame, and that’s our dad’s.”

Petry is survived by his wife Adeline, four children, nine grandchildren and six great-grandchildren.