Fewer than 100 facilities in the United States have been recognized by the American Nuclear Society with Nuclear Historic Landmark status. These facilities range from the Ames Laboratory Uranium Purification to the USS Enterprise (CVN-65), the first nuclear-powered aircraft carrier.
The Armour Research Foundation Reactor became the latest first-of-its-kind reactor to be awarded Nuclear Historic Landmark status on April 18, 2025, during a ceremony in Perlstein Hall.
“In places and spaces, there’s meaning,” said American Nuclear Society President Lisa Marshall at the dedication ceremony. “It’s very important to have these various landmarks—and even more important for us to talk about what was done there.”
Illinois Tech Vice Provost for Research Jeff Terry stated, “These are the groundbreaking reactors in history. Basically, every single major reactor that was the first of its kind is commemorated.”
Terry also commented on the significance of the Armour Research Foundation Reactor being the first private nuclear reactor, highlighting the contributions of 25 industry partners during its construction in 1956. Companies such as IBM, Inland Steel, Caterpillar, Inc., Kimberly-Clark, U.S. Steel, and Whirlpool were integral to the project. “It’s an incredible list of companies that partnered with us to build this reactor and we are happy for the Armour Research Foundation Reactor to be honored in the same vein as the more famous neighbor to the south, Fermi’s Pile CP-1,” he said.
The Armour Research Foundation Reactor, also known as the atomic furnace, operated for 11 years, contributing to research impacting various fields such as agriculture, chemistry, food safety, and medicine. Its use in isotope production and materials analysis led to significant advances still in practice today.
A unique aspect of the reactor was its design which employed a liquid nuclear fuel, Uranium-235 in the form of uranyl sulfate dissolved in water, a safety feature especially important in a densely populated city like Chicago. “If the reaction ran away, the liquid would expand and the change in geometry would stop the criticality,” explained Terry, describing it as a "really clever design."
Early operational challenges, like a hydrogen-oxygen recombination incident in 1956 and a fuel leakage in 1957, led to a redesign, allowing the reactor to operate without incident after December 1957. Though operations stopped in 1967 and the reactor was decommissioned in the late 1970s, its legacy remains. The reactor was pivotal in advancing nuclear technology and application-driven science, with tools such as neutron diffraction and isotope tracing continuing to be fundamental in nuclear science.
“The story of the Armour Research Foundation Reactor reflects both the optimism and the challenges of embracing new technologies,” said Terry. “As we continue to explore the possibilities of nuclear energy today, this pioneering effort at Illinois Tech serves as a reminder of the progress made and the potential that still lies ahead.”