A drawing of the Graphite Reactor's predecessor: Fermi's CP-1 reactor at the University of Chicago.
ORNL’s beginnings as an East Tennessee-located national laboratory have their roots in Chicago.
ORNL’s beginnings as an East Tennessee-located national laboratory have their roots in Chicago. That’s where the Nobel laureate Enrico Fermi (1938) and a host of physicists and engineers constructed CP-1, the first nuclear reactor: a “pile” of graphite blocks and control mechanisms in a disused squash court at Stagg Field on the University of Chicago campus.
Several of ORNL’s nuclear pioneers were either present in the room or working at the university in December 1942, when Fermi assembled his pile and fueled it with uranium for a risky proof of principle experiment. This was before there was an ORNL or even an Oak Ridge Reservation. One of those present at the CP-1 experiment on Dec. 2, 1942, and destined for a long career at ORNL was the late Richard J. Fox.
Dick Fox came to UC in 1941 to work for Sam Allison, another Nobel laureate, who was experimenting with neutrons. Fox’s timing was spot-on because Allison’s program was about to blossom into the Metallurgical Laboratory, which under Fermi and Arthur Compton set up the CP-1 experiment to investigate the possibility of plutonium production in a "pile," which was Eugene Wigner’s original word for a nuclear reactor.
“I don’t claim that I was chosen for the project," Fox said in a 1967 interview in the ORNL News. "It was entirely fortuitous that I applied for work at the University of Chicago physics department at just the right time."
Allison's program, at least at first, was modestly endowed. Fox recalled in 1993, at an ORNL reception marking the Graphite Reactor's 50th year, that his team frequented a Chicago salvage store they dubbed “Dirty Dan's” for used instruments such as chart recorders for their experiments.
Resources likely improved after Fermi and scientists from Princeton and Columbia universities arrived at Chicago to join the Metallurgical Laboratory. Fermi and his colleagues would conduct evening classes to familiarize the team with some of the project’s theoretical concepts and basic knowledge.
“Fermi would stand before us thumbing that pocket slide rule, trying to fill some of our heads with knowledge that was right at his fingertips,” Fox said.
Fox worked on CP-1’s regulating rod and its instrumentation and contributed one of the control rod operating mechanisms. Fox’s device was simple: “The manual speed control was nothing more elaborate than a variable resistor with a piece of cotton clothesline over a pulley and two lead weights to make it ‘fail safe’ and return to its zero position when released,” Fox said in 1992 for ORNL Review’s 50-year history, The First 50 Years.
It was one of several control mechanisms built into the pile for safety. One of the rods was attached to a rope that would be with an axe in case of an emergency, dropping the rod into the pile. A final contingency was buckets of a cadmium sulfate solution to be dumped into the reactor to quench any runaway reaction. (Fox referred to the bucket brigade as the “suicide crew.” Wallace Koehler was one of them, and he lived to become a neutron scattering pioneer at ORNL.)
The experiment was potentially dangerous — CP-1 had no real containment. But the team was reassured by Fermi’s genius and data from a previous 30 experimental subcritical piles that informed Fermi and his associates of the design and selection of uranium and graphite for the experiment.
On Dec. 2, 1942, Fermi, accompanied by a host of colleagues and workers, closely monitored the instruments as the control rods were withdrawn from the uranium-fueled pile. Eventually his serious countenance lit into a smile and he announced, “The reaction is self-sustaining.” Eugene Wigner produced a bottle of Chianti for the occasion; the wine was distributed in paper cups.
Fox described the gathering as elated. “It was as if we had discovered fire!” he recalled in 1992. In his 1967 interview he was a bit more introspective: “True, there was a bottle of Chianti and toasts were drunk to the pile and Fermi ... and yet there were some mixed feelings, I think, among those who considered how this knowledge might someday be used.”
Fox moved from Chicago to muddy, dusty Oak Ridge in 1943 to work on instrumentation for CP-1’s successor, the X-10 Pile, or Graphite Reactor as it was later known. Fox joined the Lab as a machinist — he began working for Allison with no college degree but subsequently earned a b.s. in physics. In the ensuing years Fox developed solid-state radiation detection devices in the former Instrumentation & Controls Division. He designed the vacuum-sealed boxes for storing lunar rock samples for the Apollo missions and later worked on a NASA project to simulate conditions in outer space and for metallurgical experiments on the Space Shuttle missions. He died in 1996. — Bill Cabage