The Sound of Science

Celebrating 80 Years: Top-Secret Science

Celebrating 80 Years: Top-Secret Science

Eighty years ago, the U.S. government embarked on a secret mission that would change the world. The Manhattan Project was a massive effort that resulted in the world’s first nuclear weapons and the end of World War II. But its legacy extends well beyond the war, as it laid the foundation for groundbreaking science for decades to come. Oak Ridge National Laboratory is one of the facilities born out of the Manhattan Project. Over the past 80 years, its mission has evolved and expanded to become a world leader in supercomputing, materials research, isotopes, clean energy — to name a few — but to this day is still strongly associated with its Manhattan Project roots. In this episode, you'll hear the story of the lab's top-secret origin from Alan Icenhour, the lab’s recently retired deputy for operations.


ALAN ICENHOUR: This was a time the country was at war, facing an existential threat, and that can be very focusing for people. And I think it's that kind of urgency, coming together focused on a very compelling problem, that even today that make the National Labs special places. 




JENNY: Hello everyone and welcome to “The Sound of Science,” the podcast highlighting the voices behind the breakthroughs at Oak Ridge National Laboratory.  


MORGAN/JENNY: We’re your hosts, Morgan McCorkle and Jenny Woodbery.  




JENNY: Eighty years ago, the U.S. government embarked on a secret mission that would change the world. 


MORGAN: It was called the Manhattan Project, and it was a massive effort that would result in the world’s first nuclear weapons and end World War II.  


JENNY: But that was just the beginning. The Manhattan Project laid the foundation for groundbreaking science for decades to come. 


MORGAN: While Oak Ridge National Laboratory’s initial mission was aimed at ending the war, it’s since evolved and expanded to become the U.S. Department of Energy’s largest science and energy laboratory. 

JENNY: ORNL has become a world leader in supercomputing, materials research, isotopes, clean energy – to name a few -- but to this day is still strongly associated with its Manhattan Project roots.  


MORGAN: And for many people from East Tennessee, the history of the lab is a personal one – including us. My father, Dennis McCorkle, and grandfather, Calvin Burwell, both worked at ORNL starting in the 1960s.  


JENNY: And my grandfather, Al Sutton, Jr., worked in ORNL’s chemistry division from 1953 to 1989. 


MORGAN: So, in honor of the 80th anniversary, we’re dedicating a few episodes to exploring the lab’s storied history, its post-war transformation and what the next 80 years might hold.  




JENNY: In the late 1930s, the world was at the brink of war and a new scientific discovery in Germany set off alarm bells in the physics community.  


MORGAN: In 1938, German scientist Otto Hahn, with help from Lise Meitner -- a Jewish researcher who had escaped to Sweden only months before, discovered that the core of a heavy atom like uranium could be split apart – releasing energy and neutrons. Researchers around the world soon recognized the potential – and dangers -- of this new atomic phenomenon, called nuclear fission. 


JENNY: In August 1939 – a month before World War II began – renowned scientist Albert Einstein sent a letter to President Franklin D. Roosevelt detailing the risk that the Germans could build “extremely powerful bombs of a new type.” 


MORGAN: Einstein, with the support of fellow physicists Edward Teller, Leo Szilard and Eugene Wigner – who, a few years later, would become ORNL’s first research director – urged the president to accelerate the United States’ research on nuclear chain reactions. 


JENNY: President Roosevelt heeded Einstein’s advice and directed the Army to embark on what would become one of the largest research and development efforts in history – the Manhattan Project.  


MORGAN: To help us tell this story, we sat down with Alan Icenhour, the lab’s former deputy for operations, who recently retired after 32 years at ORNL.  


JENNY: A nuclear engineer by training and a history buff by nature, Alan knows the story of the Manhattan Project like the back of his hand.  


ICENHOUR: It's really a fascinating story. If you back up even a little earlier. It was only in 1932, that the neutron was discovered. And then in the late 1930s, fission was discovered -- that you could break apart an atom, in this case, an atom of uranium, and that when it broke apart, it also emitted neutrons. So that's very intriguing. And so the concept was, could you have a self-sustained nuclear reaction. In this case, when you break apart an atom, the neutrons from it can go on and cause additional fissions and that can be self-sustaining.  


MORGAN: A team of Manhattan Project scientists – including Szilard and Nobel Prize winner Enrico Fermi, who had emigrated to the US to escape fascist Italy – managed to create the first self-sustained nuclear reaction under a football field at the University of Chicago in December 1942. 


ICENHOUR: At the Chicago Pile, CP-1, which was at Stagg Field, it was under the stands at this field at the University of Chicago, where they assembled uranium and graphite together, and they proved that you could have a self-sustained chain reaction. Now that assembly wasn't practical for use. And that led them to the concept of building a more continuous controlled nuclear reactor. And that's the origins of the Graphite Reactor.  


JENNY: After the success of the Chicago Pile, sites in Oak Ridge, Tennessee; Hanford, Washington; and Los Alamos, New Mexico, were quickly established in the next phase of the Manhattan Project. 


ICENHOUR: It's interesting when you look at this area that we're sitting at today. In the spring of 1942, there really was nothing here other than a lot of trees and hills, and some farmers. And very quickly that evolved as the need was identified to build facilities to support the Manhattan Project. And this area, which was nearby to Clinton, Tennessee, and of course, a little further outlying Knoxville was a good candidate for that, because there was a need for secrecy. So, it was isolated. And there was a need for power, and from the TVA, there was ample supply of power. And there was need for workforce. And so the nearby communities provided that. So, it was those combinations of things that made it an ideal location for this Manhattan Project effort. 


MORGAN: As scientists at Los Alamos began racing to figure how to design and assemble an atomic weapon, Manhattan Project leaders knew they needed to start production of larger quantities of uranium and plutonium – and hedged their bets by exploring multiple methods.  


ICENHOUR: There were four sites involved here in the Oak Ridge area. And, you know, the focus was in two areas, one was to make enriched uranium, and a number of processes were explored, established to do that, and the other was to make plutonium. And so, three sites were focused on enriching uranium, the S-50 thermal diffusion plant, the K-25 gaseous diffusion plant, and then the Y-12, which focused on electromagnetic separation of uranium using calutrons. And then, at this site, which at the time was called X-10 and some of us old timers still call it X-10, it was focused on plutonium.  


JENNY: In February 1943, just months after the Chicago Pile reached criticality, construction began on the X-10 Graphite Reactor, giving birth to what would one day be known as Oak Ridge National Laboratory. 


MORGAN: A scaled-up and improved version of the Chicago Pile, its mission was to demonstrate that plutonium could be produced from uranium in a nuclear reactor. 


ICENHOUR: So, as efforts were undertaken to find fissile materials that could be used for weapons in this case, the candidates were first and foremost uranium and particular uranium-235. And then plutonium, which had only recently been discovered by Seaborg in 1940. And so, plutonium was also being explored as a possible material that could be used. And so the Graphite Reactor, they started construction on it in February of 1943. And it became operational at 5 a.m. on November 4th, 1943, think about that, nine months, from beginning of construction to the world's first continuously operating nuclear reactor. That's just an astonishing achievement. 


JENNY: The Graphite Reactor was proof-of-concept that plutonium could be made from uranium in a nuclear reaction, but it didn’t produce any of the material actually used in one of the atomic bombs. 


MORGAN: The bomb used on Aug. 6, 1945, was made from uranium produced at Y-12. The second bomb used plutonium produced at the Hanford site in Washington State, which built its reactors with insights from the X-10 Graphite Reactor.  


ICENHOUR: They built a much larger production reactor in Hanford, Washington. And so, this production here at much smaller scale enabled larger quantities of plutonium to be available to work out the chemistry for separations. And then some of this material also was provided to Los Alamos for study. 


MORGAN: The success of the Graphite Reactor set the stage for X-10 to move forward as a scientific institution after the war ended. 


ICENHOUR: Not only you know, the science of how do you build a nuclear reactor and control it, and what are the characteristics of it, but then from the plutonium production, what's the separation chemistry you do to retrieve that material, you know, when you produce it. So there was a lot of really good science and engineering that went on to make this possible. 


After the war, it was recognized what a great capability that had been established, that combined academics, scientists along with industry focused on compelling, challenging problems. And what a resource that had been established not only here at Oak Ridge, but at other locations around the country. And that really was memorialized under the Atomic Energy Act, which really serves as even today for the foundation of how we exist and work. And under that act, then we were focused more on the peaceful uses of this new technology that had been developed, which I think's just a tremendous outcome is that, you know, even though the technology was originally established, focused on weapons and war, it was recognized that there were, you know, many useful applications, for this technology that are for the betterment of us all. 




JENNY: Thank you for listening to this episode of The Sound of Science. 


MORGAN: We hope you enjoyed this episode and will keep an eye out for the next installment of this special series for the 80th anniversary.  


JENNY: Until next time!