On the eve of the 80th anniversary of the first controlled nuclear chain reaction, Nuclear Newswire is back with the second of three prepared #ThrowbackThursday posts of CP-1 coverage from past issues of Nuclear News.

On November 17, we surveyed the events of 1942 leading up to the construction of Chicago Pile-1, an assemblage of graphite bricks and uranium “pseudospheres” used to achieve and control a self-sustaining fission reaction on December 2, 1942, inside a squash court at the University of Chicago’s Stagg Field.

Today we’ll pick up where we left off, as construction of CP-1 began on November 16, 1942.

“They’d think we are crazy”: “The First Pile,” published in the November 2002 issue of NN (p. 34) was an edited and adapted version of an essay by the same title written in the fall of 1946 by Corbin Allardice and Edward R. Trapnell, two public information officers for the Atomic Energy Commission who conducted postwar interviews with more than a dozen scientists involved in the project to produce the first narrative account of the experiment. They describe the scene:

An outsider looking into the squash court where Fermi was working would have been greeted by a strange sight. In the center of the 30-by-60-foot room, shrouded on all but one side by a gray balloon cloth envelope, was a pile of black bricks and wooden timbers, square at the bottom and a flattened sphere on top. Up to half of its height, its sides were straight. The top half was domed, like a beehive. During the construction of this crude appearing but complex pile (the name that was applied to all such devices for the first few years of the atomic age, but which gradually gave way to “reactor”) the standing joke among the scientists working on it was: “If people could see what we're doing with a million-and-a-half of their dollars, they'd think we are crazy. If they knew why we are doing it, they'd know we are.”

Just over two weeks of construction: The pile was constructed around the clock, with a team divided into two 12-hour shifts: a day shift under Walter Zinn and a night shift under Herb Anderson. Allardice and Trapnell described it thus:

Day after day the pile grew toward its final shape. And as the size of the pile increased, so did the nervous tension of the men working on it. Logically and scientifically they knew this pile would become self-sustaining. It had to. All the measurements indicated that it would. But still the demonstration had to be made. As the eagerly awaited moment drew nearer, the scientists gave greater and greater attention to details, the accuracy of measurements, and exactness of their construction work. Guiding the entire pile construction and design was the nimble-brained [Enrico] Fermi, whose associates described him as “completely self-confident but wholly without conceit...”