My Piece Of The Pile

While Nuclear Medicine probably began with the Curies, Frédéric Joliot-Curie and Irène Joliot-Curie, as well as Marie Curie (mother of Irene), the true Nuclear Era began in Chicago on December 2, 1942. From the Wiki:

Chicago Pile-1 (CP-1) was the world’s first artificial nuclear reactor. CP-1 was built on a rackets court, under the abandoned west stands of the original Alonzo Stagg Field stadium, at the University of Chicago. The first artificial, self-sustaining, nuclear chain reaction was initiated within CP-1, on December 2, 1942. The site was designated a National Historic Landmark in 1965 and was added to the newly created National Register of Historic Places a little over a year later. The site was named a Chicago Landmark in 1971. It is one of the four Chicago Registered Historic Places from the original October 15, 1966, National Register of Historic Places list.


The reactor was a pile of uranium and graphite blocks, assembled under the supervision of the renowned Italian physicist Enrico Fermi, in collaboration with Leo Szilard, discoverer of the chain reaction. It contained a critical mass of fissile material, together with control rods, and was built as a part of the Manhattan Project by the University of Chicago Metallurgical Laboratory. The shape of the pile was intended to be roughly spherical, but as work proceeded Fermi calculated that critical mass could be achieved without finishing the entire pile as planned.

A labor strike prevented construction of the pile at the Argonne National Laboratory, so Fermi and his associates Martin Whittaker and Walter Zinn set about building the pile (the term “nuclear reactor” was not used until 1952) in a rackets court under the abandoned west stands of the university’s Stagg Field. The pile consisted of uranium pellets as a neutron-producing “core”, separated from one another by graphite blocks to slow the neutrons. Fermi himself described the apparatus as “a crude pile of black bricks and wooden timbers.” The controls consisted of cadmium-coated rods that absorbed neutrons. Withdrawing the rods would increase neutron activity in the pile, leading to a self-sustaining chain reaction. Re-inserting the rods would dampen the reaction.

First nuclear reaction

On December 2, 1942, CP-1 was ready for a demonstration. Before a group of dignitaries, a young scientist named George Weil worked the final control rod while Fermi carefully monitored the neutron activity. The pile reached the critical mass for self-sustaining reaction at 3:25 p.m. Fermi shut it down 28 minutes later.

Unlike most reactors that have been built since, this first one had no radiation shielding and no cooling system of any kind. Fermi had convinced Arthur Compton that his calculations were reliable enough to rule out a runaway chain reaction or an explosion, but, as the official historians of the Atomic Energy Commission later noted, the “gamble” remained in conducting “a possibly catastrophic experiment in one of the most densely populated areas of the nation!”

Operation of CP-1 was terminated in February 1943. The reactor was then dismantled and moved to Red Gate Woods, the former site of Argonne National Laboratory, where it was reconstructed using the original materials, plus an enlarged radiation shield, and renamed Chicago Pile-2 (CP-2). CP-2 began operation in March 1943 and was later buried at the same site, now known as the Site A/Plot M Disposal Site.

Significance and commemoration

The site of the first man-made self-sustaining nuclear fission reaction received designation as a National Historic Landmark on February 18, 1965. On October 15, 1966, which is the day that the National Historic Preservation Act of 1966 was enacted creating the National Register of Historic Places, it was added to that as well. The site was named a Chicago Landmark on October 27, 1971. A small graphite block from the pile is on display at the Museum of Science and Industry in Chicago, another can be seen at the Bradbury Science Museum in Los Alamos, NM. The old Stagg Field plot of land is currently home to the Regenstein Library at the University of Chicago. A Henry Moore sculpture, Nuclear Energy, in a small quadrangle commemorates the nuclear experiment.

As it turns out, several tiny slivers of the graphite, encased in lucite, were also given to friends of the University of Chicago (I assume that translates to big donors and such), and several have found their way to eBay.  A fellow Nuclear Aficionado found one a few years back:

This 25th Anniversary memento popped up on eBay not long ago and I paid dearly for it. However, there’s not much of this stuff left; all but a couple bars of this famously pure graphite went on to be incorporated in CP-2 and thereafter entombed in concrete under a nondescript field in Illinois. The eBay seller would only say “I do know that my grandfather worked on the building of the atomic bomb but other than that I don’t know much else.” I have a feeling that the human story could be interesting, but on account of the seller’s reluctance to share so much as her grandfather’s name and other “personal information,” there’s nothing more to say right now.

The momento is pictured above.

I had almost won one of these several years ago, but I was outbid at the last minute (darn snipers!) and I’ve been watching for one ever since. By some miracle, two of them came up for bid a few weeks ago, and I bid successfully on one identical to that pictured above.  The second actually sold for double the amount I paid, which I guess makes mine worth more as well.  It was slightly different, perhaps encased in lucite at a different point in time.

I’ll never do anything historical, but at least I can own a piece of history.  What better way to start a new year than to hold a connection to the past in the palm of my hand?  No, it’s not radioactive, and it doesn’t glow in the dark.

Happy New Year, everyone!


3 responses to “My Piece Of The Pile

  1. I was given the same lucite paperweight containing graphite from cp-1 I am no nuclear aficionado, and was wondering what I might ask for it on ebay. Any help would be greatly appreciated! Thanks

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