Herb Anderson's piece of the Chicago Pile
Channel: Carl Willis
Date: 2014-10-28

**TIME INDEX BELOW** This video shows a "live block" from the first nuclear reactor, the "Chicago Pile" or CP-1, built in secrecy beneath the stands of Stagg Field at the University of Chicago in 1942.  The block was owned as a commemorative item by physicist Herbert L. Anderson.  It consists of a piece of graphite with holes milled for two pieces of uranium metal nuclear fuel.  In narrating this video I mostly blather unscripted for almost half an hour (sorry!), but I do touch on the following points:

01:48 The uranium fuel emits some radiation, amounting to an external gamma exposure rate of about 7.4 mR / hour on contact with the artifact.
05:15 I show how uranium metal fuel is held in the much larger holes in the graphite that were milled to accommodate uranium oxide "pseudosphere" fuel elements.
06:02 I mention the various different types of graphite-fuel arrangements found in CP-1, owing to the different types of fuel.
06:20 The fuel elements have numbers stamped on them, the significance of which is unknown.
07:16 I take out one of the fuel elements and show how it is supported in the graphite.  I question whether the acrylic spacers were original or were added later for display purposes.
09:05 I weigh the fuel element I have removed from the block.
10:09 I discuss the AGOT graphite in this block as well as the properties of the various types of graphite used to build CP-1.
12:18 The gamma radiation from this fuel is characteristic of fission products because this fuel has been exposed to reactor operation.  We examine both a scintillation gamma spectrum and an HPGe gamma spectrum.
18:04 From the gamma spectra we can quantitatively estimate the burnup at about 200 kW-days per metric ton of uranium.
19:25 This burnup is only consistent with this fuel having been not only in CP-1, but also CP-2.
22:45 I very briefly discuss the life and work of Herb Anderson.
25:37 I discuss the origins of the uranium used in CP-1, virtually all of which came from the Shinkolobwe Mine in what was then the Belgian Congo.