What was the principal nuclear reaction of Fermi's nuclear pile

Villhelm

I've known about the basic story of the first nuclear pile since before I can remember, but never found information on what the associated nuclear reaction actually was and was wondering if anyone here knew or could point me in the right direction.

mathman

The reactor fuel was Uranium, so I presume the reactions would be the same as any Uranium reactor.

cmb

From various sources, etc., as far as I have pieced together the following should address your question (and related factoids) regarding the first reactor pile, CP-1. (I trust I will be corrected if any of these have come from inaccurate sources.)

Principle reaction = Absorption of slow neutrons by U-235 in un-enriched uranium.

Fuel used = 40 tons of un-enriched uranium dioxide pressed into 17,000 'pseudospheres', plus 6 tons of "Spedding’s eggs", uranium metal in cylinders of 2 1/4" OD x 3" long.

Moderator = 4,000 x 6 lbs ultra-pure graphite blocks, drilled with holes to take the above uranium, plus a further 300 tons of graphite in layers.

Control rods = cadmium.

Safety moderator = buckets of boric acid to be poured in from above

Power output = 0.5 W