Timeline for For Fermi's CP-1 experiments, why didn't they use much smaller slugs of natural uranium?
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 29 at 14:32 | comment | added | Young Jun Lee | In retrospect, it has something to do with the neutron diffusion equation. | |
| Sep 4, 2023 at 0:27 | vote | accept | Young Jun Lee | ||
| Aug 31, 2023 at 12:12 | answer | added | NuclearFission | timeline score: 2 | |
| Aug 26, 2023 at 3:05 | comment | added | Young Jun Lee | @JonCuster I see, so they can theoretically be smaller, but Fermi must have had some experimental reason for making the slugs the size they are. Thank you! | |
| Aug 26, 2023 at 2:59 | comment | added | Jon Custer | Fermi had a very good idea of the various cross sections of interest, having done a variety of experiments with Uranium over the previous years. If many neutrons can get out of 1.5 inch diameter slugs with zero or perhaps one scattering event there is no need to make the slugs smaller. So, what is the mean free path? If more than a centimeter or so, things are just fine - the slug is small enough for neutrons to get out to be moderated by the graphite. Also remember that CP-1 was unenriched, naturally occurring uranium oxide, so the ~2MeV neutrons could fission the U-238. | |
| Aug 26, 2023 at 2:43 | comment | added | Young Jun Lee | @JonCuster I have not, but I get your point. You are saying the slugs must be thick enough to "catch" the neutrons? | |
| Aug 26, 2023 at 2:41 | comment | added | Jon Custer | Have you calculated the mean free path of a ~2 MeV neutron in uranium oxide? | |
| Aug 26, 2023 at 2:23 | history | asked | Young Jun Lee | CC BY-SA 4.0 |