More common than gold, uranium is abundant on Earth. But less than one percent of the naturally occurring element is useful ...

Natanz, Isfahan and Fordow, killing several Iranian nuclear scientists. The facilities are heavily fortified and largely ...

Not that anyone asked, but uranium enrichment is certainly a newsworthy topic where a little science might be helpful. Here's ...

When Israeli aircraft recently struck a uranium-enrichment complex in the nation, Iran could have been days away from ...

ON bombarding uranium with neutrons, Fermi and collaborators1 found that at least four radioactive substances were produced, to two of which atomic numbers larger than 92 were ascribed. Further ...

Uranium is a naturally radioactive element. It powers nuclear reactors and atomic bombs. ... When a free neutron bumps into the atom, it splits the nucleus, throwing off additional neutrons, ...

Once that uranium is enriched, power plant operators pair it with a moderator, like water, that slows down the neutrons in the uranium. This increases the probability of a consistent chain reaction.

Uranium-238 (92 protons plus 146 neutrons) is the most abundant form, and about 99.3 percent of all uranium is U-238. The rest is U-235 (0.7 percent), with a trace amount of U-234.

But neutrons emitted from the fission of uranium are fast. So for the Chicago experiment, the physicists used graphite to slow down the emitted neutrons, via multiple scattering processes.

These additional neutrons crash into other uranium 235 atoms, causing them to break apart and release additional neutrons, and on and on. This is how you get a chain nuclear fission reaction.

Uranium-233 has a high probability of undergoing fission when it is struck by a neutron of any energy, and fission releases enough neutrons to continue the conversion of thorium to new uranium-233.