Natural Occurrence
Because of the short half-life of all isotopes of fermium, all primordial fermium, that is fermium that could possibly be present on the Earth during its formation, has decayed by now. Synthesis of fermium from naturally occurring actinides uranium and thorium in the Earth crust requires multiple neutron capture, which is an extremely unlikely event. Therefore, most fermium is produced on Earth in scientific laboratories, high-power nuclear reactors, or in nuclear weapons tests, and is present only within a few months from the time of the synthesis. Einsteinium and fermium did occur naturally in the natural nuclear fission reactor at Oklo, but no longer do so.
Read more about this topic: Fermium
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