abstract:Uranium-233 is a fissile isotope of uranium that is bred from thorium-232 as part of the thorium fuel cycle. Uranium-233 was investigated for use in nuclear weapons and as a reactor fuel; however, it was never deployed in nuclear weapons or used commercially as a nuclear fuel.
The conversion is not direct, and involves the initial formation of thorium-233, which decays rapidly to protactinium-233, and then to uranium-233 over a period of about a month.