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Why are uranium-238 and thorium-232 called fertile materials?
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nuclear fission
Italian-born physicist Enrico Fermi explaining a problem in physics, c. 1950. He was awarded the 1938 Nobel Prize for Physics.
Uranium-238 and thorium-232 are classified as fertile materials because, while they cannot undergo fission when struck by low-energy neutrons, they can be transformed into fissile materials through neutron capture within a nuclear reactor.12
The process works as follows:
- Thorium-232: When it captures a neutron, it becomes thorium-233, which subsequently decays through beta emission into protactinium-233 and finally into the fissile isotope uranium-233.23
- Uranium-238: Upon capturing a neutron, it becomes uranium-239, which decays through a series of steps into neptunium-239 and ultimately into the fissile isotope plutonium-239.23
By converting these abundant fertile materials into fissile fuel, nuclear reactors can extend their operational life and improve the efficiency of fuel utilization.23