Isotopes that can be turned into fissionable isotopes are called what?

Isotopes that can be turned into fissionable isotopes are called what?

• A. Fissile
• B. Non-fissile
• C. Fertile
• D. Stable

Answer: (C)

The idea being tested is that some isotopes are fertile—they can be turned into fissile (fissionable) isotopes by absorbing a neutron and undergoing beta decay. These fertile materials themselves may not readily sustain a chain fission reaction, but after neutron capture they become fissile nuclides that can. For example, uranium-238 captures a neutron and becomes uranium-239, which beta decays to neptunium-239 and then to plutonium-239, a fissile isotope. Thorium-232 follows a similar path to uranium-233. This distinguishes fertile materials from those that are already fissile (capable of sustaining a chain reaction with thermal neutrons) or from non-fissile and stable isotopes that don’t readily become fissile.

The idea being tested is that some isotopes are fertile—they can be turned into fissile (fissionable) isotopes by absorbing a neutron and undergoing beta decay. These fertile materials themselves may not readily sustain a chain fission reaction, but after neutron capture they become fissile nuclides that can. For example, uranium-238 captures a neutron and becomes uranium-239, which beta decays to neptunium-239 and then to plutonium-239, a fissile isotope. Thorium-232 follows a similar path to uranium-233. This distinguishes fertile materials from those that are already fissile (capable of sustaining a chain reaction with thermal neutrons) or from non-fissile and stable isotopes that don’t readily become fissile.