Neutron capture

Neutron capture is a type of nuclear reaction. In this reaction, a nucleus gets hit by a neutron, and the two combine into a larger nucleus. Neutron capture is one of the most important basic nuclear reaction types.

Because the number of protons stay the same, neutron capture makes a heavier isotope of the same element. This isotope can be more or less stable, and goes through different kinds of radioactive decay. Through this, neutron capture is often the first step of nuclear transmutation.

Example

Uranium-238 is a fertile isotope of uranium. This means it cannot be used as fuel for a thermal-neutron reactor, but it is possible for it to be transmuted into a fissile isotope that can. This reaction starts with neutron capture, changing the ²³⁸U into ²³⁹U.

²³⁸U + n⁰ → ²³⁹U

This isotope then goes through beta decay twice to become the fissile plutonium-239.