What is the Difference Between Fissile and Fertile Isotopes?

The main difference between fissile and fertile isotopes lies in their ability to undergo fission reactions.

Fissile isotopes are materials that can undergo fission reactions directly, while fertile isotopes are materials that can be converted into fissile isotopes through irradiation in a nuclear reactor.

Some examples of fissile isotopes include uranium-235, plutonium-239, and uranium-233. These isotopes can undergo fission reactions directly when struck by slow (low-energy) neutrons.

On the other hand, fertile isotopes, such as thorium-232 and uranium-238, are not themselves fissile but can be converted into fissile materials like plutonium-239 and uranium-233, respectively, through irradiation in a nuclear reactor. These fertile materials are used in special types of reactors called breeder reactors, which irradiate a fertile isotope inside, causing the isotope to absorb a neutron and decay to a fissile isotope.

In summary:

• Fissile isotopes can undergo fission reactions directly.
• Fertile isotopes can be converted into fissile isotopes through irradiation in a nuclear reactor.

Examples of fissile isotopes include uranium-235, plutonium-239, and uranium-233, while examples of fertile isotopes include thorium-232 and uranium-238.

Comparative Table: Fissile vs Fertile Isotopes

The main difference between fissile and fertile isotopes lies in their ability to undergo fission reactions. Fissile isotopes can undergo fission reactions directly, while fertile isotopes cannot undergo fission directly and must be converted into fissile isotopes first. Here is a table summarizing the differences between fissile and fertile isotopes:

In the context of nuclear reactors, fissile and fertile materials are used together. Fertile materials partially replace fissile materials that are destroyed by fission, thus sustaining the nuclear reaction.