Th-232 and Uranium-238, naturally occurring, are best described as which category?

Th-232 and Uranium-238, naturally occurring, are best described as which category?

• A. Naturally occurring
• B. Common fissionable fuels
• C. Nuclear Fusion
• D. Nuclear Fertile Elements

Answer: (D)

Fertile materials are not themselves easily fissile but can be converted into fissile material by absorbing a neutron and undergoing subsequent beta decays. Thorium-232 and uranium-238 are naturally occurring isotopes that fit this role: Th-232 captures a neutron to become Th-233, which beta decays to Pa-233 and then to U-233, a fissile isotope; U-238 captures a neutron to become U-239, which beta decays to Np-239 and then to Pu-239, also fissile. Because they can breed fissile fuel inside a reactor, they’re classified as Nuclear Fertile Elements. They aren’t typically used as the primary fissionable fuels themselves, and fusion isn’t what defines them in this context.

Fertile materials are not themselves easily fissile but can be converted into fissile material by absorbing a neutron and undergoing subsequent beta decays. Thorium-232 and uranium-238 are naturally occurring isotopes that fit this role: Th-232 captures a neutron to become Th-233, which beta decays to Pa-233 and then to U-233, a fissile isotope; U-238 captures a neutron to become U-239, which beta decays to Np-239 and then to Pu-239, also fissile. Because they can breed fissile fuel inside a reactor, they’re classified as Nuclear Fertile Elements. They aren’t typically used as the primary fissionable fuels themselves, and fusion isn’t what defines them in this context.