Nuclide Fission with Slow Neutrons

Nuclear fission is the process where an atomic nucleus splits into smaller parts. The ability of a nuclide to undergo fission depends on the energy of the incident neutron.

Fissile vs. Fertile Nuclides:

• Fissile nuclides readily undergo fission when struck by low-energy (slow) neutrons. Key examples include Uranium-235 ($^{235}\text{U}$), Plutonium-239 ($^{239}\text{Pu}$), and Uranium-233 ($^{233}\text{U}$). These are crucial for sustaining chain reactions in nuclear reactors.
• Fertile nuclides do not easily fission with slow neutrons but can capture a neutron to transform into a fissile nuclide. Uranium-238 ($^{238}\text{U}$) is the most common fertile nuclide.

Fission Characteristics of $^{238}\text{U}$

While $^{235}\text{U}$, $^{239}\text{Pu}$, and $^{233}\text{U}$ are fissile with slow neutrons, $^{238}\text{U}$ primarily undergoes fission only when exposed to high-energy (fast) neutrons. It predominantly captures slow neutrons, leading to the formation of $^{239}\text{U}$, which then decays to Neptunium-239 ($^{239}\text{Np}$) and subsequently to Plutonium-239 ($^{239}\text{Pu}$), a fissile material.

Therefore, $^{238}\text{U}$ is the nuclide among the choices that does not undergo fission with low energy (slow) neutrons.