Neutron-induced fission

Definition

Neutron-induced fission is a nuclear reaction in which the nucleus of an atom splits into two or more smaller nuclei, along with the release of energy, when it absorbs a neutron. This process is critical in nuclear reactions, particularly in nuclear reactors and atomic bombs, as it can lead to a chain reaction that sustains further fission events.

5 Must Know Facts For Your Next Test

1. Neutron-induced fission typically occurs with heavy nuclei like uranium-235 or plutonium-239, which are capable of absorbing neutrons and undergoing fission.
2. The process releases a significant amount of energy, primarily in the form of kinetic energy of the fission fragments and gamma radiation.
3. Each fission event can release additional neutrons, which can go on to induce further fission in nearby nuclei, leading to a self-sustaining reaction.
4. Nuclear reactors use controlled neutron-induced fission to produce energy for electricity generation, where control rods are used to regulate the number of neutrons available for further fission events.
5. In atomic bombs, neutron-induced fission occurs in an uncontrolled manner, resulting in a massive and rapid release of energy.

Review Questions

• How does neutron-induced fission contribute to sustaining a chain reaction in nuclear physics?
  • Neutron-induced fission contributes to sustaining a chain reaction by releasing additional neutrons when a nucleus splits. These emitted neutrons can then be absorbed by other fissile nuclei, inducing further fission events. This self-propagating cycle allows for continuous energy release as long as there is sufficient fissile material present. Thus, neutron-induced fission is essential for both controlled reactions in nuclear reactors and uncontrolled reactions in atomic explosions.
• Discuss the role of uranium-235 in neutron-induced fission and its significance in nuclear reactors.
  • Uranium-235 plays a crucial role in neutron-induced fission because it is one of the few naturally occurring isotopes that can sustain a chain reaction. In nuclear reactors, uranium-235 is used as fuel due to its ability to efficiently absorb neutrons and undergo fission. The design of reactors ensures that enough uranium-235 is present to maintain the critical mass needed for the reaction while allowing for control mechanisms that regulate the rate of fission. This makes uranium-235 essential for generating controlled nuclear energy.
• Evaluate the implications of neutron-induced fission on energy production and global security.
  • Neutron-induced fission has significant implications for both energy production and global security. On one hand, it provides a powerful source of energy through nuclear reactors, contributing to electricity generation with lower greenhouse gas emissions compared to fossil fuels. On the other hand, the same process is utilized in the development of nuclear weapons, posing risks related to proliferation and geopolitical tensions. As nations pursue nuclear technology for energy, it raises concerns about the potential for misuse and the need for strict regulatory frameworks to ensure safety and prevent nuclear conflict.

Related terms

Chain reaction: A sequence of reactions where a reactive product or by-product causes additional reactions to occur, allowing the process to continue indefinitely.

Uranium-235: An isotope of uranium that is fissile and can sustain a neutron-induced fission chain reaction, commonly used as fuel in nuclear reactors.

Critical mass:

The minimum amount of fissile material needed to maintain a sustained nuclear chain reaction.