In nuclear fission, which form of energy accounts for the largest fraction of the total energy released per fission event?

Introduction / Context:
Understanding the energy partition in nuclear fission is essential for reactor heat balance, shielding, and safety analysis. A typical fission of U-235 releases around 200 MeV, distributed among various carriers such as fragment kinetic energy, gamma rays, neutrons, and decay energy.

Given Data / Assumptions:

• We focus on the immediate and subsequent energy forms following a fission event.
• Ballpark values: the largest share appears as kinetic energy of the two main fission fragments.
• No numerical calculation is required beyond qualitative comparison.

Concept / Approach:
When a heavy nucleus splits, the two nascent fission fragments repel each other due to strong Coulomb forces, acquiring substantial kinetic energy. This fragment kinetic energy is rapidly converted into heat in the fuel. Smaller fractions are carried by prompt gamma rays, kinetic energy of neutrons, and later by beta and gamma emissions from radioactive decay of fission products. Antineutrinos carry away energy but do not deposit it in the reactor core. Thus, the largest single component is the kinetic energy of the fission products.

Step-by-Step Solution:
List the main energy carriers: fragment kinetic energy, neutron kinetic energy, prompt gammas, delayed decay energy, antineutrinos.Recall typical partitioning: fragment kinetic energy is the dominant portion.Select the option that names fission product kinetic energy as the maximum contributor.

Verification / Alternative check:
Introductory reactor physics texts and heat balance tables consistently show fragment kinetic energy forming the majority share (often on the order of 160+ MeV out of ~200 MeV for U-235 fission), with other components much smaller.

Why Other Options Are Wrong:
Radioactive decay of fission products: significant but smaller than fragment kinetic energy.Instantaneous gamma rays: contribute a modest fraction.Neutron kinetic energy: a relatively small portion.Antineutrinos: energy is not recovered as heat; they escape.

Common Pitfalls:
Overestimating the role of prompt gammas or decay heat relative to the dominant fragment kinetic energy in immediate core heating.

Final Answer:
Kinetic energy of fission products (heavy fragments)