Nuclear fission is the physical process where the heavy nucleus of an atom splits into two or more smaller nuclei while releasing a massive amount of energy. First discovered in 1938 by scientists Otto Hahn, Lise Meitner, and Fritz Strassmann, it serves as the foundational mechanism behind all modern commercial nuclear power plants and atomic weapons. How Nuclear Fission Works
Nuclear fission generally occurs when a heavy, relatively unstable isotope is struck by a particle, though it can occasionally happen spontaneously.
Neutron Bombardment: A slow-moving, free neutron collides with a heavy “fissile” nucleus, such as Uranium-235 (U-235).
Absorption and Instability: The nucleus absorbs the incoming neutron, briefly transforming into an highly unstable isotope (U-236).
The Split: To regain stability, this compound nucleus violently splits into two lighter atoms known as fission products (commonly Barium and Krypton).
Neutron Release: The split simultaneously ejects two or three free neutrons along with high-energy gamma photons.
The Chain Reaction: If there is enough fissile material nearby (known as critical mass), those newly freed neutrons collide with neighboring uranium atoms, initiating a self-sustaining nuclear chain reaction. The Source of Energy (E=mc²) DOE Explains…Nuclear Fission – Department of Energy
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