Question

Explain the difference between nuclear fission and nuclear fusion.

Hint:

Fusion is the source of energy in stars; fission is widely used in nuclear power plants.

Answer 1

Step 1: Nuclear fission is a process in which a heavy atomic nucleus (such as uranium-235 or plutonium-239) splits into two or more lighter nuclei, along with the release of a large amount of energy and free neutrons. The energy released comes from the conversion of a small amount of mass into energy, as described by Einstein’s equation \( E = mc^2 \). The emitted neutrons can initiate further fission reactions, leading to a chain reaction which is the basis of nuclear reactors and atomic bombs.
Step 2: Nuclear fusion is a process where two light atomic nuclei (typically isotopes of hydrogen such as deuterium and tritium) combine to form a heavier nucleus (such as helium), releasing an enormous amount of energy in the process. Fusion is the energy source of the sun and other stars. The energy yield from fusion is significantly greater than that from fission. However, achieving the extremely high temperatures and pressures required to initiate and sustain fusion reactions makes it technologically challenging.
Step 3: Both fission and fusion are sources of nuclear energy, but they differ in their mechanisms and practical applications:

Nuclear fission is currently used in nuclear power plants for electricity generation.
Nuclear fusion is still under experimental development but holds promise as a cleaner and more abundant energy source for the future.
While fission produces radioactive waste, fusion produces minimal long-lived radioactive byproducts, making it more environmentally friendly if harnessed successfully.