Differences between Nuclear Fission and Nuclear Fusion

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Nuclear Fission vs. Nuclear Fusion[edit]

Nuclear fission and nuclear fusion are two distinct types of nuclear reactions that release large quantities of energy.[1] Fission is the process of splitting a heavy, unstable atomic nucleus into two smaller ones.[2] Conversely, nuclear fusion is the process where two light atomic nuclei combine to form a single heavier nucleus.[3] While both processes are used in energy production, their underlying principles, applications, and byproducts differ significantly.

Comparison Table[edit]

Category Nuclear Fission Nuclear Fusion
Process Splitting a heavy nucleus into lighter nuclei.[2] Combining two light nuclei to form a heavier nucleus.[2]
Fuel Typically heavy elements like uranium-235 and plutonium-239.[4][5] Typically light elements like deuterium and tritium (isotopes of hydrogen).[2][3]
Energy Release Releases a large amount of energy, but less than fusion on a per-mass basis. Releases several times more energy per kilogram of fuel than fission.
Natural Occurrence Does not typically occur naturally, though some radioactive elements undergo spontaneous fission.[5] Occurs in stars, including the Sun.[4]
Byproducts Produces long-lived radioactive waste. Primarily produces helium, an inert gas, with some short-lived radioactive material like tritium being produced and consumed within the reactor.
Current Applications Used in nuclear power plants for electricity generation and in nuclear weapons.[5] Primarily experimental, with research focused on developing fusion reactors for power generation. It is also used in thermonuclear weapons.[2]
Control The chain reaction can be controlled and sustained in nuclear reactors.[4][2] Reactions are difficult to sustain due to the extreme temperature and pressure required.[4][3]
Venn diagram for Differences between Nuclear Fission and Nuclear Fusion
Venn diagram comparing Differences between Nuclear Fission and Nuclear Fusion


Nuclear Fission[edit]

Fission reactions are initiated by bombarding a heavy nucleus, such as uranium-235, with a neutron. This causes the nucleus to become unstable and split into smaller nuclei, known as fission products, while also releasing additional neutrons and a significant amount of energy.[2] If these released neutrons strike other uranium-235 nuclei, they can trigger a self-sustaining chain reaction. This controlled chain reaction is the principle behind nuclear power reactors, which harness the heat produced to generate electricity.[4] Fission is a mature technology used for commercial power generation and has applications in medicine and research.[3] A primary concern with fission is the production of radioactive waste, some of which remains hazardous for thousands of years.

Nuclear Fusion[edit]

Fusion reactions involve the merging of light atomic nuclei, such as the hydrogen isotopes deuterium and tritium, under conditions of extreme temperature and pressure.[3] This process, which powers the sun and other stars, results in the formation of a heavier nucleus, like helium, and the release of a substantial amount of energy.[4] Fusion is considered a potentially cleaner and more sustainable energy source than fission because its fuel is abundant and it does not produce long-lived radioactive waste.[2] However, achieving and maintaining the necessary conditions for a sustained fusion reaction on Earth presents significant technological challenges. Research into controlled fusion is ongoing, with the goal of developing commercially viable fusion power plants in the future.[2]


References[edit]

  1. "libretexts.org". Retrieved November 15, 2025.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 "orano.group". Retrieved November 15, 2025.
  3. 3.0 3.1 3.2 3.3 3.4 "energy.gov". Retrieved November 15, 2025.
  4. 4.0 4.1 4.2 4.3 4.4 4.5 "wikipedia.org". Retrieved November 15, 2025.
  5. 5.0 5.1 5.2 "twi-global.com". Retrieved November 15, 2025.