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Nuclear Fission
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Nuclear Fusion
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| Splitting of a large atom into two or more smaller ones. |
Fusing two or more lighter atoms into a larger one. |
| It involves a chain reaction, which can lead to dangerous meltdowns. |
There is no chain reaction involved. |
| Does not usually occur in nature. |
Fusion occurs in stars, such as the sun. |
| Produces many highly radioactive particles (nuclear waste). |
The fusion reaction produces few radioactive particles, but radioactive particles will result if a fission "trigger" is used. |
| A critical mass of the substance and high-speed neutrons are required. |
High density, high-temperature environment is required. |
| Takes little energy to split two atoms. |
Extremely high energy is required to bring two or more protons close enough that nuclear forces overcome their electrostatic repulsion. |
| The energy released by fission is a million times greater than that released in chemical reactions. |
The energy released by fusion is three to four times greater than that in fission. |
| Used in an atomic bomb. |
Used in a hydrogen bomb, which uses a fission reaction to "trigger" a fusion reaction. |
| Fission is used in nuclear power plants. |
Fusion is an experimental power-producing technology. |
| Uranium and Plutonium isotopes are the primary fuel. |
Hydrogen isotopes (Deuterium and Tritium) are the primary fuel in experimental fusion power plants. |
| Nuclear waste, a by-product of fission, is an environmental challenge. |
There is no nuclear waste produced in a thermonuclear reactor. |