What is the difference between nuclear fission and fusion?

Nuclear fission involves splitting a heavy nucleus into smaller ones, while nuclear fusion involves combining lighter nuclei.

Nuclear fission and fusion are two types of nuclear reactions that release a large amount of energy. In nuclear fission, a heavy nucleus, such as uranium-235, is bombarded with a neutron, causing it to split into two smaller nuclei, releasing energy and more neutrons. These neutrons can then go on to split other nuclei, creating a chain reaction. This process is used in nuclear power plants to generate electricity.

In contrast, nuclear fusion involves combining two lighter nuclei, such as hydrogen, to form a heavier nucleus, such as helium. This process releases a large amount of energy and is the process that powers the sun. However, achieving nuclear fusion on Earth has proven to be difficult due to the high temperatures and pressures required to overcome the repulsive forces between positively charged nuclei.

While both nuclear fission and fusion release a large amount of energy, they have different advantages and disadvantages. Nuclear fission produces radioactive waste that can remain dangerous for thousands of years, while nuclear fusion produces no radioactive waste. However, nuclear fusion is currently not a viable source of energy due to the technological challenges involved in achieving it.