What is the different between nuclear fusion and nuclear fission?

Answer 1

Difference between fusion and fission

Nuclear fusion is taking two atoms and combining them in to one atom, while nuclear fission takes one atom and splits it into two atoms.

Both reactions involve the nucleus of an atom, and in both reactions, lots and lots of energy are released. Other than that, the two reactions are pretty much opposite. Fission involves the splitting of an atomic nucleus. Fusion involves the fusing of two or more units to create a new, heavier nucleus.

Links are provided to articles on both subjects that have been posted by our friends at Wikipedia, where knowledge is free.

In nuclear fusion two lighter nuclides fuse (join together) to form a heavier nuclide.

In nuclear fission one heavy nuclide splits into two smaller ones. These two are not necessarily identical.

Nuclear fission releases energy only if the resulting nuclides are as heavy as or heavier than Iron40.

Fusion releases energy only if the resulting nuclide is as light as or lighter than Iron40.

It is possible to make elements heavier than Iron40 by fusion, but these reactions are strongly endothermic ( which means that a great deal of energy must be supplied from an external source). This can be done in an accelerator, but the process takes place in any quantity only in an exploding star.

Nuclear fission is when a large nucleus such as uranium or plutonium splits into two smaller nuclei. When Uranium with an Atomic Mass of 235 absorbs a neutron and becomes Uranium 236 (its critical mass) it splits into two nuclei releasing loads of energy.

Nuclear fusion is when two small nuclei (smaller the iron) fuse together to make a bigger one. The high energies and pressures are needed are very hard to recreate on earth because if you think about it the sun is hot because nuclear fusion is happening inside so we have to create the sun on earth. The only place fusion can happen naturally in stars. Fusion releases even more energy than fission. Most fusion happens between two hydrogen atoms to make a helium atom.

Deuterium is hydrogen with one proton and one neutron (normal hydrogen is 1 proton only). Tritium is Hydrogen with two neutrons and one proton. These particles are what form hydrogen. If you add up the number of particles you will notice that one neutron is left over in the making of helium. This is turned into the massive amount of energy released in a fussion reaction and relased as light but mostly heat.

Nuclear fision is the splitting of atoms and fusion is the combining of atoms

Answer 2

Fusion is when something is being put together, or fused together. Fission is where things are being pulled apart.

Answer 3

Fusion means to combine light atoms into heavier atoms.

Fission means to split heavier atoms into lighter ones.