Its use in atomic bombs for military purposes.
In general, physicists, and specifically nuclear physicists, use nuclear fission in experiments.
Fission
Nuclear reactors use nuclear fission.
There are no pros or cons of nuclear fission, it simply IS. Nuclear fission is a natural phenomena that has always existed, no matter how much one likes or dislikes it.However there are pros and cons to how humans choose to use or not use nuclear fission; the technologies we choose to build with it.
In nuclear fission reactors
We can use plutonium in nuclear fission devices.
Yes. Nuclear power plants and nuclear powered ships and submarines use controlled fission reactions.
We use nuclear energy on a limited basis due to its instability. One reason we do not use it more is because the energy is not sustainable. There are two types of nuclear fission. Hot fission and cold fission. Hot fission is currently the only method we know how to utilize. Cold fission produces approximately 10 times the energy and produces fewer radiation spikes. We simply do not know how to initiate cold fission.
One use is in nuclear power plants to produce steam and turn turbines to generate electricity.Nuclear bombs ^.^
We don't know much about fusion as it is still very experimental. It will not produce the dangerous fission products that fission does, but it may have other dangers unknown as yet. Nuclear fusion has more destructive potential than fission. Fusion is the principle powering the H-bomb developed in the Cold War. Just to put the power of a Fusion bomb in perspective, it is detonated by a fission bomb half the size of the one dropped on Japan. THAT'S JUST THE DETONATOR.
Fission bombs. They use one or more of 3 fuels: Uranium-233, Uranium-235, or Plutonium-239.
Nuclear fission is defined as splitting large nuclei into smaller ones.