Column: What is "Nuclear Fusion"?

Nuclear fusion is the way the "Sun" produce energy.
If you knew that there's no oxygen in the Sun, you'll notice that the Sun is not actually burning, right?

There are two kinds of nuclear energy: fission and fusion.
Fission means producing energy by splitting an atom into two or more. It is held with heavy atoms, like Uranium (U).
Fusion means producing energy by combining two or more atoms into one. It is held with light atoms, like Hydrogen (H).

Just like marriage and divorce both takes a lot of energy.
hehehe...

Q: Why fission for heavy atoms and fusion for light atoms?
A: Because those atoms are unstable, and trying to become stable.
The atoms in the middle, like Iron (Fe) are very stable.

Q: Which is more effective to produce energy?
A: Fusion.
I don't like this example, but it is the difference of Nuclear Bomb and Hydrogen Bomb.

Q: Is it practically used?
A: NO.
The "Nuclear Power Plants" are all by fission.
It is very difficult to make an environment which allows to have fusion, since it requires more than 100 Million Kelvins.
At present, the ONLY possible way to make a fusion is the Hydrogen Bomb, which is triggered by fission to produce that extremely high temperature.

Q: When the fusion will be practically used?
A: About a century later.
It requires enormous amount of basic research.

Q: Is it safe?
A: I want to answer "Yes", but my answer is "No".
ITER is making a promotion that it is safer than fission reaction,
but the problems about flying neutrons, radioactive waste materials, etc. are still unanswered.
It is one of the big subject to research.

about ITER, click here.