Nuclear energy today and in the future

Phew, it's warm! I'll have to get into the shade soon, or I'll turn to steam. Mmm. Hey, where does it all come from, anyway? I mean, how does the sun make so much heat and light?

It's called fusion. Atomic nuclei smash together and give off energy. Aha! Like in a nuclear power plant, then. No, that is fission.

This is a completely different thing. How's that, a different thing? Well. Um... Well, imagine that the tangerines are protons, and the kiwis are neutrons -- The sun consists mostly of the elements Hydrogen and Helium.

Those are the smallest and lightest of all atoms. What happens in the sun is that light atom nuclei crash into each other and create heavier atoms with larger nuclei. Hydrogen nuclei create helium nuclei. But then something interesting happens. If you weigh the two hydrogen nuclei that merge together, and then weigh the helium nucleus that's created...

the weights don't quite match. The helium nucleus weighs slightly less. The weight that's missing has been turned into energy: into heat, light, and the radiation that gives you sunburn. So: when two nuclei bind together... ... and make a larger nucleus... ...

while at the same time releasing energy, it's called fusion. In a nuclear power station however, very heavy atoms are used, usually uranium. When an uranium nucleus is hit by a neutron, the uranium nucleus is split, and two lighter nuclei are created, plus free neutrons. And the same thing happens as during fusion. If you weigh the neutrons and the nuclei that are formed during the split -- and compare with the large uranium nucleus we initially had -- we see that some mass is missing.

The mass that's missing has become energy. Kinetic energy in the two new nuclei and the free neutrons. That energy is then transformed into heat, which in turn is used to generate electricity. This is called fission, when atoms are split. But hey?

Does it have to be fission in a nuclear power plant? That's pretty dangerous and tricky. Can't we use fusion instead? Yeah... Crack that one and you'll get a Nobel prize.

Promise! Why? Well, fusion energy has several great advantages, compared to fission energy. Fuel can be made from ordinary sea water and a metal called lithium that's pretty common. Less than one gram of fuel is enough to cover one person's energy usage for a whole year!

You don't end up with lots of radioactive waste... ... and there's no chain reaction that could become dangerous. But if it's so good, why don't we have any fusion power plants? Because... there has to be high pressure, and a temperature of fifteen million degrees celsius for it to work.

Like in the sun. Some scientists are working hard to develop fusion power plants on Earth. Others prefer the idea of trying to make the fission power plants work better than they do now. -- In that case, we might get a hundred times more energy from the fuel than with current technology, and hopefully we won't have the problem of storing the dangerous waste for such a long time. Right, so then fission power plants wouldn't be so bad... ? If they could get better and better...

But what about fusion! Imagine providing your whole life's energy needs with a couple of drops of water. Yeah -- And win a Nobel Prize while at it.