Nuclear energy is something fascinating, but also something that is very misunderstood, from almost every side of the argument.
There are two kinds of nuclear reactions that we are currently trying to use to produce energy: nuclear fission, the splitting of large unstable atoms, and nuclear fusion, the building up of larger atoms.
Fission is currently the only one that we’ve had much success with. The reactors that provide something like a fifth of the US’s energy are fission reactors. It produces a huge amount of energy from a tiny amount of mass; in a fission reaction, neutrons are slammed into unstable nuclei such as uranium-235 and in the resulting split of the nucleus, a small amount of mass is actually “lost” or converted to energy. Remember E = mc2? No matter how small the mass is, once we multiply it by the square of the speed of light, it becomes significant.
There is a great deal of danger associated with fission reactors, though.
The Chernobyl disaster, Three Mile Island near miss, and Fukushima 1 disaster all occurred in fission reactors.
Additionally, another type of fission reactor, called the breeder reactor, can be even more dangerous. It creates fissile material from nuclear wastes, which is why it is an attractive option; however, some varieties also require the use of liquid salts or metals as coolant, rather than the currently-used water. In the case of a leak, the catastrophe would be many times worse than in a current fission reactor.
So let’s talk about nuclear fusion.
Nuclear fusion really isn’t viable at the moment; our longest fusion burns so far have been around five minutes, if I recall correctly, and it takes a pretty ridiculous amount of power to start a reaction. And we can’t just produce energy from water; anyone who says that is misinformed. We need deuterium and tritium, which are isotopes of hydrogen that can be isolated from water in small amounts.
However, there are significant benefits to fusion.
The picture above shows a tokamak reactor, which confines fusion plasma with an external magnetic field. Z- and theta-pinches have also been investigated; these use the plasma’s own magnetic field to confine the reaction.
The good thing about a tokamak is that even in initial experiments with an unreliable confinement system, there was never even a minor accident. As soon as the confinement fails and the plasma begins to exit the tokamak, the reaction stops automatically. Thus, a major disaster from a tokamak is incredibly improbable, and a disaster like Chernobyl, where the reaction continued for weeks after the initial breach, would be impossible.
Similarly safe is a cylindrical reactor produced by Lockheed Martin’s Skunk Works. They hope to have fusion power working in four years and on the market in a decade and a half.
So we just have to develop stuff a little.
— John 2