Is Nuclear Energy The Best Future’ Solution?
Five fundamental points about this technology you have to consider.
Recently the EU has included the nuclear energy as a clean and green energy, but in fact it is not. It does not emit Co2, except for the construction of the plant and the mining of the resources, but it cannot be defined as ‘clean’, because it has negative impacts on the surrounding environment. The plants in operation today exploit only the energy released in the fission reactions. Although there are several ongoing experiments, in fact, there are still no fusion reactors that are able to release more energy than they absorb. But fission reactors, of any generation and size, are based on a reaction that produces fission fragments, isotopes of chemical elements lighter than the uranium from which they started and which are unstable, radioactive. Let’s imagine the nucleus of an atom of a heavy element (uranium, thorium, plutonium) as a charged firecracker which just a tap is enough for it to burst. The tap gives it a neutron. By bursting, splinters are produced that interact with what is around and their energy is transformed into heat used, as in a thermal power plant, to produce steam and electricity.
What do we do with the radioactive waste?
We can only put them somewhere, but the problem is understanding where and for how long since they are harmful to the biosphere and, in particular, to human beings. Once you have found a site, you cannot be sure that, in the next hundreds or thousands of years, the water that melts things and carries them around will not arrive or that no one is going to put their nose in it. Definitive solutions have never been found: most of the waste produced so far in the world is in temporary deposits. Even if the reactors worked perfectly, we would have an advantage for a few decades, leaving a legacy for centuries or millennia for future generations.
The Most Safe
There are no safe machines or machines that never fail. In Chernobyl it is not that the reactor did not work well, but they conducted an unplanned experiment, thinking of checking what was going on by hand. Who can design a foolproof reactor? Nobody. Who can design a machine that never fails? Nobody. I hear about one chance of an accident in a hundred thousand. This is not correct, as Chernobyl, Fukushima, Three Mile Island and Windscale in England also demonstrate, and the scale of the damage, in the event of an accident, is far in excess of the size of the reactor. Those that tend to shut down by themselves and contain the damage inside are considered ‘safe’, but the problem of the reactor that remains there, as a monument to human stupidity, is not solved. At Three Mile Island the reactor was dismantled, it took over twenty years to decide what to do and the residues are in one of the temporary deposits used for waste. For posterity.
The distinction by generation is more of a narrative. The reactors differ according to the fissile material that is placed in the core (the fuel), the moderator (water, heavy water and graphite) which slows down the speed of the neutrons, increasing the chances of producing a chain reaction or the coolant which collects the heat produced: gas, light, heavy water, boiling water, under pressure, liquid metals (sodium or lead) or molten salts. The fourth generation will not be ready for ten years: water is replaced as a coolant by fluids that allow you to work at higher temperatures and lower pressures. Helium, molten salt, liquid metal (sodium and lead) refrigerated reactors are being studied, aiming to recycle waste to produce fuel. And there is a lot of interest in ‘fast’ neutron reactors that are supposed to burn waste.
But at the end of the day, the main characteristic of fourth generation reactors is that they do not exist. These are projects, of various types, in which it would be thought of implementing certain measures to make them safer. But we always talk about fission, none of the problems we talked about disappears, besides the fact that fast reactors have more control and safety problems.
The other ‘hope’ is in the fusion. There are several projects carried out around the world. The largest is called Iter, the construction of the reactor is underway in Cadarache, France, but the EU, USA, Russia, China, Japan, India and South Korea participate in it.
Unlike fission, fusion occurs between the lightest and most compact elements on the periodic table. Two isotopes of hydrogen, deuterium and tritium, can approach each other, but the nuclei of the electrically charged atoms do not want to approach. With ‘force’ we can trigger a physical mechanism: the isotopes lose their electrons and fuse into the plasma, which must be brought to temperatures of tens of millions of degrees containing it in magnetic fields. In the end, as we said, the energy released is less than that absorbed. I am in favor of research to understand how to control plasma, but not to subtract funds from more useful areas, nor to sell fusion as an operational solution to the problem, fueling the illusion of an infinite and clean source of energy. Even if a way was found to produce more energy than absorbed, the reaction is based on deuterium (in nature there is approximately one atom of deuterium for every 6400 of hydrogen) and tritium, which in nature there is not. Even if it is found in traces, it is unstable and decays in a few years. To make a fusion machine work, a production chain would be needed. One way to obtain it is to break the nucleus of an isotope of a slightly heavier element, lithium, which splits into a helium and a tritium nucleus. A fission to obtain tritium, which would then be used (together with deuterium) in the fusion.
It’s pathological. Lithium is much less abundant than deuterium and is used for various purposes (from electric car batteries to smartphone batteries). And the conditions of the lithium mines are not very different from those of uranium. Once the fusion has taken place, then, neutrons are also emitted, absorbed by what is in the machine. Even for these radioactive materials there would be the problem of dismantling and storage, to be left to those who will come after us.
We have to question the mechanisms underlying the economy, which push governments to treat energy as a commodity that is bought and sold. And since there is a great hunger for it, it is worthwhile to produce it anyway. But energy is a vital resource and must be used from long-lasting sources, sun, tides, wind, geothermal. We need to focus on stabilizing energy volumes and reducing consumption, because any other mythical solution leads to depleting the planet’s reservoir with impacts on the living conditions of all humanity and future generations.