Nuclear Energy: The Nuclear Reactors of the Future


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Status: 04/16/2023 07:01 a.m

New reactor types should become safer, more efficient and cleaner. The trend is towards new coolants and smaller reactors, which are intended to stabilize the power supply in a decentralized manner.

Generation IV – that’s what the nuclear reactors are called that are supposed to replace the current ones. Above all, they should be safer, but also more efficient and produce less highly hazardous nuclear waste.

Most of the reactors built to date are water-cooled. The dissipated heat is then used to produce electricity. A disadvantage of this is that the cooling water has to be kept constantly moving and has to be cooled down again in order not to evaporate. Otherwise it cannot continue to cool the reactor. A power failure can lead to a meltdown. The developers of these new reactors want to prevent this, among other things, by replacing the water with other coolants.

Newer reactors are said to be cooled with liquid metal such as sodium or lead, or liquid salt. These coolants can continue to passively cool the reactor – without evaporating – even if the cooling system fails completely. The nuclear disasters of Chernobyl and Fukushima would have been very different with such reactors, a core meltdown would probably not have happened in either case.

Less high-level radioactive waste

Such reactors can also be operated as “fast reactors”. The fast neutrons released by nuclear fission are used directly to maintain the chain reaction instead of being intercepted as in most older reactor types. As a result, the reactor produces more energy with the same amount of fuel.

In addition, no so-called transuranium waste should be produced, i.e. substances that are heavier than uranium. It is the transuranic waste from classic reactors that remains dangerous for several hundred thousand years. The waste from “fast reactors”, on the other hand, only has to be stored safely for a few hundred years. Still a long time, but much more manageable. That would also simplify the requirements for a repository.

Smaller but more reactors

The trend in nuclear power is also towards smaller reactors that are mass-produced. They are called SMRs or small modular reactors. The individual components are produced in a factory, from where they are transported by truck or train to the power plant site. This is how routine should be created. The power plants should be able to be built more cheaply and quickly.

Of course, the new generation of reactors also have disadvantages. SMRs are much smaller than classic reactors. As a result, they are less efficient, a possible efficiency advantage of “Fast Reactors” may be lost again, and they produce less energy. A city like Stuttgart alone would need two such reactors. This requires more locations, which are already difficult to find, and radiative material needs to be further distributed.

Future reactors also harbor dangers

Liquid sodium is very reactive. If it comes into contact with oxygen, it starts to burn. When it comes into contact with water, it produces hydrogen, which can ignite in air and cause an explosion.

The lead alloys in lead-cooled reactors can harden if they get too cold. This makes the reactor unusable and possibly a billion dollar grave.

And every reactor relies on its manufacturer’s special fuel. In this way, many power plants of Russian design in Eastern Europe are dependent on Russia in terms of energy, analogous to the gas crisis here. In theory, a universal fuel would be conceivable, at least for reactors that function in a similar way, but manufacturers are unlikely to let this additional revenue stream slip away.

Another risk is that many fast reactors are so-called breeder reactors. On the one hand, this leads to greater efficiency, but in the course of combustion, weapons-grade plutonium is also produced. So which countries should have access to such technologies must be checked very carefully.

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