India develops thorium-based weapons

Nuclear Energy: Thorium Reactors: Safe Energy Sources of the Future?

When it comes to nuclear energy, opinions differ widely. What appears to some to be the solution to energy problems is to others as the devil's stuff. It is therefore worthwhile to look at the facts soberly first. Even if Germany is pushing ahead with the nuclear phase-out, many countries, including in Europe, are still using nuclear energy and are investing in new types of reactors, among other things. A new variant that has been particularly hotly debated recently are the so-called thorium reactors, which use the chemical element thorium rather than uranium as fuel.

In this video on the YouTube channel "Terra X Lesch & Co" produced by ZDF, the astrophysicist and well-known moderator Harald Lesch addresses numerous aspects of thorium reactors with a skeptical undertone. In view of the necessary brevity and the complex topic, this is not easy to cope with, even for an experienced physicist like Lesch.

You can see that from the fact that the editorial team decided to publish the video again with minor corrections after receiving queries from viewers. In doing so, she responded to the comments in a pleasingly consistent and technically clean manner. But of course, many questions still remain open, the aspects range from basic nuclear physics to geopolitics.

Thorium is found in the earth's crust more often than uranium, which makes it interesting for the nuclear economy. However, it cannot be used directly for nuclear fission. Rather, it first has to be converted into the isotope uranium-233 in a nuclear reactor by absorbing a neutron - and through further intermediate stages. This isotope, which does not occur in nature and consists of 141 neutrons and 92 protons, can be split easily and provides a similar amount of energy as the naturally occurring uranium-235, with which nuclear reactors are usually operated. Another advantage of uranium-233, which is somewhat lighter, is that less long-lived, highly radioactive waste material is produced and therefore less material has to be disposed of. No wonder, then, that some countries are interested in thorium technology and are investing in its research and development.

However, the video does not address an important point that nuclear energy experts are discussing intensively: Thorium reactors could also make novel atom bombs possible. With certain techniques it is possible to extract the explosive uranium-233 isotope from the reactor before it is split. The notorious, highly radiotoxic plutonium-239 is mostly used for today's atomic bombs. Uranium-235 was also of historical importance, for example the Hiroshima bomb was based on it. In the early years of the Cold War, however, researchers found that uranium-233 would also be an excellent bomb substance. Certain amounts of this substance were even produced on a trial basis, but then mainly used as fuel for reactors.

According to more recent research results and contrary to previous assumptions, thorium reactors should even be very suitable for the production of weapons material. Some experts have therefore already warned against their development.