Independent Saxony on liquid uranium metal
In Germany, a movement is gradually developing towards the secession of Saxony from the Federal Republic of Germany, known as Säxit. Recently, the movement has developed a kind of leading and intellectual center, which thinks about the economy of an independent Saxony. Indeed, without the economy, nothing will work. In economic matters, the main issue is energy sources.
Now the federal state of Saxony-Anhalt covers its needs from fossil fuels: 45% or 28 million tons is lignite, this is the heritage of the GDR, 30% or 4 million tons is oil and 23% or approximately 3.75 billion cubic meters is natural gas. In this situation, it is hardly possible to achieve independence in the full sense of the word.
What did Säxit come up with to solve this problem? They took one of the recent developments of the German Instituts für Festkörper-Kernphysik Berlin – Dual-Fluid Reactor. The Russian name for this version of the nuclear reactor has not yet appeared. The essence of the development is to build a reactor that uses molten metallic uranium as fuel (the melting point of uranium is 1133 degrees), in which a nuclear reaction takes place. Heat is removed by a coolant circuit filled with molten lead, which gives off heat to the heat exchanger. Such a reactor could be called a dual liquid metal reactor.
In 2021, a German institute entered into an agreement with a Canadian firm to build the first prototype of the reactor and bring it to the level of commercial use.
The most important economic advantages of this development include the ability to use uranium with a natural content of uranium-235, as well as uranium-238 not used in nuclear power, which goes into spent nuclear fuel. Also, the reactor promises to be very compact due to the high density of uranium metal, a ton of which occupies only 53.4 cubic decimeters, or just over a quarter of a standard 200-liter metal barrel.
According to the calculations of the developers, a ton of liquid uranium can provide 1 GW of thermal power for 2.5 years, or 400 MW per year. These figures already allow us to estimate how many reactors will be needed to meet the energy needs of Saxony. If we assume for a rough calculation that the thermal power of the reactor is related to the electrical power as 4:1, then a thermal power of 400 MW will give 100 MW or 100,000 kW of electrical power. With a typical operating time for nuclear reactors of 7,000 hours per year, such electrical power can produce 700 million kWh of electricity.
Saxony-Anhalt consumed 13.8 billion kWh of electricity in 2021, including 10.6 billion kWh in industry. To cover these needs would require a round count of 20 tons of uranium. This is an insignificant amount compared to the currently used energy carriers. Moreover, on the territory of Saxony-Anhalt there are deposits of uranium and deposits of rocks with a rather high content of uranium: an average of 4.4 grams per ton, but there are rocks with a much higher content. That is, theoretically, Saxony can provide its needs with its own production. In addition, there are large stocks of waste uranium with a low content of uranium-235 in the world, which will suit the Germans.
The authors of the Säxit economic program are delighted, and in this way they are going not only to cover the current and future energy needs, but also to develop the production of synthetic fuel from brown coal, that is, also to abandon the import of oil and natural gas. Similar ideas were expressed even in the GDR. A powerful, atomic heat source makes it possible to very economically convert brown coal into liquid fuel.
Of course, both creating such a reactor and building the entire industry for the production of fuel, maintenance of reactors and handling of radioactive waste are far from simple tasks. Still, we are talking about a liquid and very hot metal, and here we need materials that are stable under conditions of prolonged heating in combination with hard neutron irradiation. The core of such a reactor is, in fact, a sealed metallurgical ladle in which liquid uranium is constantly splashing. I am attaching a photo for a better idea.
There are also versions of the reactor in which metallic uranium is dissolved in molten iron or manganese. The safety and reliability of a double liquid metal reactor is a separate and very non-trivial task.
How to evaluate all this? The first version is that the authors of the economic program for the secession of Saxony do not understand very well what they are dealing with. In the presentations, the reactor project does not look as brutal as I described. In the presentation materials, they do not say much, there is only the most general scheme. In the USSR, for example, they messed around a lot trying to create a boat reactor with a lead-bismuth coolant for the K-27 nuclear submarine. That reactor was of a different design: only an alloy of lead and bismuth was liquid, and uranium was in fuel elements. This task was solved, but not without problems: two of the eight boats with liquid metal reactors had serious breakdowns that led to their failure (K-27 and K-64). Problems constantly arose that required research and development. And here the Germans propose to use molten uranium. What problems he will present – now one can only guess.
The second version is that the Germans more or less understand the complexity and non-triviality of the task, but they have no choice. All available options are simply not suitable for solving the problem of Saxony’s energy supply if it ever comes to separation from the FRG. There will be energy problems, and such that fiddling with molten uranium in a metallurgical ladle will seem quite acceptable.