The American company X-energy has developed a new type of nuclear fuel with built-in protection against one of the most dangerous phenomena in the operation of nuclear power plants - melting of the core of a nuclear reactor. Officially, the new product is called TRISO-X FUEL, but the developers themselves called them "uranium balls" or "uranium candies", because of the characteristic shape. Most of all, this type of fuel resembles numerous candy-coated tablets in a glaze.
The idea is to surround the nuclear energy source, released in the form of heat, with such a heat-resistant shell that it does not collapse in critical situations. The ideal material is ceramics, which accumulates a huge amount of heat and can give it out, but does not deform even with prolonged heating. And in order to reduce dangerous radiation, a layer of graphite is added between the core and the shell. The fuel cell is shaped like a sphere, which further enhances the candy-like appearance.
To produce such a fuel, uranium is mixed with a chemical reagent that divides the entire mass into many tiny balls, about 1 mm in diameter. The balls are fed into the furnace with gaseous graphite, which is deposited on the uranium, forming the first protective layer. Thousands of balls are then packed into individual granules and sealed in a ceramic shell.
Such fuel is considered as the main raw material for low-power mobile nuclear reactors of the future. In modern stationary nuclear power plants, the lion's share of all equipment belongs to safety and protection systems. If it is possible to reduce risks and eliminate a number of dangers, this will open the way to minimizing the design of nuclear power plants and the emergence of a new generation of powerful and efficient reactors.