A new alloy has been developed to enhance nuclear fusion reactors, paving the way for limitless energy.

Japanese scientists have developed a new alloy with high heat resistance that could address many challenges in nuclear fusion reactors, where nearly limitless energy will be generated. These reactors can replicate conditions similar to those found in the core of the Sun, producing fusion energy that is clean and virtually boundless. In their experiments, the new alloy withstood the corrosive coolants used in fusion reactors. These coolants are employed to help generate more fuel needed for the reactors. The research was published in the journal Corrosion Science, as reported by Popular Mechanics.

The researchers started with an existing heat-resistant alloy from the Kantal category, composed of iron, chromium, and aluminum. They then added aluminum oxide to enhance its strength and resistance to high temperatures and corrosion. The oxide dispersion strengthened alloy (ODS) was coated with additional aluminum oxide to test the combined heat resistance of the fully assembled material.

The treated alloy endured turbulent liquid metal at a temperature of 600 degrees Celsius. The scientists also tested the coating for delamination and found that even at high temperatures, it remained firmly attached to the ODS alloy base. According to the researchers, even the bare version of the ODS alloy, without the additional aluminum oxide coating, spontaneously formed its own outer layer, which they believe contributed to its high heat resistance. Essentially, it did not melt, peel off, or weaken.

Why is the temperature of 600 degrees Celsius critical in this context when plasma temperatures in a nuclear fusion reactor can reach millions of degrees Celsius? In this case, the study focused on the coolants rather than the temperatures of the plasma in a tokamak (a type of nuclear fusion reactor).

The scientists are using liquid metals, such as lithium-lead alloy, to serve two purposes. Firstly, they help initiate the nuclear fusion reaction that generates more deuterium or tritium, which are the fuels for the reactor. In other words, they provide the fuel necessary to start the fusion reaction. Deuterium and tritium are isotopes of hydrogen, which the Sun uses to create fusion energy. Secondly, liquid metals act as protective coolants.

As the scientists explain, heavy liquid metal coolants, such as lead, lead-bismuth alloy, and lithium-lead alloy, are corrosive fluids despite their excellent thermal resistance properties. Corrosion is a process where even relatively stable metals seek and absorb oxygen particles, ultimately leading to oxidation, or the formation of oxide patches.

Since corrosion is inherent to liquid metal cooling fluids, the scientists sought ways to seal any materials that come into contact with them for protection. In this experiment, the prepared ODS alloy sample with the aluminum oxide coating withstood corrosion. This means that future nuclear fusion reactors will be significantly stronger and more efficient in generating limitless energy.

For comparison, the crystalline form of aluminum oxide becomes rubies and sapphires, which are variations of the mineral corundum. This mineral is the second hardest after diamond.