Unlimited energy? France's reactor sets a new benchmark in nuclear fusion

Nuclear fusion technology could drastically change our energy landscape. By mastering the merging of atomic nuclei, scientists are opening the door to a revolutionary energy source. As reported by National Geographic, the French WEST fusion reactor kept plasma at approximately 50 million degrees Celsius for six minutes, a temperature much higher than the Sun's core, which is around 15 million degrees Celsius.

Scientists from the Princeton Plasma Physics Laboratory made this achievement. While setting a new record is a crucial step towards harnessing nuclear fusion technology, it's essential to recognize that constructing power plants based on this technology will likely take several more years. Understanding how to keep plasma stable for hours, not just minutes, is vital.

Nuclear fusion replicates processes happening at the core of the Sun. It involves hydrogen atoms merging to form helium, releasing a vast amount of energy more remarkable than that from nuclear fission. National Geographic notes that one kilogram of fusion fuel, predominantly deuterium and tritium, can generate energy fourteen million times that of a kilogram of coal without producing greenhouse gases. This underscores nuclear fusion's potential as a limitless and clean energy source.

Luis Delgado-Aparicio, the director of advanced projects at PPPL, likens nuclear fusion to creating an "artificial Sun on Earth," a task of incredible difficulty. Due to the lower pressure environment for fusion on Earth, achieving higher temperatures than those at the Sun's core is necessary.

Moreover, scientists are challenged with maintaining the nuclear fusion reaction, which can rapidly extinguish, particularly if the fuel mixture becomes contaminated. Ensuring fusion longevity is also crucial – the process must last long enough to produce more energy than is required to heat the plasma to the requisite temperature. Although the latest record showed a 15% increase in power compared to previous attempts, achieving net energy production remains elusive.

With their distinctive doughnut shape, Tokamaks rely on a powerful magnetic field to contain the plasma. Selecting the right materials for the reactor walls is a crucial consideration.

The WEST reactor initially used carbon for its walls due to its ease of handling despite absorbing tritium from the fuel mixture. In 2012, carbon was swapped for tungsten despite tungsten's own set of challenges. Tungsten can melt and contaminate the plasma at high temperatures, leading to cooling and hindering nuclear fusion. Tungsten is also planned for use in parts of the ITER reactor, the most significant experimental reactor currently being constructed in southern France.

PPPL scientists have further developed an advanced diagnostic tool that precisely monitors plasma temperature and tracks unwanted tungsten migration from the walls. This technology will be applied in the ITER reactor project.