Researchers at the U.S. Department of Energy(Link is external) ‘s (DOE) Princeton Plasma Physics Laboratory (PPPL) have achieved a new milestone in fusion technology. They have recorded a new high for a fusion device internally clad in tungsten, which is considered to be the most suitable element for commercial-scale fusion machines.
The device successfully maintained a hot fusion plasma of around 50 million degrees Celsius for an unprecedented six minutes, with 1.15 gigajoules of power injected. This marks a 15% increase in energy and twice the density compared to previous achievements. The ability to sustain a hot and dense plasma is crucial for generating reliable power for the grid.
The record was set in a fusion device known as WEST, the tungsten (W) Environment in Steady-state Tokamak, which is operated by the French Alternative Energies and Atomic Energy Commission (CEA).
Fusion reactions, essential for the Sun’s power and life on Earth, present a challenging dilemma when it comes to replicating the process on our planet. On one extreme, fusion triggers instantaneously in the heart of a hydrogen bomb, releasing immense energy capable of devastating a city.
On the other hand, fusion can be achieved at a lab-bench level with minimal energy returns, as demonstrated at the General Electric pavilion at the 1964 New York World’s Fair.
The real challenge lies in bridging these extremes to create a reactor capable of generating more energy than it consumes on a sustained, practical, and commercial scale.
In order to achieve this, the reactor must not only be capable of sustaining fusion but also do so consistently and at a large scale. This requires a machine that can withstand the immense stresses involved in replicating the conditions found in the core of the Sun.
According to the U.S. Department of Energy’s PPPL, the recent achievement by the WEST is noteworthy. WEST sustained a reaction for six minutes after an injection of 1.15 gigajoules of power and achieved a steady-state central electron temperature of 4 keV. Although this isn’t an absolute record, WEST’s practicality sets it apart.
Situated at the nuclear research center of Cadarache, Bouches-du-Rhône in Provence, France, WEST is a modified version of the Tore Supra tokamak. During the six-minute run, the plasma inside the reactor’s magnetic fields reached a temperature of 50 million ºC (90 million ºF) and generated 15% more energy with twice the plasma density.
The highlight of this achievement was that it was accomplished using a tokamak chamber equipped with a tungsten lining. Previous versions had utilized a graphite lining, which delivered superior performance. However, graphite has the drawback of absorbing the fuel, making it unsuitable for a commercial reactor. In contrast, tungsten exhibits a much lower rate of fuel absorption, rendering it more practical and desirable.
Nevertheless, tungsten atoms can enter the plasma, causing rapid cooling. According to PPPL, while WEST is still far from being a practical reactor, it represents a significant advancement as the laboratory continues to refine the use of tungsten.
