Since 1983, the Joint European Torus (JET) laboratory in Oxfordshire, UK has been dedicated to research working toward controllable nuclear fusion. A scaled-down validator for the larger ITER, the JET laboratory achieved its previous world record back in 1997.
During that test run, JET’s fusion reactor used carbon as the heat shield between the million-degree plasma and the reactor shell. However, carbon absorbs the reactor’s tritium fuel, which decreases the fusion reactor’s efficiency and could pose a threat to the environment.
This time for the record-breaking experiment, the JET lab swapped out the carbon inner walls with beryllium and tungsten, which absorb 10 times less tritium. As a result, the JET fusion reactor was able to maintain a stable fusional power output for five seconds, reaching over 100 million degrees Celsius internally. During those five seconds, the JET fusion reactor produced 59 megajoules, or 11.8 megawatts of power—more than double its previous fusion energy output.
These test results reflect the feasibility of large-scale nuclear fusion, and thus validate the design choices of JET’s bigger brother, the ITER fusion reactor. The outcomes put the nuclear fusion industry one step closer to a commercially feasible nuclear reactor and demonstrate JET scientists’ ability to create a mini star for the harnessing of clean and renewable energy.
Nevertheless, nuclear fusion still comes with many uncertainties, especially how soon it can become commercially feasible. Scientists would need to level up the scale of the reaction to achieve targets for zero carbon emissions. So far, it has taken the JET lab 25 years to double its power output.
So, why is it taking so long?
It all comes down to the fundamentals of fission and fusion reactions. Considering that highly concentrated uranium above critical mass can start a chain/fission reaction on its own, a nuclear fission reaction is simpler to achieve.
Still, the only type of nuclear fusion yet found in the observable universe occurs within the center of the stars—at over 10 million degrees Celsius and 100 billion times’ atmospheric pressure. Replicating a proper environment for nuclear fusion can be more difficult than starting the reaction itself. Since recreating the pressure requirements is currently impossible, JET scientists utilize magnets to constrain the nuclear fusion fuel and slowly increase the temperature to above 100 million degrees Celsius.
The fundamental concern regarding nuclear fusion is its ability to self-sustain. Scientists know by theory that nuclear fusion is occurring in the core of stars, but no one is certain about artificial replication. All fusion reactors in existence require more energy than they can provide in order to maintain their environment.
Although nuclear fusion projects entail enormous costs, once self-sustained nuclear fusion is achieved, energy could become virtually free. As a result, dependence on pollution-creating fossil fuels may finally cease.
To learn more about nuclear fusion, read ITER Assembly Officially Begins in France.