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UK nuclear fusion reactor achieves new world record for energy output

Image credit: New Scientist

The UK’s Joint European Torus (JET) fusion reactor in Oxfordshire achieved a world record for energy output in its final runs before being shut down for good, 

It was a 40-year-old reactor which began operating in 1983 which achieved the hottest point in the solar system, reaching 150 million°C during its last and final run recently.

in its final tests in late 2023, it sustained a reaction for 5.2 seconds while also reaching 69 megajoules of output, using just 0.2 milligrams of fuel.

This translates to a power output of 12.5 megawatts – enough to power 12,000 homes, said Mikhail Maslov of the UK Atomic Energy Agency at a press conference on 8 February.

Why is fusion power so important?

Fusion power is important because it could provide a sustainable, abundant, and carbon-free form of energy for the future. Fusion power is based on the same process that powers the sun and other stars, where two light atomic nuclei combine to form a heavier one and release massive amounts of energy. Fusion power has many advantages over other energy sources, such as:

- It uses deuterium and tritium as fuel, which are heavy types of hydrogen that can be extracted from water and lithium, respectively. These resources are widely available and can last for millions of years.

- It does not produce carbon dioxide or other greenhouse gases that contribute to climate change12. The only by-product of fusion is helium, which is an inert and non-toxic gas.

- It does not generate long-lived radioactive waste that needs to be stored or disposed of12. The materials used in a fusion reactor become less radioactive over time and can be recycled or reused within 100 years.

- It has a limited risk of proliferation of nuclear weapons, as fusion does not employ fissile materials like uranium or plutonium. The radioactive tritium used in fusion is neither a fissile nor a fissionable material.

- It has no risk of meltdown or a Fukushima-type nuclear accident, as fusion requires precise and controlled conditions to happen. If any disturbance occurs, the fusion reaction stops within seconds and the plasma cools down.

Fusion power is not yet a reality, but scientists and engineers around the world are working on developing fusion reactors that can achieve a net fusion power gain, meaning that they produce more energy than they consume. 

One of the most ambitious projects is ITER, an international collaboration to build the world’s largest tokamak, a doughnut-shaped device that uses magnetic fields to confine and heat the plasma. ITER aims to demonstrate the feasibility and scalability of fusion power for peaceful purposes. A larger and more modern replacement for JET, the International Thermonuclear Experimental Reactor (ITER) in France, is nearing completion and its first experiments are due to start in 2025.

Tim Luce, deputy head of the ITER construction project, told a press conference that ITER will scale up the energy output to 500 megawatts, or possibly even 700.

“These are what I usually call power plant scale,” he said. “They’re at the lower end of what you would need for an electricity generating facility. In addition, we need to extend the timescale to at least 300 seconds for the high fusion power and gain but perhaps as long as an hour in terms of energy production. So what JET has done is exactly a scale model of what we have to do in the ITER project.”

Another reactor using the same design, the Korea Superconducting Tokamak Advanced Research (KSTAR) device, recently managed to sustain a reaction for 30 seconds at temperatures in excess of 100 million°C.

There are other approaches to creating a working fusion reactor being pursued around the world as well, such as the National Ignition Facility at Lawrence Livermore National Laboratory in California. This bombards capsules of fuel with immensely powerful lasers, a process called inertial confinement fusion, and has managed to unleash almost twice the energy that was put into it.

Mankind is always hungry for more energy. Even the AI revolution these days relies, at its backend, on huge energy requirements for training and running complex models that process huge amounts of data, the complexity of the model, and the volume of requests made to the AI by users. Even though there are already numerous use cases of AI in energy applications, one study found that training a large natural language processing model can emit as much carbon as five cars in their lifetimes. Therefore, AI poses both opportunities and challenges for the energy sector, and it is important to find ways to make AI more efficient and at the same time we have to find more efficient and sustainable energy sources like the nuclear fusion reactor.


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Arun Bhatia

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