Fusion Energy: the 35-Country Clean-Energy Effort to "Bottle the Sun'

This week CNN published an article chronicling how 35 countries "have come together to try and master nuclear fusion, a process that occurs naturally in the sun - and all stars - but is painfully difficult to replicate on Earth. "Fusion promises a virtually limitless form of energy that, unlike fossil fuels, emits zero greenhouse gases and, unlike the nuclear fission power used today, produces no long-life radioactive waste. Mastering it could literally save humanity from climate change, a crisis of our own making."If it is mastered, fusion energy will undoubtedly power much of the world. Just 1 gram of fuel as input can create the equivalent of eight tons of oil in fusion power. That's an astonishing yield of 8 million to 1. Atomic experts rarely like to estimate when fusion energy may be widely available, often joking that, no matter when you ask, it's always 30 years away. But for the first time in history, that may actually be true.... The main challenge is sustaining it. The tokamak in the UK - called the Joint European Torus, or JET - held fusion energy for five seconds, but that's simply the longest that machine will go for. Its magnets were made of copper and were built in the 1970s. Any more than five seconds under such heat would cause them to melt. ITER uses newer magnets that can last much longer, and the project aims to produce a 10-fold return on energy, generating 500 megawatts from an input of 50 megawatts.... The dimensions are mind-blowing. The tokamak will ultimately weigh 23,000 tons. That's the combined weight of three Eiffel towers. It will comprise a million components, further differing into no fewer than 10 million smaller parts. This powerful behemoth will be surrounded by some of the largest magnets ever created. Their staggering size - some of them have diameters of up to 24 meters - means they are are too large to transport and must be assembled on site in a giant hall.... Even the digital design of this enormous machine sits across 3D computer files that take up more than two terabytes of drive space. That's the same amount of space you could save more than 160 million one-page Word documents on. Behind hundreds of workers putting the ITER project together are around 4,500 companies with 15,000 employees from all over the globe... Now commercial businesses are preparing to generate and sell fusion energy, so optimistic they are that this energy of the future could come online by mid-century. But as ever with nuclear fusion, as one challenge is overcome another seems to crop up. The limited stocks and price of tritium is one, so ITER is trying to produce its own. On that front, the outlook isn't bad. The blanket within the tokamak will be coated with lithium, and as escaped plasma neutrons reach it, they will react with the lithium to create more tritium fuel... First plasma is now expected in 2025, and the first deuterium-tritium experiments are hoped to take place in 2035, though even those are now under review - delayed, in part, by the pandemic and persistent supply chain issues. "This article has some nice photography," writes Slashdot reader technology_dude. "It really makes it hit home on the incredible amount of design and planning work that is required." The article notes that when Stephen Hawking was asked which scientific discovery he'd like to see in his lifetime, Hawking answered, "I would like nuclear fusion to become a practical power source."

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