Photo by Steve Johnson on Unsplash
 

From theory and small-scale tests to reality, will fusion ever scale?

US Energy Secretary Chris White says Nuclear Fusion Will Soon Power the World.

Don’t worry too much about planet-warming emissions, the US Energy Secretary has told the BBC, because within five years AI will have enabled the harnessing of nuclear fusion – the energy that powers the sun and stars.

“With artificial intelligence and what’s going on at the national labs and private companies in the United States, we will have that approach about how to harness fusion energy multiple ways within the next five years,” said Mr Wright.

“The technology, it’ll be on the electric grid, you know, in eight to 15 years.”

Scientists believe nuclear fusion, which Mr Wright studied at university, could one day produce vast amounts of energy without heating up our atmosphere.

But it’s a very complex process. Replicating it on Earth involves heating atoms to temperatures many times hotter than the sun.

He acknowledged that climate change is a “very real, physical phenomenon” and said that he believes the world will decarbonise: “It’s just generations from now, not two or three decades from now.”

Fossil Fuel + Fusion or Realistic Energy Resilience? America’s Crossroads

Also consider Fossil Fuel + Fusion or Realistic Energy Resilience? America’s Crossroads

U.S. Energy Secretary Chris Wright recently suggested that nuclear fusion could be a commercially viable energy source within five years. At the same time, he lamented Britain”s focus on renewables, implying that the U.S. should stay the course with existing fossil fuel infrastructure while waiting for “fusion miracles.” While optimism about fusion is admirable, it is not a credible near-term solution for America’s energy challenges.

The problem: fusion is still in the experimental stage. Net energy gain has only been achieved briefly in lab conditions, and engineering challenges—materials that can withstand extreme heat, neutron flux, and sustained plasma—remain daunting. Even if these hurdles are overcome, the cost of commercial fusion power will likely be very high at first.

My Conversation with Grok

Me: How can we ever harness something hotter than the sun, and extract energy from it, in scale, without melting everything?

Grok: Paywalled Link

Nuclear fusion involves creating a plasma—a superheated, ionized gas—hotter than the sun’s core (around 100-200 million degrees Celsius compared to the sun’s 15 million degrees) to fuse atomic nuclei and release energy. This is necessary on Earth because we can’t replicate the immense gravitational pressure at the sun’s core, so higher temperatures compensate to achieve sufficient fusion rates.

The key challenge is containing this extreme heat without the plasma touching and melting the reactor walls. Here’s how it’s addressed in practical terms, focusing on the leading approaches for scalable energy production.

Containment Methods to Avoid Melting

Fusion reactors don’t let the hot plasma directly contact materials in a way that would cause widespread melting. Instead, they use sophisticated isolation techniques:

• Magnetic Confinement (e.g., Tokamaks and Stellarators): This is the most pursued method for steady-state power production, as in projects like ITER and private ventures from companies like Commonwealth Fusion Systems. Superconducting magnets generate powerful magnetic fields that suspend and shape the plasma in a vacuum chamber, keeping it levitated in the center without touching the walls. 2 sources The plasma’s low density (much thinner than air) means its total thermal energy is manageable, even at extreme temperatures—think of it like a hot but sparse gas cloud held at bay by invisible forces. Any minor contact is mitigated by:
  • Divertors: Components that handle exhaust plasma and heat, often made of heat-resistant materials like tungsten, which can withstand up to ~3,000°C before melting.
  • Active Cooling: Liquid coolants (e.g., helium or water) circulate through the reactor walls to dissipate heat.
  • Plasma Edge Control: Techniques like injecting impurities or shaping fields to reduce edge turbulence and prevent “disruptions” (sudden plasma collapses that could damage walls).
• Inertial Confinement (e.g., Laser-Based Systems like NIF): Used in facilities like the U.S. National Ignition Facility, this pulses high-powered lasers to compress a tiny fuel pellet (deuterium-tritium) in microseconds, igniting fusion before the heat can propagate and melt surroundings. It’s more like controlled micro-explosions than sustained burning, but scaling it for continuous power remains challenging and less mature for grid-scale use.

Even with these methods, some energy escapes as neutrons or radiation, which bombard the reactor’s “blanket” (a surrounding layer). This blanket absorbs the neutrons, breeds more fuel (tritium), and transfers heat without direct plasma contact.

Materials science advancements, like nanostructured alloys and ceramic composites, further enhance resilience against neutron damage and erosion.

Extracting Energy at Scale

Once fusion occurs, energy extraction mirrors fission reactors but with fusion’s unique outputs:

1. Heat Transfer: Neutrons from deuterium-tritium fusion (the easiest reaction) carry kinetic energy, heating the blanket and coolant to produce steam.
2. Power Generation: Steam drives turbines connected to generators, producing electricity—similar to coal or nuclear plants but with no greenhouse gases or long-lived waste.
3. Efficiency and Scaling: Current demos (e.g., China’s EAST tokamak sustaining plasma for over 1,000 seconds) show progress toward “burning plasma” where reactions self-heat the system. For grid-scale (gigawatts), reactors like DEMO (post-ITER) aim for net energy gain by the 2030s-2040s, with private firms targeting earlier demos. Challenges include sustaining reactions, managing tritium supply, and cost reduction, but no fundamental physics barrier prevents it.

Challenges and Realism

While feasible in principle, scaling isn’t trivial—plasma instabilities, material fatigue from neutrons, and high costs are hurdles.

The linked article appears skeptical, arguing fusion isn’t a credible near-term fix for U.S. energy needs, potentially favoring “realistic resilience” via renewables or efficiency over long-shot tech like fusion (which some critics call “fossil fuel fusion” due to hype or indirect fossil dependencies in development).

However, fusion’s potential for unlimited, clean baseload power makes it worth pursuing alongside solar, wind, and batteries for a diversified grid. Progress in the 2020s (e.g., net gain at NIF in 2022, extended runs in tokamaks) suggests it’s moving from sci-fi to engineering reality, without needing to “melt everything” thanks to non-contact confinement.

Elon Musk Backs Universal High Income, Fearing AI Will Take Every Job

As soon as we get AI humming, with fusion providing the energy, and robots doing the maintenance running on free energy, what do we need humans for?

That question was the subject for my post Elon Musk Backs Universal High Income, Fearing AI Will Take Every Job

Musk predicts employment will become obsolete.

Universal High Income is a socialist dream. Everyone shares the wealth of free energy and free stuff and lives happily ever after.

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