Big AI’s Fig Leaf to Cover their Fossil Fuel Energy Splurge? – Watts Up With That?

The “new alloys” article is a bit of a hint that there are serious problems which likely won’t be solved anytime soon.

Even if the problem of controlling fusion plasmas is solved in the next few years, which seems a trifle optimistic, there is the more serious problem that the fusion containment system has a distressing tendency to crumble into dust. Despite their reputation for being “clean”, fusion plasmas produce a blizzard of fast neutrons, so much so they can physically wreck the structural integrity of the plasma containment chamber.

Covering the fusion chamber in tungsten, lead or elemental iron, or other radiation resistant material, poisons the plasma. The heavy ion contamination from erosion of the armoured chamber walls makes it difficult to keep plasma hot. Even at millions of degrees heavy element ions keep some electrons, which help provide an unwanted channel for radiation of heat away from the plasma.

What about covering the chamber with Lithium? Using Lithium as the fusion chamber wall lining would eliminate the heavy ion contamination problem, and some lithium will fission into tritium in a fusion plasma. But Lithium’s melting point is only 180c, so using a Lithium fusion plasma vessel lining presents some challenges.

Beryllium might be a better choice, although it is less likely to fission into tritium like Lithium, like Tungsten it is a neutron reflector. Beryllium has a melting point of 1287C, far higher than Lithium. But Beryllium is a major human health hazard, like working with asbestos but far worse. Beryllium is brittle, and easily crumbles into dust. Inhalation of dust causes a range of horrible symptoms, including cancer. Maintaining the Beryllium fusion reaction chamber liner would be a rather stressful undertaking.

The final choice of reactor chamber lining will likely be a complex alloy or ceramic. But there is a lot more work to do in this space, to find the right balance between reactor friendly elements, structural resistance to radiation damage, and not killing the workers with toxic dust every time someone opens the hatch on the reactor chamber.

There is also the problem of sourcing all the tritium which would be required for a commercial fusion plant. Tritium is rare – there is only around 25kg of Tritium in the entire world. Like other isotopes of hydrogen, Tritium leaks effortlessly through the most determined containment efforts. Even surrounding the fusion plasma with a bed of lithium may not be enough to produce the tritium required to keep the reactor running.

Deuterium / Deuterium fusion would solve the fuel supply problem, the oceans contain enough Deuterium to power the world until doomsday. But pure Deuterium fusion requires triple the temperature of Deuterium / Tritium fusion, and even at this elevated temperature, if I have understood correctly, has 20x less fusion events than Deuterium / Tritium. Triple the temperature which is already in the millions of degrees might not seem like much, but consulting our old friend Stephan Boltzmann, 3x the temperature makes the fusion plasma wants to lose its heat 3⁴ = 81x faster than an equivalent Deuterium / Tritium plasma. Given keeping plasma heat at the level fusion occurs is one of the main stumbling blocks to maintaining a long life stable fusion plasma, so tackling a problem which is between 81x and 20 x 81 =1,620 times harder than the currently marginally solved Deuterium / Tritium plasma problem doesn’t sound like a physics problem which will be ready for industrial deployment by 2028.

Helium 3 fusion has an advantage in terms of radiation. Helium 3 fusion reactions do not produce the blizzard of neutrons which would pose such a threat to the structural integrity of the fusion reactor chamber. But the nearest abundant source of Helium 3 is the surface of the moon, so we’d need to build an extensive Lunar mining operation to support Helium 3 fusion. In addition Helium 3 fusion suffers similar high temperature disadvantages as Deuterium / Deuterium fusion.

Inertial confinement fusion has made some impressive advances – but they are a long way from genuine break even, let alone energy production.

Electrostatic confinement fusion is a fascinating idea which sadly appears to be a dead end. Whenever you hear of some high school student building a desktop fusion system, the device they built is an electrostatic confinement system. Surprisingly Electrostatic fusion does have a real use – as an industrial source of fusion neutrons. But as an energy production system, Electrostatic confinement appears to suffer fatal flaws. From what I’ve read there are too many ways for energy to leak from electrostatic confinement systems, so the energy required to maintain the confinement field always exceeds the energy output.

Robert Bussard, one of the founding inventors of electrostatic confinement, claimed to his dying day that a large enough Polywell fusor electrostatic confinement fusion chamber would produce more energy than it consumed, and his ideas were plausible enough that the US Navy threw $21 million at his idea, so who knows – maybe somewhere in the future there is a currently unconsidered configuration of electrostatic and magnetic fields which can maintain a stable energy producing fusion plasma. But finding that unknown gem in the sea of wrong configurations seems more like hoping for a lottery win than a guaranteed near future breakthrough.

What about Rossi’s E-CAT? I believe there is compelling evidence E-CAT is nonsense. If Rossi’s low energy fusion invention is as ready as he claims, why can’t we buy E-CATs in Walmart? In my opinion these kinds of ideas have had more than enough time to prove themselves, if there was anything there to prove.

I love the idea of nuclear fusion. I would really like to be proven wrong about how distant we are from practical fusion energy. I have no problem with investment in fusion research. I’d love to power my house with a Mr. Fusion reactor, which looks like a cleaning bucket yet which according to Hollywood can generate enough energy to power a DeLorean Time Machine. But barring a new physics breakthrough, like an improved method of producing enough muons to catalyse energy producing room temperature fusion, a genuine cold fusion breakthrough, or significant advances in non-mainstream fusion technologies like pyroelectric fusion, I just don’t see industrial grade fusion happening by the end of this decade. Or maybe even by the end of this century.

So why the sudden uptick in expressions of confidence in imminent nuclear fusion? Why do so many people believe we are on the brink of a fusion breakthrough? Perhaps I have missed something big – please educate me in comments if this is the case. But I truly believe imminent fusion is the new fig leaf of the tech company environmental movement. I believe former environmentalist tech leaders are driving this uptick in confidence, because they are clinging to irrational hopes for an imminent fusion breakthrough like a shipwrecked sailor clings to a life raft. The alternative to belief in the imminence of nuclear fusion is to accept they are utter hypocrites, that Big Tech’s AI push is a total betrayal of their once precious green energy ideals.

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