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Axien

I noticed the waste output is helium. Does this fix the worldwide helium scarcity issue?

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Let's make some back of the envelope calculation:

* World electricity production: 25000TWh/year https://en.wikipedia.org/wiki/Electricity_generation

* Energy per Helium atom: 17.6MeV https://en.wikipedia.org/wiki/Deuterium%E2%80%93tritium_fusi...

So per year (with a 100% efficiency [1]) you would produce as a side effect 25000TWh/17.6MeV ~= 3E31 Helium atoms.

The Avogadro constant is 6,022E23 and that produces 22.4 liters of gas, so you get 1.2E9 liters, that is 1.2E6 cubic meters. Let's round that to 1 million cubic meters per year.

The worldwide production of Helium is 140 million cubic meter per year https://www.statista.com/statistics/925214/helium-production...

[1] A 100% efficiency is too optimistic. The second law and the nasty details of the real world reduce the efficiency a lot. Let me guess 50% from https://en.wikipedia.org/wiki/Energy_conversion_efficiency#E... But this is good! If you waste half of the produced energy, you need the double of fusion plants, and that means the double of Helium balloons.

This calculation was done on an HN thread a few years ago. I have not reviewed it recently.

If all power generated right now was from D+T fusion, it would generate about 8.2% of the current helium consumption. We consume 153,596 TWh of thermal energy per year [1]. Each D+T reaction releases 17.59 MeV [2]. Multiply by the atomic mass of He4 and divide by Avogadro's number to get the mass of He4 produced per energy produced. Divide by the density of He4 at STP to get volume of He4 produced per second [3]. Divide by the consumption of He4 to get the ratio of He4 produced to He4 consumed [4].

(153596 TWh / year) / (17.59 MeV) / (avogadro's number 1/mol) * (4.002602 g/mol) / (0.1786 g / liter) / (88 million m^3 / year)

https://www.wolframalpha.com/input/?i=(153596+TWh+%2F+year)+...

1. https://ourworldindata.org/energy-production-and-changing-en...

2. http://hyperphysics.phy-astr.gsu.edu/hbase/NucEne/fusion.htm...

3. https://www.engineeringtoolbox.com/gas-density-d_158.html

4. https://link.springer.com/article/10.1007/s11053-017-9359-y

No, fusion power plants will likely need helium to run: it's necessary to cool the magnetic coils. Unless there will be a breakthrough in room-temperature superconductivity, helium will still be needed and consumed (through leakages) at a faster rate than the fusion reactions can provide.

source: https://doi.org/10.1016/j.fusengdes.2013.01.059

Even with hypothetical very high temperature superconductors we still want to run cryogenics to push the critical current higher. At some point mechanical stress would be the limiting factor but there is no path towards discovering such a miracle material. If one were to be discovered it would revolutionize our world.

For the foreseeable, we use HTS materials, that can superconduct at LN2 temperatures, with helium.

No, there's very little helium produced for the same reason that fusion generates massive amounts of energy from very tiny amounts of fuel. In fact there'd be more helium produced in the nuclear reactor generating the tritium than there would be in the fusion reactor burning it. Eventually commercial nuclear fusion reactors will generate their own tritium from a lithium blanket but for now that's all from fission reactors.

One thing's for sure - the scientists working there will all have really squeaky voices

No idea. But it would be absolutely awesome if we had another age of airships.

I thought they'd found masses of deposits recently?

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