Marathon fusion claims to invent alchemy, making 5000 kgs gold per gigawatt

How the scheme works (as discussed)

• Commenters note this is an add‑on to a future deuterium‑tritium tokamak: use 14 MeV neutrons in the blanket to turn Hg‑198 into Au‑197 via (n,2n) → Hg‑197 → Au‑197.
• Gold is claimed as a by‑product: the plant supposedly still generates full power and breeds tritium.
• Several comments emphasize this is not a fusion reactor design, but a neutronics blanket configuration around one.

Radioactivity and storage issues

• Produced material is a mix of stable gold and radioactive mercury isotope; refining could isolate gold, but refineries may avoid radioactive feedstock.
• Paper estimates: ~13 years storage to avoid radioactive‑waste labeling; ~17 years to reach “banana level” activity.
• Some think this delay is trivial for vault‑stored bullion; others expect strong public/market stigma against “nuclear gold.”
• Industrial uses (electronics, medical) might be more sensitive to residual radioactivity; jewelry and vault storage less so.

Economics and impact on gold price

• One calculation (assuming 5000 kg per GW‑year) claims raw electricity cost alone could exceed current gold price, but others stress electricity is the main product; gold is extra revenue.
• If many GW‑scale plants existed, thousands of tonnes/year of gold could be added, potentially lowering prices—but commenters note fusion deployment at that scale is many decades away and may never fully saturate demand.
• Financial engineering ideas: “maturing” notes for 17‑year vault gold, analogous to bonds or aging whisky/cheese.

Mercury‑198 supply and separation

• Hg‑198 is ~10% of natural mercury; discussion centers on isotope separation to bring costs toward a few $/kg as assumed in the paper.
• Some question current very high Hg‑198 prices; others argue they reflect tiny bespoke markets, not scalable separation costs.
• Concerns that global mercury and Hg‑198 supply fundamentally cap how much gold can ever be produced this way.

Fusion vs other neutron sources

• Commenters ask why not use fission or accelerators; responses note the need for ≥9 MeV neutrons.
• D‑T fusion’s 14.1 MeV neutrons provide both sufficient energy and huge flux; fission/accelerator neutrons would likely be uneconomic at scale.

Feasibility, timeline, and use cases

• Multiple comments describe this as “fun, almost sci‑fi,” but stress it depends on commercially viable fusion, which is still decades away.
• Some see it mainly as a way to enhance early fusion‑plant economics or as a form of mercury waste disposal, not a route to unlimited cheap gold.

Skepticism and presentation

• Some distrust the marketing tone (“once‑in‑a‑century feat” with little discussion of pitfalls).
• Others link to an external technical critique suggesting the physics and simulations are plausible but the concept remains very low TRL and tightly constrained by tritium‑breeding design margins.

Broader implications and side topics

• If any stable element can be synthesized with fusion neutrons, commenters speculate that many metals (silver, rhodium, iridium) could lose scarcity as stores of value.
• This leads to joking about only cryptocurrencies remaining as “un-synthesizable” scarce assets, alongside general gold/crypto/finance humor.