Fusion reactors could turn mercury into gold and pay for themselves doing it

A physics preprint proposes using fusion reactors to transmute mercury into gold through nuclear reactions, simultaneously removing a persistent environmental toxin and generating revenue. If the neutron flux is high enough, every mercury isotope becomes convertible, potentially valuing recoverable global mercury at $200 trillion and tripling a fusion plant's revenue while cleaning up the environment.

This is speculative physics, not deployed technology — a theoretical argument that fusion's economic case improves if you add a pollution-remediation revenue stream. The claim is that fusion stops being merely a low-carbon energy source and becomes actively anti-polluting, which changes the policy story from 'we need fusion to replace coal' to 'fusion also fixes historical environmental damage and pays for itself doing it.' The catch: this requires neutron flux levels that don't yet exist in commercial reactors, and the paper offers no experimental data showing mercury transmutation actually works at the proposed scale. It's a mathematical model of what could happen if certain physics conditions hold.