You can't spell "demonstrations" without "demon" (or "monstra").

must sit for about 17.7 years to be below a banana equivalent level of activity.

Banana for scale!

I understood some of those words. Nevertheless, thanks for providing some crucial context.

The safe level isn't that important, because the gold can be put into an ETF investment vehicle, which is a substantial enough demand for gold. National reserves (the vast majority of gold demand) too are long term holders.

2t/GWhth is a huge amount. While the best case economics for fusion is 30c/kwh cost = $3m/Gwhe, that would be 3GWhth = 6T of gold. Even at $45/oz (1/100th of current value) that would be $8m/Gwhe revenue, and would likely be able to sell electricity at market rates as the "waste product", or not even bother with the expense/complexity of electricity generation.

It also helps that we're talking about rather dense nuclei too. So it's not just a neutron absorbing blanket, but a rather high-performing one at that. Which you need to convert fusion outputs to heat and power anyway. And gold is soluble in mercury anyway, so extraction is already a known (albeit incredibly dangerous) process. Win-win.

yielding several tonnes of gold per plant-year

Mother of god that's a lot to magic-up outta nowhere. At first I thought this would disrupt the market, but it looks like yearly global gold production is around 3000 tons a year. So it would take a lot of reactors to impact the gold market, so... yeah. Reactors really could start paying for themselves.

Infinite gold would be useful for electronics, but it would destroy gold's utility as a long-term store of value. So the wealth for shareholders would be finite, taken from today's gold holders.

“If," ["the management consultant"] said tersely, “we could for a moment move on to the subject of fiscal policy. . .” “Fiscal policy!" whooped Ford Prefect. “Fiscal policy!" The management consultant gave him a look that only a lungfish could have copied. “Fiscal policy. . .” he repeated, “that is what I said.” “How can you have money,” demanded Ford, “if none of you actually produces anything? It doesn't grow on trees you know.” “If you would allow me to continue.. .” Ford nodded dejectedly. “Thank you. Since we decided a few weeks ago to adopt the leaf as legal tender, we have, of course, all become immensely rich.” Ford stared in disbelief at the crowd who were murmuring appreciatively at this and greedily fingering the wads of leaves with which their track suits were stuffed. “But we have also,” continued the management consultant, “run into a small inflation problem on account of the high level of leaf availability, which means that, I gather, the current going rate has something like three deciduous forests buying one ship’s peanut." Murmurs of alarm came from the crowd. The management consultant waved them down. “So in order to obviate this problem,” he continued, “and effectively revalue the leaf, we are about to embark on a massive defoliation campaign, and. . .er, burn down all the forests. I think you'll all agree that's a sensible move under the circumstances." The crowd seemed a little uncertain about this for a second or two until someone pointed out how much this would increase the value of the leaves in their pockets whereupon they let out whoops of delight and gave the management consultant a standing ovation. The accountants among them looked forward to a profitable autumn aloft and it got an appreciative round from the crowd.”

― Douglas Adams, The Restaurant at the End of the Universe

Sell lead to a scrapyard, buy porn with the proceeds.

led -> gold -> buys computer -> internet -> porn

No, silly, we'll make infinite gold and use that to purchase infinite helium.

Foolproof!

Can we not spam neutrons at hydrogen?

There's a lot of hydrogen.

It looks that way.

Monte Carlo transport calculations show that neutrons produced in a tokamak power plant can convert the abundant isotope 198Hg to stable 197Au via the (n,2n) channel, yielding several tonnes of gold per plant-year without compromising the tritium breeding ratio.

I wonder what the next "ground currency" will be once we can replicate everything at the atomic level. I'm hoping it's human trust