It will be interesting to see how this mechanism fares, for sure.
If they can master this, they're at least 10% of the way toward figuring out how to contain high-level radioactive waste! That brilliant (!) engineering marvel needs to be contained at least ten times longer than this clock is supposed to run.
Just a minor technical quibble (because that's what HN is for, after all)--"too cheap to meter" refers to the expected cost-effectiveness of fusion power, not fission, and "too cheap to meter" doesn't necessarily mean that power is free, just that the costs of power delivery are dominated by the delivery infrastructure rather than the generation of the power in the first place. In other words, you'd pay a flat rate per month for unlimited power to keep the power grid up and running.
Fusion power would also be cost-effective enough to literally turn CO2 and water back into hydrocarbons, desalinate ocean water for large-scale irrigation, sustainably produce nitrogen-based fertilizer from the air, and otherwise solve virtually every sustainability problem we face or will conceivably face for centuries. (The rest can be solved by harvesting mineral resources from asteroids instead of the Earth's surface, but that problem can be solved through better orbital infrastructure, which turns into an energy problem.)
Even in principle, this is similar to saying a bridge is "too cheap to meter". There's no fuel cost, but it can certainly take a long time to pay for pricey infrastructure via tolls.
I don't see why anyone would charge a flat rate for unlimited electricity when you can pay off the enormous debt faster by charging market rate.
This might be a case where public infrastructure makes more sense than private infrastructure; if a large industrial country like China standardizes on a design and builds dozens to hundreds of identical plants, they would enjoy vast economies of scale and probably regain their investment in GDP growth purely from the economic activities made possible through fusion.
I shudder to think about the vastly different usage patterns flat rate electricity will bring. Why bother insulating houses? Why not run the A/C at full power instead of turning down the heating?
Lots of operational expenses are dominated by energy usage. Cryptocurrency mining would only be the start of it...
If they can master this, they're at least 10% of the way toward figuring out how to contain high-level radioactive waste! That brilliant (!) engineering marvel needs to be contained at least ten times longer than this clock is supposed to run.
Easy peasy!
"Clean! Safe! Too cheap to meter!"