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Comment by RodgerTheGreat | Hacker News Reader

Perhaps we will yet see the real-world deployment of the nuclear subterrene: https://projectcamelot.org/la5354ms.pdf

(Assuming, of course, that three-letter agencies haven't already been using this technology to honeycomb the country with networks of secret tunnels for decades...)

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I am glad we are getting this capability now, who knows when ISIS and the Taliban will have enriched uranium to the point where they have subsurface ships prowling the depths of our planet, attacking our freedoms from below.

We cannot allow a mineshaft gap.

This would make good origin story for the new Backrooms fiction thats developing.

Link?

https://www.youtube.com/watch?v=H4dGpz6cnHo is the "original"[1] video, though many SCP games had similar environments and settings beforehand. See various memes spawned from it, such as https://www.reddit.com/r/tf2/comments/tb0v29/the_backrooms/ and https://www.youtube.com/watch?v=72Y0LHM1vGs

[1] Responsible for the most recent set of trends, but derivative of creepypasta that's been gathering traction for a while. https://knowyourmeme.com/memes/the-backrooms - points to 2018, but I'm pretty sure that SCP wiki had versions before then.

From googling around, most rock melts at around 1000C, so I guess the biggest challenge is making a reactor that will survive heating up to 1000C? The melting point of uranium is barely 1100C, so seems like an awful thin margin.

How would they handle not irradiating (and generating all sorts of isotopes in) the tunnel walls? A 10MW reactor generates a fuckton of radiation.

Nobody could come anywhere near the "melting" head, even after shutdown.

Wouldn't hitting even a tiny amount of water would be catastrophically bad, causing a steam explosion? Hitting oil deposits, coal...minerals that contain water...

The reactor doesn't need to touch the rock

I needs coolant though.

The melting point of uranium metal may be around there, but these reactors would use a much higher temperature fuel form, such as the everyday uranium oxide (UO₂) used in nearly all commercial reactors, which melts around 2900°C. Usually it's the coolant and structural materials that limit temperature in nuclear reactors. These could use exotic materials like SiC for structure. Interesting that they use liquid metal heat pipes in this study to transfer the heat to the rock melting surfaces.

Not a Nuclear Mechanical Engineer, but I bet you could concentrate the heat of the reactors using a giant nuclear-grade heat pump to concentrate heat well above the point-temperature of the reactor itself. As long as the fuel is generating X Watts of power, you can theoretically concentrate that energy away and down to smaller and smaller areas, increasing temperature as you go.

We should probably ask someone who took a heat transfer or other undergrad physics class, but from my basic understanding of the physics, "concentrating heat" isn't really a thing - at the very least, you'd need to extract the energy from a heat differential into some other form to do this.

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