How do you make safe, cheap nuclear reactors? Bury them a mile deep

The "you can't be 100% sure" argument is impossible to defeat, and I don't think this design will move the needle.

It also provides the argument that wanting to bury reactors 1 mile deep shows how incredibly dangerous nuclear power really is.

>so if it does manage to overheat, the nuclear reaction will automatically dampen itself down.

This seems extremely blasé. "it will fix itself". By radiating the surrounding environment ?

I am a believer in nuclear power. It can already be done safe and is being done safe in most cases. This isn't solving any real problem.

Where does the "1 mile down" come from? That seems more like based on emotion than on science / engineering. If it isn't, I'd like to see some of the tradeoffs of different depths.

I could imagine that drilling this deep might be the most expensive part, so if you could get away with, say, half of the depth, that would be quite the advantage.

What do we know about the safety tradeoffs of putting a reactor that far underground?

I'm not trying to shoot down the idea, it's just so unexpected that I feel I haven't even begun to think of the right questions yet.

There are many to choose from now.

The high cost of nuclear fission plants comes from deliberate government, petro-corporation and environmentalist attempts to kill it off (usually funded by petrostate interests like Russia, Qatar or oil corporations directly).

What happens to the two one mile long pipes attached to the reactor?

> Since the water column is a mile high, it would pressurize the reactor by its sheer weight, much like sticking it a mile under the sea, so no need for a pressurizer and the cooling system would be entirely passive.

> In addition, being encased in solid rock far below any water table removes any need for a containment system. If things get really bad, fill in the shaft and cap it.

Why is it cheaper to have this with a ready to activate shaft filling sarcophagus (and the redundant backup systems for that) vs doing it on the sea floor or land + a 0.1 mile deep hole?

Every once in a while some crazy idea like breaking down atoms to generate electricity works out and we're all better off thanks to it.

But molten salt ones are literally impossible to cause any harm.

Cant explode, cant cause uncontrolled pollution, can be safely decomissioned whenever.

But they are not cheap.

> In addition, being encased in solid rock far below any water table removes any need for a containment system. If things get really bad, fill in the shaft and cap it.

"Solid rock" feels like there's a lot of geological asterisks there. How about the casing around that mile-deep hole? Where do you pump all the inevitable leaks?

9 out of 10 startups go bankrupt, what happens to the hole if the company (or the project-specific LLC) goes belly-up? "Just fill it up" is a bit disingenuous and ignores how groundwater tends to seep into everything given enough dozens of years... Texas is littered with half-capped polluting shale wells that were just kinda left there when the wells stopped being productive and the project-specific drilling LLC was dissolved when it hit the bankruptcy-by-design phase of the corporate lifecycle.

Centuries of potential contamination feels like a risk that should have more than 2 sentences.

Let's set aside the safety argument. They're claiming $0.46 per kilowatt-hour for a technology they haven't developed yet. I believe that's about an order of magnitude more expensive than what wind can do right now. Heck, right now my local utility's website is reporting a retail spot price of seven cents per kilowatt-hour. Maybe paying six times as much is worthwhile for the reduced carbon footprint relative to fossil fuels, but if that's the argument then just say that rather than weakening your position by calling it "cheap" when it's easy to see that it isn't.

A nuclear power plant is a nuclear rector plus a thermal power plant, i.e. a turbine. Even if the safety of the reactor is 100%, what happens if there's an accident with the turbine? How do you perform maintenance? Sure, you have elevators to move people up and down, but how do you move things that are several tons up and down? A typical fuel rod assembly is about 4-5 meters long. The efficiency of the thermal power plant is about 30%, which means you need to dispose of 70% of the heat coming from the reactor. With regular nuclear power plants you use cooling towers; how are you going to do this when you are 1 mile underground? Do you install some pipes that bring cold water from the surface? Sounds reasonable until you do the math and find out you need to move 10 tons per second. The pumps that need to push the water up will need to fight the gravity of a column of water one mile high and push 10 tons each second. The math is not that difficult (potential energy = mgh), such pumps need to have a power of about 150 MW. That's ignoring the friction of the water in the pipe. But that's a big thing to ignore for a mile-long pipe. Oh, and the pressure at the bottom is 165 bar, about the same as the pressure in the reactor. You can avoid this huge pressure by creating moving the water up and down in stages, but that complicates the engineering, and increases the construction and maintenance cost.

Those who oppose will simply keep coming up with new reasons not to do it. They will only accept a reduction in usage. Anything that allows us to maintain our existing level of energy consumption will not be tolerated.

You have serious constraints in neutronics when constrained to a drillable borehole diameter and low-enriched uranium. The radial peaking will be high. May still be an ok tradeoff.

What a strange, science fictional way to describe fission! Surely it's not breaking down matter itself any more than burning wood or coal is. Would you say, about eating a sandwich, that it 'offers the promise of limitless energy by breaking down matter itself'?

If it will put people at ease, then just do it so we can finally have nuclear energy.

EDIT: There's also the fact that your steam is fighting a 1mi vertical column worth of pressure.. If your steam at the boiler is limited to 600°F that seems counterproductive to put it 1mi underground?

It's not too dissimilar from running a hydro energy turbine backwards.

Why bother with the nuclear reactor, then?

I failed to see how one mile deep shaft is going to help that, standard boring or not

If you're wanted to dig a mile down for a massive piece of infrastructure, wouldn't geothermal be more price competitive at that point?

I mean part of the problem with meltdowns is the pollution of groundwater. "It's beneath the water table" yeah sure, there's no way fission products can go up a shaft. No way.

So what safety does this really address besides paranoia? I mean I guess if you have a runaway solid rod fuel reaction, you can just drop a bomb down there and blow the fuel rods apart.

That’s…not actually cheap? As a consumer, I pay less than half that per kWh delivered at peak hours.