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Comment by notrustincloud | Hacker News Reader

below and penetrating the water table with the potential for short and long half-life transuranic fissile products and a path of least resistance for any runaway conditions which is directly to an uncontained well head... with the extra bonus of installation proposed in 'spent' hydrocarbon bearing regions which implies reduced density substrates with all the tiny seismic outcomes and risks.

perfectly safe /s

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I greatly dislike this sort of "doesn't work perfectly everywhere by default therefore doesn't work" take. The steam engine didn't replace all the mules at once.

It should be pretty trivial to pick and choose geologies and depth where it is safe. Maybe that's a lot of places. Maybe that's a few. But it should be trivial regardless.

> it should be trivial regardless.

So should nuclear fission reactors. The concept is absurdly simple.

In practice, however ...

We can then build a primary school on top! And use the water from the well for heating directly.

What could possibly go wrong!?!?

For example in Finland there is research done for nuclear district heating.

https://www.world-nuclear-news.org/articles/fourth-finnish-m...

"Feasibility of small modular reactors for decarbonizing district heating systems: a case study of the Helsinki metropolitan area"

https://www.sciencedirect.com/science/article/pii/S002954932...

Haiyang’s District Heating Project in China

https://www.iaea.org/newscenter/news/carbon-free-heating-kee...

The USSR built a nuclear district heating system in Gorky (now Nizhny Novgorod) but never commissioned it because of the general anti-nuclear sentiment at that time.

It's certainly possible and not even very hard (by nuclear standards) because the reactor can operate at ambient pressure.

The biggest issue is inefficiency and cost of district heating except for places like Finland. It's now cheaper to install heatpumps instead.

It's also about use of "waste" heat of an existing nuclear plant, similar to many Cogeneration or combined heat and power (CHP) power plants.

https://en.wikipedia.org/wiki/Cogeneration

Bohunice Nuclear Power Plant is used for nuclear district heating.

"Upon development of a district heating supply network in the town of Trnava near Bohunice NPP, V2 switched to co-generation. Part of this system is a heat feeder line commissioned in 1987. In 1997, a heat feeder line to Leopoldov and Hlohovec was created, branching off from the Trnava line."

https://en.wikipedia.org/wiki/Bohunice_Nuclear_Power_Plant

There are plans to implement this also in Mochovce Nuclear Power Station.

https://www.nucnet.org/news/slovakian-utility-plans-district...

Only if the primary school is exclusively for the children of oligarchs.

The nuclear fuel is contained inside a reactor vessel. The water pressure just allows it to be much cheaper.

https://www.nrc.gov/docs/ML2419/ML24191A372.pdf

Page 7 looks like a single point of failure in an unmaintainable device that would result in a well of contaminated water a mile deep that passes through the water table that could never be fixed.

This sounds like the worst idea I've ever heard.

Yeah, 76cm (30 inch) bore hole drilling with standard oil&grass rig.

Fill with unshielded nuclear reactor of novel type: super skinny.

Gently lower down until depth of 1 mile is reached.

Repeat 1000x for a 1 GWe power plant.

What could possibly go wrong? Best horror story of the year in 15 slides.

Please explain exactly what you think can go wrong.

Seismic activity collapses the well, trapping the nuke underground, pressure find a way to escape via polluting a "faraway" aquifer, or it doesn't escape and you have a man-made volcano in the works

Not a plausible scenario. The entire point is that by putting these a mile deep that they will self seal if they meltdown. They can't create a volcano because they are only 15MW. If the reactor cracks the radioactive fuel can only contaminate the water at the very bottom of the shaft because it is a mile deep.

I thought the whole point was that the reactor would deliver heated water to the surface for utilization...? But it will magically stop trying to do that if the main shaft is obstructed and there is a separate egress?

Or are you also burying the turbine and power lines a mile deep?

Also, I want to add on that if you lined the well to be single fault tolerant you will still be vulnerable to a high likelihood common mode failure from a single seismic event. Truly just the worst. The founders should pivot hard and fast.

There are plenty of places with very little seismic activity.

And how many of those places have we dug 100 mile deep holes in and verified nothing has changed? It doesn't take a long look at fracking research to see that this line of reasoning doesn't hold.

100 miles deep? What are you even talking about?

100x one mile deep holes. It's in the deck you linked for a 1 GWe plant.

You're describing everywhere with mines and a stable seismic environment. Arizona comes to mind.

A mile is much deeper than the water table is almost everywhere. It is normally solid bedrock. So you can just fill the hole with concrete and dirt.

How does this look in practice? You need the water to transfer the heat, so in response to a disaster that has already poisoned the water table you need to extract the water, put it somewhere, and backfill with concrete, all while you've already poisoned miles of water table and fighting from spreading further and damning all workers involved? For what gain?

How exactly will it poison the water table? A mile is in bedrock much deeper than the water table and any radioactive material will stay at the bottom because it is heavy.

I think the goal is if it melts down, nobody should be very bothered. You just leave it there and plug the well

Exactly, the bedrock is an excellent containment material.

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