Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Millimeter wave technology drills 100 meters into granite

thinkgeoenergy.com

Post reply on HN
Print view View original

51–60 of 133 posts

Re: Millimeter wave technology drills 100 meters into granite

#51

Post by UltraSane »

cyberax wrote: post #39
baron816 wrote: post #32

I really like what https://www.deepfission.com/ is trying to do. They have the absolute simplest model for nuclear fission that I can imagine. They’re digging one mile (1.6 km) holes dropping low enriched nuclear fuel to the bottom, and filling them with water. The pressure from the one mile column of water is perfect for the reactor. From there, it’s basically a geothermal well. No need for an expensive containment…

It's an extremely stupid idea. Your whole water column is going to be contaminated with fission products. And you won't be able to get any reasonable amount of power out of that contraption. And even if you are stupid enough to actually do this, the fuel efficiency will be terrible. Your only negative feedback for fission is the Doppler effect and thermal expansion. So you will only be able to utilize a tiny percenta…

The water column is isolated fron the fuel. The weight of the water column just allows for a cheaper enclosure.

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

Re: Millimeter wave technology drills 100 meters into granite

#52

Post by UltraSane »

notrustincloud wrote: post #37
baron816 wrote: post #32

I really like what https://www.deepfission.com/ is trying to do. They have the absolute simplest model for nuclear fission that I can imagine. They’re digging one mile (1.6 km) holes dropping low enriched nuclear fuel to the bottom, and filling them with water. The pressure from the one mile column of water is perfect for the reactor. From there, it’s basically a geothermal well. No need for an expensive containment…

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

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

Re: Millimeter wave technology drills 100 meters into granite

#53

Post by trashb »

baron816 wrote: post #32

I really like what https://www.deepfission.com/ is trying to do. They have the absolute simplest model for nuclear fission that I can imagine. They’re digging one mile (1.6 km) holes dropping low enriched nuclear fuel to the bottom, and filling them with water. The pressure from the one mile column of water is perfect for the reactor. From there, it’s basically a geothermal well. No need for an expensive containment…

Create a small sun a mile under the ground, what could go wrong?

Also the actual article it seems has nothing to do with fission, they are focusing on extracting the heat already down there. "superhot rock needed for next-generation geothermal power"

Re: Millimeter wave technology drills 100 meters into granite

#54

Post by willis936 »

UltraSane wrote: post #52
notrustincloud wrote: post #37

Earlier quoted context omitted.

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

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.

Re: Millimeter wave technology drills 100 meters into granite

#55

Post by stavros »

cyberax wrote: post #40
notrustincloud wrote: post #37

Earlier quoted context omitted.

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

We can then build a primary school on top! And use the water from the well for heating directly. What could possibly go wrong!?!?

[flagged]

Re: Millimeter wave technology drills 100 meters into granite

#56

Post by da-x »

trashb wrote: post #53
baron816 wrote: post #32

I really like what https://www.deepfission.com/ is trying to do. They have the absolute simplest model for nuclear fission that I can imagine. They’re digging one mile (1.6 km) holes dropping low enriched nuclear fuel to the bottom, and filling them with water. The pressure from the one mile column of water is perfect for the reactor. From there, it’s basically a geothermal well. No need for an expensive containment…

Create a small sun a mile under the ground, what could go wrong? Also the actual article it seems has nothing to do with fission, they are focusing on extracting the heat already down there. "superhot rock needed for next-generation geothermal power"

The sun performs fusion, not fission.

Re: Millimeter wave technology drills 100 meters into granite

#57

Post by leonidasrup »

rcxdude wrote: post #49
simonebrunozzi wrote: post #41

Earlier quoted context omitted.

Quite the opposite. They use proven reactor tech, and they are now going straight to commercial, vs other startups that need to go supercritical first.

I'm not sure that makes the approvals that much cheaper and easier. As I understand it, the slight differences between existing nuclear power plants that are for the most part the same design is already one of the reasons why they are so expensive to build.

Building nuclear power plant underground could save significant costs, because the massive containment building is made from nuclear grade steel and nuclear grade concrete and is very expensive. But you need a low cost excavation technology.

https://ifp.org/nuclear-power-plant-construction-costs/

"Nuclear-grade components don’t necessarily have higher performance requirements than conventional components. Reinforcing steel in nuclear-grade concrete, for instance, is the same material used in conventional concrete. Instead, the additional cost often comes from the additional documentation and testing required. Documentation requirements also increase costs indirectly, by reducing market competition among manufacturers. Because these requirements are difficult for manufacturers to implement, many simply don’t bother to manufacture nuclear-grade components."

"Sources of Cost Overrun in Nuclear Power Plant Construction Call for a New Approach to Engineering Design"

https://www.sciencedirect.com/science/article/pii/S254243512...

"Similarly, while our analysis identifies the rebar density in reinforced concrete as the most influential variable for cost decrease, changes to the amount and composition of containment concrete are constrained by safety regulations, most notably the requirement for containment structures to withstand commercial aircraft impacts. New plant designs with underground (embedded) reactors could allow for thinner containment walls. However, these designs are still under development and pose the risk of high excavation costs in areas or at sites with low productivity."

Re: Millimeter wave technology drills 100 meters into granite

#58

Post by leonidasrup »

rcxdude wrote: post #48
noja wrote: post #35

Earlier quoted context omitted.

What are the side-effects of regularly detonating nuclear bombs at that depth?

I'm not sure how this question would be relevant. Nuclear bombs are impractical for power generation and a nuclear reactor is not ever going to turn into a nuclear bomb.

"Project PACER, carried out at Los Alamos National Laboratory (LANL) in the mid-1970s, explored the possibility of a fusion power system that would involve exploding small hydrogen bombs"

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

Re: Millimeter wave technology drills 100 meters into granite

#59

Post by Karliss »

Animats wrote: post #43

That's impressive. But why are there no near-term products? If you can cut through granite and such this way, it ought to be useful for other cutting jobs. There should be useful tools, such as small units for drilling pipe holes through concrete and rock. Going for a 10km hole as the initial product raises the suspicion that the real product is the stock.

For shorter holes traditional mechanical methods work just fine. If you are going to build a giant excavator you don't waste time making shovels for gardeners. The problem drilling deep into ground is that the power source on the surface of earth and drill bit deep underground are connected by long floppy noodle while the hole is getting crushed from the sides by bunch of elephants. It is difficult to transfer rotation from the motor/power source at the top to the boring head, and reinforce the walls to prevent them from collapsing, having whole thing heated to few hundred ℃ doesn't make it easier on hardware.

In case of something like underground tunnels these problems are avoided by having hole big enough to fit the drilling machine as well as all the equipment and crew to reinforce the walls with concrete.

The fact that people have made a way to drill few hundred to few km using mechanical means is already an engineering marvel. In the context of everyday manufacturing beyond the hole depth to diameter ratio of 5:1 things already start to get more complicated. With more specialized techniques you might get 10:1 - 100:1. A bit easier for softer materials like wood or if you don't care about precision. But for deep underground drilling we are talking about ratio of thousands to 1.

It's not like they are not making tests at shorter depths. Once technology is sufficiently developed it might also trickle down to some shorter few km holes if geological conditions are right. Although probably never for something like few dozen meter water wells or making a hole in concrete at construction site. Not sure how well it works in soft dirt. Who knows about distant future, we now have relatively cheap desktop laser cutters, laser pointers, measuring equipment, microwave ovens, but those were not the initial products when developing those technologies. On the other hand some tech like wire EDM has remained niche manufacturing technology, even though modern electronics and software could allow making it much cheaper.

Re: Millimeter wave technology drills 100 meters into granite

#60

Post by leonidasrup »

trashb wrote: post #53
baron816 wrote: post #32

I really like what https://www.deepfission.com/ is trying to do. They have the absolute simplest model for nuclear fission that I can imagine. They’re digging one mile (1.6 km) holes dropping low enriched nuclear fuel to the bottom, and filling them with water. The pressure from the one mile column of water is perfect for the reactor. From there, it’s basically a geothermal well. No need for an expensive containment…

Create a small sun a mile under the ground, what could go wrong? Also the actual article it seems has nothing to do with fission, they are focusing on extracting the heat already down there. "superhot rock needed for next-generation geothermal power"

There many kinds of geothermal power and if you don't have access to hot fluids found naturally in basement rock, you have use hot dry rock geothermal energy.

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

Here the biggest obstacle to economy of the geothermal power is the very low heat conductivity of rock.

"The conductive heat flux averages 0.1 MW/km2. These values are much higher near tectonic plate boundaries where the crust is thinner. They may be further augmented by combinations of fluid circulation, either through magma conduits, hot springs, hydrothermal circulation. "

https://en.wikipedia.org/wiki/Geothermal_energy#Resources

For comparison: Thus the solar energy arriving at the surface with the sun directly overhead can vary from 550 MW/km2 with cirrus clouds to 1025 MW/km2 with a clear sky

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

Post reply on HN