Rendered at 10:11:53 GMT+0000 (Coordinated Universal Time) with Cloudflare Workers.
baron816 5 hours ago [-]
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 dome, or expensive plumbing. If anything goes wrong, the nuclear fuel is already a mile underground. When the fuel is used up, they can leave it where it is since it’s below the water table. No need for expensive and hard to source highly enriched uranium.
The hard part is digging the wells, but that seems trivial compared to Quaise, who’s trying to dig 3-20km wells. The Deep Fission wells can just go anywhere (perhaps next to a disused former coal turbine?).
trashb 1 hours ago [-]
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"
leonidasrup 7 minutes ago [-]
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.
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. "
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
That sounds like an absolute nightmare to get approvals for.
simonebrunozzi 3 hours ago [-]
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.
rcxdude 2 hours ago [-]
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.
leonidasrup 34 minutes ago [-]
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.
"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"
"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."
cyberax 4 hours ago [-]
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 percentage of the fissionable materials.
rcxdude 2 hours ago [-]
Would the fuel efficiency be sufficiently bad to make the fuel costs relevant to the cost of running the plant, though?
UltraSane 1 hours ago [-]
The water column is isolated fron the fuel. The weight of the water column just allows for a cheaper enclosure.
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
UltraSane 1 hours ago [-]
The nuclear fuel is contained inside a reactor vessel. The water pressure just allows it to be much cheaper.
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.
cyberax 4 hours ago [-]
We can then build a primary school on top! And use the water from the well for heating directly.
What could possibly go wrong!?!?
stavros 43 minutes ago [-]
Omg there are things that can go wrong? We should definitely not build it then, do we even need energy anyway?
Seriously, what's wrong with the world is people who go "omg what about the one in a million chance the water table is damaged" when right now Europe is dying from the heat that centuries of burning fossil fuels has caused.
noja 4 hours ago [-]
What are the side-effects of regularly detonating nuclear bombs at that depth?
seems it usually happened at lesser depths, and for ones deep enough to contain debris, the main effects were geological, from the actual explosion? not what i expected tbh
rcxdude 2 hours ago [-]
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.
leonidasrup 29 minutes ago [-]
"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"
"For the application in EGS drilling, this device uses a metallic waveguide to carry the
millimeter wave (MMW) beam to a standoff distance from the crystalline rock. Argon gas is
used as the waveguide fill medium due to its ability to stay transparent to MMW’s at such
deep depths and thus higher pressures [12]. Purge gas is also used to pump out the excess
material that has been transformed into smaller particles (Figure 2.4). "
As a former geologist involved in drilling, thats going to get real expensive, real fast, in terms relative to regular mechanical drilling thanks to the requirement for argon. Perhaps theres an economically efficient changeover point at depth as mechanical drilling becomes less capable due to increasingly plastic deformation.
MadnessASAP 9 hours ago [-]
You don't need a significant flow of argon, just enough to keep unwanted gasses out of the waveguide.
It's possible there exists a material that is transparent to mm waves, airtight, and can survive the conditions at the bottom of the hole. In such a case they could cap the waveguide and prevent any gas leakage.
I'm quite sure Quaise is well aware that Argon isn't cheap and are already exploring multiple avenues for reducing its usage.
It is interesting that they have to use Argon instead of the more typical Nitrogen or SF6. A waveguide with such a significant pressure differential is decidedly unusual and a unique challenger for what they are doing.
pfdietz 8 hours ago [-]
SF6 is a horrifically powerful greenhouse gas, so I doubt it could be used. Its GWP is somewhere around 23,000 on a 100 year timescale.
MadnessASAP 7 hours ago [-]
Oh yeah, there's no shortage of reasons not to use SF6. Even in conventional waveguides, as far as I know most designs these days prefer nitrogen or dried atmospheric air.
audunw 2 days ago [-]
There is definitely an economic changeover point, I’m sure I read they will use conventional drilling down to a certain depth, before switching to MMW
I doubt argon is the purge gas.
tekacs 9 hours ago [-]
Yeah, they say in their launch video for Project Obsidian (https://www.youtube.com/watch?v=xmrna_r_b3A) that they'll drill the first 3km using conventional rotary drilling and mmWave beyond that.
I'd be curious if anyone (perhaps the parent) knows why – my assumption is that it's more expensive and/or not as reliable to drill higher up with mmWave, not least because the ground might be uneven materials, etc., and then it becomes something predictable and harder to rotary drill lower down, incl. as you would spend more time doing things like replacing bits low down and sending things up and down?
rcxdude 2 hours ago [-]
That's pretty much it. They're not going to beat conventional drilling on price at lower depths, so why bother with it?
tomtom1337 3 days ago [-]
You mean the argon gas used as medium specifically? I assume the purge gas is something else, cheaper?
anakaine 3 days ago [-]
If the goal is to simply purge the content of the hole, compressed air is typically sufficient. That said, the wider the hole, and the deeper it is, the harder it is to lift material on air.
To be clear though, I'd love to have one of these rigs on my old project and compare rate of progression and hole quality. Particularly when establishing the hole in sedimentary gravels and clays. I imagine casing will still be required.
One thing that I'd be concerned about is the ability to collect samples if most of the material is being vaporised or melted. Similarly, the cooking of the side of the hole on the way down could make geophysical responses much more difficult to interpret. Sonic velocity would probably increase, televised would probably be harder to interpret, harder to spot hydrothermal infill in sedimentary cover, would it affect gamma tools (probably not)
Edit: also wondering how the hole holds up around aquifers. Does the super heating cause wall instability immediately above the non geothermal aquifers as superheated steam is created? How does this affect the hole stability if we are not casing?
Edit 2: if we are not casing, how does the hole hold up around aquifer sands, loose fill, fractured or brecciated mass?
Edit 3: Also! Do we ream open the top of the hole to down past the last aquifers before the geothermal horizon? If not, how are we stopping stopping aquifers interplay and interaquifer contamination?
fleetwood 3 days ago [-]
i think they plan to drill with a traditional rig until they get deep/hot enough to necessitate a switch to mm wave
tomtom1337 3 days ago [-]
Great response! I'm just a layman here (former material scientist) but it's fun to think about this stuff!
mzhaase 3 days ago [-]
Maybe you could hook up a mass spectrometer to the purge gas to get real time composition.
nerdsniper 20 hours ago [-]
perhaps, but usually things like "which fossil species are present" are also utilized to figure out what's going on near the drill bit, like if you're trying to reach oil deposits right along the edge of an old riverbed.
Some shale formations in Michigan, for example, sometimes requires drilling to a 4" thick target. You don't know the exact depth because the depth of that 4" thick layer can vary by many feet from an another spot 100m north/south.
I'm aware that if you search "thickness of Antrim shale" or "thickness of Collingswood shale", Google will happily tell you that it's 20-40 feet thick, but for modern drilling techniques, the economics of the well depend on hitting a much more narrow target than that, which can be delicately guided in by analyzing fossils that come up.
consensus1 9 hours ago [-]
[dead]
westurner 9 hours ago [-]
Why mmwave instead of ultrasonic? FWIU 28 kHz shreds the quartzite in granite?
hangonhn 7 hours ago [-]
Isn't the idea here to gasify the rock by essentially microwaving it? With ultrasound, wouldn't you still need to remove the leftover rocks?
saltcured 3 days ago [-]
Naively, I wonder how much the density of argon gas helps here, in terms of being able to recover and reuse the argon gas in a relatively closed-loop system.
Animats 3 hours ago [-]
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.
Karliss 26 minutes ago [-]
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.
swiftcoder 2 hours ago [-]
> There should be useful tools, such as small units for drilling pipe holes through concrete and rock.
We already have cheap and effective mechanical drills capable of these tasks, and it's unlikely a brand new technology can compete with those on cost.
Unlike in the actual design niche, where mechanical tools are infeasible due to the temperatures involved.
Might want to do yourself a favor and figure out the implied question behind 400(?)
It's... not a lot of work. At least for me personally it rubs me the wrong way to name an important metric in Fahrenheit and then to give an estimate with a question mark for the proper SI unit.
roarcher 3 hours ago [-]
Looks to me like the author wrote themselves an inline note and forgot to remove it before publishing.
moebrowne 2 hours ago [-]
I'd assumed that the question mark was supposed to be a degrees (°) symbol but got mangled somehow. 752F is exactly 400C
justinhunt 7 hours ago [-]
Its worth noting the original article was written July 2025. Not June 2026
Can someone explain how this works? A gyrotron is some kind of maser (like a laser but with microwaves). Are they vaporizing the rock?
tliltocatl 4 hours ago [-]
Gyrotron isn't quite a maser, more akin to a free-electron (i.e. electron beam) RF source. AFAIR (might be wrong, but based on what I could find there: https://www.thinkgeoenergy.com/wp-content/uploads/2021/03/mi...) they aren't literally vaporizing the rock, rather locally heating it til it crushes into particles that can be blown away.
eternityforest 3 days ago [-]
They made the laser drill from The Core IRL?
adrian_b 3 days ago [-]
Except that it is not a laser but a high power radio transmitter made with a vacuum tube (gyrotron).
For generating the highest possible power of radio waves, vacuum tubes remain the only solution.
This drilling method resembles more a microwave oven (which uses a magnetron), than a laser.
mikelitoris 9 hours ago [-]
Impressive, but how long did it take to drill 100 meters? I didn't see a mention of that.
DoctorOetker 9 hours ago [-]
They mentioned about 1 hour per meter at 1 MW.
jauntywundrkind 7 hours ago [-]
The video mentions that they did all the drilling so far at 100kW and are expecting to start doing 1 MW within the year.
I wonder what their transmission voltage is. They're talking about a 1km deep shaft. That feels like a lot of conductor to get to 1MW, unless you can send at 20kV or something high. Reciprocally though if you're not transmitting major force through a drillshaft, perhaps it still is a major net win for cost.
Figuring out heat management down there feels like it would likewise be pretty tricky! Again I wonder though how that would compare to the heat generated from drilling and how much management/circulation that requires.
tliltocatl 4 hours ago [-]
Based on what I could find:
They generate the RF on the surface and transmit it down the borehole thru a waveguide, so it's only limited by arching in the waveguide. Since we only need power transfer and don't care about multimode propagation, the waveguide diameter isn't limited, and probably on the larger side to reduce copper losses. And the heat management is provided by blowing argon which also carries abalated rock particulate to the surface.
No need for an expensive containment dome, or expensive plumbing. If anything goes wrong, the nuclear fuel is already a mile underground. When the fuel is used up, they can leave it where it is since it’s below the water table. No need for expensive and hard to source highly enriched uranium.
The hard part is digging the wells, but that seems trivial compared to Quaise, who’s trying to dig 3-20km wells. The Deep Fission wells can just go anywhere (perhaps next to a disused former coal turbine?).
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"
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
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."
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 percentage of the fissionable materials.
https://www.nrc.gov/docs/ML2419/ML24191A372.pdf
perfectly safe /s
https://www.nrc.gov/docs/ML2419/ML24191A372.pdf
This sounds like the worst idea I've ever heard.
What could possibly go wrong!?!?
Seriously, what's wrong with the world is people who go "omg what about the one in a million chance the water table is damaged" when right now Europe is dying from the heat that centuries of burning fossil fuels has caused.
seems it usually happened at lesser depths, and for ones deep enough to contain debris, the main effects were geological, from the actual explosion? not what i expected tbh
https://en.wikipedia.org/wiki/Project_PACER
"For the application in EGS drilling, this device uses a metallic waveguide to carry the millimeter wave (MMW) beam to a standoff distance from the crystalline rock. Argon gas is used as the waveguide fill medium due to its ability to stay transparent to MMW’s at such deep depths and thus higher pressures [12]. Purge gas is also used to pump out the excess material that has been transformed into smaller particles (Figure 2.4). "
As a former geologist involved in drilling, thats going to get real expensive, real fast, in terms relative to regular mechanical drilling thanks to the requirement for argon. Perhaps theres an economically efficient changeover point at depth as mechanical drilling becomes less capable due to increasingly plastic deformation.
It's possible there exists a material that is transparent to mm waves, airtight, and can survive the conditions at the bottom of the hole. In such a case they could cap the waveguide and prevent any gas leakage.
I'm quite sure Quaise is well aware that Argon isn't cheap and are already exploring multiple avenues for reducing its usage.
It is interesting that they have to use Argon instead of the more typical Nitrogen or SF6. A waveguide with such a significant pressure differential is decidedly unusual and a unique challenger for what they are doing.
I doubt argon is the purge gas.
I'd be curious if anyone (perhaps the parent) knows why – my assumption is that it's more expensive and/or not as reliable to drill higher up with mmWave, not least because the ground might be uneven materials, etc., and then it becomes something predictable and harder to rotary drill lower down, incl. as you would spend more time doing things like replacing bits low down and sending things up and down?
To be clear though, I'd love to have one of these rigs on my old project and compare rate of progression and hole quality. Particularly when establishing the hole in sedimentary gravels and clays. I imagine casing will still be required.
One thing that I'd be concerned about is the ability to collect samples if most of the material is being vaporised or melted. Similarly, the cooking of the side of the hole on the way down could make geophysical responses much more difficult to interpret. Sonic velocity would probably increase, televised would probably be harder to interpret, harder to spot hydrothermal infill in sedimentary cover, would it affect gamma tools (probably not)
Edit: also wondering how the hole holds up around aquifers. Does the super heating cause wall instability immediately above the non geothermal aquifers as superheated steam is created? How does this affect the hole stability if we are not casing?
Edit 2: if we are not casing, how does the hole hold up around aquifer sands, loose fill, fractured or brecciated mass?
Edit 3: Also! Do we ream open the top of the hole to down past the last aquifers before the geothermal horizon? If not, how are we stopping stopping aquifers interplay and interaquifer contamination?
Some shale formations in Michigan, for example, sometimes requires drilling to a 4" thick target. You don't know the exact depth because the depth of that 4" thick layer can vary by many feet from an another spot 100m north/south.
I'm aware that if you search "thickness of Antrim shale" or "thickness of Collingswood shale", Google will happily tell you that it's 20-40 feet thick, but for modern drilling techniques, the economics of the well depend on hitting a much more narrow target than that, which can be delicately guided in by analyzing fossils that come up.
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.
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.
We already have cheap and effective mechanical drills capable of these tasks, and it's unlikely a brand new technology can compete with those on cost.
Unlike in the actual design niche, where mechanical tools are infeasible due to the temperatures involved.
Nice article on an earlier demo: https://newatlas.com/energy/quaise-energy-millimeter-wave-dr... ; linked from this (nice but lots lots of ads): https://newatlas.com/energy/quaise-energy-millimeter-wave-dr... .
Company https://www.quaise.com/ on YT https://www.youtube.com/@quaise
MS thesis (2024; browsable) on the vitrified wall, for that and its intro: https://www.proquest.com/openview/624989df3cdd8055a6cee9affc...
Search for papers "Millimeter Wave Drilling for Deep Geothermal Energy Production" https://scholar.google.com/scholar?hl=en&as_sdt=0%2C33&q=Mil...
Very interesting application of radio waves.
For generating the highest possible power of radio waves, vacuum tubes remain the only solution.
This drilling method resembles more a microwave oven (which uses a magnetron), than a laser.
I wonder what their transmission voltage is. They're talking about a 1km deep shaft. That feels like a lot of conductor to get to 1MW, unless you can send at 20kV or something high. Reciprocally though if you're not transmitting major force through a drillshaft, perhaps it still is a major net win for cost.
Figuring out heat management down there feels like it would likewise be pretty tricky! Again I wonder though how that would compare to the heat generated from drilling and how much management/circulation that requires.
They generate the RF on the surface and transmit it down the borehole thru a waveguide, so it's only limited by arching in the waveguide. Since we only need power transfer and don't care about multimode propagation, the waveguide diameter isn't limited, and probably on the larger side to reduce copper losses. And the heat management is provided by blowing argon which also carries abalated rock particulate to the surface.
See the schematics here: the schematic here: https://www.thinkgeoenergy.com/wp-content/uploads/2021/03/mi...