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Millimeter wave technology drills 100 meters into granite

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Re: Millimeter wave technology drills 100 meters into granite

#91

Post by leonidasrup »

Asooka wrote: post #78
Someone wrote: post #71

Earlier quoted context omitted.

> They’re digging one mile (1.6 km) holes dropping low enriched nuclear fuel to the bottom, and filling them with water. > When the fuel is used up, they can leave it where it is since it’s below the water table. To do both, they’ll have to guarantee that that column of water stays isolated from groundwater for a long time after the fuel is used up. Reading https://www.deepfission.com/faq , they answer that question…

> To do both, they’ll have to guarantee that that column of water stays isolated from groundwater for a long time after the fuel is used up. I wonder if just letting the water gradually dissolve the uranium might not be fine, actually. If it is done far from wells and rivers used for drinking water, then the small amount of radioactive minerals that slowly seep out might not pose a danger. I can't find any studies to…

Of the all the radioactive elements in a nuclear reactor, uranium is one of the least dangerous (is very weakly radioactive, but it's toxic, it's a heavy metal). It's all the radioactive fission products (many have short half-life and in process of decay produces lot of ionizing radiation) and trans-uranic elements (because they have very long half-life and produce a bit small bits of ionizing radiation for very long time).

One possible of measure of danger is median lethal dose LD50:

Uranium LD50 in mice 114 mg/kg (about the same as Cocaine LD50 96 mg/kg)

Plutonium LD50 in dog 320 μg/kg

Caesium-137 LD50 245 μg/kg

Polonium-210 LD50 10 ng/kg (estimated)

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

There are places underground with high concentration of uranium, they are called uranium ore and sometimes they are mined for uranium.

"The deposit is located at depth of 450 m (1,480 ft), surrounded by and isolated within a layer of water-impermeable illite-chlorite clay, within the Athabasca Sandstone formation. Its age is estimated to be 1.3 billion years. Due to natural containment and lack of any traces of radioactive elements on the surface, the deposit is used as an example of an effective natural deep geological repository."

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

Re: Millimeter wave technology drills 100 meters into granite

#92

Post by leonidasrup »

Ma8ee wrote: post #87
stavros wrote: post #65

Earlier quoted context omitted.

"We don't need to research any more potential solutions to this existential problem we're facing" is certainly a take.

I don't say we shouldn't do research. What I do say is that we do have all the technology we need. And more importantly, we don't have the time to wait for some future technology that potentially could solve all our problems. The climate disaster has already started (and this [0] is not "the new normal", this is just the beginning, a hint of what we should expect). The only reason we are in this shithole is because o…

We don't need new technology, it took France only about 20 years to replace it's coal and oil based electric generation with nuclear power generation (between 1976 and 2000).

Because of lack of political will in US and many European countries we continued to burn fuels to generate electric energy.

https://world-nuclear.org/information-library/country-profil...

Developing countries like China and India prioritized cheap coal power generation.

Re: Millimeter wave technology drills 100 meters into granite

#93

Post by quotemstr »

Someone wrote: post #71
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…

> They’re digging one mile (1.6 km) holes dropping low enriched nuclear fuel to the bottom, and filling them with water. > When the fuel is used up, they can leave it where it is since it’s below the water table. To do both, they’ll have to guarantee that that column of water stays isolated from groundwater for a long time after the fuel is used up. Reading https://www.deepfission.com/faq , they answer that question…

What a waste of perfectly good reprocessing input. "Spent" convention nuclear fuel retains 95% of its energy. Discarding "spent" fuel is a shamefully profligate energy practice we can get away with because we're using not nearly enough nuclear power, making and virgin fissiles are dirt cheap.

Re: Millimeter wave technology drills 100 meters into granite

#94

Post by Dibby053 »

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…

>They have the absolute simplest model for nuclear fission that I can imagine

Agree. What I don't understand is: why has it never been done before? They can't possibly be the first to come up with this idea, which doesn't seem to rely on any novel technology.

Re: Millimeter wave technology drills 100 meters into granite

#95

Post by superxpro12 »

MadnessASAP wrote: post #31
pfdietz wrote: post #27

Earlier quoted context omitted.

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.

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.

Anytime i see fluoride, im immediately concerned about anything in its immediate surroundings...

Re: Millimeter wave technology drills 100 meters into granite

#96

Post by AnimalMuppet »

cucumber3732842 wrote: post #75
Someone wrote: post #71

Earlier quoted context omitted.

> They’re digging one mile (1.6 km) holes dropping low enriched nuclear fuel to the bottom, and filling them with water. > When the fuel is used up, they can leave it where it is since it’s below the water table. To do both, they’ll have to guarantee that that column of water stays isolated from groundwater for a long time after the fuel is used up. Reading https://www.deepfission.com/faq , they answer that question…

>I don’t think those are good answers. Steel and concrete are what we use above ground so..... >They say what they want to do, but almost nothing about how they’ll do that, and try to avoid making hard statements on the what by using “is expected” and “is intended”. They say nothing about how because those are trivial problems in the well (and oil) drilling industry.

We use steel and concrete. We don't usually expect them to last 10,000 years, though.

Re: Millimeter wave technology drills 100 meters into granite

#99

Post by pfdietz »

superxpro12 wrote: post #95
MadnessASAP wrote: post #31

Earlier quoted context omitted.

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.

Anytime i see fluoride, im immediately concerned about anything in its immediate surroundings...

Some fluorine compounds are quite stable. SF6 has two downsides: its GWP from very great stability in the atmosphere (it needs to rise into the mesosphere to be decomposed, not just the stratosphere, giving it an atmospheric lifetime of as much as 3000 years) and toxic compounds produced when it finally is broken down by energetic processes like arc discharges.

Re: Millimeter wave technology drills 100 meters into granite

#100

Post by cyberax »

rcxdude wrote: post #47
cyberax wrote: post #39

Earlier quoted context omitted.

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…

Would the fuel efficiency be sufficiently bad to make the fuel costs relevant to the cost of running the plant, though?

Yes, it would. Fuel is around 2-4% of the total costs for a regular nuclear power plant, but that's because regular reactors can burn it deeply. This reactor will only burn a couple of percents of the available fuel, so the fuel costs will probably be around 10-20 times higher.

BTW, this tradeoff can be acceptable for some very specific applications. Kilopower ( https://en.wikipedia.org/wiki/Kilopower ) is designed to use passive regulation.

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