[Dezakin]

Mining Uranium from the asteroids is incredibly foolish and unecissary, partly because earth has rather unique conditions in the solar system that concentrate uranium and thorium nearly exclusively in the crust at a very high density; The average pile of dirt in your backyard has several times the energy content than an equivelant mass of coal combusted, with nearly 10ppm of uranium and thorium.

A more precise picture:

http://nuclearinfo.net/Nuclearpower/Ura ... stribution

We have roughly 1 trillion tons avaliable that are recoverable with an extrapolated energy return above 10 (from shales and phosphates) in light water reactors, enough to run 20000 light water reactors for a quarter million years. Uranium supply is trivially obvious as a nonbarrier to nuclear expansion.

[padisah]

$this->bbcode_second_pass_quote('Dezakin', 'M')ining Uranium from the asteroids is incredibly foolish and unecissary, partly because earth has rather unique conditions in the solar system that concentrate uranium and thorium nearly exclusively in the crust at a very high density; The average pile of dirt in your backyard has several times the energy content than an equivelant mass of coal combusted, with nearly 10ppm of uranium and thorium.

A more precise picture:

http://nuclearinfo.net/Nuclearpower/Ura ... stribution

We have roughly 1 trillion tons avaliable that are recoverable with an extrapolated energy return above 10 (from shales and phosphates) in light water reactors, enough to run 20000 light water reactors for a quarter million years. Uranium supply is trivially obvious as a nonbarrier to nuclear expansion.

[Dezakin]

$this->bbcode_second_pass_quote('', 'u')ranium and thorium is a finite resource just like oil is. Which means it is sooner or later reaches that particular eroi point where extracting it on the earth surface is pointless

[padisah]

uranium in the crust: I don't know the speciel chemistry and physics around that, but it is completely illogical

uranium is a very heavy element, the largest of all naturally occuring, so without evidence, or experiences, about the subject it is obvious, that during the formation of earth any material that contained larger concentrations of uranium slowly sinks toward the melt core

any material that is in the core of earth is practically unaccssible for us, and the same events should have happened to venus or mars too

so, most of the fission capable material that have become part of larger planats, became part of the inner parts of the planet, and it is right now supplying the energy for vulcanic activities

uranium content in granite can be explained by the fact that granite is formed below deep the surfce, by vulcanic activity, which brings some material from the mantle. Due to the density of the uranium it is very logical, that the mantle contains a higher ppm uranium than the crust has, and lower than the core possibly have. When the melt rocks become solid, they can repeat this gravity driven process, and getting enriched in certain regions

also uranium became enriched in sedimentary rocks by similar gravity driven processes (this created the uranium sources here in hungary)

which is more important is the whole story is that the original source of the fission capable material is now exists in the meteorites, and comets especially in the oort field

here in earth surface we have an environment which is separated by gravity -something that is never affected the meteorites, so all meteorites have a relatively large concentrations of rare materials (including uranium and thorium)*

this means a practically endless amount of fissionable material, which will not be affected by and peak-like process, meteorites have no special deposites, or enriched locations for rare materials, they have a generally much higher concentration of them

of course, which I'm speaking about unlikely to be feasible with existing space technology, but that is something that can develop a lot

*the presence of heavy, and rare elements in meteorites was one of the decisive eveidence for the meteor-impact theory for the create extinstion event, because there were a layer of sediments around the globe with some 20 or 30 times higher ppm of iridium, one of the most dense metal that exists

[padisah]

I have a strange feeling that we are not understanding the word eroi the same way...

I would be interested for some basic calculations on nuclear eroi, let's say for 1 tons of U235, enriched to 5%, fuel rod quality + the amount of plutonium that is generated during use

(I tried to look up the forum but that's too much in pages, and there is no search ability for the forum engine)

[Tanada]

$this->bbcode_second_pass_quote('padisah', 'I') have a strange feeling that we are not understanding the word eroi the same way...

I would be interested for some basic calculations on nuclear eroi, let's say for 1 tons of U235, enriched to 5%, fuel rod quality + the amount of plutonium that is generated during use

(I tried to look up the forum but that's too much in pages, and there is no search ability for the forum engine)

[Dezakin]

$this->bbcode_second_pass_quote('', 'u')ranium is a very heavy element, the largest of all naturally occuring, so without evidence, or experiences, about the subject it is obvious, that during the formation of earth any material that contained larger concentrations of uranium slowly sinks toward the melt core

[Tyler_JC]

This is Hubbert's assessment of global coal production.


According to Hubbert, Peak Coal isn't for another century or two.



Nuclear Energy and the Fossil Fuels by M. King Hubbert Chief Consultant (General Geology)

Dr. M King Hubbert believed that Peak Oil was not a big deal and that humanity's future was nuclear powered.

Hubbert's original 1956 paper, the "Old Testament" of Peak Oil wasn't even about oil! It was about the replacement of oil with nuclear power.

$this->bbcode_second_pass_quote('', 'I')n order to see more clearly what these events may imply, it will be informative to consider them on a somewhat longer time scale than that which we customarily employ. Attention is accordingly invited to Figure 30 which covers the time span from 5000 years ago - the dawn of recorded history - to 5000 years in the future. On such a time scale the discovery, exploitation, and exhaustion of the fossil fuels will be seen to be but an ephemeral event in the span of recorded history. There is promise, however, provided mankind can solve its International problems and not destroy itself with nuclear weapons, and provided the world population (which is now expanding at such a rate as to double in less than a century) can somehow be brought under control, that we may at last have found an energy supply adequate for our needs for at least the next few centuries of the "foreseeable future."

[padisah]

This is interesting debate, I would eagerly accept that nuclear has a far better EROI than I previously thought, but right now i don't se decisive evidence for that.

http://www.pmc.gov.au/umpner/docs/commi ... report.pdf

I have this document, on last pages there are the results in energy intensity, and energy payback times. (6.5 or 7 according to reactor type) EROI can be calculated from the payback ratio, divided with the 35 or 34 years they used their calculations for PPlant life span, and then we get an eroi around 5. This is a quite general number I have seen in other documents too.

There are also tables that show the energy input distributions, which showed quite a few proprtion for mining and milling energy costs. It was together only about 6% of total energy input.

This data would show that there is a lot of area in ore grade down, that is still feasible to produce. This fact affcts the uranium reserves usable to production very much.

I will look after the chemical behaviour, and it's side effects on uranium ore presence.

[Doly]

$this->bbcode_second_pass_quote('padisah', '
')I have this document, on last pages there are the results in energy intensity, and energy payback times. (6.5 or 7 according to reactor type) EROI can be calculated from the payback ratio, divided with the 35 or 34 years they used their calculations for PPlant life span, and then we get an eroi around 5. This is a quite general number I have seen in other documents too.

[mkwin]

The new 4th generation plants are supposed to be far more effcient than the ones built 30 years ago. In terms of energy produced, fuel effciency and waste production.

[padisah]

this particular document is made in australia, and they mentioned in the document, that australia don't have any nuclear plants yet, so I think the authors plan include future nuclear plants

however i agree in that future, or 4h generation nuclear plants can have considerably higher eroi, especialy the lack of need for enrichment can make it higher

I also have to admire to Dezikin that he (or she) has right, earth crust has sg 69 times larger concentration of uranium than the rest of the solar system, including chondrites

these have generally 15-9 ppb - parts per billion uranium content which is far below levels of earth crust

[Dezakin]

$this->bbcode_second_pass_quote('', 'I') have this document, on last pages there are the results in energy intensity, and energy payback times. (6.5 or 7 according to reactor type) EROI can be calculated from the payback ratio, divided with the 35 or 34 years they used their calculations for PPlant life span, and then we get an eroi around 5. This is a quite general number I have seen in other documents too.

[MCrab]

$this->bbcode_second_pass_quote('', 'C')hecking that document, they get that citing Storm van Lewen of the infamous stormsmith paper, who grossly misrepresent data in a series of half truths and outright lies.

[padisah]

$this->bbcode_second_pass_quote('Dezakin', '')$this->bbcode_second_pass_quote('', 'I') have this document, on last pages there are the results in energy intensity, and energy payback times. (6.5 or 7 according to reactor type) EROI can be calculated from the payback ratio, divided with the 35 or 34 years they used their calculations for PPlant life span, and then we get an eroi around 5. This is a quite general number I have seen in other documents too.

[Dezakin]

$this->bbcode_second_pass_quote('', 'A')n EROI of 5 or a slightly more fits well to the coal plants, and the oil usage's 6-8 eroi level, and gives a reasonable explanation why we use still coal instead of the better uranium.

[yesplease]

$this->bbcode_second_pass_quote('Dezakin', 'T')he reason we use coal more often than uranium has more to do with financing and other limits than energy. While most limited resources can be boiled down to functions of energy over a long enough time, money is the limited resource that matters most in these short term decisions.

[MCrab]

Recent news on the Olympic Dam expansion in Australia:

http://www.smh.com.au/news/business/oly ... 94344.html

$this->bbcode_second_pass_quote('', 'I')n a revised resource statement, BHP said the amount of mineralised material at Olympic Dam had risen by 77 per cent to 7.738 billion tonnes at a grade of 0.87 per cent copper, 0.29 kilograms per tonne of uranium and 0.30 grams per tonne of gold.

But given previous resource statements had been geared towards its existing underground operation rather than its planned open pit, the reported grades fell. While the copper resource rose 38 per cent to 67.3 million tonnes and the uranium resource rose 27 per cent to 2.2 million tonnes, the gold resource increased by a relatively meagre 11 per cent to 79 million ounces.

[padisah]

$this->bbcode_second_pass_quote('Dezakin', '')$this->bbcode_second_pass_quote('', 'A')n EROI of 5 or a slightly more fits well to the coal plants, and the oil usage's 6-8 eroi level, and gives a reasonable explanation why we use still coal instead of the better uranium.

[Dezakin]

$this->bbcode_second_pass_quote('', 'i')f I had a lot of data available, then I would personnaly exclude Olimpic Dam from the investigation, because it can distort our data, what we would need here is a commercially based mine that produces only uranium, and some more of them to compare energy needs with ore grade, and draw some graphs and predict the energy costs with various ore grades.