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210 comments on Mining the Oceans: Can We Extract Minerals from Seawater?
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210 comments on Mining the Oceans: Can We Extract Minerals from Seawater?
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well, you seem to infer a little too much from my conclusions. If we have an efficient breeder reactor, conventional mining will be sufficient for a very long time and there won't be any need for mining the oceans for uranium. But it is a marginal point: the point is whether we'll ever have an efficient breeder reactor. But that is another subject
Russia has had a prototype breeder for many years, and are building a full scale one.
Molten salt reactors etc have already been prototyped as far back as the 60's, and what is involved in building them is well understood.
The main thing holding back more efficient reactors has been the low price of uranium and fossil fuels, and so considering that a relatively small exploration effort has greatly expanded known uranium resources and we know perfectly well how to build reactors to burn the more abundant thorium then very modest progress is required to reach an efficiency at which the extraction of uranium from seawater has a perfectly acceptable EROI by the time we need to do so.
So, as I previously stated, we have sufficient uranium and thorium for our needs at the moment, and as far as we know there are no show stoppers to prevent their making a major contribution to energy supply for many thousands of years.
Thank you for clarifying that in detail.
An alternative to extracting uranium from seawater would be to extract thorium from it, which is much more abundant and so would have a greater EROI without going to a breeder program.
The estimates given here for the abundance of thorium seem excessive, as they show it as 3,000 times more abundant in seawater than uranium!
http://environmentalchemistry.com/yogi/periodic/Th.html
http://environmentalchemistry.com/yogi/periodic/U.html
they nevertheless serve to illustrate that we could, perhaps, simply burn thorium extracted from seawater in CANDU reactors.
There is also a good understanding of how to increase the efficiency of CANDU reactors to very high levels.
I've tracked down better figures for uranium in seawater - the previous source I was suspicions of has it's decimals tangled.
Should be around 3ppm:
http://213.253.134.43/oecd/pdfs/browseit/6608031E.PDF
6608031E.PDF
This sounds reasonable, as thorium being around 3 times as abundant in the sea as uranium would tie in nicely with crustal abundances.
So by simply burning thorium instead of uranium, assuming the technology to get that from seawater is similar, which there seems no reason to doubt, the efficiencies Ugo suggests could be multiplies by 3 times, or maybe 4 if uranium could be extracted in the same process.
Since this has taken a just a few hours to work out, it does not seem as though any suggestion that this article proves the impossibility of ever obtaining all the nuclear fuel we need from the sea would be well founded.
David,
Your link says 3-4 ppb on p. 27, not ppm. This is in agreement with Ugo's table. On the other had, that figure is not better in any sense than what Ugo has given.
Chris
Sorry for the confusion - in any case, the point is that thorium is 3 times as abundant as uranium in the crust and seawater, if the decimal places would behave themselves.
Of course, no research has been done on the practicality of extracting thorium from seawater, as it is so cheap and abundant. if we do need to at some time in the future, decades away at least, at first blush it would appear that the economics of extraction and the EROI would be several times better than Ugo has suggested, even without assuming advanced burning technologies.
David,
I see the difficulty now. No, thorium is much less soluble than uranium: http://www.marscigrp.org/ocpertbl.html
Chris
Thanks for setting me straight on that Chris.
Scratch seawater thorium!
Good job there is plenty on land! ;-)
"simply burning thorium"
Burning thorium isn't that simple, I'm afraid. In short: There were (and are) several attempts to do this in pilot plants, but so far this wasn't successful.
My understanding is that thorium burn has been successful in CANDU reactors:
http://www.nuclearfaq.ca/brat_fuel.htm
If this is in error, perhaps you would supply better data.
Thanks.
I'm not an expert in this technology, but this was my conclusion I remember from a general research on this technology a few months ago. As for your weblink: Keep in mind that this document is from the Atomic Energy of Canada Limited, so the author may tend to have a rather optimistic look on the outcome. To be sure you should also check it with statements from neutral or sceptical entities.
I just grabbed the first one that came up on a list by googling, as it is, AFAIK, common knowledge.
If you don't like my link, do you actually have any links at all or information to support your statement?
Yes, of course, but from a certain point I concluded to discard this technology, so I didn't collect much data.
But if you find something that might convince me please free to post it right here or send me a short email.
Not a problem, and if I chance on anything authoritative I will forward it, as I have not bothered investigating as AFAIK it is not in question - incidentally the Westinghouse reactor is also supposed to be adaptable to burn thorium.
Perhaps it is worth pointing out though that I believe the conventions of this site, at least as I have observed them, are that when you are asked for your sources for statements such as you made you substantiate or withdraw - not liking the link I gave is on a different level to not having any backing at all.
I am not too bothered about it though, so unless I hear something from you which substantiates in some way your comment, I will continue in my previous persuasion.
I've spotted a more detailed discussion here:
http://www.world-nuclear.org/info/inf62.html
Thorium
You are correct in that not every issue is fully resolved especially the high cost of fabrication as thorium is cheap enough that reprocessing issues are hardly critical for the present, but the main reason for the lack of development appear to be the same as for all the more advanced techniques, that uranium is so cheap and plentiful at the moment that no-one has bothered to develop alternatives.
But to conclude from that that the difficulties are so severe as to warrant 'discarding the technology' as you have done is strange, and may perhaps indicate that you were in no mood to reach a favourable conclusion regarding the technology, IOW perhaps looking for an excuse to reject it.
Everything has some level of difficulty, and thorium technology is hardly unique in this.
Wasn't successful? I'm aware of two demonstrations said to be highly successful:
I think you've sucumbed to the hype here about the molten salt reactor. It did not have a breeding blanket. It did run on U233 for a little while.
Chris
what does breeding have to do with burning it? The U-233 bred from Th-232 burned just fine in both, and was bred nicely in Shippingport.
The MSRE did not require a breeding blanket to prove the system. The elements of neutron economy were proven in the reactors which made the U-233 for its test, and Shippingport demonstrated an all-up system in a converted LWR.
The MSRE is an example of the kind of reactors which
Do you propose that the U233 used was derived in a manner that was self-sustaining? If so, please provide details. Otherwise, stand corrected.
Chris
Define your terms, troll.
You're right, Chris.
The 1977-1982 Shippingport mini-reactor contained .55 tons of U-233 bred at a different breeder reactor and 40 tons of thorium to produce 235 MW thermal of power(60 MWe).
http://www.presidency.ucsb.edu/ws/print.php?pid=6972
If you want to evaluate the practicality of a thorium program you should look at India's nuke program which was required to use domestic thorium as fuel. They have 17 existing small(most <<500 MWe) mainly CANDU style heavy water reactors for a total for India of 3779 MWe, which is smaller than the largest single US nuke, Palos Verde and the largest nuke plant Japan's Kashiwazaki is 8500 MW.
The new generation of reactors for India are
uranium based and many of their current reactors
have been running half-loads due a shortage of uranium and are buying model Russian VVER-1000 design LWR instead.
They actually have a goal of 20000 MW of nukes in 2020. I believe they only think they can get there with uranium based technology.
Why is India ABANDONING thorium?
Well, they simply haven't been able to push the technology
and are still desparately dependent of uranium as I'm sure you can see as it is in the news(Singh-Bush agreement).
Thorium is certainly a fuel, but it currently will not satisfy nuclear cornucopians who are addicted to uranium whether they admit it or not.
http://world-nuclear.org/info/inf53.html
You are right to question the practicality of the thorium as a major nuclear program based entirely on thorium in India is switching to
uranium.
Rather than citing theoretical studies I'd like to hear the explanations for why this is happening in India from the thorium lovers.
Also CANDU heavy water reactors require much more heavy water than LWRs because deuterium is required for moderation AND cooling.
Abandoning the Nuclear Non-proliferation Treaty was a very grave error. One hopes that someone will have the guts to repudiate that move.
Chris
Russia current breeder reactor is a commercial size reactor 600 Megawatts.
It generates about 3800 GW·h/year.
Over 25 times bigger than Nevado One (one of the largest solar thermal electricity generators)
It is over 6 times more than all of the solar PV generated in the USA.
http://www.eia.doe.gov/cneaf/alternate/page/renew_energy_consump/table3....
http://www.world-nuclear.org/info/inf98.html
Construction has started on Beloyarsk-4 which is the first BN-800, a new, more powerful (880 MWe) FBR, which is actually the same overall size as BN-600. It has improved features including fuel flexibility - U+Pu nitride, MOX, or metal, and with breeding ratio up to 1.3. However, during the plutonium disposition campaign it will be operated with a breeding ratio of less than one. It has much enhanced safety and improved economy - operating cost is expected to be only 15% more than VVER. It is capable of burning up to 2 tonnes of plutonium per year from dismantled weapons and will test the recycling of minor actinides in the fuel. Further BN-800 units are planned.
Russia has experimented with several lead-cooled reactor designs, and has used lead-bismuth cooling for 40 years in reactors for its Alfa class submarines. Pb-208 (54% of naturally-occurring lead) is transparent to neutrons. A significant new Russian design is the BREST fast neutron reactor, of 300 MWe or more with lead as the primary coolant, at 540°C, and supercritical steam generators. It is inherently safe and uses a U+Pu nitride fuel. No weapons-grade Pu can be produced (since there is no uranium blanket), and spent fuel can be recycled indefinitely, with on-site facilities. A pilot unit is being built at Beloyarsk and 1200 MWe units are planned.
A smaller and newer Russian design is the Lead-Bismuth Fast Reactor (SVBR) of 75-100 MWe. This is an integral design, with the steam generators sitting in the same Pb-Bi pool at 400-480°C as the reactor core, which could use a wide variety of fuels. The unit would be factory-made and shipped as a 4.5m diameter, 7.5m high module, then installed in a tank of water which gives passive heat removal and shielding. A power station with 16 such modules is expected to supply electricity at lower cost than any other new Russian technology as well as achieving inherent safety and high proliferation resistance. (Russia built 7 Alfa-class submarines, each powered by a compact 155 MWt Pb-Bi cooled reactor, and 70 reactor-years operational experience was acquired with these.)
In China, a 65 MWt fast neutron reactor - the Chinese Experimental Fast Reactor (CEFR) - is under construction near Beijing and due to achieve criticality in 2008. There has been some Russian assistance in its development. R&D on fast neutron reactors started in 1964. A 600 MWe prototype fast reactor is envisaged by 2020 and there is talk of a 1500 MWe one by 2030. CNNC expects the technology to become predominant by mid century.
In India, research continues. At the Indira Gandhi Centre for Atomic Research a 40 MWt fast breeder test reactor (FBTR) has been operating since 1985. In addition, the tiny Kamini there is employed to explore the use of thorium as nuclear fuel, by breeding fissile U-233.
In 2002 the regulatory authority issued approval to start construction of a 500 MWe prototype fast breeder reactor (PFBR) at Kalpakkam and this is now under construction by BHAVINI. It is expected to be operating in 2010, fuelled with uranium-plutonium oxide (the reactor-grade Pu being from its existing PHWRs) and with a thorium blanket to breed fissile U-233. This will take India's ambitious thorium program to stage 2, and set the scene for eventual full utilisation of the country's abundant thorium to fuel reactors. Four more such fast reactors have been announced for construction by 2020. Initial Indian FBRs will be have mixed oxide fuel but these will be followed by metallic-fuelled ones to enable shorter doubling time.
======= from Wikipedia
Currently operating
Phénix, 1973, France, 233 MWe, restarted 2003 for experiments on transmutation of nuclear waste, scheduled end of life 2014
Jōyō, 1977-1997, 2003-, Japan
BN-600, 1981, Russia, 600 MWe, scheduled end of life 2010
FBTR, 1985, India, 10.5 MWt
Under construction
Monju reactor, 300MWe, in Japan. was closed in 1995 following a serious sodium leak and fire. It is expected to reopen in 2008.
PFBR, Kalpakkam, India, 500 MWe. Planned to open 2010
China Experimental Fast Reactor, 65 MWt, planned 2009
BN-800, Russia, planned 2012
In design phase
KALIMER, 600 MWe, South Korea, projected 2030
Generation IV reactor US-proposed international effort, after 2030
Gas-cooled fast reactor
Sodium-cooled fast reactor
Lead-cooled fast reactor
JSFR, Japan, project for a 1500 MWe reactor begin in 2010
It seems that these days we can't even get a conventional reactor that is efficienct enough to be economical. Lovins and Sheikh argue that the cost of new nuclear power is prohibitive and much higher now compared to superior alternative: http://www.rmi.org/images/PDFs/Energy/E08-01_AmbioNucIllusion.pdf
Our flirtation with breeders has mainly led to meltdowns. It seems very unlikely that breeders could overcome the issues already facing conventional reactors since their present poor circumstances are not yet primarily owing to fuel costs.
Chris
"Our flirtation with breeders has mainly led to meltdowns. " -- Reference please?
We have mainly focused on sodium cooled reactors for breeders. They populate the early portions of the list of nuclear accidents: http://en.wikipedia.org/wiki/List_of_civilian_nuclear_accidents.
Chris
There are 2 sodium reactor accidents out of 23 accidents listed there, neither of which appeared to hurt anyone or lead to major contamination.
Of those two accidents, one (1966) created no contamination outside the reactor vessel, and the other (1959) released an unknown amount of radioactive contamination (interestingly, the source does not support the claim of the wikipedia page that this release was "substantial", nor that 10 of 43 is "one-third"; some guy just arbitrarily re-wrote it to say that in April 2007).
Yes, sodium cooled reactors proved to be pretty unreliable so we don't use them now. Stupid design really since sodium burns in water.
Superphenix used to leak quite a lot of the stuff: http://query.nytimes.com/gst/fullpage.html?res=9B0DE7DA113CF936A25757C0A...
This video from Japan shows the results of one of these breeder accidents: http://www.youtube.com/watch?v=SiSqW6pFuR8
Basically, the things are very very dangerous.
Chris
You say that as if some evidence has show it, but no such evidence has been presented.
Are sodium-cooled reactors more or less dangerous than other reactors of similar development level (i.e., experimental vs. experimental)? We have not seen evidence of that, so we cannot reasonably conclude whether or not that is the case. You may be right or you may not be, but simply pointing to the existence of an accident involving a sodium-cooled reactor doesn't tell us one way or the other, as the number of accidents involving sodium is only a small fraction of the total.
So? From the sounds of it, leaking sodium didn't cause any damage or injuries.
Nothing is 100% safe, so the goal is to make the expected and worst likely cases as safe as possible. The risks of nuclear need to be understood in the context of 600,000 yearly deaths from air pollution, much of which is due to coal-fired power generation. Coal killed thousands in London in four days in 1952; compare that to 60 direct deaths from Chernobyl. Even counting all the eventual cancer cases, Chernobyl will still not match coal's toll from those four days.
The question is not "is this technology safe?", because the answer to that is "no", pretty much regardless of what technology you're talking about. The question is "is this technology safer than the alternatives?"
Importantly, "safer" has to take into account more than direct effects: it would most likely not be "safer" if all the world's coal plants shut down tomorrow - despite the hundreds of thousands of fewer pollution-related and mining-related deaths, the net result would probably be negative due to the societal disruption and loss of services such as refrigeration.
As I've pointed out elsewhere in the thread, our spending on nuclear power rather than renewbables is pretty much responsible for all coal related deaths in the last twenty years since we'd have more than replaced coal with the same level of spending on renewables. The opportunity cost of nuclear power is enourmous.
I invite you to investigate the history of the liquid metal cooled reactors. A large fraction have had meltdowns and others fires. This is not a very promising technology.
You seem to minimizing the direct death toll from nuclear power generation. A bias perhaps?
Chris
That doesn't make any sense. The technology for replacing coal with renewables wasn't available over the last 20 years, so how could spending on nuclear then be "responsible" for coal?
Your claim here is, on the face of it, kind of nutty. It requires a whole lot more explanation than you've offered.
No - reality is. There simply hasn't been much of a direct death toll from nuclear power generation, at least based on all the evidence I've seen. Go here for an introduction to the topic.
If you think I'm wrong, though, please by all means provide some evidence. If you believe the direct death toll from nuclear power generation for all time is higher than the direct toll for that one incident for coal, please provide some evidence showing that. As of now, all available evidence says the opposite.
Absolutely - I have a very strong bias in favour of evidence.
I can link again: http://www.repp.org/repp_pubs/pdf/subsidies.pdf
As you can see nuclear power was subsidised early and often but never produced electricity too cheap to meter and thus never displaced coal. We know for certain now that wind will be cheaper than coal and can thus displace it. The technology for today's wind might easily have been developed with the sort of subsidy nuclear has received much earlier and thus coal would no longer be in use.
Wind is now way ahead of nuclear in adding new capacity and will soon surpass natural gas, the current leader. We might have done this forty years ago and have been paying less for electricity all these years. Instead, we tried to pick a winner by putting all the subsidy into jee-wiz nuculur. Now coal mining deaths are on the rise again all because of this wasted detour with nuclear power.
All those comic books the government distributed in schools with propaganda for nuclear power: a complete waste. It has led to nothing but death and poisoning across our country. And now the pampered industry is so complacent that it can't even look to see if a problem it has already had is recurring: http://www.timesargus.com/apps/pbcs.dll/article?AID=/20080920/NEWS01/809...
There is no reason to have any confidence in the safety of nuclear plants in the US.
As to deaths from the one accident in Chernobyl, one estimate comes in at 30 to 60 thousand: http://www.greens-efa.org/cms/topics/dokbin/118/118559.torch_executive_s...
Other accidents have occured.
Chris
Quoth the troll:
Nuclear was also heavily penalized by the legal tactics of so-called "environmental" groups, many of which turned out to be financed by coal interests. The anti-nukes were objectively pro-coal.
Coal was also subsidized, with government research into variations such as MHD. Wind technology wasn't up to the job at the time; it cost upwards of 30¢/kWh in the early years, and hadn't a prayer of competing. It required advances in things like fiber composites to get where it is now.
If the external costs of coal were included, nuclear would have put it off the market 20 years ago and we wouldn't be having this discussion.
Wind has plenty of potential, but it's wrong to think that a system requiring materials and processes not developed until the 70's or 80's could have been competitive at the time with something feasible with techology of 30 years earlier. Only now is it closing that gap.
It takes some real illogic to pin the blame on a technology for deaths due to not using it.
Recent US energy funding analysis from Management Information Services. Which is more a more all inclusive study, looking at all energy and all kinds of support.
Europe went deep into feed in tariff support for wind and solar but they have not displaced their coal energy.
Chris, I really can't be bothered to get into yet another debate on the general subject of nuclear power, particularly since you have made it clear on many occasions that you are ideologically opposed to it anyway, and so though I spoke with the tongues of men and angels you would find another objection from somewhere, after having cherry picked your sources from those of like mind.
I am grateful to Ugo though for having clarified on a numeric basis why, with any reasonable assumptions of future technological progress, far less extreme than those assumed for renewables, we not only have plenty of nuclear fuel now but are likely to continue to do so for as far as we can see into the future.
For those who object to breeder reactors, there are other uranium burning designs possible, quite apart from the the thorium burning CANDU reactor.
I will continue to support the deployment of solar and other renewables as and when they become practical, but unlike others I feel that if we are in a shortage situation of low-carbon fuels, the thing to do is jolly well get on with it and build what we can.
David,
Why reply if you are not interested in discussion? I did not reply to you in the above comment. As Ugo points out, you have incorrectly interpreted his article. You seem to wish to persist in that error here. That's rather sad I think.
Chris
I replied so as to affirm the boundaries of what I was and was not prepared to debate.
Since Ugo's comments are relevant to the topic of this thread rather than being a more generalised discussion I will comment that although it is clear that although he wishes to infer from the data he has presented that the extraction of nuclear fuels is impractical, I am perfectly at liberty to draw a different conclusion from the same data that he has amassed, that form his figures either the extraction of thorium is likely to be practical, or uranium with modest advances in present reactors.
It is therefore clear that there is no misunderstanding of the case he wishes to present involved, but a different conclusion.
Well David, that seems just a little campy. But, I suppose you can continue to misread the article if you choose.
Chris
Just as you can and will continue to entirely misread what I write.
It is pretty clear. I understand very well what he is arguing based on the data he gives.
I disagree with his conclusions whilst accepting the data.
There is nothing very complicated there.
Dave, I think you miss the point, there are at least a trillion barrels of oil in the world but they get less and less affordable the more depleted the reserves get, so consumption will peak - in short, consumption of oil has nothing to do with oil reserves, but the affordability of reserves.
The same is true of uranium, thorium, indium, lithium, phosphorus etc etc the reserves have nothing to do with consumption it has to do with affordability - low concentration reserves will be less affordable than those in current use, so production will peak - production will NOT keep growing forever.
But most important of all, if the alternatives to what we are using now are less affordable than now we will use less than now - and less and less as time goes on, not the more and more you envision.
I think we are pretty close to peak nuclear power now just because the Price Anderson liability is now so large that a single payout could bankrupt the government. There might be an opportunity to privatize the risk using AIG as a vehicle but that won't help to delay the peak because the actuaries will want to close most of the Entergy plants owing to poor operations and a number of others besides owing to too high real estate values near the plants. http://www.theoildrum.com/node/4555#comment-411423
I don't think it will be fuel shortages that end the use of nuclear power but rather other costs which are too high.
Chris
I based my reply on the arguments Ugo made.
He found the EROI marginal for seawater extraction of uranium and the area needed large.
I pointed out that this was assuming present day efficiencies for reactors, indeed he specifically says that they would not apply to breeder reactors.
It is therefore clear that if we use either breeder reactors, which we have a good idea of how to do and working examples his figures prove that this would be entirely practical.
Other designs are also perfectly practical by the time we need them, as we have enough uranium to go on with, and in addition thorium is around 3 times as abundant as thorium in seawater as well as the earth's crust and so it seems that he has set our minds at rest about not only present supplies but future availability as we know perfectly well how to produce power with thorium reactors.
It boils down to the flow rate being just fine, according to Ugo's figures, given modest efficiency improvements in burn over the next 20 years or so.
Cost estimates for the production of uranium from seawater are available here:
http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/mirai-en/2006/4_5.html
4-5 Confirming Cost Estimations of Uranium Collection from Seawater
Uranium when burnt with any reasonable efficiency is such a dense energy source that it is extractable at very low concentrations, and so is thorium - note that I did not try to make the same argument for lithium, as I don't bother worrying about far out technologies like fusion which may or may not work, and if you need batteries there are a number of alternatives, one being zinc which Toyota is looking at as a replacement for lithium.
No way lithium could be economically extracted from seawater, but Uranium and thorium could be according to the best figures we have.
The reason we have not bothered is because there has not been a shortage of cheap uranium, the same reason as for the lack of reprocessing in the States, or the slow development of breeders.
Perhaps it is more productive to consider the numbers for specific resources, rather than going for broad semi-philosophical statements, like we will have to cope with less and less - presumably, the counter to that is some sort of faith in the inexhaustible nature of human ingenuity, which is not a statement which I would go along with or particularly useful.
If we are said to be running out, I want to know of what and why?
It appears that from the figures Ugo gives that either if we use thorium or modestly increase present uranium burn efficiency, we are in no danger of running out of nuclear fuel at any rate, whatever may be the case for lithium or phosphates.
There is no problem at the moment, and as far as can be calculated, likely to be no problem for the foreseeable future.
I believe he'd be infringing on your territory if he did. You have a history of doing this, as you did to me here.
I corrected him once as did Ugo, thus my remark. I corrected you once but you seem to have lost all sense of the thermal issues. 500 feet down? Isolated from the environment? A complete fantasy.... This is much worse than your insistence that home cogen is a more efficient use of gas than modern turbines. Sometimes you get the numbers wrong. Here you've completely missed basic physics. Every once in a while when I correct David, he thanks me. You might give that a try too.
Chris
Behind a multi-foot concrete barrier? Isolated from the environment? Standard practice since the 1950's. (Extracting heat is simple: you pump cold water INTO the concrete vessel through a pipe, and take steam OUT through another.)
But not good enough to satisfy the more paranoid among us, so the reactor should be put behind more mass but less physical distance. This provides isolation from anything less than a multi-megaton nuclear weapon, and allows the heat to be brought up to heat homes, businesses and industry with a simple thermosiphon loop.
I won't expect you to agree with this. Your ability to appraise physics goes out the window when something violates the tenets of your ideology.
Are you really serious that all you want to do is to provide heat? No electricity? I'm sorry if I've misunderstood you. In that case, this seems just stupid though not crazy as it seemed at first.
You can store solar energy in the ground at less depth for winter heat. There is no need to try to run a seasonal reactor. I guess you're just in it for the jee-wiz effect. Nothing practical in this I think.
Chris
No. Who would operate a system at 650°C or more just to provide space heat for houses? You have to be willfully blind to even think that (which I am sure that you are).
The point is that all heat engines create substantial waste heat, and that heat has value for many uses if it can be delivered to where it's needed. 500 vertical feet is a very reasonable distance; several miles horizontally is not.
The reactors would provide high-grade heat to gas turbines as the primary heat engines, driving electric generators. The cold side of the gas turbines would be cooled by water, generating hot water or low-pressure steam. This hot water and/or steam would be sent to the surface for various domestic or industrial uses. The heat exchangers would require no pumps, just gravity.
There are a number of engineering riffs on this theme I won't go into, for the sake of brevity and not giving you anything else you can maliciously misinterpret.
So, half the year you need a 500 foot cooling vent and the other half you need a complex array of miles of distribution plumbing.
Small reactors are not cost effective. That is why we use big ones. We don't put them in the ground because that is too expensive. And, they are hands on. You need access.
Also, your cooling system is going to need a secondary lower temperature system because heat will build up in the rock otherwise and make operation difficult. This stuff runs on delta T, not just T.
Finally, you are right there with the ground water. You are not isolated from the environment at all. In fact, your leaks may well be the worst kind, like those at Los Alamos, impossible in principle to clean up.
Sorry you are so thin skinned about this.
Chris
You are getting increasingly irrational and trollish. If you can't bring yourself back to rationality, I'll act accordingly.
Half the year you use steam for space heat, and the other half you use steam to run absorption chillers for your A/C.
You mean small PWR's are not cost-effective. PBMR's appear to have different economics. MSR's have many of the same engineering properties as PBMR's.
Massive forgings would require much larger tunnels to move. Small, modular systems would only require small ones. You could also group several reactors together to make a larger power station but with a much smaller maximum component size. This was mentioned elsewhere in this thread, but you're blind to it. Or trolling.
Your blindness is showing again. Nothing says you've got to plug up all the tunnels after you finish construction, you just put sturdy doors in them.
You've gone from blindness to nonsense. Reactor containment buildings do not need secondary cooling systems, and there's always cold water if you need it.
If you go down a ways from where I'm sitting right now, you reach a layer of rock salt; if groundwater went there, it would have dissolved away millions of years ago. It's both easy and profitable to mine, to boot; putting reactors down there would have a revenue stream before any equipment was installed.
You are just getting silly.
Perhaps you'll see the problem if I were to suggest dumping biochar down a 500 foot hole to burn for carbon neutral cogen.... Do you begin to see why your thing invites derision? Maybe not, maybe that is you next proposal. If so, please don't give me credit for suggesting it.
Chris
Quoth the troll:
If you're going to stop at biochar, terra preta is a better option than dumping it down a hole.
An ideologue like you will deride any competing concept, especially if it's superior (and thus threatens your own).
Actually, it was proposed some time ago, and I have independently proposed it both stand-alone 3 years ago and as part of a comprehensive solution (step 8), which was received with no small amount of enthusiasm at the time.
But none of this will affect your position, because you're either a blinkered ideologue or a worthless troll (or both).
I see no mention a 500 foot hole in your biomass proposal. Stop trying to be a weasel.
Chris
<E-P comes in after a long day in search of an evening's relaxation. He fires up the web browser and sets it to load a set of tabs while he fills a highball glass with ice. Returning to the desk, he's reaching for the drawer where he keeps the cherry cordial as he spies a trollish name in a reply. He stops in mid-motion and shakes his head. Returning to the bar sink he dumps the ice, then goes to the freezer whence he extracts a frosty bottle of 151-proof Sarcanol. He pours himself 3 fingers neat and downs half of it. Properly fortified, he returns to the computer.>
Quoth the troll:
Indeed, no 500-foot holes are mentioned anywhere. Obviously the depth of the hole is paramount and must be exact. It must be 500 feet; neither 499 nor 501 will do, let alone 1000 or 5000. And carbon can only be sequestered as biochar in those exactly-500-foot holes, not in any other form or in any other place. Why, if you tilled it into soil somebody might come along with tweezers and pull it all out to grill some hamburgers or something. The world climate could be completely wrecked by careless Americans preparing food over Labor Day weekend.
I bow to your superior perspicacity and humbly beg your forgiveness for my impudence.
<Sarcanol finished, E-P goes in search of ice to pick up where he left off.>
Reread when you've come to your senses to see why you're in a hole on this one.
Chris
Here's a crutch for that comeback.
The global "flirtation with breeder reactors" has generated several times more commercial electrical power than from global solar power.
27 years for BN-350 (probably 1000 GWh/year) probably 25,000+ Gwh total
27 years and counting for BN-600 (3800 Gwh per year) probably about 80,000+ Gwh
Superphenix connected for two years 7700 Gwh total
How are any of the issues that you are bringing up going to alter plans in Russia, South Korea, China and India ? Japan is going to go along for the ride with Russia because their domestic issues will probably prevent them from going as fast as they would like.
Russia being flush with oil and gas money has ensured the funding of their breeder reactor program. Russia wants to stay an energy power long term and nuclear and breeder tech is their plan. Whatever happens in US politics and policy is irrelevant to this result.
Looks like the contribution of energy or fuel from these is "homeopathetic." At least Superphenix was quickly shut down. As we know from experience, the russian program is built on high risk.
Chris
You can tut-tut the Russian program all you want, but their program has been running and generating power for five decades. It will be greatly expanded, as will the India and Chinese programs and probably South Korea and Japan.
http://cns.miis.edu/pubs/week/070522.htm
Plans call for BN-800 to be commissioned by 2012, and the work on the next fast neutron reactor, BN-1800, to start immediately after that. [1800MW version of a fast breeder]
http://www.eng.runtech.ru/node/354
BN-1800 would complete 2018-2020
The real world which includes Russia and India and China. The real world will have a lot of breeder nuclear reactors.
Nice article Ugo as it made me think. What about the concentration of anions in seawater? Do you have any information? I was specifically thinking of phosphate as a source for fertilizer.
I recall that mineral phosphate is currently being deposited in some places on the ocean floor, but this is the best info on it I could find with a quick search.
If phosphate is precipitating today, it is near saturation and should be relatively easy to recover.
test
My connection goes on and off.... let me see if I can answer this comment. Yes; there is of course a whole field in anion extraction. Just think of sodium chloride, the main mineral extracted from seawater. I didn't examine this area in my paper; it would have been too long. But indeed it is a good question: can we extract phosphates from seawater? I think the concentration is way too small to be feasible, but that should be looked at in some detail