Liquid Fluoride Thorium Reactors?

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Is this technology feasible?
 
Do you really want to get me started on this? It could get long...
Creating demand for Th is GOOD. You get it anyway while mining for RE's which we need right now, might as well use the stuff, else it's a hazardous waste.

The glossing over by just stating some numbers in this amounts to telling a lie by leaving out a ton of the truth.

Several points. Th232 isn't fissionable. It's an input to a breeder that makes U233, which is about the best bomb stuff there is - and the most easy to separate from the waste. Ponder that. No centrifuges required, just "simple" chemistry (on some very hot crap, has to be done with robots at a distance, but still - simple).

That low number for utilization of uranium is true, but also untrue. Here's the deal.
When we decide to not reprocess fuel (due to the proliferation concerns like the above), yes, we only get a little of the energy out of the U. There are a couple reasons that Fukishima amply demonstrates. After some running, a fission reactor has built up, guess what, a buncha fission products (you hear about Cs137 as a biggie, but there are a lot). This means that even after you drop the control rods and there's no fission anymore, all this hot decaying stuff still creates heat that there is no way to turn off (other than waiting a long time, which is what they do when they stuff used fuel rods into pools - they are still so hot, radioactively and thermally, you can't process them again for a few years with any tech we have - too dangerous). That's not the only problem. Some of the things that build up as reaction products absorb neutrons, and thereby "poison" the reactor - after long enough, you can't even make it go critical anymore, unless you designed it to be damn dangerously (potentially) over-critical before this crud built up. So they don't design that way - they are trying to be safe the best they know how...(which could be argued either way how well that is). In the end, it comes down to how continuously responsible a set of humans can be, or become - taking human nature, greed, profit motive etc into account. The balance might not be good enough for we teenagers (as a species) yet.

The breakdown products from fissioning U233 are different, and it's a separate complex study from what you get from burning U235 while also breeding Pu239 out of the U238 always present (except in bombs and research reactors...).

But they are still there, and big time - the devil is in details I'd have to go look up to be sure about, but you're going to get nearly the same series of junk as byproducts, still have the excess heat even after you turn the reaction off, and nope, just dumping the molten salts into a different container doesn't fix that problem.

So, feasible, yes, desirable, maybe - we need energy, and Th is not only cheap, it's otherwise a problem we need to find a way to use up or get rid of. The problem of handling the thorium "waste" from RE mining is why we let China have that market back in the day.

But statements like "we'll never run out" - heck, that's an obvious falsehood, and things like that make the rest suspect.

Right now, only India seems to be interested in making mixed cycle Th->U breeders, and they are moving pretty slow (probably a good thing, this stuff has dangers and it's good to be careful).

Note, I've recently joined up at google plus and been having a ball over there. I'm signed up to do an official show Wednesday nights at 6 pm EST, as "Professor Doug Coulter" and am taking all comers questions and trying to answer them. We did a dry run last Sunday that brought in a huge crowd, and I went 5 hours and made my brain sore, but we had a ton of fun. For the first one (next week) we plan to do almost the same thing - which will include a demo run of my fusor and discussion of that and whatever Q&A the audience comes up with.

Kind of like being half a talk show host, half guest, with the entire audience interviewing you. There's some other smart guys out there too...fun.
 
"Unlike conventional nuclear technologies which we are used to today. The LFTR is different in two major ways.

1) It is fueled by Thorium, which is plentiful, cheap and profiliation resistant, something which no nation will ever need to go to war over because it is everywhere!

2) It is a liquid fuel reactor, unlike current technology which uses solid fuel rods. this is it's greatest strength, it can use up all the fuel put in and produces almost no nuclear waste AND does not emit pollutants!

Because it uses liquid salts as the medium of choice, it can use very efficient power generators (Brayton cycle turbines) that is about 11%-12% more efficient than steam turbines.

Because of the above traits, the LFTR is inherently safe! It has no risk of dreaded nuclear meltdowns or massive steam explosions. In that light, the LFTR needs no safety clearance zone around it, and if that wasn't enough, the small size of the LFTR means it can be built underground.

Additionally, because of the liquid fuel form factor, there is no need for extremely expensive manufactured fuel rods like those in traditional nuclear power plants. It's literally almost as easy as filling up a tank of gas. (Compare US$50-US$60million in fuel rods to an estimated $10,000 in Thorium in an equivalent LFTR). This same property means that all fuel reprocessing can take place onsite, there is no need to transport the waste fuel offsite to reprocess, thereby saving on security and cost of transportation."
 
Sorry Benjamin, those are non-factual statements. See my post above. I think we cross posted there.

That is good to know. I have heard about Thorium reactors on and off over the years. They always claim to be so much better than current reactors, but never seem to go anywhere with it. Now I know why!
 
Th seems nice at first, but unless and until we solve most of the same problems with the U reactors, there's not much point. The two main problems are the roughly 8 megawatts of heat even a turned off 1 gw reactor makes after being run awhile (that's about where we cut them off these days - Fukishima BTW broke that rule and had even more heat they couldn't dump without the backup systems - profit motive) - and that's always going to be around. It doesn't matter what state (solid, liquid, gas) the fuel and byproducts are in all that much - they're there, it's truly evil-nasty.

Reprocessing is one of those "scientifically feasible but politically prevented" kinds of things, but one I think we need to get over (speaking politically). If we reprocessed the fuel of a conventional reactor - the net waste volume goes down to near nothing and then storing what is the actual waste gets a whole lot easier - scientifically, that is, but still not politically. Tons become ounces. Waste/pollution comes in about 3 grades. Big ol chunks of now radioactive stainless steel - not dangerous, but there's a lot of it. You couldn't sleep in a pipe of it, but it will sit there safe - it's not that hot.

The original (or results of reprocessing) which is middling hot. Pu is a lot hotter than U, but it's something you'd put back in for the next "go" in a reactor - you've bred it from the U238 that was in the original fuel, and it's very energetic, not something to bury in a mountain but something to utilize. The trouble is, it makes good bombs.

Then there's all this short half life stuff that's super hot - by the very nature of this, the super hot stuff is also short lived, and this is your ounces from the tons of input.
Cs137, with about a 30 year half life (U is billions, Pu is tens of thousands of years), is about the worst one, but there are others too that are nasty - but only for a few half lives. The trouble is, this junk is SO hot that a golf ball size chunk will fry you to death if you drive over it at 60 mph...so it's kind of hard to handle, it all has to be done remotely. We're just about there with robotics good enough to do that with reasonable risks (define that one and we're home)...and that's really the next step we have to take.

But the problems there, which arise no matter the actual reactor tech - are political, not scientific. Different technologies for reactors give rise to different other problems and solutions, it's basically a separable debate - passive safety which all new designs attempt to have and so on. There's been a highly enriched U boiling water reactor in operation since the '40's with no big issues, and it's only 14" in diameter, and regulates itself by losing density when some of the content (U compounds dissolved in water) boils into steam - it works completely passively....no one mentions that one because....it's made out of bomb-grade material...kind of risky to have laying around in some people's minds. That one can't go bang - but if you stole the fuel and knew how, you could make a bomb....

And there we are back to politics...
 
But statements like "we'll never run out" - heck, that's an obvious falsehood, and things like that make the rest suspect.

Average content of continental Earth's crust is 10 ppm. You could mine 80,000 tonnes to get 800 kgs of thorium fuel, which can generate 1 GWyear of electricity - enough to supply all of the electricity requirements of a city of 1 million people (domestic, shops, offices, industry, etc., etc.), for 1 year.

Presently, we have to mine 3,200,000 tonnes of coal to produce the same amount of electricity, so mining the ground beneath you feet is a far more economical way of producing electricity, than the mining we do at the moment.

So, it will never run out - LFTRs can supply all of the energy (including liquid fuels for transport) to every individual on the planet (at developed world standards) for all of time (at least for the 5 billion years the Sun has left).

Get the benefits of LFTRs here: http://lftrsuk.blogspot.co.uk/p/benefits-of-lftrs.html
 
Definitely an area we should look into more. The real question I have is how capital intensive it would be to create these plants that use thorium? The video makes it sound safer, but there is always some sort of catch to these kinds of things. Why haven't we seen anyone develop this kind of plant?
 
The earth's crust is a lot deeper than we can mine it. And there's like, you know, farms, homes, and cities over a lot of it, and oceans over the rest...Do the math and forget the outrageous claims.

We'd have 100x more uranium energy if we mined what we knew, and reprocessed fuel too - nothing preventing us from doing that except stupid human politics and attitudes. The problem isn't the science here - a lot of things will and can work, including thorium breeders. Maybe even fusion - that one I'm working on and think I'm going to have some surprise very good results within another year.

The problem is stupid humans...and science sadly has no answer for that one I'm aware of. History says "let war kill the stupid violent ones" but we kinda gave up on mass wars after we got nukes. Good one way, but it doesn't let Darwin work right in another way.

In case you hadn't heard, I'm fully off-grid solar since 1980, and even drive my electric car (a Volt) off the excess power I generate on just one roof out of the 4 building campus I maintain here (3 more available!)...There's more than one way to skin a cat...I get 8-9 kw in full sun...Car takes 3.5kw to charge (4 hours from zero to full). A welder might draw 1.5kw...perspective, my man.

Politics is the art of the possible, and the only good thing about it is that it sometimes substitutes words for fists (or kinetic weapons).
 
Yet more outstanding information DCF. Thank you.

May you forever cause my head to hurt (-;

And may your efforts on the fusion front be successful in creating a source of energy that we can all believe in.
 
Thanks for that, rb.

Truly, the problems aren't scientific, they're human. Limitations on percieved re-elect-ability and funds prevent looking into a lotta stuff that's potentially fantastically good. Fusion is one such, Th reactors are another. In my own field, the tokomak has captured all the "spare" money - and spare money is damn scarce these days, which is why I, as a "true believer" simply made my own to fund the research on a couple of alternate approaches, because I (and a lot of others) don't think tokomaks are going to be "the way".

This produces a bunch of tinfoil hat types. A couple of science boards I inhabit have a few nut cases that are just so sure LENR (cold fusion) is being supressed, or that dense aether theory is the one - but those clowns never lift a finger or drop a buck on seeing for themselves....just whine that their favored thing ain't gettin all the bucks. India is at least getting going on Th reactors at all - they've got a lot of the stuff to play with, and a lotta mouths to feed so to speak. Which particular tech for breeders will turn out best is an open question at this point - no breeders of any kind have proved stable enough for humans to operate safely - they all melt so far.

There's a lot of stuff one could imagine would work until one has real engineering experience as well. It's not a simple "here's what to think" kind of issue. Making one state change in the fuel type ain't going to fix all the issues, it just moves things around in the trade-off space. Beginners don't realize this, that's all - so they think that some simple change is all that's required.

Sure, there's a simple change required - transform humans into angels. GoodLuckWithThat - we've been working on that how long and with what results so far? This doesn't matter with a lot of things, but for things where mistakes are VERY expensive, it matters more. Heck, we can't even seem to run a world economy on a beautiful planet full of resources and at least a big number of very smart people!

And now we think the only possible answer to a percieved lack of this or that (per too many capita) is to find a way to produce and consume more of it? That's too "inside the box" thinking, I believe.
It's not just a matter of always "more". It's a matter of how good a steward we are of whatever - that's now the weak spot.
 
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