10 ms·
Thorium
- JohnRandall 14y agoHere's an introductory video (10 mins) http://www.youtube.com/watch?v=N2vzotsvvkw http://www.youtube.com/watch?v=N2vzotsvvkw a longer video http://thoriumremix.com/2011/ http://thoriumremix.com/2011/ (the surrounding links are worth exploring) and a summary http://cybercemetery.unt.edu/archive/brc/20120621060336/http://www.brc.gov/sites/default/files/comments/attachments/flibe_energy_-_lftr_thorium_top_ten.pdf http://cybercemetery.unt.edu/archive/brc/20120621060336/http... The important point to get is that the excitement is not just "thorium" (as the title of the thread suggests) but the reactor as well.
- Permit 14y agoDoes anyone know how much less waste Thorium produces when used compared to Uranium? Both this article and Peter Thiel's linked article say "less", but neither are exact.
- pkrein 14y agoIt's actually a bit hard to quantify. The true cost of radioactive waste is related to what type of radiation it emits (gamma? alpha particles?), how long-lived the radiation is i.e. it's half-life, and the actual quantity of that material that is produced per Watt. This triple-axis makes it a bit hard to quantify in simple terms, but the main idea behind thorium is that the waste has a significantly shorter half-life[1]. Depending on the exact reactor design, there may also be ways to reduce the quantity of secondary waste (like water that's been exposed to heavy neutron flux while transferring energy from nuclear core --> steam turbines). [1] : http://www.forbes.com/sites/williampentland/2011/09/11/is-thorium-the-biggest-energy-breakthrough-since-fire-possibly/ http://www.forbes.com/sites/williampentland/2011/09/11/is-th...
- ScotterC 14y agoThe best way to think of it is since U-233 is so much easier to burn then U-235 is like tinder instead of lumber. It reduces to much less and burns thoroughly.
- WiseWeasel 14y agoThere's also the huge difference between solid fuel rods used in uranium-fueled nuclear reactors and the liquid fuel used in molten salt thorium reactors. Solid fuel rods break down beyond use after less than one percent of the fissile material has been consumed, at which point the entire reactor must be shut down and the fuel rods replaced. With molten salt reactors, the fuel is constantly being replenished and the waste removed during operation, allowing a much larger portion of the fissile material (up to 99%) to be consumed before being treated as waste. http://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor#Economy_and_efficiency http://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor...
- g8oz 14y agoOfftopic: how did you get a .pk domain?
- umairsiddique 14y agohttp://www.pknic.net.pk http://www.pknic.net.pk
- JohnRandall 14y agoThere is a misconception about the waste from current reactors. In short, the waste is not waste (as in something useless to be discarded, disposed of). This is all explained in the long video linked in my first post so I'll not repeat it. So much so that two MIT students (and their Professors) have come up with the acronym WAMSR, Waste Annihilating MSR, http://web.mit.edu/nse/inaround/dewan-massie.html http://web.mit.edu/nse/inaround/dewan-massie.html and started a company. http://transatomicpower.com/products.php http://transatomicpower.com/products.php The LFTR itself can also burn the waste from a conventional reactor. http://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor http://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor (the item "Destruction of existing long lived nuclear wastes" in the "Advantages" section) This infographic is a nice compact presentation http://imgur.com/pm4Ux http://imgur.com/pm4Ux
- Gravityloss 14y agoYou have to understand a bit about the subject. 1. Current reactors have U-238 and U-235. U-238 turns into Plutonium and some of that fissions but some is turned into heavier long lived transuranics. U-235 is very rare so we can't run just on that: this is what is enriched with centrifuges (no chemical separation possible as it's chemically similar to U-238) and what people mean when they say we will run out of uranium. Most of spent nuclear fuel is still just U-238. Maybe one could simplify and say that the spent fuel is not "used up" : instead it is "poisoned". 2. Thorium reactors have Th-232 and U-233. Simplified, the Th-232 turns into U-233 when it absorbs a neutron. U-233 fissions very well and releases more than two neutrons when it captures a neutron. There's quite many steps up to transuranics from that where fission can still happen, so you get very little transuranics. 3. There is the "breeder reactor" that would use just U-238 by making plutonium out of that. But you need fast spectrum and it's hard to control. It would have plenty of fuel though since there's lots of U-238. 4. What's more significant is that since U-233 is so good, you only need very little. AND you can use thermal spectrum making control easy. The thorium system is very clever in so many ways but it only works well if you design the whole reactor concept understanding what you have - neutronics and chemistry. It's not very complex at all, just read up on it, the basics can be understood in a couple of hours. Then you understand why it produces less waste, consumes less fuel, why putting thorium rods to solid fuel reactors doesn't make sense (protactinium) etc etc...
- KitemanSA 14y agoThe answer, when compared to typical light water reactors is... A hell of a lot less. First, since Thorium is a byproduct of Rare Earth Element mining and Uranium is mined specifically, there is all the mining waste that is saved. Second, since Thorium is used up ~completely and Uranium is used only about 0.5%, you need about 200 times more raw Uranium metal than Thorium meaning even MORE mining waste. Third, all the extra metal is RadioActive Waste. Fourth, in making the solid fuel elements, various reactants etc. become even more RAW. Fifth, the pellets are clad, then assembled into bundles using metal that gets irradiated and becomes ever more RAW. Sixth, the vast majority of the fuel pellet is U238 which gets irradiated and some becomes transUranic elements, significantly more than in a LFTR. only then do the two become ALMOST equivalent in the amount of fission products made, though even there the LFTR can be substantially more efficient at turning heat into electricity, so less fuel needs to be converted. Oh, and most fission products decay to stability in hours, some take years, a few take a few hundred years and the rest are transmutable. It is the TRUs that represent the big storage problem. But guess what, LFTRs can burn them up too. Not only do LFTRs not generate significant amounts of "wastes" but they can burn the problem waste from PWRs. How cool is that?!!!
- mtgx 14y agoThis seems to be an update on the Norway story at the end: http://singularityhub.com/2012/12/11/norway-begins-four-year-test-of-thorium-nuclear-reactor/ http://singularityhub.com/2012/12/11/norway-begins-four-year... And how come he didn't even mention LFTR? http://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor http://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor
- pkrein 14y agoLFTR are a type of molten salt reactor, which is mentioned, though certainly not given enough attention in this first short article ;) will see what i can do.
- macrael 14y agoAre there serious arguments against Thorium? Or is it just early stage waiting to be a bit more experimented with before going mainstream?
- pkrein 14y agoyes. a recent nature article pointed out how thorium can be used to make uranium-233 which can be used to make nuclear weapons.[1] (see the conclusions section at the end of the article) here's a more detailed explanation: the "old" idea before this nature article was that the uranium-233 produced in thorium reactors would be inevitably mixed with uranium-232 (which isn't useful for making bombs). but the nature article pointed out that the real decay path is thorium-233 --> protactinium-233 --> (uranium-232 AND uranium-233), and that by separating the protactinium-233 from the thorium reactor's neutron flux after 1 month, you can ensure that the protactinium-233 converts to uranium-233 instead of uranium-232.[2] ... step 3 you can make a weapon. [1] http://www.nature.com/nature/journal/v492/n7427/full/492031a.html http://www.nature.com/nature/journal/v492/n7427/full/492031a... (sorry for the paywall :( ) [2] http://en.wikipedia.org/wiki/Thorium_fuel_cycle http://en.wikipedia.org/wiki/Thorium_fuel_cycle
- ScotterC 14y agoBut this isn't practical in reality. First of all, you need a core of U-233 to start the process but once you start you're adding thorium at different points in time so the fuel slurry is going to be always a mix of thorium, protactinium, u-232, u-233 and other various products which makes extracting anything a royal pain. There's much easier ways of isolating weapons grade uranium instead of trying to extract it from a ongoing fuel process.
- slurgfest 14y agoThe question isn't whether there are easier ways of producing, but whether the thorium reactor doesn't provide better concealment for producing what would bring unwanted attention when done in the 'easier' way.
- peasoup 14y agoThis Nature article throws some cold water on the claims that thorium isn't very useful for making weapons. http://www.nature.com/nature/journal/v492/n7427/full/492031a.html http://www.nature.com/nature/journal/v492/n7427/full/492031a... Unfortunately the article is paywalled.
- martey 14y agoThat Nature article was also linked in the original article. See point 3 towards the end.
- adam-f 14y agoU233 more readily fizzes than booms, since it fissions faster it tends to pre-explode before getting into a really good super critcal state (probably something to do with the .6 instead of 1.6 delayed neutrons per 100 fissions mentioned above, it also has a slightly better neutron production factor than u-235). U233 will have U232, which decays through some very high energy gamma emitters, making U233 impossible to smuggle through shipping ports etc... These gamma emissions also kill humans in minutes, so would-be bomb makers would need to use robots or other remote handling techniques to fabricate a bomb. This is something a rouge state would have a hard time pulling off, and is practically out of reach of basic terrorists. It's not impossible but it would be easier/cheaper to just mine/steal some natural uranium and build centrifuges. It's easy to make U233 from thorium and thorium is abundant, so, really, how would reactors make thorium/U233 more available to rouge states when they could basically make it themselves, and why would they choose the U233 route?
- fl3tch 14y agoDo you have an email address?
- KitemanSA 14y agoScorecard Uranium derived bombs extant ~20,000 Thorium derived bombs extant =ZERO. The US & USSR would have been making Thorium derived weapons if it were practical. We DIDN'T. That should tell you something.
- nwh 14y agoI'd be much more comfortble seeing resources going to improving solar and wind power. Storage of waste is always going to cause massive issues.
- stcredzero 14y agoThorium reactors can burn our current nuclear waste store, reducing its volume by an order of magnitude and the duration of dangerous radioactivity to under 300 years.
- DasIch 14y ago300 years is still far too long. You simply cannot expect most organizations to survive that long and remain trustworthy. Apart from that the real costs would still be very high.
- DennisP 14y agoThe point is, we have a lot of nuclear waste right now that needs containment for 10,000 years. Put it through liquid thorium reactors (or integral fast reactors) and you reduce the amount of waste by a couple orders of magnitude, while reducing the timeframe to 300 years. Do you have a better plan for it?
- danielweber 14y agoFrance seems to do okay by recycling it. Of course it's cheaper to just toss the old stuff somewhere and dig up fresh uranium.
- stcredzero 14y ago> 300 years is still far too long. 300 years is feasible from an engineering perspective while 300,000 years is not. We know how to build a storage facility that won't let materials leach into the water table for 300 years. > You simply cannot expect most organizations to survive that long and remain trustworthy. Not needed. > Apart from that the real costs would still be very high. We've already built buildings with the required longevity. You'll have to be more specific/give better support to your assertion.
- GiraffeNecktie 14y agoA pretty good article overall but he seems to go off the rails when he starts talking about construction costs and assumes that a thorium reactor would cost the same as a uranium reactor. My understanding is that a thorium reactor should be dramatically cheaper for a variety of reasons (no need for a big containment bubble for one thing).
- aidenn0 14y agoThat is currently all speculative. We don't know how much it would cost to build a thorium reactor. There is strong evidence that it would be cheaper, but has yet to be demonstrated. To quote the article: "Safety features of nuclear plants seem to dominate the cost. There are many claims about the inherent safety features of thorium Molten Salt Reactors. But those claims have yet to be proven in working prototypes. If thorium reactor designs and prototypes could prove the claims of inherent safety mechanisms, then thorium could dramatically reduce the cost of nuclear power."
- fatbird 14y agoI've seen several thorium-boosting articles like this, and none of them say why research and industrial development selected for uranium over thorium. Is it just because the initial research into power came out of weapons research?
- aidenn0 14y agoIt's really, really complicated, since nearly all R&D came from huge government funding and that means politics. A lot of it is that it came out of weapons research, and u-235 and Pu-239 were well understood from weapons research. [edit] Also, plutonium fast breeder reactors looked very attractive in the '50s since they could use U-238, with just Plutonium feedstock, and also produced material usable for weapons. It turned out that 1) it's Not That Easy and 2) we don't need more atomic weapons.
- Strshps1MoreTim 14y ago>> we don't need more atomic weapons Speak for yourself, the Pentagon, UK, France, Russia, China, India, Pakistan, Israel, North Korea, possibly others still replacing and/or building tons of those.
- ender7 14y agoPartially. Also, the first really "working" nuclear reactor was built for a submarine. However, every modern nuclear reactor uses essentially the same design. This has resulted in some...idiosyncrasies in this design.
- Symmetry 14y agoYup. One of the good things about the light water reactors that everybody uses is that you can make them relatively small. That's a big deal when you're deciding what sort of reactor to put on a submarine. And then everybody who knew how to make a nuclear power plant only knew how to make a light water reactor, and then lock-in happened.
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- stcredzero 14y agoNot only is thorium much more plentiful than Uranium, creating demand for thorium also solves diffuses the Chinese economic control of rare earth metals. Rare earths are plentiful in monazite sands as well as thorium and are available in the US. Right now, thorium is a radioactive byproduct that largely prevents economic extraction of rare earths. Build good thorium reactors in the US, and both energy and rare earth situations are alleviated.
- Tuna-Fish 14y agoThe rare earth situation has already been solved. Mining has restarted in the US and US will likely be self-sufficient in REE in 2 years.
- alecdibble 14y agoDo you have any citations? I'm not trying to nitpick, I am just interested in reading more.
- troymc 14y agoI was also curious, so I did some digging and found this article: http://www.sfgate.com/opinion/article/U-S-rare-earth-mine-revived-4057911.php http://www.sfgate.com/opinion/article/U-S-rare-earth-mine-re...
- Ras_ 14y agoAlso Europe could be somewhat self-sufficient in REE with just one new project (Norra Karr mine in Sweden).
- KitemanSA 14y agoWhich just means there will be a lot of free fuel available!
- allerratio 14y ago> but thorium reactors have been pretty experimental Not all thorium reactors. A good example for an industrial grade thorium reactor is the thtr-300 a high temperature thorium pebble bed reactor (http://en.wikipedia.org/wiki/THTR-300 http://en.wikipedia.org/wiki/THTR-300) > Thorium reactors are inherently stable, so “nuclear meltdowns” can’t happen. This was also one reason for the design of the AVR in Jülich and it's successor the THTR-300. Although there wasn't any "nuclear meltdown", there were various other problems: - Small amounts of water leaking into the primary cooling circuit. Bigger amounts could have lead to a buildup of hydrogen and oxygen which can cause explosions. This is very comparable to a meltdown - The pebbles proved to be not very stable. This lead to a bigger amount of radioactive matter being released into the surrounding environment by the THTR-300 - The AVR leaked a big amount of radioactive matter into the ground water - various other problems Newer thorium reactor types won't have these problems because they will be considered in their designs, but there's still the problem with the timeframe. Estimates are that 2030 is the time when Gen IV reactors will get rolled out (http://en.wikipedia.org/wiki/Generation_IV_reactor http://en.wikipedia.org/wiki/Generation_IV_reactor). Meanwhile Germany replaced 3.5% of it's electric power sources from 2010 to 2011 with renewable ones.
- mtgx 14y agoI think Germany replaced a lot more than 3.5% with renewable energy. http://cleantechnica.com/2012/07/26/germany-26-of-electricity-from-renewable-energy-in-1st-half-of-2012/ http://cleantechnica.com/2012/07/26/germany-26-of-electricit...
- quote 14y agoOne of you talks about absolute numbers, the other about % change. I don't have any numbers easily at hand but you might both be correct.
- slacka 14y agoIf you want to help raise public awareness of this issue, sign the petition on the We-The-People website to preserve U233 used to make LFTR reactors. http://wh.gov/5Rmc http://wh.gov/5Rmc More info can be found here http://thoriumpetition.com/ http://thoriumpetition.com/
- troymc 14y agoFun related trivia: I just read Robert A. Heinlein's first "Heinlein juvenile" (i.e. young adult) novel Rocket Ship Galileo. It was published in 1947. The rocket ship's power plant was a nuclear reactor using... thorium.
- pjscott 14y agoProbably not the best choice for fuel, though. It takes around a month after capturing a neutron for thorium to become fissile, and if they just needed to get to the moon and back, a thorium breeder reactor isn't going to be too helpful with that. Highly enriched uranium is the way the NERVA guys went. If they needed long-term power for a moon base, of course, it might be another story.
- cpeterso 14y agoAbove [1], someone pointed out that a thorium reactor would produce gamma radiation that is highly penetrating and heavily ionizing. Probably not the "roommate" you want in the small confines of a spaceship. :) [1] https://news.ycombinator.com/item?id=4913976 https://news.ycombinator.com/item?id=4913976
- JohnRandall 14y agoHere's a full, frank discussion of the use of thorium in a LFTR http://www.peakprosperity.com/podcast/79398/kirk-sorensen-detailed-exploration-thoriums-potential-energy-source http://www.peakprosperity.com/podcast/79398/kirk-sorensen-de... The nice thing about this item is that there's a transcript. For example, "Why thorium, not uranium?" Well the technicalities are explained (thermal vs fast reactors).
- CurtMonash 14y agoI took a nuclear engineering class in 1975. In essence we discussed three reactor design ideas: 1. Water, pressurized or otherwise. 2. Gas-cooled. 3. Molten-salt. The big problem with molten salt was that you sent it through a whole lot of pipes. Hence, the physical plant that would get radioactive was much bigger than just the core of a water-based reactor. Also, you just had to deal with a whole lot of radioactive sludge. A huge advantage was that the thing couldn't lose coolant and melt down; a catastrophic failure would amount to the molten salt sinking into the earth below. It seemed at the time that if any major change would be made, it would be to HTGRs -- high-temperature gas reactors. But it also seemed as if the true "best" idea was molten-salt.
- Kronopath 14y agoFor those interested, here's a TEDx talk about liquid fluoride thorium reactors and how they could be used to power a moon colony: http://www.youtube.com/watch?v=N2vzotsvvkw http://www.youtube.com/watch?v=N2vzotsvvkw
- joss82 14y agoCould someone please open a kickstarter for a new thorium reactor design and construction? I'll gladly contribute to the initial cost (probably billions) just to get a lifetime of free and CO2-efficient electricity. Couldn't this way of funding bypass most "big firm" inefficiencies and legacy cruft, just as SpaceX did?
- andrewjmcd 14y agoThere's a non-profit to support development of LFTR here: https://www.facebook.com/EnergyFromThorium?ref=nf https://www.facebook.com/EnergyFromThorium?ref=nf If you are an American, another thing you can do is sign the petition to stop the destruction of the U233. http://wh.gov/5Rmc http://wh.gov/5Rmc
- sneak 14y agoNote well that you are reading an article by someone who doesn't know the difference between fission and fusion (he says that a uranium fission reaction can result in a "thermonuclear explosion").
- pkrein 14y agommmm, yes quite inaccurate on my part. apologies. of course... uranium fission was a critical part of the hydrogen bomb ;) will correct that thanks.
- acd 14y agoPossibly Graphen coating of the metals could be used to solve the corrosion problem in molten salt Thorium reactors. If we solve the corrosion problem we get cheap abundant energy with little to no nuclear waste and little to no material which can be used to make weapons of mass destruction. http://www.gizmag.com/graphene-metal-corrosion/24434/ http://www.gizmag.com/graphene-metal-corrosion/24434/
- KitemanSA 14y agoWhat corrosion issue? It has already been shown the a combination of adding one additional alloying element to the Hastalloy N while keeping the salt slightly fluorine poor will greatly reduce the already minimal corrosion issue.
- tripzilch 14y agoShouldn't one rather frame this debate not as "proponents vs opponents" but as "scientists trying to figure out what is actually the case and hopefully inventing better nuclear power in the process"?
- KitemanSA 14y ago"Safety features of nuclear plants seem to dominate the cost. There are many claims about the inherent safety features of thorium Molten Salt Reactors. But those claims have yet to be proven in working prototypes." Actually, yes they have. The three main safety features have all been demonstrated. First, the working fluid is non-volatile, no pressure nor chemical reactivity to drive dispersion of trapped gaseous fission products like Xenon and Iodine. Those were the two significant dispersed radionuclides in Fukushima. Second, those same kind of radionuclides are removed from the salt continuously so there is not a store of them to BE dispersed. Third, any loss of power to the reactor will passively result in a dump of the salt into a non-reactive tank where it will be passively cooled. It will be "walk away safe"!