12 ms·

Thorium Reactors

328 points by ivolo 14y ago

jakozaur 14y ago
Thorium has an enormous potential, but R&D + regulations cost will be huge. In case of the nuclear energy, they were covered partly by military, but that would not be the case for Thorium. I would be extremely happy, if instead of paying for war we would bet on that technology, but unfortunately it is rather unlikely that it will became commercial available soon. Still looks more promising than fusion reactor - ITER.
- inopinatus 14y ago
  I would bet money that China will get there first.
- InclinedPlane 14y ago
  Yup. Thorium isn't all sunshine and roses, there are some difficult fundamental problems requiring novel research to tackle, aside from all of the complex engineering issues of designing a real reactor. Uranium/Plutonium fission power is already billions of dollars and decades ahead of Thorium in those regards, so it'll likely be quite some time before a Thorium power plant is able to compete head to head with a Uranium one. More so, fission power in the developed world has been in a bit of political trouble for the last 3 decades or so, no one is building new fission reactors of any sort. Maybe the developing world can trailblaze the technology and prove that it's an order of magnitude or more superior to fission power, which might re-ignite interest for fission power in the US, Europe, and Japan.
  - pkrein 14y ago
    could you outline the problems with thorium reactors that you know of? i've been searching high and low to figure out what they are. obviously they exist, but they often seem brushed over and ill-defined. any extra light you can shed on it would be useful. thanks!
    - jakozaur 14y ago
      Thorium is not a fuel that could be use alone, you still need an enriched uranium: http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009factsheet.pdf http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009fac... So thorium reactors will still have some problems similar to uranium reactors.
      - thingification 14y ago
        Need for enriched Uranium: that is correct, though liquid fueled Th reactors are designed to operate as a closed system that breed and "burn" their own Uranium from the Th, starting from an initial supply of neutron flux to start the process. That source of neutrons, it's usually assumed, will be Uranium. LFTR designs breed U233 (as opposed to the U235 used in conventional "thermal" reactors). The people trying to revive liquid-fueled reactor development say that U233 is by far the most practical "starter" to provide the neutrons to start a reactor going. The US has a stockpile of U233, which would provide a significant advantage for in the US any race to develop the technology. Sadly, the US has a program costing hundreds of millions of dollars to destroy its stock of U233, thus throwing away that advantage, for dubious gain. Last I heard, they were due to have started by now. Video on the subject from the guy who did the excellent Thorium remix 2011 video (on skimming it seems it doesn't really explain why U233 is better than alternative neutron sources as a way to start the reaction): https://www.youtube.com/watch?v=-p49Sq7mbpE https://www.youtube.com/watch?v=-p49Sq7mbpE I don't think they're done destroying it: if you're a US citizen, I guess there's still time to write to your member of congress. "some problems similar to uranium reactors": I think you need to be much more specific for the comment to be useful.
    - fatbird 14y ago
      In every article about thorium reactors, I never see any real discussion of drawbacks, or why uranium triumphed over thorium early, so I asked here the last time this author's article was linked. I got good answers: http://news.ycombinator.com/item?id=4912614 http://news.ycombinator.com/item?id=4912614 The short version is that the typical thorium reaction still requires/produces U-232, which is weapons grade uranium, so you have all the same problems as before regarding proliferation concerns; and more seriously, the product U-233 produces a lot of gamma radiation, which is really deadly at a distance and terribly difficult/expensive to shield against by comparison to the radioactive products of U-235/238 fission reactors. Also, there's a general engineering issue that lots of work and research has been done on current reactor designs, while little has been done on thorium reactors, comparatively. Thorium looks good on paper, but there are bound to be a bunch of practical issues that come up that raise the expense and mitigate the advantages. Basically, uranium fission is far more advanced, practically speaking, so a better bet for commercial applications. ETA: And on reading the article linked above, I find that Mr. Reinhart addresses neither of these two issues.
  - cglace 14y ago
    "no one is building new fission reactors of any sort" They are building one in Georgia http://www.scientificamerican.com/article.cfm?id=first-new-nuclear-reactor-in-us-since-1978-approved http://www.scientificamerican.com/article.cfm?id=first-new-n...
    - InclinedPlane 14y ago
      Yes, I'm aware. I made an intentional sacrifice of accuracy to benefit brevity. If you look at a graph of new fission reactors built in the west you'll notice that it flat-lines. Taking into account this new reactor, that would put the rate of new reactor construction in the US at an average of somewhere around 0.06 reactors per year. At this rate we can expect to build 5 additional reactors in the 21st century...
    - uvdiv 14y ago
      29 under construction in China, simultaneously: http://www.iaea.org/PRIS/WorldStatistics/UnderConstructionReactorsByCountry.aspx http://www.iaea.org/PRIS/WorldStatistics/UnderConstructionRe... Rather an exception of course. But a big one.
  - thingification 14y ago
    How long it takes depends critically on what we say and do. "Fundamental problems"? I guess one man's applied metallurgy is another's fudamental research, but the problems are better characterised as engineering ones, not science ones.
- idupree 14y ago
  In the heyday of that military funding, the military wanted the plutonium. Now the military mostly wants to get rid of plutonium because it is a liability if it gets into the wrong hands. Thorium reactors are one of the few ways to get rid of plutonium, so maybe they'll fund this too! (/dreamy optimism)
  - uvdiv 14y ago
    This is dubious. The cheapest way to "get rid" of weapons-grade plutonium is to dilute it as fuel in conventional reactors (so-called "MOX fuel" -- MOX for "mixed oxide", mixture of uranium and plutonium). It's not difficult. This doesn't make economic sense, and has no other benefit, but it does convert weapons-grade plutonium into non-weapons-grade plutonium; and this is politically correct. (Non-weapons grade means: too much thermal, radioactive, and neutron contamination to be practical for weapons.) This is pure politicking, unless you think (e.g.) the US Air Force is in danger of terrorist pirates stealing its nuclear weapons. The US is doing exactly this: (NNSA is the National Nuclear Security Administration) http://www.nnsa.energy.gov/mediaroom/factsheets/mox http://www.nnsa.energy.gov/mediaroom/factsheets/mox
ComputerGuru 14y ago
His final point about a nuclear kickstarter project is made in jest, but may be truer than he realizes...
- sixdimensional 14y ago
  It's a wild idea... but has anybody tried it? Other than all the obvious reasons why a nuclear Kickstarter project might not work, why the heck not??? It would be an interesting experiment to see the response, if nothing else. NOTE: IANANE (I am not a nuclear engineer).
  - sixdimensional 14y ago
    Oh, I spoke too soon - try searching "reactor" on Kickstarter. Looks like the idea is floating around (and some documentaries regarding same).
gatsby 14y ago
Blake Masters has a great overview from Peter Thiel's Stanford CS183 class about the future of Thorium and why it may be a very promising cleantech energy solution: http://blakemasters.com/post/23787022006/peter-thiels-cs183-startup-class-14-notes-essay http://blakemasters.com/post/23787022006/peter-thiels-cs183-...
Retric 14y ago
There plenty of good things about Thorium, however the advantages are generally overstated. Yes it's more common but uranium is plentiful and a small fraction of operating costs. Yes, it produces less waste but The difference is minimal. In theory it's safer, but current designs are vary safe with a multi decade track record where Thorium's is unproven. So, while there are benefits the ROI on a multi billion dollor Thorium R&D progect are probably negative.
- stcredzero 14y ago
  > Yes, it produces less waste but The difference is minimal. As far as I understand, the difference is orders of magnitude! http://en.wikipedia.org/wiki/Thorium#Benefits_and_challenges http://en.wikipedia.org/wiki/Thorium#Benefits_and_challenges > So, while there are benefits the ROI on a multi billion dollar Thorium R&D progect are probably negative. It could be possible to rebrand Thorium and overcome many of the PR challenges of nuclear power. A solution to a substantial part of the global warming problem is indeed worth hundreds of billions.
  - danielweber 14y ago
    What do they mean by "long-lived waste"? Things that are highly radioactive stop being radioactive very quickly. Things that are lowly radioactive stay radioactive for a long time, but at low levels so you don't worry much about them. There's a middle "unsweet spot" of things that are radioactive enough to worry about but not radioactive enough that they quickly burn out. So where does thorium fit in that taxonomy?
    - pkrein 14y ago
      well -- it's complicated. i started building a javascript library (nuclear.js : https://github.com/reinpk/nuclear.js https://github.com/reinpk/nuclear.js) to calculate the decay chains... the problem is that short lived isotopes, which are dangerous, can decay into long-lived isotopes, but basically the decay chains are complicated. i'll do a post about that soon :)
    - 14y ago
avar 14y ago
I recommend the Thorium Remix 2011 for a good overview: http://www.youtube.com/watch?v=P9M__yYbsZ4 http://www.youtube.com/watch?v=P9M__yYbsZ4
tokenadult 14y ago
Back in May 2012, I happened to be on a drive while National Public Radio here in the United States was broadcasting a Science Friday story, "Is Thorium A Magic Bullet For Our Energy Problems?" http://www.npr.org/2012/05/04/152026805/is-thorium-a-magic-bullet-for-our-energy-problems http://www.npr.org/2012/05/04/152026805/is-thorium-a-magic-b... Many of the issues considered in that story are glossed over by advocates of thorium reactors. The author of the blog post kindly submitted here explicitly admits, "My last article about thorium as an alternative nuclear reactor fuel drew way more readers than I expected. I intentionally glossed over the complexities of specific reactor designs for the sake of simplicity, but in this article I want to go deeper." He mentions a number of interesting technical trade-offs involved in using thorium reactor fuel and the latest reactor designs as compared to earlier nuclear reactor designs, but the tone is still largely a tone of credulity, without a lot of examination of non-nuclear means of generating electrical power. The Physics Stack Exchange discussion of thorium reactors is interesting, http://physics.stackexchange.com/questions/20034/what-practical-issues-remain-for-the-adoption-of-thorium-reactors http://physics.stackexchange.com/questions/20034/what-practi... as is the article from The Guardian in June 2011, "Don't believe the spin on thorium being a greener nuclear option." http://www.guardian.co.uk/environment/2011/jun/23/thorium-nuclear-uranium http://www.guardian.co.uk/environment/2011/jun/23/thorium-nu... Advocacy groups are already mobilizing to cast doubt on thorium reactors, with webpages like "Thorium Fuel – No Panacea for Nuclear Power" http://ieer.org/resource/factsheets/thorium-fuel-panacea-nuclear-power/ http://ieer.org/resource/factsheets/thorium-fuel-panacea-nuc... (with a link to an interesting fact sheet, http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009factsheet.pdf http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009fac... that gets into the practicalities and economics of using thorium as a reactor fuel). It's not clear yet that thorium offers any economic or political advantages over the uranium that fuels the nuclear reactor that provides much of my home electricity. The two nuclear reactors here in Minnesota result in lower-than-average cost for electricity here, compared to the rest of the United States, and have had a perfect safety record. Ongoing concern about where to store high-level radioactive waste on a long-term basis has made many politicians here reluctant ever to approve another nuclear plant in this state, despite the perfect safety record and inexpensive electricity we enjoy with the current plants. Minnesota, as a matter of state policy, is strongly promoting wind energy, fitting the wind-swept prairie geography of much of the state. I'm not aware of any part of the world where local politics would make a thorium plant more likely than another wind power plant or natural-gas-fired power plant. So maybe thorium power generation is a technical solution looking for a problem.
voidlogic 14y ago
I'm not any kind of nuclear expert, but it sounds like the author is comparing Molten Salt Reactors to 1970s era traditional reactors: "and the decay heat from these products requires continuous cooling for weeks even after core shutdown. That cooling process also must be human managed and actively powereed." My understanding is the reactors currently under construction in the US are being built with passive fail-safes that make them much safer than the 1960s/70s reactors. Is this incorrect? http://www.world-nuclear.org/info/inf41.html#New_build http://www.world-nuclear.org/info/inf41.html#New_build
- uvdiv 14y ago
  My understanding is the reactors currently under construction in the US are being built with passive fail-safes that make them much safer than the 1960s/70s reactors. Is this incorrect? Modern passive heat-removal systems are limited: the ESBWR mentioned on that page -- one of the most "advanced" -- has about 72 hours of heat-absorption capacity. [0] [0] https://en.wikipedia.org/wiki/Economic_Simplified_Boiling_Water_Reactor#Passive_safety_system https://en.wikipedia.org/wiki/Economic_Simplified_Boiling_Wa...
  - voidlogic 14y ago
    Thanks for the info. `one of the most "advanced" -- has about 72 hours of heat-absorption capacity.` That is still a pretty decent "oh shit" buffer. I imagine Fukushima or Chernobyl would have benifited from 72 hours extra to get their act together.
    - uvdiv 14y ago
      I imagine Fukushima or Chernobyl would have benifited from 72 hours extra to get their act together. Well, I'm not sure. Chernobyl isn't relevant because its issue was one of supercriticality (milliseconds, explosions), not decay heat (hours, gradual melting). In Fukushima, there actually were passive systems, not as sophisticated as ESBWR, and some failed instantly (a steam injector in reactor #1). And IIRC off-site power too a lot longer than 72 hours to restore, but I don't know if the explosions contributed to this. I'm not a nuclear engineer so I can't meaningfully assess this. But there is data here. As a curiosity, ESBWR is actually a direct descendant of the BWR/3 at Fukushima, from the same designer (GE Nuclear). Not a scare tactic: I'd be pretty happy living next to an ESBWR.
krschultz 14y ago
Great article, I would love to see more of this kind of stuff on HN. The 350 million dollar question is why the government has to be the sole source of funding. Obviously the cost is very high, the regulations are very intense, but where are the VCs willing to tackle this kind of "startup" (in reality it would likely be more of a public/private partnership). It's a longer view with higher cost but the payoff could be massive. Big innovation isn't going to happen if it requires congress to agree on supporting it for 10-20 years.
- pkrein 14y ago
  from what i understand http://flibeenergy.com/ http://flibeenergy.com/ shopped around at VCs in Silicon Valley, but apparently it didn't work out? i think the trick is to find an angle into the business that doesn't involve govt approval up front. some aspect of the problem that can be solved to show momentum, without hitting regulations. maybe the chemistry side of things?
  - krschultz 14y ago
    SpaceX had a lot of the same challenges but the first money making contract - flights to ISS - was only about 5-10 years out. NASA also paid them when they hit certain design milestones toward that contract. I would think that the best path forward on this would be for the DOE to setup similar milestones w/ large cash rewards. Private companies compete on getting to those milestones with oversight by the appropriate regulatory bodies. Then once through the initial milestones the company could actually build a small scale reactor, make money on it, then build a large scale and really make some money. Not saying it is going to happen, but that is MORE likely to happen than the DOE building this kind of reactor themselves.
    - apendleton 14y ago
      SpaceX also had the advantage of a very wealthy founder willing to pour lots of his own money into the project. This certainly wasn't enough to finance the entire development up until the first ISS flight, but it did allow him to hire a bunch of hotshot engineers right from the get-go, and probably establish a degree of legitimacy that made attracting more funds, government contracts, etc., somewhat easier. I'd wager that if Elon Musk had decided to fund LFTRs instead of rockets, we'd already have a prototype.
rapind 14y ago
Apologies for the off-topic comment, but I really love the layout and style of this blog. Any chance it's not a custom jobby and someone knows where it's from?
- AlexDanger 14y ago
  I agree its amazing. Reminds me of svbtle.
  - rapind 14y ago
    Yeah, very similar, but I like it even more than svbtle.
    - rdl 14y ago
      I hate the misuse of the pk ccTLD, though. In general I don't care that much, but anything related to nuclear technology related to Pakistan produces an automatic "reach for the safety catch on my Browning" stress response.
jcfrei 14y ago
There was an interesting study by the national nuclear laboratory of the UK comparing thorium and uranium: http://www.decc.gov.uk/assets/decc/11/meeting-energy-demand/nuclear/6300-comparison-fuel-cycles.pdf http://www.decc.gov.uk/assets/decc/11/meeting-energy-demand/... the article is difficult to understand for a layman as myself but an important fact (among others) is that the uranium reserves on earth are considered to last for 100 years at 2008 levels of consumption. furthermore if demand rises, higher prices will make accessing more reserves economically viable. hence resource availability doesn't appear to be a concern for the near term future.
- uvdiv 14y ago
  the article is difficult to understand for a layman as myself but an important fact (among others) is that the uranium reserves on earth are considered to last for 100 years at 2008 levels of consumption. An even more important fact is that uranium nuclear power is a couple of percentage points of 2008 energy consumption, and energy demand itself is growing exponentially. The metrics the DECC bureaucrats are plodding through are no-growth extrapolations of past trends. If clean energy is to be a reality, and if nuclear power is that clean energy, then we must scale it up by three or more orders of magnitude, and sustainability within the century is (potentially) a critical issue. DECC bureaucrats aren't considering this in that report; they are being conservative, in a bad way. Don't look to government bureaucrats for revolutionary vision ;)
  - dalke 14y ago
    "Don't look to government bureaucrats for revolutionary vision" Which bureaucrats should we look to? ;) You seem rather negative towards bureaucrats. Some bureaucratic positions are influential. Some people have visions which they can't do on their own or in a company. Some people figure out that the best way to achieve those visions is to become an influential bureaucrat. Vannevar Bush is one of those. He had a vision of how he wanted the US to fund science research. That vision became the NSF. His bureaucratic work started much earlier. For example, he was a key figure in organizing the Manhattan project. Other bureaucrats with vision include: Secretary of Commerce Herbert Hoover (Hoover Dam, and more importantly the interstate compact which lead to it), the Health and Environmental Research Advisory Committee of the DOE (to start the Human Genome Project), J. C. R. Licklider (his DARPA memo on the "Intergalactic Computer Network" lead to ARPANet lead to the Internet), and Viktor Zhdanov, Deputy Minister of Health for the USSR (call for the WHO to undertake a global initiative to eradicate smallpox; the previous smallpox vaccination programs were also government driven).
uvdiv 14y ago
A “fast breeder” version of a molten salt reactor has fast neutrons in the reactor core. These neutrons easily interact with the actinides, transmuting them into fissile isotopes and then fissioning them to produce energy. In other words, molten salt reactors burn actinides. The same is not true for traditional uranium reactors because they have thermal (slow-moving) neutrons in the reactor core. Neutrons at these slower speeds don’t interact with the actinides, so you can’t burn actinides in a traditional uranium reactor. This is no different from a panoply of fast breeder reactors which are NOT molten salt reactors, particularly liquid-sodium cooled (solid-fuel) reactors. The difference is that liquid sodium reactors have dozens of commercial-scale demonstrations, and hundreds of billions of $$$ of R&D investment -- whereas the molten salt fast breeders (chloride salt reactors) are nothing more than paper models to date. As a side note, it looks like using thorium as a fuel is not actually critical. Thorium can be used as fuel in molten salt fast breeder reactor, which is a benefit for long-term sustainability, but thorium has little relation to the cost of constructing a new reactor today. There's a plausible suggestion that liquid-fuelled reactors could be cheaper than LWRs. E.g.: they are far more compact (smaller), and the nuclear components apparently have less complexity. (Speculative) But the point is an important one. The "big" selling points of thorium -- fuel efficiency, and spent fuel -- are very long-term issues. It's safe to argue they can be deferred. ("Thorium is premature optimization") As of this past month, China now has a $350m institute with 140 PhDs plugging away on molten salt fast breeder reactors. Actually they are thermal reactors (not fast breeders), and the focus is on solid-fuel reactors with molten salt as a coolant (although they are also considering molten-fuel reactors, as a lower priority).
- pkrein 14y ago
  thanks for the correction on china, will update!
  - uvdiv 14y ago
    Here's a source to back that -- a talk from one of the researchers involved: http://www.youtube.com/watch?v=5UT2yYs5YJs http://www.youtube.com/watch?v=5UT2yYs5YJs Relevant stuff (liquid-fuel vs. liquid-coolant) somewhere around @23:30.
raphaelj 14y ago
The future is fusion
- uvdiv 14y ago
  The near future is fission. Fission reactors are compact, dense, cheap, and actually work.
- lukifer 14y ago
  The future is also the heat-death of the universe. Lucky for us, how far off in the future things are happens to be relevant. ;)
realrocker 14y ago
Indian Thorium Breeding Technology: http://large.stanford.edu/courses/2011/ph241/bhattacharyya1/ http://large.stanford.edu/courses/2011/ph241/bhattacharyya1/ Since we don't have enough Uranium and no one would sell us, It's pretty much our only strategy.
- thingification 14y ago
  This is true. However, the article is about molten salt reactors. The Indian program, as far as I know, is focused entirely on conventional solid fueled reactors. Most of the advantages of MSR aren't shared by solid fuel Th reactors. China already has an MSR program, but perhaps India could catch up if it switched tack quickly.
- uvdiv 14y ago
  You've been free to buy uranium from since George W. Bush backed you in a treaty modification with the nuclear suppliers group. You had been blacklisted before that, because your nuclear weapons pissed off the world (don't blame the world). https://en.wikipedia.org/wiki/Indo-US_civilian_nuclear_agreement#NSG_waiver https://en.wikipedia.org/wiki/Indo-US_civilian_nuclear_agree... A quick google search turns up the Australian PM agreeing to sell you uranium: http://www.abc.net.au/news/2012-10-18/gillard-visit-paves-way-for-india-uranium-sales/4319654 http://www.abc.net.au/news/2012-10-18/gillard-visit-paves-wa... "Prime minister Singh and I have agreed that we will commence negotiations for the nuclear safeguards agreement, the civil nuclear cooperation agreement given Australia is now prepared to sell uranium to India," she said.
  - justatdotin 14y ago
    well, that's one statement from the PM. it hasn't got through parliament yet, and this highly controversial proposal will face stiff opposition. Successive polls have shown that most australians are opposed to exporting our uranium to nuclear weapons states (tho I'll admit most respondants probably haven't connected the dots, since one major customer is us[a]). In the case of India, these concerns are magnified by the ongoing regional arms race and the recent violent suppression (including murder) of Indian opponents to the industry.
bd_at_rivenhill 14y ago
One issue with the review of previous nuclear disasters: Chernobyl was qualitatively different than Three Mile Island and Fukushima. The latter 2 designs were both water cooled and water moderated; both suffered loss of coolant (LOC) events which resulted in the core melting from residual decay heat as described in the article, with Fukushima experiencing subsequent detonations of hydrogen gas formed from reactions with the heated fuel rods (some have claimed that this happened at TMI as well, but clearly not to the same scale). The Chernobyl design (http://en.wikipedia.org/wiki/RBMK http://en.wikipedia.org/wiki/RBMK) is also water cooled, but is moderated by graphite, which is much more dangerous (and scary that there are still many of these in operation). Instead of a loss of coolant event, Chernobyl experienced an exponential power spike which pushed operating power up to 10 times normal, resulting in a series of steam explosions in the coolant lines that blew off the 2000 ton cover of the reactor, sprayed part of the core out the top to contaminate the immediate vicinity (i.e. large chunks of the graphite moderator lying on the ground outside the reactor building), and set the graphite moderator on fire. The fire then spread many more fission products into the atmosphere with the smoke to share the fun with people in a much wider area. Despite what has been written about Fukushima recently, I expect that it was a couple of orders of magnitude worse than Three Mile Island, which did not result in significant amounts of radioactive material escaping from the site (depending on whose analysis you believe); Chernobyl was between 1 and 2 orders of magnitude more severe than what we know about what happened at Fukushima at this point as far as I can tell.
- thingification 14y ago
  I'm told that Xe poisoning played a major role in Chernobyl. MSRs have a major advantage here because the Xe can easily be removed. In a solid fuel, it is not really possible to remove it, and it can cause instability because it causes time lag between control input and reactor response output.
- dmfdmf 14y ago
  Good review but "qualitatively different" is a bit of an understatement. tl;dr: Chernobyl/RBMK reactors are inherently dangerous in nuclear design and in operation without suitable containment structures, unlike Western reactors like TMI or Fukushima. TMI and Fukushima are comparable to a degree but it is important to note that TMI is a Westinghouse pressurized water reactor whereas the Fukushima plants are GE boiling water reactors. TMI had a LOC event due to a stuck pressurizer vent valve that went undetected after a reactor scram which, combined with incorrect assumptions in the operating procedures, led to a core melt. Fukushima experienced station black out which means loss of both offsite and backup power. The reactors shutdown and operated as designed for this scenario but the design basis assumption is that power would be restored in 4 or 5 days (don't know the exact number). It actually took more than a week to restore power due to the devastation of the earthquake and tsunami. Core cooling was maintained by discharging steam into the containment cooling pools but this method can not be run indefinitely and as the pools overheat it threatens the containment. Without a source of power the H2/O2 recombiners could not safely burn off the hydrogen which led to explosions of the reactor service buildings. In contrast, the RBMK reactors are graphite moderated but water cooled. The reason for this design was they were developed for civilian power generation by scaling up military reactors used for plutonium production for nuclear weapons (graphite moderator allows fuel extraction without shutdown). During low power operation, the RBMK design has a positive reactor power void coefficient. What this means is that an increase in power lowers the density of the water coolant which allows more neutrons to escape into the graphite moderator where they are slowed down and thus split more atoms. In other words these reactors have an inherently dangerous operating region where an increase in power can lead to more power in a positive feedback cycle. This is what destroyed the Chernobyl reactor. (Note that water moderated reactors such as TMI or Fukushima have a negative power void coefficient where an increase in power reduces the density of the coolant and moderator which allows neutrons to escape the core without causing a fission thus dropping power, the opposite of an RBMK) Of course the designers were aware of the positive power void coefficient, so they added safety systems to prevent reactor operation in bad regions. On the night of the accident, a maintenance shutdown was scheduled but on scram the operators wanted to run a turbine spin down test, i.e. after the scram, see how long the residual steam could drive the turbines before backup systems had to be operational. Previous attempts to run these tests had failed and the operators were pressured by Moscow to get it done or else (Siberia?). To maximize the chance of a successful test the operators maneuvered the reactor into the low core flow, low power region of the reactor's operating domain with the dangerous positive void coefficient and thus positive power feedback. To get the reactor into this state the operators had to override numerous safety systems designed to prevent such operation. At the commencement of the test there was a power excursion that led to a power runaway that cause a steam (not a nuclear) explosion that blew the lid off the reactor. One final important point, the Chernobyl reactors (and all RBMKs) are not housed in any containment structure like Western reactors (they are too big). The containment buildings of reactors like TMI or Fukushima are designed to withstand and contain the operating energy and nuclear material should anything go wrong and as these accidents have shown, they work. The Chernobyl accident was made much worse because the lack of containment allowed widespread dispersion of radioactive material due to the explosion and subsequent graphite fire.
justatdotin 14y ago
s/weapons//g hmmm.. thorium reactors would still produce unmanagable high level nuclear waste (tho not as bad, not as much), and would still open up significant weapons proliferation vectors, both material and capacity. As for safety, these designs merely substitute one catastrophic failure mode (meltdown) for another (volatility of the continuous onsite reprocessing) inarguably, thorium designs offer stepwise improvements to the major disqualifications of catastrophic failure, unmanagable waste production and WMD prolifertaion. But I'm concerned that we should judge the nuclear industry on its present day detriments and hazards, not the promises of future designs. there's a big thorium mine down the road from me - well, a big rare earths mine, where the dominant product is thorium. They're planning to come and bury all the (enriched) thorium back on site after extracting the lucrative rare earths. I read that as a pretty clear indication of the state of the market. (incidentally, and as far as minesite impacts go, the thorium mine is going to be at least as hazardous as a comparable uranium mine) When Chernobyl went off, we were told don't worry, it's an outdated design, the new reactors would never do that. When Fukushima went off, we were told don't worry, it's an outdated design, the new reactors would never do that. Who can guess what they'll tell us when Indian Point goes off? this is an industry that has consistently over-promised and under-delivered. Remember "energy too cheap to meter"? by their deeds, not their words. let's try to manage the industry by the realities of today, not the promises for tomorrow.
martinced 14y ago
I've got one question... The main issue is that now at Fukushima there are products like Cesium-90 in the sea, contaminating the entire sealife, which have crazy long half-life (ninety years). Thankfully they're "heavy" so they go down towards the center of the earth, but only at about 5 cm per year. So in ten years the're going to be highly radioactive Cesium-90 at 50 cm behind rocks still polluting the sealife. In case the worst sht happens: the worst SNAFU conceivable... Would MSRs also generate highly products like Cesium-90? I mean: I don't care about all the security and the great design meaning an uncontrolled reaction shall never happen. I know: it won't happen. Just like Fukushima. It didn't happen because it couldn't. We got your point. It IS safe. But I tell you: a sht you didn't expect is going to happen (maybe an asteroid striking your reactor or whatever). What then? Would MSRs pollute less than Uranium based reactors in the worst of the worst scenario? If so I'm all for it.
- thingification 14y ago
  It's intermediate half-lives that are problematic. Very long half lives (for example, billions of years, like Th 232) are not a problem, because they have low activity (few particles emitted per second). Very short half lives (for example, minutes) are not a long-term problem, because they are entirely gone after those minutes. It's the middling half lives that get you: short enough to be highly active, long enough to stick around for years. So, Cs 137 and I 90 stick around for a few hundred years. That's bad, and LFTR still produces these. On the other hand, it's a lot better than the situation with conventional U reactors, because those produce transuranic elements with intermediate half lives measured in tens of thousands of years. There is a qualitative difference to human civilisation between 300 years and tens of thousands of years. LFTR produces those transuranic elements too, but in orders of magnitude less quantity -- that combined with the liquid phase leads us to expect that would be a much smaller problem than with conventional reactors. Wikipedia suggests some other LFTR advantages here, which I haven't thought about: https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reacto... Low mobility of radioactivity. Even if there is an accident beyond the design basis for the multiple levels of containment and passively cooled systems, fluorides do not easily enter the biome. The salts do not burn, explode, or chemically degrade in air and react only slowly with water. Fluorine combines ionically with most fission products to form stable fluorides. This is not only an MSFR's first level of containment, but also serves as a high inherent safety level during any beyond-design basis event. Fluoride is especially good at holding biologically active "salt loving" wastes such as cesium-137 and strontium-90, which are permanently bound as stable, nonvolatile CsF and SrF2. The fluoride salts of radioactive actinides and fission products are generally not soluble in water at lower temperatures. Even though Caesium fluoride is one of the fission product fluorides that is highly water soluble, its extremely high boiling point and chemical stability, combined with the lack of stored energy sources (hydrogen, steam, etc.) in the LFTR, prevent it from being blown into the air and carried with the wind to contaminate a large amount of land.[citation needed]
twentysix 14y ago
There was a TEDx talk I saw a while back by two MIT graduates working on a "Waste Annihilating Molten Salt Reactor". https://www.youtube.com/watch?&v=AAFWeIp8JT0 https://www.youtube.com/watch?&v=AAFWeIp8JT0 It looks promising and they have formed a start-up, http://transatomicpower.com http://transatomicpower.com http://www.forbes.com/sites/pikeresearch/2012/09/27/a-pair-of-mit-scientists-try-to-transform-nuclear-power/ http://www.forbes.com/sites/pikeresearch/2012/09/27/a-pair-o...
j00lz 14y ago
As much as I am interested in the topic. I could only read a few paragraphs, due to being irritated by the cheesy couple picture in the corner.
varjag 14y ago
The troubling attitude in TR advocacy is the claims of inherent safety. A sustainable energy-positive reaction can't be inherently safe. You can argue if it has better failure modes than the alternatives but it's harmful to ignore a multitude of factors which could be not yet considered. The previous catastrophic failures with other reactor designs were also not exactly forethought. For instance, xenon poisoning was little studied in the beginning of nuclear era. It is not implausible some critical piece of knowledge is missing in the current evaluation of "safe" designs. Another thing is too much reliance on the neat presentations. E.g. this blog refers to a freeze plug as a kind of panacea of any mismanagement. What if freeze plug fails for whatever reason? Like, tectonic activity breaks the pipework, or it's sabotaged, or groundwater leaks into the dump tanks?
louischatriot 14y ago
Of course thorium reactors is not a proven technology but if there is a scientific consensus saying it is promising, I don't see why utility companies and civil nuclear reactor manufacturers try to make it viable. They have everything to gain, in my opinion. Tldr of the article: http://tldr.io/tldrs/50f73bbe983c81b86a00012b/thorium-reactors http://tldr.io/tldrs/50f73bbe983c81b86a00012b/thorium-reacto...
Create 14y ago
As far as I know, there are no (public) models on Th reactors. The most advanced is an analytic simulation (without CFD) from a Chinese nuclear engineering lab, but nobody has a real clue about the precise input variables anyway, therefore no MC is even in sight, as of today. But marketing is well advanced. And as the Japanese say, assuming we do have a functionally correct model and a Th reactor design (or designs, since there are several configurations), that still doesn't say anything about the economic aspect (I do not mean the old economic model, where the byproduct of plutonium factories were sold as energy).
lucian303 14y ago
The Downfall in the US is that no new nuclear reactor of any kind has been built since the 70's and no significant funding or consideration has been given to this (other than weapons, nuclear warheads can be delivered in every conceivable way of course) and there is a culture of irrational fear around the subject. Especially in Congress. We will see a new nuclear reactor of significant size in America when pigs fly. The fossile fuel industry and the politicians entrenched in it are getting way too rich to let something like this happen in our lifetimes. And really thinking about it, we are already 40++ years behind. When you consider that 1 out of 2 Americans think the world will end in their lifetimes this is not surprising.
Barosan 14y ago
See this recent EnergyFromThoriumFoundation facebook album for a historic brochure about ORNL's Molten Salt Reactor Experiment between 1965-1972. https://dl.dropbox.com/u/15726934/Historic_Molten_Salt_Reactor_Experiment_Brochure_ORNL_1965-1972.pdf https://dl.dropbox.com/u/15726934/Historic_Molten_Salt_React... http://www.facebook.com/media/set/?set=a.10152449471560377.951501.10150132132910377&type=1&l=91f3ea2327 http://www.facebook.com/media/set/?set=a.10152449471560377.9...

328 points by ivolo 14y ago

Thorium has an enormous potential, but R&D + regulations cost will be huge. In case of the nuclear energy, they were covered partly by military, but that would not be the case for Thorium. I would be extremely happy, if instead of paying for war we would bet on that technology, but unfortunately it is rather unlikely that it will became commercial available soon. Still looks more promising than fusion reactor - ITER.

inopinatus 14y ago
I would bet money that China will get there first.
InclinedPlane 14y ago
Yup. Thorium isn't all sunshine and roses, there are some difficult fundamental problems requiring novel research to tackle, aside from all of the complex engineering issues of designing a real reactor. Uranium/Plutonium fission power is already billions of dollars and decades ahead of Thorium in those regards, so it'll likely be quite some time before a Thorium power plant is able to compete head to head with a Uranium one. More so, fission power in the developed world has been in a bit of political trouble for the last 3 decades or so, no one is building new fission reactors of any sort. Maybe the developing world can trailblaze the technology and prove that it's an order of magnitude or more superior to fission power, which might re-ignite interest for fission power in the US, Europe, and Japan.
- pkrein 14y ago
  could you outline the problems with thorium reactors that you know of? i've been searching high and low to figure out what they are. obviously they exist, but they often seem brushed over and ill-defined. any extra light you can shed on it would be useful. thanks!
  - jakozaur 14y ago
    Thorium is not a fuel that could be use alone, you still need an enriched uranium: http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009factsheet.pdf http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009fac... So thorium reactors will still have some problems similar to uranium reactors.
    - thingification 14y ago
      Need for enriched Uranium: that is correct, though liquid fueled Th reactors are designed to operate as a closed system that breed and "burn" their own Uranium from the Th, starting from an initial supply of neutron flux to start the process. That source of neutrons, it's usually assumed, will be Uranium. LFTR designs breed U233 (as opposed to the U235 used in conventional "thermal" reactors). The people trying to revive liquid-fueled reactor development say that U233 is by far the most practical "starter" to provide the neutrons to start a reactor going. The US has a stockpile of U233, which would provide a significant advantage for in the US any race to develop the technology. Sadly, the US has a program costing hundreds of millions of dollars to destroy its stock of U233, thus throwing away that advantage, for dubious gain. Last I heard, they were due to have started by now. Video on the subject from the guy who did the excellent Thorium remix 2011 video (on skimming it seems it doesn't really explain why U233 is better than alternative neutron sources as a way to start the reaction): https://www.youtube.com/watch?v=-p49Sq7mbpE https://www.youtube.com/watch?v=-p49Sq7mbpE I don't think they're done destroying it: if you're a US citizen, I guess there's still time to write to your member of congress. "some problems similar to uranium reactors": I think you need to be much more specific for the comment to be useful.
  - fatbird 14y ago
    In every article about thorium reactors, I never see any real discussion of drawbacks, or why uranium triumphed over thorium early, so I asked here the last time this author's article was linked. I got good answers: http://news.ycombinator.com/item?id=4912614 http://news.ycombinator.com/item?id=4912614 The short version is that the typical thorium reaction still requires/produces U-232, which is weapons grade uranium, so you have all the same problems as before regarding proliferation concerns; and more seriously, the product U-233 produces a lot of gamma radiation, which is really deadly at a distance and terribly difficult/expensive to shield against by comparison to the radioactive products of U-235/238 fission reactors. Also, there's a general engineering issue that lots of work and research has been done on current reactor designs, while little has been done on thorium reactors, comparatively. Thorium looks good on paper, but there are bound to be a bunch of practical issues that come up that raise the expense and mitigate the advantages. Basically, uranium fission is far more advanced, practically speaking, so a better bet for commercial applications. ETA: And on reading the article linked above, I find that Mr. Reinhart addresses neither of these two issues.
- cglace 14y ago
  "no one is building new fission reactors of any sort" They are building one in Georgia http://www.scientificamerican.com/article.cfm?id=first-new-nuclear-reactor-in-us-since-1978-approved http://www.scientificamerican.com/article.cfm?id=first-new-n...
  - InclinedPlane 14y ago
    Yes, I'm aware. I made an intentional sacrifice of accuracy to benefit brevity. If you look at a graph of new fission reactors built in the west you'll notice that it flat-lines. Taking into account this new reactor, that would put the rate of new reactor construction in the US at an average of somewhere around 0.06 reactors per year. At this rate we can expect to build 5 additional reactors in the 21st century...
  - uvdiv 14y ago
    29 under construction in China, simultaneously: http://www.iaea.org/PRIS/WorldStatistics/UnderConstructionReactorsByCountry.aspx http://www.iaea.org/PRIS/WorldStatistics/UnderConstructionRe... Rather an exception of course. But a big one.
- thingification 14y ago
  How long it takes depends critically on what we say and do. "Fundamental problems"? I guess one man's applied metallurgy is another's fudamental research, but the problems are better characterised as engineering ones, not science ones.
idupree 14y ago
In the heyday of that military funding, the military wanted the plutonium. Now the military mostly wants to get rid of plutonium because it is a liability if it gets into the wrong hands. Thorium reactors are one of the few ways to get rid of plutonium, so maybe they'll fund this too! (/dreamy optimism)
- uvdiv 14y ago
  This is dubious. The cheapest way to "get rid" of weapons-grade plutonium is to dilute it as fuel in conventional reactors (so-called "MOX fuel" -- MOX for "mixed oxide", mixture of uranium and plutonium). It's not difficult. This doesn't make economic sense, and has no other benefit, but it does convert weapons-grade plutonium into non-weapons-grade plutonium; and this is politically correct. (Non-weapons grade means: too much thermal, radioactive, and neutron contamination to be practical for weapons.) This is pure politicking, unless you think (e.g.) the US Air Force is in danger of terrorist pirates stealing its nuclear weapons. The US is doing exactly this: (NNSA is the National Nuclear Security Administration) http://www.nnsa.energy.gov/mediaroom/factsheets/mox http://www.nnsa.energy.gov/mediaroom/factsheets/mox

ComputerGuru 14y ago

His final point about a nuclear kickstarter project is made in jest, but may be truer than he realizes...

sixdimensional 14y ago
It's a wild idea... but has anybody tried it? Other than all the obvious reasons why a nuclear Kickstarter project might not work, why the heck not??? It would be an interesting experiment to see the response, if nothing else. NOTE: IANANE (I am not a nuclear engineer).
- sixdimensional 14y ago
  Oh, I spoke too soon - try searching "reactor" on Kickstarter. Looks like the idea is floating around (and some documentaries regarding same).

gatsby 14y ago

Blake Masters has a great overview from Peter Thiel's Stanford CS183 class about the future of Thorium and why it may be a very promising cleantech energy solution: http://blakemasters.com/post/23787022006/peter-thiels-cs183-startup-class-14-notes-essay http://blakemasters.com/post/23787022006/peter-thiels-cs183-...

Retric 14y ago

There plenty of good things about Thorium, however the advantages are generally overstated. Yes it's more common but uranium is plentiful and a small fraction of operating costs. Yes, it produces less waste but The difference is minimal. In theory it's safer, but current designs are vary safe with a multi decade track record where Thorium's is unproven. So, while there are benefits the ROI on a multi billion dollor Thorium R&D progect are probably negative.

stcredzero 14y ago
> Yes, it produces less waste but The difference is minimal. As far as I understand, the difference is orders of magnitude! http://en.wikipedia.org/wiki/Thorium#Benefits_and_challenges http://en.wikipedia.org/wiki/Thorium#Benefits_and_challenges > So, while there are benefits the ROI on a multi billion dollar Thorium R&D progect are probably negative. It could be possible to rebrand Thorium and overcome many of the PR challenges of nuclear power. A solution to a substantial part of the global warming problem is indeed worth hundreds of billions.
- danielweber 14y ago
  What do they mean by "long-lived waste"? Things that are highly radioactive stop being radioactive very quickly. Things that are lowly radioactive stay radioactive for a long time, but at low levels so you don't worry much about them. There's a middle "unsweet spot" of things that are radioactive enough to worry about but not radioactive enough that they quickly burn out. So where does thorium fit in that taxonomy?
  - pkrein 14y ago
    well -- it's complicated. i started building a javascript library (nuclear.js : https://github.com/reinpk/nuclear.js https://github.com/reinpk/nuclear.js) to calculate the decay chains... the problem is that short lived isotopes, which are dangerous, can decay into long-lived isotopes, but basically the decay chains are complicated. i'll do a post about that soon :)
  - 14y ago

avar 14y ago

I recommend the Thorium Remix 2011 for a good overview: http://www.youtube.com/watch?v=P9M__yYbsZ4 http://www.youtube.com/watch?v=P9M__yYbsZ4

tokenadult 14y ago

Back in May 2012, I happened to be on a drive while National Public Radio here in the United States was broadcasting a Science Friday story, "Is Thorium A Magic Bullet For Our Energy Problems?" http://www.npr.org/2012/05/04/152026805/is-thorium-a-magic-bullet-for-our-energy-problems http://www.npr.org/2012/05/04/152026805/is-thorium-a-magic-b... Many of the issues considered in that story are glossed over by advocates of thorium reactors. The author of the blog post kindly submitted here explicitly admits, "My last article about thorium as an alternative nuclear reactor fuel drew way more readers than I expected. I intentionally glossed over the complexities of specific reactor designs for the sake of simplicity, but in this article I want to go deeper." He mentions a number of interesting technical trade-offs involved in using thorium reactor fuel and the latest reactor designs as compared to earlier nuclear reactor designs, but the tone is still largely a tone of credulity, without a lot of examination of non-nuclear means of generating electrical power. The Physics Stack Exchange discussion of thorium reactors is interesting, http://physics.stackexchange.com/questions/20034/what-practical-issues-remain-for-the-adoption-of-thorium-reactors http://physics.stackexchange.com/questions/20034/what-practi... as is the article from The Guardian in June 2011, "Don't believe the spin on thorium being a greener nuclear option." http://www.guardian.co.uk/environment/2011/jun/23/thorium-nuclear-uranium http://www.guardian.co.uk/environment/2011/jun/23/thorium-nu... Advocacy groups are already mobilizing to cast doubt on thorium reactors, with webpages like "Thorium Fuel – No Panacea for Nuclear Power" http://ieer.org/resource/factsheets/thorium-fuel-panacea-nuclear-power/ http://ieer.org/resource/factsheets/thorium-fuel-panacea-nuc... (with a link to an interesting fact sheet, http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009factsheet.pdf http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009fac... that gets into the practicalities and economics of using thorium as a reactor fuel). It's not clear yet that thorium offers any economic or political advantages over the uranium that fuels the nuclear reactor that provides much of my home electricity. The two nuclear reactors here in Minnesota result in lower-than-average cost for electricity here, compared to the rest of the United States, and have had a perfect safety record. Ongoing concern about where to store high-level radioactive waste on a long-term basis has made many politicians here reluctant ever to approve another nuclear plant in this state, despite the perfect safety record and inexpensive electricity we enjoy with the current plants. Minnesota, as a matter of state policy, is strongly promoting wind energy, fitting the wind-swept prairie geography of much of the state. I'm not aware of any part of the world where local politics would make a thorium plant more likely than another wind power plant or natural-gas-fired power plant. So maybe thorium power generation is a technical solution looking for a problem.

voidlogic 14y ago

I'm not any kind of nuclear expert, but it sounds like the author is comparing Molten Salt Reactors to 1970s era traditional reactors: "and the decay heat from these products requires continuous cooling for weeks even after core shutdown. That cooling process also must be human managed and actively powereed." My understanding is the reactors currently under construction in the US are being built with passive fail-safes that make them much safer than the 1960s/70s reactors. Is this incorrect? http://www.world-nuclear.org/info/inf41.html#New_build http://www.world-nuclear.org/info/inf41.html#New_build

uvdiv 14y ago
My understanding is the reactors currently under construction in the US are being built with passive fail-safes that make them much safer than the 1960s/70s reactors. Is this incorrect? Modern passive heat-removal systems are limited: the ESBWR mentioned on that page -- one of the most "advanced" -- has about 72 hours of heat-absorption capacity. [0] [0] https://en.wikipedia.org/wiki/Economic_Simplified_Boiling_Water_Reactor#Passive_safety_system https://en.wikipedia.org/wiki/Economic_Simplified_Boiling_Wa...
- voidlogic 14y ago
  Thanks for the info. `one of the most "advanced" -- has about 72 hours of heat-absorption capacity.` That is still a pretty decent "oh shit" buffer. I imagine Fukushima or Chernobyl would have benifited from 72 hours extra to get their act together.
  - uvdiv 14y ago
    I imagine Fukushima or Chernobyl would have benifited from 72 hours extra to get their act together. Well, I'm not sure. Chernobyl isn't relevant because its issue was one of supercriticality (milliseconds, explosions), not decay heat (hours, gradual melting). In Fukushima, there actually were passive systems, not as sophisticated as ESBWR, and some failed instantly (a steam injector in reactor #1). And IIRC off-site power too a lot longer than 72 hours to restore, but I don't know if the explosions contributed to this. I'm not a nuclear engineer so I can't meaningfully assess this. But there is data here. As a curiosity, ESBWR is actually a direct descendant of the BWR/3 at Fukushima, from the same designer (GE Nuclear). Not a scare tactic: I'd be pretty happy living next to an ESBWR.

krschultz 14y ago

Great article, I would love to see more of this kind of stuff on HN. The 350 million dollar question is why the government has to be the sole source of funding. Obviously the cost is very high, the regulations are very intense, but where are the VCs willing to tackle this kind of "startup" (in reality it would likely be more of a public/private partnership). It's a longer view with higher cost but the payoff could be massive. Big innovation isn't going to happen if it requires congress to agree on supporting it for 10-20 years.

pkrein 14y ago
from what i understand http://flibeenergy.com/ http://flibeenergy.com/ shopped around at VCs in Silicon Valley, but apparently it didn't work out? i think the trick is to find an angle into the business that doesn't involve govt approval up front. some aspect of the problem that can be solved to show momentum, without hitting regulations. maybe the chemistry side of things?
- krschultz 14y ago
  SpaceX had a lot of the same challenges but the first money making contract - flights to ISS - was only about 5-10 years out. NASA also paid them when they hit certain design milestones toward that contract. I would think that the best path forward on this would be for the DOE to setup similar milestones w/ large cash rewards. Private companies compete on getting to those milestones with oversight by the appropriate regulatory bodies. Then once through the initial milestones the company could actually build a small scale reactor, make money on it, then build a large scale and really make some money. Not saying it is going to happen, but that is MORE likely to happen than the DOE building this kind of reactor themselves.
  - apendleton 14y ago
    SpaceX also had the advantage of a very wealthy founder willing to pour lots of his own money into the project. This certainly wasn't enough to finance the entire development up until the first ISS flight, but it did allow him to hire a bunch of hotshot engineers right from the get-go, and probably establish a degree of legitimacy that made attracting more funds, government contracts, etc., somewhat easier. I'd wager that if Elon Musk had decided to fund LFTRs instead of rockets, we'd already have a prototype.

rapind 14y ago

Apologies for the off-topic comment, but I really love the layout and style of this blog. Any chance it's not a custom jobby and someone knows where it's from?

AlexDanger 14y ago
I agree its amazing. Reminds me of svbtle.
- rapind 14y ago
  Yeah, very similar, but I like it even more than svbtle.
  - rdl 14y ago
    I hate the misuse of the pk ccTLD, though. In general I don't care that much, but anything related to nuclear technology related to Pakistan produces an automatic "reach for the safety catch on my Browning" stress response.

jcfrei 14y ago

There was an interesting study by the national nuclear laboratory of the UK comparing thorium and uranium: http://www.decc.gov.uk/assets/decc/11/meeting-energy-demand/nuclear/6300-comparison-fuel-cycles.pdf http://www.decc.gov.uk/assets/decc/11/meeting-energy-demand/... the article is difficult to understand for a layman as myself but an important fact (among others) is that the uranium reserves on earth are considered to last for 100 years at 2008 levels of consumption. furthermore if demand rises, higher prices will make accessing more reserves economically viable. hence resource availability doesn't appear to be a concern for the near term future.

uvdiv 14y ago
the article is difficult to understand for a layman as myself but an important fact (among others) is that the uranium reserves on earth are considered to last for 100 years at 2008 levels of consumption. An even more important fact is that uranium nuclear power is a couple of percentage points of 2008 energy consumption, and energy demand itself is growing exponentially. The metrics the DECC bureaucrats are plodding through are no-growth extrapolations of past trends. If clean energy is to be a reality, and if nuclear power is that clean energy, then we must scale it up by three or more orders of magnitude, and sustainability within the century is (potentially) a critical issue. DECC bureaucrats aren't considering this in that report; they are being conservative, in a bad way. Don't look to government bureaucrats for revolutionary vision ;)
- dalke 14y ago
  "Don't look to government bureaucrats for revolutionary vision" Which bureaucrats should we look to? ;) You seem rather negative towards bureaucrats. Some bureaucratic positions are influential. Some people have visions which they can't do on their own or in a company. Some people figure out that the best way to achieve those visions is to become an influential bureaucrat. Vannevar Bush is one of those. He had a vision of how he wanted the US to fund science research. That vision became the NSF. His bureaucratic work started much earlier. For example, he was a key figure in organizing the Manhattan project. Other bureaucrats with vision include: Secretary of Commerce Herbert Hoover (Hoover Dam, and more importantly the interstate compact which lead to it), the Health and Environmental Research Advisory Committee of the DOE (to start the Human Genome Project), J. C. R. Licklider (his DARPA memo on the "Intergalactic Computer Network" lead to ARPANet lead to the Internet), and Viktor Zhdanov, Deputy Minister of Health for the USSR (call for the WHO to undertake a global initiative to eradicate smallpox; the previous smallpox vaccination programs were also government driven).

uvdiv 14y ago

A “fast breeder” version of a molten salt reactor has fast neutrons in the reactor core. These neutrons easily interact with the actinides, transmuting them into fissile isotopes and then fissioning them to produce energy. In other words, molten salt reactors burn actinides. The same is not true for traditional uranium reactors because they have thermal (slow-moving) neutrons in the reactor core. Neutrons at these slower speeds don’t interact with the actinides, so you can’t burn actinides in a traditional uranium reactor. This is no different from a panoply of fast breeder reactors which are NOT molten salt reactors, particularly liquid-sodium cooled (solid-fuel) reactors. The difference is that liquid sodium reactors have dozens of commercial-scale demonstrations, and hundreds of billions of $$$ of R&D investment -- whereas the molten salt fast breeders (chloride salt reactors) are nothing more than paper models to date. As a side note, it looks like using thorium as a fuel is not actually critical. Thorium can be used as fuel in molten salt fast breeder reactor, which is a benefit for long-term sustainability, but thorium has little relation to the cost of constructing a new reactor today. There's a plausible suggestion that liquid-fuelled reactors could be cheaper than LWRs. E.g.: they are far more compact (smaller), and the nuclear components apparently have less complexity. (Speculative) But the point is an important one. The "big" selling points of thorium -- fuel efficiency, and spent fuel -- are very long-term issues. It's safe to argue they can be deferred. ("Thorium is premature optimization") As of this past month, China now has a $350m institute with 140 PhDs plugging away on molten salt fast breeder reactors. Actually they are thermal reactors (not fast breeders), and the focus is on solid-fuel reactors with molten salt as a coolant (although they are also considering molten-fuel reactors, as a lower priority).

pkrein 14y ago
thanks for the correction on china, will update!
- uvdiv 14y ago
  Here's a source to back that -- a talk from one of the researchers involved: http://www.youtube.com/watch?v=5UT2yYs5YJs http://www.youtube.com/watch?v=5UT2yYs5YJs Relevant stuff (liquid-fuel vs. liquid-coolant) somewhere around @23:30.

raphaelj 14y ago

The future is fusion

uvdiv 14y ago
The near future is fission. Fission reactors are compact, dense, cheap, and actually work.
lukifer 14y ago
The future is also the heat-death of the universe. Lucky for us, how far off in the future things are happens to be relevant. ;)

realrocker 14y ago

Indian Thorium Breeding Technology: http://large.stanford.edu/courses/2011/ph241/bhattacharyya1/ http://large.stanford.edu/courses/2011/ph241/bhattacharyya1/ Since we don't have enough Uranium and no one would sell us, It's pretty much our only strategy.

thingification 14y ago
This is true. However, the article is about molten salt reactors. The Indian program, as far as I know, is focused entirely on conventional solid fueled reactors. Most of the advantages of MSR aren't shared by solid fuel Th reactors. China already has an MSR program, but perhaps India could catch up if it switched tack quickly.
uvdiv 14y ago
You've been free to buy uranium from since George W. Bush backed you in a treaty modification with the nuclear suppliers group. You had been blacklisted before that, because your nuclear weapons pissed off the world (don't blame the world). https://en.wikipedia.org/wiki/Indo-US_civilian_nuclear_agreement#NSG_waiver https://en.wikipedia.org/wiki/Indo-US_civilian_nuclear_agree... A quick google search turns up the Australian PM agreeing to sell you uranium: http://www.abc.net.au/news/2012-10-18/gillard-visit-paves-way-for-india-uranium-sales/4319654 http://www.abc.net.au/news/2012-10-18/gillard-visit-paves-wa... "Prime minister Singh and I have agreed that we will commence negotiations for the nuclear safeguards agreement, the civil nuclear cooperation agreement given Australia is now prepared to sell uranium to India," she said.
- justatdotin 14y ago
  well, that's one statement from the PM. it hasn't got through parliament yet, and this highly controversial proposal will face stiff opposition. Successive polls have shown that most australians are opposed to exporting our uranium to nuclear weapons states (tho I'll admit most respondants probably haven't connected the dots, since one major customer is us[a]). In the case of India, these concerns are magnified by the ongoing regional arms race and the recent violent suppression (including murder) of Indian opponents to the industry.

bd_at_rivenhill 14y ago

One issue with the review of previous nuclear disasters: Chernobyl was qualitatively different than Three Mile Island and Fukushima. The latter 2 designs were both water cooled and water moderated; both suffered loss of coolant (LOC) events which resulted in the core melting from residual decay heat as described in the article, with Fukushima experiencing subsequent detonations of hydrogen gas formed from reactions with the heated fuel rods (some have claimed that this happened at TMI as well, but clearly not to the same scale). The Chernobyl design (http://en.wikipedia.org/wiki/RBMK http://en.wikipedia.org/wiki/RBMK) is also water cooled, but is moderated by graphite, which is much more dangerous (and scary that there are still many of these in operation). Instead of a loss of coolant event, Chernobyl experienced an exponential power spike which pushed operating power up to 10 times normal, resulting in a series of steam explosions in the coolant lines that blew off the 2000 ton cover of the reactor, sprayed part of the core out the top to contaminate the immediate vicinity (i.e. large chunks of the graphite moderator lying on the ground outside the reactor building), and set the graphite moderator on fire. The fire then spread many more fission products into the atmosphere with the smoke to share the fun with people in a much wider area. Despite what has been written about Fukushima recently, I expect that it was a couple of orders of magnitude worse than Three Mile Island, which did not result in significant amounts of radioactive material escaping from the site (depending on whose analysis you believe); Chernobyl was between 1 and 2 orders of magnitude more severe than what we know about what happened at Fukushima at this point as far as I can tell.

thingification 14y ago
I'm told that Xe poisoning played a major role in Chernobyl. MSRs have a major advantage here because the Xe can easily be removed. In a solid fuel, it is not really possible to remove it, and it can cause instability because it causes time lag between control input and reactor response output.
dmfdmf 14y ago
Good review but "qualitatively different" is a bit of an understatement. tl;dr: Chernobyl/RBMK reactors are inherently dangerous in nuclear design and in operation without suitable containment structures, unlike Western reactors like TMI or Fukushima. TMI and Fukushima are comparable to a degree but it is important to note that TMI is a Westinghouse pressurized water reactor whereas the Fukushima plants are GE boiling water reactors. TMI had a LOC event due to a stuck pressurizer vent valve that went undetected after a reactor scram which, combined with incorrect assumptions in the operating procedures, led to a core melt. Fukushima experienced station black out which means loss of both offsite and backup power. The reactors shutdown and operated as designed for this scenario but the design basis assumption is that power would be restored in 4 or 5 days (don't know the exact number). It actually took more than a week to restore power due to the devastation of the earthquake and tsunami. Core cooling was maintained by discharging steam into the containment cooling pools but this method can not be run indefinitely and as the pools overheat it threatens the containment. Without a source of power the H2/O2 recombiners could not safely burn off the hydrogen which led to explosions of the reactor service buildings. In contrast, the RBMK reactors are graphite moderated but water cooled. The reason for this design was they were developed for civilian power generation by scaling up military reactors used for plutonium production for nuclear weapons (graphite moderator allows fuel extraction without shutdown). During low power operation, the RBMK design has a positive reactor power void coefficient. What this means is that an increase in power lowers the density of the water coolant which allows more neutrons to escape into the graphite moderator where they are slowed down and thus split more atoms. In other words these reactors have an inherently dangerous operating region where an increase in power can lead to more power in a positive feedback cycle. This is what destroyed the Chernobyl reactor. (Note that water moderated reactors such as TMI or Fukushima have a negative power void coefficient where an increase in power reduces the density of the coolant and moderator which allows neutrons to escape the core without causing a fission thus dropping power, the opposite of an RBMK) Of course the designers were aware of the positive power void coefficient, so they added safety systems to prevent reactor operation in bad regions. On the night of the accident, a maintenance shutdown was scheduled but on scram the operators wanted to run a turbine spin down test, i.e. after the scram, see how long the residual steam could drive the turbines before backup systems had to be operational. Previous attempts to run these tests had failed and the operators were pressured by Moscow to get it done or else (Siberia?). To maximize the chance of a successful test the operators maneuvered the reactor into the low core flow, low power region of the reactor's operating domain with the dangerous positive void coefficient and thus positive power feedback. To get the reactor into this state the operators had to override numerous safety systems designed to prevent such operation. At the commencement of the test there was a power excursion that led to a power runaway that cause a steam (not a nuclear) explosion that blew the lid off the reactor. One final important point, the Chernobyl reactors (and all RBMKs) are not housed in any containment structure like Western reactors (they are too big). The containment buildings of reactors like TMI or Fukushima are designed to withstand and contain the operating energy and nuclear material should anything go wrong and as these accidents have shown, they work. The Chernobyl accident was made much worse because the lack of containment allowed widespread dispersion of radioactive material due to the explosion and subsequent graphite fire.

justatdotin 14y ago

s/weapons//g hmmm.. thorium reactors would still produce unmanagable high level nuclear waste (tho not as bad, not as much), and would still open up significant weapons proliferation vectors, both material and capacity. As for safety, these designs merely substitute one catastrophic failure mode (meltdown) for another (volatility of the continuous onsite reprocessing) inarguably, thorium designs offer stepwise improvements to the major disqualifications of catastrophic failure, unmanagable waste production and WMD prolifertaion. But I'm concerned that we should judge the nuclear industry on its present day detriments and hazards, not the promises of future designs. there's a big thorium mine down the road from me - well, a big rare earths mine, where the dominant product is thorium. They're planning to come and bury all the (enriched) thorium back on site after extracting the lucrative rare earths. I read that as a pretty clear indication of the state of the market. (incidentally, and as far as minesite impacts go, the thorium mine is going to be at least as hazardous as a comparable uranium mine) When Chernobyl went off, we were told don't worry, it's an outdated design, the new reactors would never do that. When Fukushima went off, we were told don't worry, it's an outdated design, the new reactors would never do that. Who can guess what they'll tell us when Indian Point goes off? this is an industry that has consistently over-promised and under-delivered. Remember "energy too cheap to meter"? by their deeds, not their words. let's try to manage the industry by the realities of today, not the promises for tomorrow.

martinced 14y ago

I've got one question... The main issue is that now at Fukushima there are products like Cesium-90 in the sea, contaminating the entire sealife, which have crazy long half-life (ninety years). Thankfully they're "heavy" so they go down towards the center of the earth, but only at about 5 cm per year. So in ten years the're going to be highly radioactive Cesium-90 at 50 cm behind rocks still polluting the sealife. In case the worst sht happens: the worst SNAFU conceivable... Would MSRs also generate highly products like Cesium-90? I mean: I don't care about all the security and the great design meaning an uncontrolled reaction shall never happen. I know: it won't happen. Just like Fukushima. It didn't happen because it couldn't. We got your point. It IS safe. But I tell you: a sht you didn't expect is going to happen (maybe an asteroid striking your reactor or whatever). What then? Would MSRs pollute less than Uranium based reactors in the worst of the worst scenario? If so I'm all for it.

thingification 14y ago
It's intermediate half-lives that are problematic. Very long half lives (for example, billions of years, like Th 232) are not a problem, because they have low activity (few particles emitted per second). Very short half lives (for example, minutes) are not a long-term problem, because they are entirely gone after those minutes. It's the middling half lives that get you: short enough to be highly active, long enough to stick around for years. So, Cs 137 and I 90 stick around for a few hundred years. That's bad, and LFTR still produces these. On the other hand, it's a lot better than the situation with conventional U reactors, because those produce transuranic elements with intermediate half lives measured in tens of thousands of years. There is a qualitative difference to human civilisation between 300 years and tens of thousands of years. LFTR produces those transuranic elements too, but in orders of magnitude less quantity -- that combined with the liquid phase leads us to expect that would be a much smaller problem than with conventional reactors. Wikipedia suggests some other LFTR advantages here, which I haven't thought about: https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reacto... Low mobility of radioactivity. Even if there is an accident beyond the design basis for the multiple levels of containment and passively cooled systems, fluorides do not easily enter the biome. The salts do not burn, explode, or chemically degrade in air and react only slowly with water. Fluorine combines ionically with most fission products to form stable fluorides. This is not only an MSFR's first level of containment, but also serves as a high inherent safety level during any beyond-design basis event. Fluoride is especially good at holding biologically active "salt loving" wastes such as cesium-137 and strontium-90, which are permanently bound as stable, nonvolatile CsF and SrF2. The fluoride salts of radioactive actinides and fission products are generally not soluble in water at lower temperatures. Even though Caesium fluoride is one of the fission product fluorides that is highly water soluble, its extremely high boiling point and chemical stability, combined with the lack of stored energy sources (hydrogen, steam, etc.) in the LFTR, prevent it from being blown into the air and carried with the wind to contaminate a large amount of land.[citation needed]

twentysix 14y ago

There was a TEDx talk I saw a while back by two MIT graduates working on a "Waste Annihilating Molten Salt Reactor". https://www.youtube.com/watch?&v=AAFWeIp8JT0 https://www.youtube.com/watch?&v=AAFWeIp8JT0 It looks promising and they have formed a start-up, http://transatomicpower.com http://transatomicpower.com http://www.forbes.com/sites/pikeresearch/2012/09/27/a-pair-of-mit-scientists-try-to-transform-nuclear-power/ http://www.forbes.com/sites/pikeresearch/2012/09/27/a-pair-o...

j00lz 14y ago

As much as I am interested in the topic. I could only read a few paragraphs, due to being irritated by the cheesy couple picture in the corner.

varjag 14y ago

The troubling attitude in TR advocacy is the claims of inherent safety. A sustainable energy-positive reaction can't be inherently safe. You can argue if it has better failure modes than the alternatives but it's harmful to ignore a multitude of factors which could be not yet considered. The previous catastrophic failures with other reactor designs were also not exactly forethought. For instance, xenon poisoning was little studied in the beginning of nuclear era. It is not implausible some critical piece of knowledge is missing in the current evaluation of "safe" designs. Another thing is too much reliance on the neat presentations. E.g. this blog refers to a freeze plug as a kind of panacea of any mismanagement. What if freeze plug fails for whatever reason? Like, tectonic activity breaks the pipework, or it's sabotaged, or groundwater leaks into the dump tanks?

louischatriot 14y ago

Of course thorium reactors is not a proven technology but if there is a scientific consensus saying it is promising, I don't see why utility companies and civil nuclear reactor manufacturers try to make it viable. They have everything to gain, in my opinion. Tldr of the article: http://tldr.io/tldrs/50f73bbe983c81b86a00012b/thorium-reactors http://tldr.io/tldrs/50f73bbe983c81b86a00012b/thorium-reacto...

Create 14y ago

As far as I know, there are no (public) models on Th reactors. The most advanced is an analytic simulation (without CFD) from a Chinese nuclear engineering lab, but nobody has a real clue about the precise input variables anyway, therefore no MC is even in sight, as of today. But marketing is well advanced. And as the Japanese say, assuming we do have a functionally correct model and a Th reactor design (or designs, since there are several configurations), that still doesn't say anything about the economic aspect (I do not mean the old economic model, where the byproduct of plutonium factories were sold as energy).

lucian303 14y ago

The Downfall in the US is that no new nuclear reactor of any kind has been built since the 70's and no significant funding or consideration has been given to this (other than weapons, nuclear warheads can be delivered in every conceivable way of course) and there is a culture of irrational fear around the subject. Especially in Congress. We will see a new nuclear reactor of significant size in America when pigs fly. The fossile fuel industry and the politicians entrenched in it are getting way too rich to let something like this happen in our lifetimes. And really thinking about it, we are already 40++ years behind. When you consider that 1 out of 2 Americans think the world will end in their lifetimes this is not surprising.

Barosan 14y ago

See this recent EnergyFromThoriumFoundation facebook album for a historic brochure about ORNL's Molten Salt Reactor Experiment between 1965-1972. https://dl.dropbox.com/u/15726934/Historic_Molten_Salt_Reactor_Experiment_Brochure_ORNL_1965-1972.pdf https://dl.dropbox.com/u/15726934/Historic_Molten_Salt_React... http://www.facebook.com/media/set/?set=a.10152449471560377.951501.10150132132910377&type=1&l=91f3ea2327 http://www.facebook.com/media/set/?set=a.10152449471560377.9...