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).
What you say about U/Pu fast breeders is true, but there are other pertinent differences between those and LFTR:
1. LFTR safety is based on passive cooling. Pu breeders do not share this property. Fukushima-style accidents involving loss of active cooling power for decay products are not a failure mode of LFTR.
2. MSR reactors don't suffer from the safety problems introduced by the use of liquid sodium.
3. MSR reactors don't suffer from the control complications introduced by Xe poisoning in solid fuels.
4. MSRs involve a continuous liquid process. Essentially all industrial chemical processes work that way, and that's because liquids are very convenient to work with. There are good reasons to think this will pay off in multiple cost-saving ways.
Another way of looking at the billions spent on Pu breeders is that it might be an indication that other technologies are worth a bet. Orders of magnitude less have been spent on MSR than on U/Pu breeders.
I'd say the big selling points of Th are not fuel efficiency and spent fuel, for exactly the reasons you note. The big selling points are the promise of lower cost and public acceptance (both of these promises come to a large extent from the real safety advantages of MSR over conventional reactors).
The hard one, public acceptance, will only happen if we can figure out how to sell it, but luckily, making that effort is something that those of us who think we need nuclear power have a duty to choose to support, not something that's in the lap of the gods.
Re China: it's possible my memory is playing tricks on me, but I believe that one of the guys at the top of that program, when he came to a North American conference to speak about it, said that MS as coolant was the initial focus simply because that is a natural early step, but MS fuel was very much a long term goal (it's on youtube if somebody wants to check). Edit: I just checked (somebody already linked to it), and my memory was playing tricks: he said that they're developing both in parallel, with the priority initially on MS as coolant, because that is "more technically ready". It still seems that MS as fuel is where they want and intend to go eventually.
Oh, thank you. I intended only a very narrow point about chloride reactors being untested (not MSRs: just fast-spectrum chloride MSRs). I didn't mean to provoke a debate between molten-salt and liquid metal reactors. I claim neutrality. :)
LFTR safety is based on passive cooling. Pu breeders do not share this property.
I'm unfamiliar with the details, but I read that liquid-sodium reactors are capable of fully-passive decay heat removal, e.g. [0] (slide 6). Certainly sodium has a much higher boiling point than water.
By the way, fast-spectrum MSRs are really Pu breeders -- that's the point of actinide burning!
3. MSR reactors don't suffer from the control complications introduced by Xe poisoning in solid fuels.
This is not a relevant issue with fast-spectrum reactors, e.g. [1] (c.f. [2]):
"The xenon-135 and samarium-149 mechanisms are dependent on their very large thermal neutron cross sections and only affect thermal reactor systems. In fast reactors, neither these nor any other fission products have a major poisoning influence."
4. MSRs involve a continuous liquid process. Essentially all industrial chemical processes work that way,
Ah, I did notice you were talking about fast reactors, then hastily slid back to thermal ones! Sorry. I guess my error reflects the fact that I think the thermal LFTR is more important.
Re passive cooling in sodium breeder reactors: that's certainly interesting. I'd not heard about this.
About your first point, this depends on the scale of the reactor, since the capacity of passive cooling scales with the surface area and the energy generation scales with the volume of the reactor. AFAIK submarine reactors can utilize passive cooling, since they are only about 100 MW.
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.
The basic problem that nuclear faces is that it's too dangerous to allow private companies to develop. Normally, having private companies engage in dangerous activity is not itself a problem. Since the legal system (theoretically) forces the company to bear the cost of any harms, the company has an incentive to take precautionary measures proportional to the risk-weighted potential harm.
When you get to situations like Fukushima or BP, this breaks down. The real economic cost of a nuclear disaster can stretch into the trillion dollar range when you factor in not just cleanup and direct compensation, but disruption of life.[1] A private company could never compensate the public for such costs, and as a result a private company has no incentive to exercise caution proportional to the risk weighted cost, but rather only an incentive to exercise care proportional to the risk weighted expected payout.
Of course the flip side of this is that the potential cost of disaster being so high blinds people to the fact that the probability of disaster is low. So the regulation tends towards more stifling than warranted.
[1] What's the real cost of something like Fukushima? Is it just the cost of cleanup? The cost of paying for destroyed houses? The cost of paying the families of people killed? It is partly that, but it's a lot more in fact. Consider: what would I have to pay you to get you to live in an emergency shelter for six months? Disaster payouts almost never compensate for cleanup and health bills much less for disruption to one's routine, but in economic terms it's a very real cost.
"What's the real cost of something like Fukushima?"
Maybe the better question is what will the purveyors of fear, uncertainty and doubt cause the price to be.
The cost will be negligible, at least compared to the local portion of the general quake and tsunami cost. But FUD will make the government do stupid things, like what they have already done regarding the allowable radioactivity level in food. Stupid, stupid, stupid. But that is the purveyor's purpose.
> What's the real cost of something like Fukushima?
The PR: West denouncing nuclear and retiring nuclear capacity ahead of time -> flight of investment from nuclear -> replace with coal/peat/etc -> climate badness.
Reactor designs are licensed by the NRC, new reactor designs require quite a long review process (as people really have a lot of "What if a ... happened?" questions that need answers) So funding a new reactor design is a multi-decade process. That is pretty far outside the "VC" range of funding since their funds want to be 'done' in 10 years, not just "almost approved for considering to build."
And the thorium folks, much as I love them, do themselves a disservice by not addressing the fuel cycle problem. If a uranium 'water' reactor leaks the radio-isotopes in the water decay rapidly, and are easily blocked by modest shielding. So that steam that escapes into the big containment dome? Well its radioactive initially but a couple of days later its not. This is not true is U233, a necessary byproduct of a thorium reactor fuel cell and present in the molten sodium leaks out. As sodium reacts violently with water, and molten sodium leak will cause an explosion and disperse highly dangerous, and difficult to shield U233 contaminated with U233 [1]
So when a thorium reactor does have a problem, it will be very serious very quickly. Not a lot of understanding on how to protect against that yet.
You're confusing molten-salt reactors with molten-sodium reactors (different beasts). Molten fluoride is also reactive with water (hydrogen fluoride anyone?), but often MSR proposals don't involve water (they go for helium or CO2 gas turbines), and the ones that do separate steam far away from nuclear components, through intermediate coolant loops. Sodium reactors do the same thing. The risks really are manageable (in theory).
Radioactivity is dominated by short-lived fission products, not U-233/U-232 and company. U-232 is very radioactive, yes; but in a nuclear reactor, there exist vicious things far more radioactive than that. (Note that U-232 is a trace contaminant, but fission products are present in bulk amounts. U-232 is highlighted only because it's impossible to separate from U-233, a point of theoretical (and meaningless) debate involving nuclear weapons. Otherwise it's unimportant.)
It's relative. It's difficult to shield relative to U-235 (for example), which means that handling raw fuel is more difficult. (It requires robotic manipulators -- hot cells, "waldos" [0] -- unlike conventional fuels which can be handled manually [1]). This is barely relevant for MSRs, because there is no fuel fabrication step (no fuel pellets). It is a difficulty for solid-fuelled thorium reactors.
It's of no importance in nuclear reactors, because there there rest vastly greater amounts of vastly more radioactive monsters.
The reason people talk about U-232 is this confusing debate about nuclear weapons -- there's a weak (I think spurious) argument that thorium is weapons-resistant, because the U-232 gamma radiation makes it difficult to machine/work with weapons cores. It's really not relevant to molten-salt reactors.
U-232: I'm not sure that's really the good argument. The better argument is that it doesn't matter whether it is weaspons-resistant, because it is much easier to enrich U 235, even for U-poor countries. Is that argument also flawed? Unfortunately, I suspect some of the relevant knowledge is secret.
U-232: I'm not sure that's really the good argument. The better argument is that it doesn't matter whether it is weaspons-resistant, because it is much easier to enrich U 235, even for U-poor countries.
Yes, that's right. That's why the "debate" is spurious.
hold up -- you are confusing molten salt with liquid metal. molten salt reactors do not contain liquid sodium metal. in a molten salt the sodium is chemically bound to Fluorine or Chlorine, etc. the explosive fire danger you're talking about applies to "Liquid Metal Fast Breeder Reactors" which is a different animal altogether. but yes, those are scary! and have had lots of accidents/fires in the past.
As several people have mentioned, you are confusing molten salt with liquid sodium. In a LFTR, the is no mechanism for driving the dispersal of the molten salt fuel. Therefore, no small particles and therefore the material is still in the hot cell where it is well shielded.
By the way, much of the stuff released by Fukushima will remain radioactive for hundreds of years not days, having a half life of about 30 years. But the activity maps I've seen suggest that at least the older folk should be allowed back pretty much everywhere. Pregnant women and little children, maybe should stay out of the hottest of the "red zone" hot spots. But FUD will cause them to keep folk out of the yellow zones too. Needless.
from what i understand 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?
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.
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.
I don't know whether they shopped around VCs, but they have said that they aim to sell to the US army. The army has a well-publicised and pressing need for portable compact power sources in places like Iraq. They have also indicated that they would like to produce medical isotopes as a first step. However, the destruction of the US U 233 reserves by the US government may put a stop to that (if it isn't halted -- which seems unlikely, due to lack of interest).
The civilian nuclear industry has regulatory lead times measured in decades, and has a mindset heavily tied to the risks posed by solid-fueled reactors. For that reason, the military may in fact be the only opportunity for a company to develop liquid fueled reactors.
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?
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]
`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.
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.
I'm not sure, but in the Wikipedia article I found that the electricity problems in the Fukushima plant lasted from March 11 to March 22 at least (the problems continued for a longer time). http://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disas...
So 72 hours = 3 days would be not enough alone, but I also don't know how the other actions had made the situation better or worse.
The amount of cooling needed is not constant over time (cf. http://en.wikipedia.org/wiki/Decay_heat), which is one of the reasons passive cooling systems are designed for days rather than weeks.
The first seconds/minutes are the most critical and after 72 hours the residual heat is down to a level which can be much more easily handled.
Yes, that's correct. In fact, pretty much any modern design that's available for purchase will be a couple of orders of magnitude safer (at least regarding decay heat removal) than the designs currently operating in the U.S.
If you look at the big nuclear disasters, usually they are a combination of design flaws, human errors and general snafu. So in theory the new designs are safer than the old ones, but the old ones have the nice advantage that we already know that they do not blow up at first criticality.
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) 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.
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.
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.
By qualitatively different I mostly meant to point out that TMI and Fukushima were both LOC accidents at water moderated reactors, while Chernobyl was of a much more dangerous variety. This was motivated by the fact that the OP glossed over that important point, and now you have filled in even more of the blanks; thanks.
Yes, I just wanted to expand on how completely different these reactors and accidents were. Also, it was a minor point but LOC Accident (TMI) is different than a Station Black Out (Fukushima), these are defined accident scenarios in the design basis documents for the reactors.
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.
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.
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!
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
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.
"there's a general engineering issue...": This is quite right. However, that is a general-purpose argument to dismiss any new technology. I don't think the rational response to that is to not develop new technologies that show promise to be significantly better than the old ones, as this one does. While nobody could disagree that we don't know for sure how much it will cost before actually commercialising it, if we want to learn more about whether it is worth a try, the argument has to focus on the specific issues, such as the one you raise in your previous paragraph. (I think it is worth a try, because there are reasons to expect that it will be cheaper and safer.)
To address your specific point about U 232: First, you have 232 and 233 reversed: it's the U 232 and not the U 233 that causes significant gamma emission [1], and the U 233 that is bred from the Th for use as fissile nuclear fuel. U 233 production from Th 232 also unavoidably produces a small amount of U 232. The gamma emissions from the U 232 are a problem for handling of U 233. However, the gamma rays (easy to spot from space) and the tricky handling are both unattractive properties for U 233 as a weapons material. The pro-Th argument goes that this means that it is much easier to enrich U 235 than it is to work with U 233. If that is the case, the proliferation properties of U 233 are arguably not relevant to the LFTR debate (I'm personally not yet convinced that it is the case).
You say that the gamma rays are "really deadly at a distance". Can you cite a reference please? I don't think it is necessary to fully shield the gamma rays, unless you are building a nuclear weapon and don't want it to be seen by a monitoring satellite. Certainly the gamma emitters here don't constitute a nuclear waste issue, because the reaction takes place quickly.
This isn't an area of my expertise. I was only trying to summarize the response to my earlier question. I think I understand the issues generally, but please look at the linked conversation for more details.
I agree that engineering inexperience with thorium isn't a reason to dismiss it. I just find it a bit telling that thorium boosters like Reinhold don't address that discrepancy, in the same way they tend to be silent on the issues with U-232/233.
Regarding gamma radiation, by "deadly at a distance" I mean that they're a coherent threat to health at a much greater distance because gamma radiation travels further than alpha or beta radiation because it's much higher energy. Likewise, that greater energy imposes a much higher cost on shielding: a sheet of paper blocks alpha, heavy clothing blocks beta, but you need significant amounts of dense material like lead or packed earth or granite to block gamma radiation. Presumably, this imposes a significant extra expense on a thorium reactor that's breeding U-232. My source to back up my vaguely recalled knowledge is this: http://www.epa.gov/rpdweb00/understand/protection_basics.htm....
Gamma radiation is not "higher energy" than alpha or beta radiation. And the energy of particle is not by itself significant as far as radiation damage is concerned - what matters is how that radiation is deposited in you as the particle passes through you. An extremely high-energy neutrino could pass through you with no effect whatsoever.
Materials such as a sheet of paper or piece of cloth have a higher stopping power (loss of energy per unit distance) for alpha particles (helium nuclei of charge +2) and beta particles (electrons of charge -1) than for gamma rays (photons - uncharged particles).
This is why an alpha emitter is much less significant if it's outside your body, but much more significant if it's in your lungs - because it dumps all its energy inside you where it can cause damage.
I'm not sure if this is semantics or not. Yes, low energy and high energy radiation both can cause bad damage and a DNA hit from one is as bad as that from another, but that isn't the point. Standing in a 20KV beam is going to do you more damage than standing in a 500KV beam on a photon by photon basis - but only because more of the 500kV beam will go straight through you.
An I missing your point though?
Edit: Yes I am. Your talking about alpha versus gamma, not low energy damage versus high energy damage.
As I said, this isn't my area of expertise. The link I provided says "Distance is a prime concern when dealing with gamma rays, because they can travel long distances. Alpha and beta particles don't have enough energy to travel very far." What does this mean, then? I assume that the EPA isn't wrong about gamma radiation traveling further than alpha or beta; in virtue of what, then, does it travel further? I suspect that "energy" is being used fairly loosely, here.
I believe that because the thorium is "burned" so effectively you don't see much in the way of U232 for the amount of energy output. I would be worried about a plant that can make many kilograms of fissile material per year. I wouldn't be worried about a plant that can make many grams of fissile material per year.
Though it's missing a few key elements. Note that a lot of the advantages of LFTR designs rely on technology that hasn't been invented let alone demoed or proven yet. For example, in-situ fuel reprocessing.
The biggest thing is that nearly every aspect of building and operating a LFTR is completely new. From how to keep the reactor humming along and avoid having a criticality excursion or avoid accidentally quenching the reaction to how you get power out of the heat from the reaction to how you refuel it. Damned near everything is untried and untested. It's going to take a lot of iterations to smooth out the bumps, even if we accept the idea that the overall inherent safety of the design is superior.
This statement is completely false. All _required_ aspects of fuel reprocessing have been demonstrated. And it has been demonstrated in two reactors with all three fissile fuels the LFTR cores are inherently stable. We have over two full-power years of experience with a LFTR core over a ~five year period
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):
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...
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.
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)
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)
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.
> 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.
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.
Actinides of half-life 100-100,000 years or so. These have a compounding disadvantage in that they are alpha-emitters, hence disproportionately radiotoxic (e.g. by ingestion) compared to gamma- and beta- emitters like common fission products. Orders of magnitude disproportionate.
The theoretical advantage is huge: (this graph is from a French nuclear research lab which appears to be temporarily offline)
i started building a javascript library (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 :)
It's complicated, high level nuclear waste can be reprocessed and it becomes cheaper to do so the longer it sit's around. Low level waste is fairly cheap to deal with. So, it's really a question of what to do with the mid level stuff and they both produce similar amounts of that.
The potential of Nuclear technology is huge, unfortunately so is the associated need for a large government intensive, multi-billion, long-term investment. That's is one of the key problems with nuclear in general having an only tangential relation with the technology itself.
Compared to an equal size total investment, broken up into multiple smaller R&D areas, the the big nuclear bet is likely at a opportunity cost disadvantage. The strategy of equivalent smaller investments in other renewable technology has multiple outlet points where private industry can take and run the results into production. Although one couldn't prove that one approach would yield better than another, my feel is that the multiple smaller bets yields earlier with the potential to scale better overall.
On the other hand, while you and I might know that today's nuclear plants are tremendously safe, they have a terrifically negative public image. In a vacuum the ROI would probably be negative, but most people want nothing to do with traditional nuclear plants and the not-in-my-backyard problem is huge. If you include getting a blank slate public relations-wise, the ROI might become positive. Engineers are loathe to worry about these kinds of things, but in practice they matter quite a bit.
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.
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 ;)
"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).
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?"
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,
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.
Glancing through the objections, the non-political ones all seem to boil down to "We don't actually know that they work at commercial scales, because we've never used them at commercial scale before." Well... yeah... but as an objections go, it's hard to imagine a much weaker one. If that's the best technical argument the detractors have, that says quite a lot about their arguing position. On the other hand, they seem to have the potential to fix some very real objections to nuclear power from the uranium cycle.
If that's the best technical argument the detractors have, that says quite a lot about their arguing position.
I'm surprised, jerf, to see this kind of comment coming from you (as I take care to follow your comments on HN). If investors are only interested in a technology after the government lavishes your tax dollars and mine on developing it, to me the technology is surely less promising than a technology that develops mostly through private investment. People spending their own money usually does better at identifying technologies with a large upside than efforts to get government backing for this or that "strategic" or "breakthrough" technology.
The current way that objections to nuclear power from the uranium cycle (the kind of power I enjoy here as I type this) are usually dealt with is try any and every technology other than nuclear power. I agree with the statements in this thread that "nuclear" by itself isn't a label that indicates that the power source is bad, but I point out that private investors seem to be seeking to invest in a lot of other kinds of power sources more than they are seeking to invest in thorium.
AFTER EDIT: I spent a while just now searching for a linkable version of the special report on the world natural gas market published in The Economist a few months ago. (I don't know what prompted the downvote that came while I was doing that.) I haven't found a link yet, but I have to recommend that special report section of the print edition of The Economist to anyone who hasn't had a chance to read it yet.
The statement from my top-level comment above that I'm being asked to defend is "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." But I'll come right back at anyone who claims that thorium power has a big future by asking, do you have a solid estimate how much it will cost to produce electricity with thorium, considering the entire technological process from mining to by-product disposal? The production of natural gas by "fracking" is revolutionizing the world energy economy
and has probably given the development of renewable energy sources two extra decades to become economically competitive. That's enough. Green energy development is a necessity around the world,
and all the other modalities will be researched and receive further commercial development. By the time thorium power could come on line, you and I and everybody will have renewable energy at competitive cost, with natural gas having bridged the transition.
AFTER SECOND EDIT: Thanks for your reply, jerf, which was posted as I was writing my first edit. Every which kind of power generation, as the references I've just added to this comment make clear, is developing in a market distorted by tax-funded subsidies. Better to let purer market forces sort out the trade-offs among different energy sources. I was just reminded that pg, our site founder, has been following this industry for a long time.
"After all, projects within big companies were always getting cancelled as a result of arbitrary decisions from higher up. My father's entire industry (breeder reactors) disappeared that way."
My comment is that any Baby Boomer who read about physics as a kid (like me) heard about thorium DECADES ago, and has heard thorium repeatedly mentioned as the energy source of the future, a future that never comes. Paul Graham's dad worked for one company in the power industry, and my late dad the industrial engineer worked for another company in the industry, manufacturing electric generators for power plants. The power sources that spin electric generators were always dinner table conversation in my home when I was growing up. I think thorium is a very interesting fissile element, but my person guess about future power development is that there will never be a thorium power plant in Japan, in Germany, in the United States, or even in nuclear-plant-friendly France.
I did limit myself to the non-political issues. Political problems need political solutions. I'm personally more interested in the foundational problem of do they even work, technically and economically. If not, that eliminates the need to consider the political case at all. And the political issue ends up sort of circular; we can't build them, because we can't build them, because we can't build them. Not interesting to me personally. YMMV (no sarcasm).
The whole private vs. public issue is really obscured by the extreme, extreme regulation surrounding the entire area. I suspect it's overkill, while at the same time I can't deny one does not want to live anywhere near an unsafe power generation facility. (I did start to say "nuclear reactor", but it's more general than that, really.)
Honestly, in this case I'd much rather trust the government (more specifically, certain sects of it) than investors in choosing and funding technologies. The government may be corrupt and unwieldy and inefficient, but it is operating on (I would argue) a better feedback loop that acts on much more data (not only scientific, but social as well) and with a much better scientific workforce.
While much of it is unfortunately directed in part towards destruction and warfare, the projects are above and beyond what investors are investing in.
Just a quick look at the Microsystems group projects:
"The Casimir Effect Enhancement (CEE) program seeks to manipulate forces very near surfaces to enable control of small-scale phenomena, including nanodevice adhesion and friction. The objectives of this single-phase DARPA program are to demonstrate unambiguous detection, neutralization, and dynamic manipulation of the Casimir force to modulate between normal and neutralized states. Some approaches to these program goals include the development of new materials, engineered nanostructures, or active elements. Recent research activities (models and experiments) have already identified manipulation of the Casimir force as an important challenge."
Edit: To clarify the feedback loop comment: I think the jury is still out on the effect of economic incentives. In my opinion, looking at the degradation of privately funded pure research over the last 30-40 years (Bell, Xerox PARC, etc), economic incentives are only effective once someone (usually academia funded by the gov't) has laid the ground work. Investors will not do that.
The post you're responding to doesn't even mention government investment; it simply says it's silly to be skeptical of a technology because you don't know that it will work at commercial scale before trying it at commercial scale, because this is true of literally every technological innovation ever, regardless of whether it's publicly or privately funded.
It would seem to me that uranium-based nuclear power itself would never have been developed or commercialized (indeed as a byproduct of the military use first being developed) without massive government investment.
I don't see this argument as a specific counterpoint to Thorium-based nuclear power. That said, I am not particularly informed as to the benefits or drawbacks of Thorium -- I'm just observing that the counter-arguments don't seem to be particularly specific to Thorium and could have easily been applied to Uranium-based nuclear power had this been 1932 instead of 2012.
You know, a lot of private investors dumped a lot of money in the dot-com boom also. Everyone has heard stories like "If you would have invested $100 in Polaroid / Apple / what have you when they first started you would be a millionaire right now". That kind of thinking drove the dot-com era, and I think it is the same kind that is driving the alternative energy market. Many sources won't make it, but some will probably make it big.
An MSR reactor investment is not at all like a dot-com investment. One can use science and math to determine the facts about what an MSR can and cannot do.
Hey Strawman! Let's not compare investment in new, non-mature businesses like dot-com businesses in 2000 for which almost none of them had any sound profit building plans, with the energy market, which is a very well known industry with clear, regular paying customers.
I'm not drawing a comparison between the business models, I'm just pointing out that often times investors will jump on something that is "the future" even if the risk is high, because the rewards for success are even higher. So how is that a strawman?
Because you are comparing two very different situations and saying "the same kind that is driving the alternative energy market". The dot-com era investment was born out of the anticipation that the Internet was somehow going to revolutionize everything and that investing now would be rewarded at a later date, even if the business did not even any idea how to make money then. The energy market is not driven by the same investors, not the same companies. Energy groups are multi-national companies generations dozens of billions of revenues, and they are the ones funding the future initiatives, and I seriously doubt anyone could kickstart their way in the energy market because of the investments required to start anything from scratch.
There is nothing that could be as remote as these two markets.
Not necessarily disagreeing with your main thrust, but this sentence: "So maybe thorium power generation is a technical solution looking for a problem." goes a bit too far. Certainly, there are it might be a political solution in search of a problem, but there are technical problems around waste, proliferation, and safety that MSRs at least attempt to address, and they also don't produce greenhouse gases the way fossil-fuel-driven generators do, and have fewer outstanding technical question-marks than renewables (at least as baseload power, a role for which huge technical challenges will need to be solved before they can be considered viable). That still may not be good enough, but there are clearly problems in current energy production that will need to be solved somehow.
Also, aside: that guardian article isn't terrible, but the author gets half-lives backwards the way lots of authors seem to, implying that elements with long half-lives are bad, I suppose because we'll need to bury them for longer. It's the elements with short half-lives that are scary; they decay really fast and give people radiation poisoning/cancer/whatever. An element with a 16-million-year half-life is barely emitting anything at all; that's the category of waste that can, as the author of this post says, be buried in a shallow pit in the desert.
I would argue that for the purpose of nuclear waste disposal the relation between half life and problem is a bit more complicated than "getting it backwards." The short half life isotopes are easily disposed of, because we know how to build an organizational structure, that oversees the disposal. For example, to securely store nuclear waste with an half life of a decade on can simply coat it in some plastic and put it in a mine with a warning nailed to the entrance. With very large half life times on the other hand there is no big problem to begin with, as you stated.
But the intermediate timescale poses problems, since there the nuclear waste is radioactive enough to be dangerous and we do not have a good idea how a facility looks like, that can survive one hundred thousand years.
Yes, I was mostly just pointing out that the "Ooh! 16 million years! Scary!" attitude is bothersome, but you're right that I'm over-simplifying. My recollection was that the thorium cycle produces a mix of very-short-lived, deadly, gamma-emitting isotopes (U-232, I think? and possibly others) and very-long-lived, low-risk stuff, with less intermediate-half-life transuranic material left over, which made it rather preferable to the uranium fuel cycle as far as waste disposal was concerned, but I may be misremembering. Either way, the Guardian article doesn't deal with the issue in much depth or in a way that makes it sound like they know what they're talking about, so I don't trust their assessment of the relative merits of LFTRs vs. conventional uranium LWRs.
Most of the links you give talks primarily about thorium as an alternative fuel in traditional nuclear reactors, which is not what this article talks about. It talks primarily about Liquid Fluoride Thorium Reactors which are entirely differently to current reactors, which are all solid-state reactors.
It's really sad to see the different topics gets confused, because they are really different. Thorium as an alternative fuel doesn't really solve much, besides it's maybe cheaper for some countries. Of course the entire expression "Thorium reactors" are somewhat at fault. It's incredible ambiguous, especially when people inside the current nuclear establishment talks about using thorium in (slightly modified) traditional nuclear reactors, such Pressurized Water Reactors.
Of course there are many things which can be said against LFTRs, mostly that it's still an unproven technology. Sadly it'll stay that way if nobody does something about it.
They take issue with the IEER report judging thorium as a fuel when they are mostly talking about it in a solid fuel reactor. I can't think of any thorium proponents who are proposing solid fuel thorium reactors. The excitement they have over thorium is almost entirely over its use in the LFTR reactor design (which is not without its own design problems but those are distinct from a solid fuel thorium reactor).
Thanks for reminding of the increasingly economical non-nuclear non-fossil options.
On the matter of Minnesota nuclear plants: I would caution that the perceived cheap power is a result of significant expenses born by the populous as a whole decades ago... expenses that aren't in your power bill today but worth remembering. And similarly, there will eventually be significant expenses born by society as a whole to deal with the waste.
The fact that waste is piling up at all reactor sites---and don't think that's not a hazard in natural disaster/accident situations, let alone targeted strikes---means there is a significant not-yet-quantifiable cost uncertainty inherent to nuclear power.
Cost uncertainty has to be thought of as a significant cost, even higher than the potential cost will actually turn out to be, since we need to assume the worst when we don't know.
Thus if we really want to talk about the true cost of existing nuclear power: it's far higher than what you're paying today per KWh
First, the government spent all that money for their own purposes. The design and construction of commercial Nuclear Power Plants has been on the user since day one. also, NPPs have been paying into a fund to handle Spent Nuclear Fuel. There is plenty of money to handle it, except that government can spend way more on anything than any rational person can imagine.
The fed gov has spent ~$16B on "renewable energy" recently. With 1/10th that money, LFTRs could have been coming off the assembly line at 100MW/day by now. And those plants could be eliminating that SNF as we speak.
The article is more about molten salt reactors than thorium as a fuel. The benefits listed are from using molten salt, not thorium.
The NPR story adds to the original article — the experimental thorium reactor ran for 14 years, not 4. The head of the project was fired by Nixon (hardly a big strike against him).
It seems to me that the NPR show simply raised two objections:
1) you still have nuclear waste — less than with current reactors but arguable how much less.
2) it does not stop nuclear proliferation (this was a heated discussion point with the thorium advocate arguing that it is much harder to harvest U233 from an MSR than plutonium or enriched uranium from other sources and the anti-nuclear guy citing a paper suggesting it's easier. (U233 is easier to make a bomb with than plutonium - i did not know this.)
It it noteworthy to remember that the reason LFTR advocates says that LFTR reactors will stop nuclear proliferation is that all the U233 will be comtaminated with the highly radioactive U232 isotope. To extract U233 from the active core of an LFTR would take just as much engineering as normal enrichment plants, if not more. The current enrichment plants would never allow U232 inside their plants since it is so difficult and dangerous.
Of course that's all hearsay from the LFTR advocates :P
Nope, it is one of the main reasons why Thorium is not that great in typical solid fuel reactors. Lots of experience there. Processing the fuel to extract and use the U233 is rather a bothersome thing to do.
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?
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?
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.
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.
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).
"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.
>> You had been blacklisted before that, because your nuclear weapons pissed off the world (don't blame the world).
Yeah Right, Its perfectly alright for us to have nuclear weapons but not others because they are irresponsible and undeserving (Hiroshima and Nagasaki anyone?)
The proposed nuclear supply is dodgy at best. The supplier countries are asking so much in return that it might not actually go well for long. France & US only agreed because Indian Army relented to buy a large cache of arms and fighter jets.India can't do that too much, too often to aggravate the already exploding arm's race vis-a-vis China and Pakistan. Thorium is India's best(and perhaps only) hope. That's why it is still betting on arcane technologies like solid fueled thorium reactors, because they have invested so much into it already. The program has "got to" produce 30% of energy needs by 2050 or all is not well for India.
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.
It's only been a few years since India was "pardoned", and Australia is just one of many potential suppliers. The broad point is, the entire world uranium market is open to India, which was not the case until recently. India's preexisting nuclear strategy is no longer valid.
Here's another sale: a settled Russian deal to supply uranium for a Russian-built VVER reactor, for its entire lifespan. (Admittedly the implication is the uranium deal is somehow tied to the Russian reactor sale, which is somewhat limiting). Not much politics here! (Not much politics in Russia either).
yes, the russians will on-sell to anyone:
its probable that australia's decision to supply russia, while not as politically charged, was a greater proliferation hit than any future decision on india :(
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:
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).
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.
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.
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?
For starters, on NPR I heard the scientist who measured the Fukushima cesium in fish. He said the level of radioactivity was a small fraction of the amount naturally in the fish. But to your question, the answer is yes, MSRs would pollute less in the worst scenario.
It's true they will generate cesium, because that's one of the things left after you fission atoms. However, since it's liquid fuel, the cesium can be removed continually and taken away to storage. (I think the idea is to encase it in glass and bury it.) The amount of cesium in the reactor at any given time is much smaller than for solid-fuel reactors.
Also, fission products like cesium are chemically contained in the molten salt. If something breaks open the reactor, the salt will escape, quickly cool, and solidify, containing the cesium. You'll get hot rocks at the reactor site but no radioactive cloud over your community.
Many of the engineers claim the reactor wouldn't need water cooling, so it wouldn't have to be on a shoreline. Put it in the desert if you want.
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:
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]
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).