My guess is that if you achieve sustainable output beyond breakeven then it's a more reasonable engineering challenge to scale that up. The key here being sustainable, none of these technologies are too close to that yet it seems.
It's looking really good. Sandia ran simulations, found a sweet spot, and recently ran a test in which they magnetically crushed a liner without fuel. That test worked out exactly how the simulations predicted.
They have several other tests to do and plan to do a complete test by the end of 2013. If it still works the way their simulation predicts, they'll approximately hit breakeven.
The next step will be to build a machine several times bigger. According to the sim, that would take us from breakeven to a 100x to 1000x energy gain (depending on how powerful they make the machine.)
Such a large gain helps a lot for turning it into a practical plant. For one thing, they'd only have to fire a shot every ten seconds or so. NIF's laser approach, by comparison, would require ten shots per second.
Fusion power is actually already above break even. There are a lot more practical engineering problems with fusion power before that means anything, though. Most of these problems have to do with materials science: Plasma is incredibly difficult to contain, and it's very difficult to design a cooling system that could work sustainably. Without a cooling system, there is no way to make use of the heat generated in fusion.
Wow, fusion power in less than 15 years! Gee whiz!
Actually, the 15 years out time frame puts it beyond what I've expected, 10 years out. That's where fusion has been for most of my life, 10 years from now.
20 years ago I remember everyone saying fusion was 40-50 years out and always had been. Honestly, I think the estimates where fairly reasonable when you consider the 30+ year gap between Jet which was designed in 1972 and came online in 1983 and ITER which is still being built. http://en.wikipedia.org/wiki/Joint_European_Torus
PS: I have heard that the real issue was scaling up Jet was assumed to be work but doing so was to far from commercially viable to be useful.
After iter is ready, in 15 years, they expect to have fusion for 1000 seconds straight. Just need to tweak that for 10 years, and then we are ready for start building the commercial reactors, which might take 5-10 more years.
1. Who said it was 10 years out? I've never heard that. Sometimes milestones are 10 years out and the public tends to confuse milestones with the finished product.
2. Ideas for parallel implementations of nuclear fusion have expanded, and as a result, funding and research has arguably become fragmented and resources have been diverted. In reality, there's a fixed amount of capital and knowledge (which is also a function of the availability of money) available for this kind of research. The amount of money the US puts into fusion research is quite paltry compared to the potential benefits. It may be a priority, but the way Washington spends money says otherwise.
Scientifically, fusion is maybe 10 years away. Politically, it's more like 40 for a real power plant, but with the current congress, I couldn't say. In addition to that, it's an expensive enough endeavor that it would be corporate suicide for a private company to attempt it, especially considering the majority of companies with enough capital to pursue something like fusion tend to be in the Oil and Gas industries.
Well, some types of fusion are too expensive for private companies. But Tri-Alpha, General Fusion, and Lawrenceville Plasma Physics are three private companies trying to achieve practical fusion power within the decade.
Tri-Alpha has over $90 million in venture capital, some from Paul Allen. General Fusion has about half that, with Jeff Bezos as an investor. LPP is a lot smaller, but also doesn't need nearly as much at this point.
There are several other approaches in the works that could conceivably by privately funded, including Helion (needs $20 million for a full-scale reactor, already built a 1/3 scale version) and petawatt picosecond laser fusion (once the lasers get a little better).
Another promising approach is levitated dipole, but I don't know what costs look like for that one.
Nope, both are fusion reactions. You fuse two particles together below 56 on the periodic table and achieve energy. After 56 and up, you have to use fission, where you split atoms apart, to achieve energy.
The H-bomb uses a fission A-bomb to get enough temperature and pressure to produce the fusion reactions.
The sun is a 100% fusion reactor.
If you mix a fusion and a fission reactor, probably you will have most of the disadvantages of the fusion reactors; in particular you will have a lot of long-living radioactive byproduct of the fission reactions.
In fusion-based nuclear weapons, a fission bomb is used to create the temperature and pressure needed to kick off nuclear fusion. Calling that "combined fusion/fission" is like calling my car an electric hybrid because it uses an electric starter.
Detonating a nuclear weapon inside of a power plant isn't really practical. :-) Existing nuclear power plants don't get anywhere near the temperature and pressure needed to start nuclear fusion.
So, now we have the engineers trying all sorts of ways to get to the needed temperature and pressure without turning the plant into a smoking crater. That's where all the fancy lasers and magnetic pulses described in the article come in: They're trying to aim the heat source so they can superheat the fuel without melting the containment vessel.
That's a popular misconception, IIRC. Actually, in thermonuclear weapon the bulk of energy comes from fission. [1] Fusion is technically only used to get the high energy neutrons to get the bulk of fissionable material to undergo fission. So, ironically, calling it a "fusion bomb" is very much like calling your car an electric hybrid.
Where those weapons get the most energy from depends heavily on the design. It's true that multi-stage thermonuclear devices often have a final fission stage where huge amounts of energy are released, however if one were to purposefully maximize energy release while minimizing fallout there are some relatively clean fusion/fission ratios achievable.
For instance, the test version of the Tsar bomb had its last fission stage removed, reportedly resulting in a 97% fusion detonation. Of course, those still cause a huge lethal neutron flux, but at least the amount of fission material released is pretty small in relation to the overall power of the device.
I think combined fusion/fission options are the clear choice for the future. (Also, yes, that is what the H-bomb does, and no, that is not what the sun does.)
Here's how combined fusion/fission plants would theoretically work:
A fusion reaction is used to create a large quantity of high-energy neutrons. These high-energy neutrons are then used to cause fission in an otherwise subcritical fission assembly with extremely low enrichment fuel. 'Natural' uranium (U-238) is fissionable, which means that it can undergo fission in the presence of /high energy/ neutrons.
Less dirty than fission, absolutely. Enough less dirty to make it manageable in a way that fission doesn't seem to be, more than likely. But not clean.
Any material in and around the reactor becomes nuclear waste in the same manner as it does for fission: by getting blasted with high-energy particles until it becomes radioactive. And while there wouldn't be any spent fuel rods to deal with, one of the products of hydrogen fusion, tritium, is also a source of concern.
Tritium is part of the fuel for this type of fusion reactor. Since tritium basically doesn't exist in nature (due to its twelve-year half-life), the reactor will produce it by absorbing as many neutrons as possible in a blanket of lithium.
The first fission plants will involve neutrons, but aneutronic fission would be the next step after that. It would require getting the fire hotter/denser.
By any measure, cleaner than what else is out there. Already a fission nuclear power plant will produce less leakage of radioactivity into the environment than many coal plants, fusion drops that level several orders of magnitude more.
First off, no fission products, which are typically the most dangerous radioactive waste from fission reactors. Second, the materials used in the reactors don't have the same engineering constraints that fission reactors do and so can be chosen to produce far lower quantities of hazardous radioactive isotopes bred from intense neutron flux bombardment. Also, Tritium is a fuel, and of enormous value so it would be handled very carefully. More so, it would be bred specifically in custom built containment vessels within the reactor.
On top of all that you have the fact that a fusion reactor cannot be made to undergo a meltdown or overload the way a fission reactor can. If something bad happens in a fusion reactor the immediate result is usually that fusion stops, which compares very favorably to the what happens in a fission reactor: fission chain reactions continue, temperatures build as the heat from fission products decaying builds up, etc. And you don't have weapon proliferation concerns.
Overall what you have with nuclear fusion reactors is no chance of a meltdown, very much less hazardous waste generated (by orders of magnitude) and a very clean energy profile.
^ -intact- fission nuclear power plant
^ should
^ might
^ dramatically greater engineering constraints than fission reactors
^ (if you exclude engineering and manufacturing and plant construction costs)
Sorry for the highlighter attack, but fusion still means building extraordinarily complex and expensive reactors that are going to have one hell of a carbon footprint and shed tons of radioactive waste in normal operation.
Let's roll it back to "potentially cleaner in some key ways".
This is just plain FUD with no backing in reality.
Let me make it as clear as possible. Fusion energy is fundamentally safer and cleaner than fission energy, period. Firstly, it is simply not physically possible for fusion energy to generate even a tenth as much of the radioactive waste as an equivalent fission power plant. Secondly, it is not possible to have a dangerous power excursion at a fusion plant. When a fusion plant malfunctions it doesn't experience a runaway reaction, it stops working. If a fusion plant experiences some sort of catastrophic structural failure everything stops. This is in stark contrast to fission reactors which can undergo continued fission chain-reactions even if, and perhaps especially if, the reactor vessel is disrupted and the fuel melts down and also produce fission byproduct isotopes which continue to generate enough heat after the fission reactions have stopped to melt the reactor core if it is not continuously cooled.
Also, there is little evidence that the construction of a fusion reactor would entail a higher energy-usage footprint than a fission reactor, and the lack of a need for massive reinforced concrete structures in a fusion reactor tends to argue that the footprint would be rather less.
Let's roll it forward back to: undoubtedly cleaner if it can be made to work.
I hear how passionate you are on this issue and I understand the enthusiasm. I'm not here to strangle the baby in the cradle. But my concerns are real.
Granted: Fusion energy is a conceptually simpler process that is virtually impossible to runaway by its very nature. That alone is a massive plus any way you look at it.
Granted: the total bulk volume of radioactive waste products is dramatically lessened.
Granted: the radionuclides created by a fusion reactor are likely to be less problematic than those from a fission reactor.
My points: There is still radioactive waste: magnetic confinement reactor liners will handle so much corrosive flux they'll essentially be disposable and replaced frequently - possibly on the order of weeks or months. Same (but lessened) story for inertial confinement reactor liners and the metallic waste products. Those have to go somewhere safe. They're not small.
Same story for the electrical generation system. Regardless of the final reactor type, it's still going to involve managing heat-exchange fluids with neutron exposure.
Then there's the environmental + carbon load from building a reactor complex, which is not going to be quantifiable until there are working reactor designs and working fuel flows and a working understanding of how much staffing and security and land and ancillary support is needed. NIMBY is going to be just as strong for fusion as it is for fission, and that's going to mean compromises.
Then there's going to be the cost of purifying the fuel source, which won't be negligible when it literally involves boiling the seas. Then packaging it. Then shipping it. Then handling the waste products. Then planning for the plant's functional lifetime, which won't be forever.
The conceptual clarity of fusion is wonderful and I fully support the research, but the execution is going to be quite a bit less sexy and come with some well-known downsides.
This article does not mention some important context.
I don't know all the ins and outs, but it's important to understand that the big US experiment in nuclear fusion was NIF, at LLNL. They (perhaps rashly) promised net energy gain by the end of this fiscal year. This whole thing was part of an elaborate political deal regarding maintaining nuclear expertise during the test ban treaty.
Anyway, net gain did not happen; the ratio of energy out to energy in at the NIF is 0.1. This had been expected for many months now (indeed, it was predicted by some as soon as the deal was cut, years ago.)
At this point, the pie of nuclear research dollars is going to be re-cut with different allocations. For one thing, the fusion/non-fusion balance at NIF is going to tilt away from fusion.
So, in the absence of a NIF fusion success story, this press release could be part of a campaign by other labs or other experiments to press their own research agenda for fusion.
Folks, the clean controllable energy source out of LENR process is almost here. Please go through my links with an open mind and consider sharing them with your family friends and colleagues...
30 comments
[ 0.20 ms ] story [ 80.6 ms ] threadWhat happens if they get just a little above break even?
They have several other tests to do and plan to do a complete test by the end of 2013. If it still works the way their simulation predicts, they'll approximately hit breakeven.
The next step will be to build a machine several times bigger. According to the sim, that would take us from breakeven to a 100x to 1000x energy gain (depending on how powerful they make the machine.)
Such a large gain helps a lot for turning it into a practical plant. For one thing, they'd only have to fire a shot every ten seconds or so. NIF's laser approach, by comparison, would require ten shots per second.
Actually, the 15 years out time frame puts it beyond what I've expected, 10 years out. That's where fusion has been for most of my life, 10 years from now.
PS: I have heard that the real issue was scaling up Jet was assumed to be work but doing so was to far from commercially viable to be useful.
(extremely speculative of course)
2. Ideas for parallel implementations of nuclear fusion have expanded, and as a result, funding and research has arguably become fragmented and resources have been diverted. In reality, there's a fixed amount of capital and knowledge (which is also a function of the availability of money) available for this kind of research. The amount of money the US puts into fusion research is quite paltry compared to the potential benefits. It may be a priority, but the way Washington spends money says otherwise.
Scientifically, fusion is maybe 10 years away. Politically, it's more like 40 for a real power plant, but with the current congress, I couldn't say. In addition to that, it's an expensive enough endeavor that it would be corporate suicide for a private company to attempt it, especially considering the majority of companies with enough capital to pursue something like fusion tend to be in the Oil and Gas industries.
Tri-Alpha has over $90 million in venture capital, some from Paul Allen. General Fusion has about half that, with Jeff Bezos as an investor. LPP is a lot smaller, but also doesn't need nearly as much at this point.
There are several other approaches in the works that could conceivably by privately funded, including Helion (needs $20 million for a full-scale reactor, already built a 1/3 scale version) and petawatt picosecond laser fusion (once the lasers get a little better).
Another promising approach is levitated dipole, but I don't know what costs look like for that one.
But we lack the infrastructure and investment to build them.
The sun is a 100% fusion reactor.
If you mix a fusion and a fission reactor, probably you will have most of the disadvantages of the fusion reactors; in particular you will have a lot of long-living radioactive byproduct of the fission reactions.
Detonating a nuclear weapon inside of a power plant isn't really practical. :-) Existing nuclear power plants don't get anywhere near the temperature and pressure needed to start nuclear fusion.
So, now we have the engineers trying all sorts of ways to get to the needed temperature and pressure without turning the plant into a smoking crater. That's where all the fancy lasers and magnetic pulses described in the article come in: They're trying to aim the heat source so they can superheat the fuel without melting the containment vessel.
1. http://en.wikipedia.org/wiki/Thermonuclear_weapon
For instance, the test version of the Tsar bomb had its last fission stage removed, reportedly resulting in a 97% fusion detonation. Of course, those still cause a huge lethal neutron flux, but at least the amount of fission material released is pretty small in relation to the overall power of the device.
Here's how combined fusion/fission plants would theoretically work:
A fusion reaction is used to create a large quantity of high-energy neutrons. These high-energy neutrons are then used to cause fission in an otherwise subcritical fission assembly with extremely low enrichment fuel. 'Natural' uranium (U-238) is fissionable, which means that it can undergo fission in the presence of /high energy/ neutrons.
Less dirty than fission, absolutely. Enough less dirty to make it manageable in a way that fission doesn't seem to be, more than likely. But not clean.
Any material in and around the reactor becomes nuclear waste in the same manner as it does for fission: by getting blasted with high-energy particles until it becomes radioactive. And while there wouldn't be any spent fuel rods to deal with, one of the products of hydrogen fusion, tritium, is also a source of concern.
Isn't tritium a nuclear fuel?
By any measure, cleaner than what else is out there. Already a fission nuclear power plant will produce less leakage of radioactivity into the environment than many coal plants, fusion drops that level several orders of magnitude more.
First off, no fission products, which are typically the most dangerous radioactive waste from fission reactors. Second, the materials used in the reactors don't have the same engineering constraints that fission reactors do and so can be chosen to produce far lower quantities of hazardous radioactive isotopes bred from intense neutron flux bombardment. Also, Tritium is a fuel, and of enormous value so it would be handled very carefully. More so, it would be bred specifically in custom built containment vessels within the reactor.
On top of all that you have the fact that a fusion reactor cannot be made to undergo a meltdown or overload the way a fission reactor can. If something bad happens in a fusion reactor the immediate result is usually that fusion stops, which compares very favorably to the what happens in a fission reactor: fission chain reactions continue, temperatures build as the heat from fission products decaying builds up, etc. And you don't have weapon proliferation concerns.
Overall what you have with nuclear fusion reactors is no chance of a meltdown, very much less hazardous waste generated (by orders of magnitude) and a very clean energy profile.
Sorry for the highlighter attack, but fusion still means building extraordinarily complex and expensive reactors that are going to have one hell of a carbon footprint and shed tons of radioactive waste in normal operation.
Let's roll it back to "potentially cleaner in some key ways".
Let me make it as clear as possible. Fusion energy is fundamentally safer and cleaner than fission energy, period. Firstly, it is simply not physically possible for fusion energy to generate even a tenth as much of the radioactive waste as an equivalent fission power plant. Secondly, it is not possible to have a dangerous power excursion at a fusion plant. When a fusion plant malfunctions it doesn't experience a runaway reaction, it stops working. If a fusion plant experiences some sort of catastrophic structural failure everything stops. This is in stark contrast to fission reactors which can undergo continued fission chain-reactions even if, and perhaps especially if, the reactor vessel is disrupted and the fuel melts down and also produce fission byproduct isotopes which continue to generate enough heat after the fission reactions have stopped to melt the reactor core if it is not continuously cooled.
Also, there is little evidence that the construction of a fusion reactor would entail a higher energy-usage footprint than a fission reactor, and the lack of a need for massive reinforced concrete structures in a fusion reactor tends to argue that the footprint would be rather less.
Let's roll it forward back to: undoubtedly cleaner if it can be made to work.
Granted: Fusion energy is a conceptually simpler process that is virtually impossible to runaway by its very nature. That alone is a massive plus any way you look at it.
Granted: the total bulk volume of radioactive waste products is dramatically lessened.
Granted: the radionuclides created by a fusion reactor are likely to be less problematic than those from a fission reactor.
My points: There is still radioactive waste: magnetic confinement reactor liners will handle so much corrosive flux they'll essentially be disposable and replaced frequently - possibly on the order of weeks or months. Same (but lessened) story for inertial confinement reactor liners and the metallic waste products. Those have to go somewhere safe. They're not small.
Same story for the electrical generation system. Regardless of the final reactor type, it's still going to involve managing heat-exchange fluids with neutron exposure.
Then there's the environmental + carbon load from building a reactor complex, which is not going to be quantifiable until there are working reactor designs and working fuel flows and a working understanding of how much staffing and security and land and ancillary support is needed. NIMBY is going to be just as strong for fusion as it is for fission, and that's going to mean compromises.
Then there's going to be the cost of purifying the fuel source, which won't be negligible when it literally involves boiling the seas. Then packaging it. Then shipping it. Then handling the waste products. Then planning for the plant's functional lifetime, which won't be forever.
The conceptual clarity of fusion is wonderful and I fully support the research, but the execution is going to be quite a bit less sexy and come with some well-known downsides.
Amongst the many attractive properties of LFTRs is the ability to burn spent fuel from existing nuclear plants.
I don't know all the ins and outs, but it's important to understand that the big US experiment in nuclear fusion was NIF, at LLNL. They (perhaps rashly) promised net energy gain by the end of this fiscal year. This whole thing was part of an elaborate political deal regarding maintaining nuclear expertise during the test ban treaty.
Anyway, net gain did not happen; the ratio of energy out to energy in at the NIF is 0.1. This had been expected for many months now (indeed, it was predicted by some as soon as the deal was cut, years ago.)
At this point, the pie of nuclear research dollars is going to be re-cut with different allocations. For one thing, the fusion/non-fusion balance at NIF is going to tilt away from fusion.
So, in the absence of a NIF fusion success story, this press release could be part of a campaign by other labs or other experiments to press their own research agenda for fusion.
For partial background:
http://www.nytimes.com/2012/09/30/science/fusion-project-fac...
Francesco Celani's experiment is being in a process of replication: http://youtu.be/Q2qWgh7Gx4g http://youtu.be/gHpYuUykWw0 http://youtu.be/qc5RoGg6n8E http://youtu.be/HN4VK82Mngc
Please, please - at least watch this video: http://youtu.be/26k3Cz3wW-8 -> This is a great initiative.
Folks, the clean controllable energy source out of LENR process is almost here. Please go through my links with an open mind and consider sharing them with your family friends and colleagues...