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Can World's Largest Laser Zap Earth's Energy Woes?
newviewmedia.com writes "Scientists at the Lawrence Livermore National Laboratory plan on using a laser the size of three football fields to set off a nuclear reaction so intense that it will make a star bloom on the surface of the Earth. If they're successful, the scientists hope to solve the global energy crisis by harnessing the energy generated by the mini-star."
The National Ignition Facility is not doing research into energy production. The research they're doing will not have applications in energy production. The hope is that by understanding ignition other nuclear fusion projects will be able to make better progress.. it is completely pure research, as you would expect from a national laboratory.
How we know is more important than what we know.
And for the record, it's been a hell of a lot longer than 20 years that fusion power has been 10 or 20 years away. I think the first promises of that sort appeared around 1950.
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http://news.bbc.co.uk/1/hi/8485669.stm
Slashdot has gone down in my estimations, if the best source they can find is CNN :-(
Despite it's earlier mention in the thread, I have to take the opportunity to point out that Focus Fusion involves a reactor design that extracts power from the reaction via 2 routes ;
Both of which are very much more direct than steam generation. I believe the reaction has plenty of waste heat which could be used industrially as well.
That tells us nothing without a measurement of density. How many Libraries of Congress worth of energy can those three football fields produce?
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You need several solar masses to make a supernova. You absolutely can't do it with a terrestial reactor.
Obligatory link to Edward Teller's article "Can We Harness Nuclear Fusion in the '70s?" in Popular Science magazine, May 1972 edition.
http://www.popsci.com/archive-viewer?id=VvyLShXydNgC&pg=88
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By "mini-star" they just mean a brief fusion reaction that is expected to last for a fraction of a second --- if for no other reason then there is only a limited amount of fuel available to it.
Also, the way in which many of those involved ultimately intend to use this is not to create a reactor drawing power purely from fusion but rather to create fusion/fission hybrid reactor in which neutrons from the fusion reaction drive fission reactions in nuclear fuel that would not become critical by itself --- i.e., so we can burn things like nuclear waste and thorium. Such a reactor would be intrinsically fail-safe because when fuel pellets stop being dropped into the reactor and ignited by lasers into "mini-stars" (which, again, is something that needs to be done continuously --- several times a second --- since the "mini-stars" burn up all their hydrogen fuel so quickly) then eventually the whole thing shuts down on its own.
In other words, this is completely unlike the ridiculous and highly implausible fusion reactor featured in Spider-Man 2 which had the magic power to sustain itself by eating everything around it --- which, incidentally, is a power that even our own *actual* sun doesn’t come close to having, since it can only burn its limited supply of hydrogen fuel.
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That's called the Leidenfrost effect.
This article concentrates on Deuterium-Tritium fusion, and I agree with it in that context.
Most of the concerns are addressed by the design of a DPF reactor.
withstand temperatures of millions of degrees for years on end
That's just FUD, I'm afraid. Even in tokamak reactors, the plasma is kept separate from the reactor vessel. The plasma is at millions of degrees ; the reactor vessel is not. In a DPF reactor, the plasma is a teensy little 12 microns across - even if the contents are running at about a billion Kelvin, they won't heat the reactor vessel to millions of degrees. The reactor is also designed to emit most of it's energy through non-thermal vectors.
constantly bombarded by high-energy nuclear particles
True, in a DT reactor. Not so true in a pB reactor - the reaction produces helium and electrons, not neutrons.
has to make its own nuclear fuel
This one is the big winner. As they rightly noted, tritium is one of the rarest elements on Earth. A pB reaction uses no tritium, it uses common or garden "normal" hydrogen, and boron, an element that's abundant enough to sell as eyewash.
no outages, interruptions or mishaps—for decades on end
When a 1 GW reactor goes offline, yes, you have a shortfall problem. When the proposed 5MW output DPF reactor goes offline for it's routine maintenance (for about 12 hours), you just lean on the others you have running. Lots of small, local, redundant reactors the size of shipping containers make for more reliability than a few whacking great behemoths the size of aircraft carriers. When they cost $300,000 instead of $10,000,000,000, you can afford to pile them high, and sell them cheap.
must also convert energy from the neutrons into heat that drives a turbine
The design is intended to use 2 methods of direct energy collection that are not heat engines, a more elegant and efficient solution that places it closer to "power plant" break-even.
At least they report the purpose of NIF correctly, albeit couched in soft language - it's about "National Security", not energy generation.
We're in the 21st century now!
It was a genetically modified spider.
on average US taxpayers pay $10/month for everything that NASA does.
Number of US tax payers is about 138 Million... NASA Budget is 18.7 $B(2010). So mathematically the average is closer to $130 per taxpayer...
$18.700.000.000 / 138.000.000 = $135 per person per year.
$135 / 12 (months in a year) = $11 per person per month.
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http://en.wikipedia.org/wiki/2010:_Odyssey_Two
As for the topic at hand, like fusion reactors the main problem will be getting MORE energy than you consume.
Way to go captain obvious.
Perhaps a smarter move would be to figure out how to harness the star we already have
Thanks for the laugh. Even with 100% efficient orbital solar stations we would need a few million km^2 of panels just to match current energy usage. That number seemed large to me so I did a little digging and found this image that details electricity consumption alone. Switching to 100% solar and building a grid capable of redistributing that power from where it is generated to where it is used (nevermind orbital based power stations) would be a megaproject to dwarf every other construction project in history combined.
E pluribus unum
I know you're not seriously suggesting that this could actually end up as a disaster movie scenario, but I'm going to babble about it anyway. This is a tritium/deuterium reaction. Deuterium is rare, and tritium is incredibly rare. There just isn't any chance of any sort of chain reaction with this, so as soon as the fuel is gone, the reaction stops. They know exactly how much fuel is in each pellet, and therefore how much energy will be released and they have the shielding to handle it. All the stuff about about this being a "sun" on earth is just a simplification for the general public. Also known as a lie.
What is going on here (if they get it to work) is a nothing like what goes on in the sun. Our suns primary fuel is plain old hydrogen, not tritium and deuterium. It's generally expected that the actual ratio of Tritium and Deuterium in the sun to regular hydrogen is minuscule compared to Earth. This is because a tritium/deuterium reaction is much easier to achieve than the standard solar fusion reaction with regular hydrogen, so the suns tritium and deuterium get consumed far, far faster. There probably wouldn't be any in the sun except that the suns environment probably keeps creating new tritium and deuterium which don't last very long. The standard fusion reaction that largely drives the sun is the proton-proton chain reaction (which does briefly involve deuterium as an intermediate step). Producing that on earth is currently considered ridiculous. This is because it requires incredibly high temperatures and pressures and, even in the suns core, it's a rare reaction. As others have pointed out in this discussion, the actual average energy generation of the sun per unit of volume is roughly comparable to a compost heap. It's just that the sun has a huge volume.
If you're wondering then why the sun is so bright and you can feel its radiated heat while a compost heap far enough away that it looks exactly the same size as the sun doesn't seem to heat you at all and isn't super bright, the answer is simple. Ok, it's actually complex and there's a lot to it that isn't even occurring to me right now, but there's a simple thought experiment that demonstrates at least part of it. It's the sqaure-cube ratio. The area of a cube with sides of length s units is 6s^2 square units. The volume of that same cube is s^3 cube units. So if s is 1, then the area is 6 square units and the volume is 1 cube unit (6/1 ratio), but if the length is 3, then the area is is 54 square units and the volume is 27 cube units (2/1 ratio), and if the length is 6, then the area is 216 square units, and the volume is 216 cube units (1/1 ratio), and if the length is 9 then the area is 486 square units, and the volume is 729 cube units (2/3 ratio), and if the length is 12, then the area is 864 square units, and the volume is 1728 cube units (1/2 ratio), and so on. So, basically, as a cube, or any other three dimensional object (such as a sphere like our sun), grows in volume, its area doesn't keep pace. So, the area of the sun we see is the front for a far greater volume of material. Or, picture a cone shaped compost heap with the blunt end pointing towards you and the pointy end pointing away with the blunt end far enough away from you that it has the same apparent size of the sun. This cone shaped compost heap has a length equal to the radius of the sun and all the heat it is generating is directed towards the blunt end of the cone, at which point it radiates out evenly over the area of the end of the cone. That should be more on the order of what you get from the sun. Actually, I think that, aside from the physical impossibility of the model, I've missed enough things that I've just vaporized you... Thought experiments are hard.
Anyway, obviously this experiment can't destroy the earth, or even create a massive explosion, or even generate more power than they put into the laser. Still, they do manage to make it sound like the opening to the plot of a disaster movie. I can't help thinking about some of these movie doomsday power g
Um... without looking at the rest, do note that 1 km^2 = 1,000,000 m^2. (consider: how many 1x1 metre squares can fit in a 1x1 km square). Your result should thus be ~11,538 km^2.