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Nuclear Fusion Real Soon Now
Mr. A. Coward writes "Researchers at the
National Ignition Facility are attempting to produce nuclear fusion. They'll focus 192 amplified lasers on a pellet of frozen hydrogen. 'NIF experiments will be the first to create fusion that gives off more energy than it takes in.' That will have to be quite a bit, since it will take 500 trillion watts to ignite the pellet in the first place. The facility has been plagued with delays, and so far only 4 of the 192 lasers have been completed. Researchers believe they will first achieve fusion sometime around 2014."
Umm, fusion is most certainly NOT impossible. Stand outside tomorrow around noon and look up at the sky. See that big burning thing that hurts your eyes? That's a nuclear fusion reaction.
Ahh, hasn't break even been passed experimentally quite some time ago?
m l
http://www.jaeri.go.jp/english/fusion/fusion.ht
This claims break even in 1996, and 1.25 power increase in 1998 in the JT-60 tokamak..
And this article seems to be stating they plan to hit breakeven in 2014 or further out.. hmmm.. perhaps they mean some special kind of break even, like the first ones using our method, or in the US, or something like that..
That would probably be the first to create a net increase in energy using fusion. Either that, or those fusion scientists are pretty good fakers over the last few decades.
Obligatory nit-pick. The article implies that about 10 Joules of energy hits the pellet. No mention of the laser system's efficiency.
National Ignition Facility home page
National Ignition Facility project status and photo gallery with lots of pictures
LLNL Science on High Energy Lasers
Fusion happens commonly in research labs. What hasn't happened yet, is getting more energy out than it took to create the fusion, in a controlled, energy-generating environment.
http://www.llnl.gov/nif/construction/photoshow.htm l
Let's see...
Assuming that '500 trillion' means 500 x 10^12 watts... They said it would be for a 'few billionths' of a second: maybe 2 x 10^-9 seconds?
Am I counting wrong, or does that come out to about a million watt-seconds, or 0.277 kilowatt-hours?
I consume more energy than that makin' coffee.
Never attribute to malice that which can be explained by mere idiocy.
As Mr. Potts says, Watts are a unit of power. 500 trillion Watts is the power being put into the reaction by the lasers. Energy is not the same thing as power. Power is energy divided by time.
According to the article, the beams will be fully on "only for a few billionths of a second". For a naive estimate of the total energy being output by the lasers, we can simply multiply (500 GW) * (2 ns).
Now, this yields a quantity with dimensions of energy: (500 GW) * (2 ns) = (1 kJ). To get a handle on this, it is the amount of energy that is output in heat and light by a 100W light bulb shining for ten seconds.
For a scenario Slashdotters are familiar with, it's the amount of heat generated by a 1 GHz Athlon thunderbird in 12 seconds.
Power is not the same as energy. It is energy per unit time. It is rubbish to say there will have to be a large energy output because the input power is high. By way of example, 500 trillion watts for a femtosecond = 500 joules. This is not an unreasonable amount of energy, contrary to the attempt to imply otherwise by shouting '500 trillion'.
Got my SI prefixes wrong. 500 trillion * 1 femto second is 0.5W. My mistake. The correction is in favour of my argument though!
I thought all you had to do to get fusion (though not break-even yet, I think) is shake some heavy acetone.
Simple Unexpected Concrete Credible Emotional Stories
Actually, if you read the article 2014 is someone else's estimate, and the scientists hope for results substantially sooner.
/.er actually read the article?
I know, I know, suggest a
Ooh, a sarcasm detector. Oh, that's a real useful invention.
Indeed. For more information on this, you could do worse than starting here: fusion.org.uk
However, is artifically created fission possible, so far it hasn't been.
Assuming you meant fusion instead of fission (which is how current nuclear plants work):
Sure it is, you ever heard of a "Hydrogen Bomb?"
What hasn't been done yet, is create a sustainable / controllable fusion reaction in a lab. If that ever happens, then we are on the way to being able to harness fusion for energy production, commercially.
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The fact that the lasers use 500 trillion watts is not related at all as to whether this is the first fusion plant 'that gives off more energy than it takes in', since watts is not a measure of energy, rather, of power (energy/time).
it's the law of conservation of matter *and* energy...
t ar_6.html
A quick lesson in where the extra energy comes from in a fusion reaction: http://observe.arc.nasa.gov/nasa/exhibits/stars/s
I'll sig you upside the head!
Compare this to the efforts of JET the Joint European Torus project, which achieved breakeven (Q=1) during 1997 (good explanation of fusion milestones here). JET's successor, ITER aims to achieve Q of at least 10, paving the way for commercial-scale power generation.
The only thing that worries me about ITER is the level of bureaucracy exhibited, but perhaps this is to be expected from a multi-national consortium.
ITER are standing on the shoulders of giants, NIF are discussing specifications for a step-ladder.
Strictly speaking, while maser is now also a word, 'microwave laser' is a perfectly valid term since the word 'microwave' merely describes a type of light (with light generically referring to photonic waves, i.e. EM waves).
"Stumble before you crawl"
That's correct, but it is also bleeding a huge amount of mass so it is not a case of getting something for nothing.
Nope. The fission reaction is just used to kick off the fusion reaction. Here, read this:
http://people.howstuffworks.com/nuclear-bomb9.htm
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I'm sorry, I just can't let this go uncorrected. A fusion power plant is incapable of 'meltdown' in any way, shape or form. Fission plants can meltdown because they contain all of their fuel within the reactor vessel (think "all my gas is stored in my engine"). A fusion plant, on the other hand has its fuel piped to the reaction chamber ("my gas is in my gas tank, at the other end of the car"). At any given point there will be less than 10mg of plasma in the reaction vessel. This is not enough to damage the vessel, let alone melt anything at all.
Taken from the Focus Fusion website:
...a website full to the brim of fringe science and laughably-bad pseudoscience.
Tubal-Cain smokes the white owl.
Since 3D Realms announced Duke Nukem Forever and Valve announced Team Fortress 2...
Karma: It's all a bunch of tree-huggin' hippy crap!
If you use a 500 meter radius piece, that's a constant 740 megawatts focused on the pinhead-sized object of your choice.
The sun isn't a point source, so you can't focus it onto a pinhead unless you have a very short focal length. If you're planning to focus in the vicinity of the mirror, (say 1km in front with an f/1 mirror), you can only focus it down to an image that's about 9 metres across. If you were planning to beam the sunlight down to the surface of the earth, multiply that size by the distance you're sending it.
100 Wh = 3.6e5 J.
5.0e14 W = 3.6e5 J/7.2e-10 sec.
Assuming "A few billionths of a sec" is 3.6e-9 sec, that's more like 100 W for 5 hours. (If my math is correct)
But your point stands.
Hands in my pocket
I think he ment things like fuel cell cars. Yes they exist, but they still arn't practical, and probably never will be. Since the whole fuel cell car idea is flawed. IE it's not freedom from fossil fuels since the practical way to get hydrogen is from fossil fuels. And even then that takes a lot of energy. They also arn't that efficient, 60% peak and thats not factoring the energy used to make the hyrdogen.
Fusion power does even come into play, since the only true break from fossil fuels and to make it renewable is from splitting water. And that means we need a super clean, cheap and massive amount of power. Hense fusion, and even then you are still wasting energy making hydrogen, just means we have clean energy, even though making the hyrdrogen and then running the fuel cell puts us at a loss. So we can't really expect the promise of fuel cell/ hydrogen economy to come true till fusion gets up and running.
Also far as hydrogen fuel cell cars they were promisied long ago, first 2000, then they all said 2004, now they say end of decade. Having worked on hybrid cars for years I and most anyone I know who works on hybrids and fuel cells agree fuel cell cars arn't going to happen. Especialy since a hydrogen IC engine beats a fuel cell in about all ways. Sure there is prototypes, and very complete ones at that, (fuel cell ford focus) and even some test fleets, but they are still nothing practical.
For now the hydrogen economy is a nice fun thing for people like George Bush to throw out there. Make it sound good, oil companies love it, it's all good.
The future for fuel cells are in laptops and cell phones were you by a small hydrogen cartrige. For uses where portable power is needed, and it must be clean. Things like stationary fuel cell powerplants are the silliest things ever. Since they need powerplant to make the hydrogen to power them.
IIRC 'priscilla' typed into SimCity 2000 opened the debug menu, which would allow you to do anything - including starting with fusion.
I don't need to be made to look evil. I can do that on my own. - Christopher Walken
In fission, the atoms are split into more smaller atoms and the energy given off is the leftovers that were ejected in the process. In fusion, the situation is similar except the atoms are fusing into fewer atoms and there are leftovers given off in the process. Fission actually gives off more energy per atom but since the atoms used are so large a relatively tiny hydrogen mass in fusion will give off more on an equal mass basis. Fission also has the habit of resulting in nasty byproducts.
It's all about *releasing* energy that is stored as mass. There's no creation of energy going on; it was already there. The power going in is just power used to release the larger quantity of energy stored within the mass. The power going out is energy released that will hopefully be greater than the power used to release it in order to power the reactor to continue the reaction and provide useful amounts of power.
This only counts the energy of the laser beams. Unfortunately, getting the deuterium (heavy hydrogen) out of ordinary water requires a huge amount of energy, relative to what will be produced by the fusion of the same amount of deuterium undergoing fusion. This expense doesn't figure into the equation for "breaking even."
Worse, this isn't even deuterium-deuterium fusion they are trying to achieve. It's the "easier" to accomplish deuterium-tritium fusion. Tritium is not even a component of natural hydrogen (it decays with a lifetime of only a couple of years). Tritium must be manufactured, atom by atom. The amount of energy that is needed for this is even larger that for extracting deuterium, and of course it also doesn't figure into the energy budget equation. It's unlikely that d-t fusion will ever produce commertially usable energy. And we are truly a long way from d-d fusion in the lab breaking even (and that's without counting the energy for getting the fuel in the first place).
The ideal reaction to use of course would be proton-proton fusion, which powers the sun. Proton is the nucleus of the normal, "light" hydrogen, so it costs very little (relatively speaking) to extract it from water. But this reaction has never been observed in a lab, and it's probably unrealistic to expect something like that to happen in this century.
Sorry...
IANAP just a technician on Omega so I'm not exactly sure of the intricate details of the problems with computer simulations etc. but from what I gather the computer simulations of ICF targets are notoriously difficult to match with experiments due to the incredibly complex problem of modeling hydrodynamic instabilities in the implosion.
- "Hear that?! The percolations are imminent! Cease your ingress!"
If you insist on using solar power, a better solution would be harnessing wave energy and sub-oceanic thermal differentials. Those oceans out there are already soaking up 70% of the solar energy that hits the earth. Why pave the land with solare panels?
Even at 100% efficiency, solar panels will never be able to provide that much energy without covering prohibitively large areas. There's only so much energy per square yard of unobstructed sunlight.
And then you run into the problem of energy diversion. If you ever found a way to make it cheap enough to cover large enough areas to provide for a large proportion of the world's energy needs, you would have to deal with the effects of diverting that solar energy (in terms of its impact on global weather systems directly, and animal and plant life indirectly).
Don't get me wrong, solar energy is a wonderful, clean source for modest energy needs. But we have a lot of problems on the horizon that will only be solved through the availability of enormous amounts of cheap, clean energy. Things like carbon sequestration, transmutation of ultra hazardous waste materials, economical high earth orbit transit, and terraforming to name a few.
Having said that, I suspect that what we'll be using in 100 years will hold little if any ancestry in the current directions fusion research is going. While it's not money ill-spent, it is money not well-spent.
I am a physicist - but I have not read these articles - I'll wait for it to be published in Nature. My recollection of the experiment that achived breakeven some years back was that they measured the power in after losses due to generating the plasma, that is to say that there was more energy out than was in the plasma to begin with, but not more than was needed to generate the plasma. The analogous case of the laser method would be like saying that we generated more energy from fusion than we put in via photons from the lasers - but since the lasers are only 2% efficient in generating the photons it is not quite what you need for commercial energy generation. As for fusion energy from bombs, there was a nice study done at Stanford (IIRC) about the economics of simply setting off bombs in a deep hole and using the residual heat to power a steam turbine. According to the study this would be economical, you just neeed to convince your neighbors it is ok to do. As for having to have a huge hole, consider that at LANL people were designing steel containment vessals for small yield tests so that the cost of the hole could be amortized over several tests. In this case the problem was not the blast so much as the molten steel melting a hole in the bottom of the containment vessal at the end of the test.
And if you did deuterium-deuterium (which is hard to do) you would have no lasting radiation at all!
It's true that the energy would be emitted as gamma rays. But ALL the energy would be gamma rays, and if you had no way to convert them to heat you wouldn't be able to use them. So the gamma rays can be ignored as a source of radiation since they would all be converted to heat.
For actual numbers see this page: Fusion Energy
-Ariel
Fusion power generation, as currently being developed is nothing like this. It's still a sensible investment for the next few centuries and as a step to better things, but it's not the panacea you suggest and you harm the credibility of science and technology by claiming it is.
Likely 21st century fusion power plants will burn tritium and deuterium. While both are isotopes of hydrogen and deuterium is acceptably common in the universe (1 in 10000 or so atoms if I recall correctly) we are not burning hydrogen. Tritium is radioactive with a 12 year half-life, so is basically not found in the universe except where it is being formed (in stars mostly). To make commercial quantities of it, you irradiate lithium 6 with neutrons producing helium and tritium. Lithium is reasonably common on Earth, but not super-abundant. The costs of extracting and purifying lithium, and in particular lithium 6 are not negligible, although we are unlikely to run out for a while.
So, effective fuel is lithium and deuterium. Both are reasonably plentiful, but neither is cost-free.
Now the tricky bit. The deuterium-tritium reaction produces a helium nucleus (alpha-particle) which is no problem and a neutron. We need a decent proportion of those neutrons to breed more tritium, but inevitably, some of them will end up hitting things other than the lithium target. When they do, they tend to make what they hit radioactive. Thus, once your reactor has been running for a few years, all of the inner structure, the lithium tanks and so on, are medium-level radioactive waste. The neutron irradiation also weakens these structures, so they need periodic replacement. Gigawatt for Gigawatt, it's a lot less radioactive waste than a fission reactor produces (and no plutonium to manage), but its not nothing, and the cost of the equipment and expertise to manage this periodic replacement with acceptable staff safety and so on is also not nothing.
Water, by the way, is not a byproduct of fusion reactors.
The final issue is safety. Here the big win is that there are no realistic disaster scenarios on the scale of a fission reactor melt-down or someone using reactor-produced plutonium to make a fission bomb. There are all the hazards common to fossil fuels and fission associated simply with running a large industrial plant -- things falling on people, leaking chemicals, etc. A tritium leak is still a real hazard, and a molten lithium leak or fire would be pretty unpleasant, and the medium-level waster would need to be managed, but it is a lot better than fission.
So, not a panacea, but a likely move forward, and I don't think we do any good by describing it as a panacea and rasing false expectations.
A candle flame reaches c. 1400K but can be touched briefly without injury or even pain. Touching boiling water at only 373K, however, will cause burns - the boiling water is more dense and contains more heat than the plasma of a candle flame.
The plasma in a fusion reactor is even less dense by a few orders of magnitude, and even though its temperature is in the hundreds of millions of K, its energy is still tiny.
Now the volume of plasma in the JET tokomak is c. 150 cubic meters. Let's assume a viable commercial reactor will be three times as big, with a plasma volume of 450m^3. The density of the plasma is c. 0.001g/m^3, so there will be a total of 0.45g of active plasma in the vessel. This plasma has a temperature of c. 2e8K. The specific heat of hydrogen is 14 J/gK[1], so the total energy of the active plasma is 1.2e9 J.
Looks like a lot, doesn't it? However, in terms of heat, a joule is tiny. This amount of energy is sufficient to boil 6 tons of water, or to raise the temperature of JET's iron core by roughly 1K. So, quite a way short of melting the reactor, let alone the entire facility.
As for a chain reaction back to the "storage area", forget it. For fusion to occur, the plasma must be contained. No containment => no plasma => no fusion. You can't contain a plasma in a pipe. Sure, you can keep it from getting out, but as soon as it touches the wall of the pipe, it cools down and is no longer a plasma, just a hot gas orders of magnitude away from fusion.
[1]Yes, I know about changes to H2 specific heat with temperature - orders of magnitude is all the precision we need here.
Here's the Google cache of the article.
Obama's legacy: (N)othing (S)ecure (A)nywhere and (T)error (S)imulation (A)dministration
The point of the Hydrogen Economy is to provide a generic and highly portable form of energy storage which can be generated from any other energy source.
And it completely fails on that point. Hydrogen is a horrible intermediate form. As a gas or liquid it is extremely light and seeps through everything. As a metal oxide, it's energy density is extremely low compared to oils and even less than batteries. And lastly converting energy into hydrogen form is also extremely inefficient.
And at this point a purely electric car is more effiecent than fuel cell. It already is easily and efficiently distributable, and can be generated by any source. Hydrogen will never reach the efficeincy that electric grids/batteries have.
Of course batteries have diminishing returns for long-haul applications, but even for that hydrogen is not the best solution. What we will likely see is mostly electric for urban transportation while long haul will use fossil fuel, biodiesel, or ethanol/methonal fuel cell, whichever turns out to be most cost efficient in the future.
"Strip-mine Venus? Why not?"
Studies have shown that the surface of Venus is basically a huge ceramic nearly indestructable (by earth standards) plate. They researched it by taking a sample of the material they believe makes up Venus's surface, exposing them to conditions like those found on the surface of Venus, and then testing what they got back. They foudn it to be one of the hardest forms of ceramic they ahve ever encountered. Not to easy to strip mine (or process) that stuff...
There's a growing sense that even if The Future comes,
most of us won't be able to afford it.
-- Lemmy
About 23 years too late. The Berkeley Tokomak achieved break-even, as published in "Fusion" Magazine, back in 1981. One of the people involved was Dr. Dr. John Coonrod, who was also involved in building the first whole-body CAT scanner.
-- Terry
you are not getting it: there are microwaves photons. There is no distinction between visual light and microwaves, other then their frequency
You are not getting it. And probably won't until the third time you learn it.
Isaac Newton said,
I know light is corpuscular because I grind my own lenses.
He knew the mathematics of waves and how they are affected by running into uneven surfaces. He knew that in grinding a lens you never make it an even surface, you use finer and finer powders to make finer and finer scratches in the surface.
Grab a copy of Richard Feynman's QED: the Strange Theory of Light and Matter. He confirms Newton's suspicion on the corpuscular nature of light.
Then reread what I said about steam and swells.
Oh. By the way. Dirt is a liquid. In case you run out of things to wonder about.