Z Machine Advances Fusion Race 220
Sandia Labs has announced a new milestone in Linear Transformer Driver technology that aims to solve one of the biggest obstacles to practical fusion reactors. Getting the current needed to "spark" a burst of fusion is doable; getting a constant series of sparks going to create a continuous chain of fusion bursts has never been achieved. The LTD, which allows the Sandia Z machine to fire once every 10.2 seconds, makes it look achievable. The press release (which has been picked up in a few places, but with no further analysis) says that practical fusion power could now be 20 years off.
Re:20 years off? (Score:5, Informative)
Z-Machine (Score:1, Informative)
Bad choice of name. The Z-Machine is a type of virtual machine used mostly for running interactive fiction, interactive tutorials, and the like, and has been for the past few decades. Its specifications are freely available and anyone can implement their own:
Versions have been implemented in C, Java, XUL/JavaScript, and even NewtonScript.
ICF, not MCF (Score:5, Informative)
Sandia Labs (Score:1, Informative)
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration. Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.
Re:Z-Machine? (Score:5, Informative)
Some harsh moderators we have here.
For those who don't know or remember, the Z-machine [wikipedia.org] was the virtual machine environment used to develop the famous Infocom [wikipedia.org] interactive fiction titles, such as Zork and its sequels. Incidentally it was also the first thing that sprang to my mind when reading the title.
Re:20 year off == 20 good funding years (Score:1, Informative)
Z-Machine (Score:4, Informative)
Re:20 year off == 20 good funding years (Score:5, Informative)
They do have a plan for that. A blanket around the reactor containing lithium will both capture heat and breed tritium that's needed for the fusion reaction. One big problem for commercial generation though is the logistical bottleneck of producing enough tritium. Just ITER will use a significant fraction of the world's supply of tritium. The lithium blanket will breed enough tritium for itself and maybe to seed another reactor.
http://www-fusion-magnetique.cea.fr/gb/cea/next/c
Re:Depends on what you mean by containment (Score:3, Informative)
Table top fusion is useful sure but not for producing energy so I don't see how it's related to the current subject.
Re:20 years off? (Score:2, Informative)
Look at it this way - pHd students who will be working on that generation are about 10 years old right now.
No, it WASNT always 20 years (Score:5, Informative)
Re:20 years off? (Score:3, Informative)
According to Bussard [google.com], practical fusion power is nearly as available as the money we decide to put into his system. He specifically says in the video that "the physics is done" --which means that only engineering problems remain.
Re:20 years off? (Score:4, Informative)
From my understanding of the problems, that'd require a HUGE plant. Right now they're talking about building the largest fusion test reactor yet. One telling thing about the design: It's as large as a modern gigawatt nuke/coal plant, yet has absolutely no provisions for making power from the reactions.
Now, I admit that my figures are estimates, based roughly on the idea that contaiment can be roughly approximated as surface area, while fusion mass is volume based. Thus, square vs. cube.
Take the test plant*, it's as large as a gigawatt reactor. Since they aren't putting any means to generate electricity in, they're obviously not planning on it producing enough power to even offset the cost of the generating equipment. IE not enough power for it's containment costs.
Now, lets pretend that we had many issues solved and could merely double the size of it**. 4 times the containment energy cost, 8 times the power produced. If we have a self-sustaining plant, where enough power is generated for it to continue operating with no external power, the doubling would give us 4X the original capacity available to sell.
Still, even if the first doubling made it self-sufficient, and the second one to produce usefull amounts of power, we're talking about a plant with 16 times the footprint of a gigawatt nuclear plant, half it's power goes to maintaining the reaction systems, and we haven't even gotten to the area need for the steam systems. Call it 20 times the footprint of a gigawatt plant.
We have a huge way to go on efficiency before it'll be practical. This may help, but I still see fusion plants as a long way away.
*last I'd heard, they're fighting over which country to build it in.
**I'm talking about the reaction area size itself. Due to inefficiencies, the rest of the equipment will likely more than double in size.
Teller's Classical Super and the tritium problem (Score:5, Informative)
The original hydrogen bomb was known as the "Super" before it was called a hydrogen bomb, and the idea is what every wide-eyed geek in elementary school imagines the H-bomb to be -- put an A-bomb next to a vat of deuterium, and the A-bomb blasts the deuterium hot enough to make it fuse.
As the dudes as Los Alamos started building computers to do numerical models of fluids and radiation and everything, it became apparent that Teller's Super was a dud. The physics of radiation were such that simply sticking a fission bomb next to a pile of heavy hydrogen was simply not going to do anything. What if you sweetened the deuterium with tritium -- then what? As it turned out, you would need gobs of tritium, so the whole thing was a non-starter.
As it turns out, Stanislaw Ulam came up with the idea of a staged atom bomb -- a small atom bomb would provide the shock to compress a big freepin pile of plutonium to make a big honkin atom bomb, and Teller got ahold of that idea to make the staged H-bomb. The staged H-bomb used to be a very dark secret, but the combination of Richard Rhodes "Dark Sun" and that Progressive Magazine article kind of let out at least the general H-bomb concept. Teller's stamp on the staged bomb was that prompt x-rays from the atom bomb would be the way of getting compression instead of Ulam's original idea of the shock wave, but that the radiation would act first is obvious once anyone with physics knowledge starts working on a staged design, and Teller kind of took all the credit.
But the actual staged H-bomb not only focuses A-bomb radiation to compress a pile of deuterium, it also compresses a plutonium "spark plug" in the middle to make Ulam's staged A-bomb. The combination of heat and pressure from the radiation compression along with the flood of fast neutrons from the plutonium spark plug manage to fuse the deuterium, which produces its yield mainly in the form of yet more neutrons, which provides fission of a U-238 blanket to provide much of the explosive power of the bomb.
Fusion is really, really hard, even with the heat and pressure from an atom bomb, and the real H-bomb is a Rube Goldberg set of multiple effects which use fission-driven neutrons to produce fusion neutrons to produce gobs of explosive power from non-critical fission of U-238. Fusion is really, really hard, even for the Sun, because while the Sun is not using deuterium but straight hydrogen, for all of the intense heat and pressure in the interior of the Sun, the reaction rates are really, really low, which is a good thing, because otherwise the Sun wouldn't have lasted 5 billion years to allow us to be here.
So back to the fusion power reactor. All of the claims of imminent fusion power are based on using lots of tritium for D-T fusion for the same reason that Teller's Classical Super would have needed gobs of tritium and for the same reason that the actual H-bomb that burns D-D needs three stages of fission to get its explosive power. Just as the need for tons of T made Teller's Super a non-starter, the need for tritium means that the current frontier of fusion power is a non-starter. Yes, you breed tritium in the lithium blanket, but you have to compare the breeding doubling time with the half life of tritium and wonder how much seed tritium will you need to get a fusion power economy going and how many decades of breeding tritium will be required to switch the economy over the fusion power before the oil runs out.
Re:20 years off? (Score:5, Informative)
So jigawatts was a correct pronunciation of the g, but not of the i.
Re:20 years off? (Score:4, Informative)
Ask Slick Willie & Friends (Score:5, Informative)
Fuck "in God we Trust," we should just print "don't rock the boat" on our money.
Bussard's Polywell fusors? (Score:3, Informative)
Interesting, how that relates to Rober Bussard [wikipedia.org]'s Polywell fusor [wikipedia.org], which he claims can be made into a prototype 100 MW plant in 7 years [emc2fusion.org], provided the needed 200M USD funding [nmcf.org]?
You can also listen to his lecture at Google Tech Talks in 2006 [google.com] to get an idea of what he's up to.
BTW, you can donate to this fund via Paypal [nmcf.org] and sign the petition [petitionspot.com] to renew his funding from the government.
Re:Bussard's Polywell fusors? (Score:3, Informative)
(I watched that presentation and while it was compelling, I actually think the funding decision made is the correct one. There's a couple of things he really ought to show on a smaller scale before trying the $200 million project; I don't think he's anywhere near exhausted what he can learn with his smaller prototypes.)
Re:Millions of Dollars Away (Score:1, Informative)
While I appreciate seeing people who recognize the near-term value of fission power, I disagree with your assessment of fusion power
In 1970, I don't think "controlled" fusion had even been achieved yet. The Russians were just starting to play with the Tokamak magnetic confinement design, but I don't believe they were able to heat their plasmas sufficiently for fusion to take place. Electrostatic and intertial confinement (at that time, intertial confinement basically meant dial-a-yield nuclear bombs) were similarly infantile.
Fast-forward 35 years to observe to see a host of electrostatic concepts showing potential (although I'm very skeptical of Brussard's optimism), as well as several decades of progressively improved Tokamak performance. The JET reactor has run tests approaching Q=1, (and reportedly could achieve unity with the right fuel). Iter will come online within the next decade, building up to more and more aggressive experiments and hopefully achieving levels of Q=5 or greater within 20 years. If everything stays on track (yeah, that is a major if, but it's a calculated one, not a fairy tale), the DEMO powerplant prototype will begin construction about that time. Depending how sucessful these projects are, I think we'll see operating fusion power in 30-50 years.
Re:it's a steam engine (Score:4, Informative)
Steam turbines are probably one of the most efficient pieces of technology in the power generation industry. More power is lost in the transmission lines (typically 7.5% per 100 miles) than the steam turbines lose.
Reference: http://www.engineersedge.com/thermodynamics/power
Re:Bussard's Polywell fusors? (Score:4, Informative)
Nope, it appears that it was a [slashdot.org] false [fusor.net] alert [blogspot.com]. "The contract has merely been continued for a year without funding".
Re:20 years off? (Score:2, Informative)