Scientific American had an article a couple years ago detailing all the obstacles and predicting that it would never prove feasible. Never is a long time, but it seemed pretty convincing.
Just consider that it was once predicted that fission reactors would make electricity “too cheap to meter”.
I would not allow flying cars above my airspace. Imagine a collision.
While it may be possible to initiate a fusion reaction and confine it, extracting energy from it may prove difficult.
The neutron flux from a fusion reactor is going to be pretty intense-so much so that we have no materials (at present) that could withstand it for long.
So while it may be possible, the engineering problems will be immense.
My (limited) understanding is that other major hurdles are extracting the energy to do useful work (you can’t just stick a pipe through it), and materials science problems (neutron bombardment).
I strongly support research into fusion as the potential payoff is very large, but there is no guarantee it will ever be viable.
Not really. Here’s the more complete quote:
This isn’t any kind of prediction. It’s standard optimistic platitudes about the glorious future. You could find it at any point over the last 150 years.
True, it was said by Lewis Strauss, then Chairman of the United States Atomic Energy Commission, in a 1954 speech to the National Association of Science Writers. But that’s called giving them something to write about. A cute quote they could use as a hook for their stories.
Wikipedia has another take on it that I can’t confirm.
Whether that’s true or not, it is true that this quote is one of the leading out-of-context turned on its head to bash something undeservedly moments in history.
If it is true, then your quoting it in this particular thread contains a buffet table’s worth of delicious irony. 
Reference this blog by Eric Drexler.
http://metamodern.com/2010/01/20/why-fusion-won%E2%80%99t-provide-power/
The bottom line is that conventional fusion won’t be cost competitive with fission without “orders-of-magnitude reductions in costs”. Frankly I regard fusion as just a false front for people who don’t want any sort of nuclear power and know there is no chance of a useful fusion reactor in their lifetime.
The unconventional approaches to fusion are all long shots, but investigating a thousand to one shot makes sense when you are talking about a million to one payoff.
Thorium and Uranium breeder reactors are what we can build and will provide power for the future. Advanced 3rd generation reactors are what we can build now and will get us over the hump for the next 50 years.
Firstly, I am not a physicist - just a former electronics engineer now systems manager so pardon the lack of detail!
Alka Seltzer has picked up two of the main issues - materials and making use of the energy. The materials have to physically resist the intense neutron flux (most materials quickly degrade when exposed to high energy neutrons) and not be activated by the neutrons. One of the key advantages of fusion over fission is the much smaller amount of radioactive waste generated and the total absence of long lived isotopes so it is not much use if the entire reactor ends up highly radioactive after a few years operation. The need for these materials is why plans for a facility called IFMIF (International Fusion Materials Irradiation Facility) - to be built in Japan - are well under way. Advanced materials are also needed to handle the heat loads in the divertor(the bit at the bottom of the vacuum vessel where the helium “ash” from the fusion reaction is removed).
Designs exist for extracting the energy using a lithium blanketaround the plasma - the neutrons interact with the lithium to produce heat (that creates steam to drive turbines as usual) and tritium that is needed to fuel the reactor. Obviously these designs have not been tested yet and developing these is one of the ITER objectives.
Another key issue is the production of suitable super-conducting materials for the magnets. To reduce the input energy required and to allow for sustained pulses(hours rather than seconds) it is essential to use superconducting magnets but these require superconducting cables to be manufactured on a major industrial scale.
Fuelling the plasma is is not one of the major problems. Current machines are fuelled by puffing gas into the vessel and by firing neutral particles into the plasma but these will be insufficient on a machine as big as ITER or a future power plant. For a large machine this will be done by firing pellets of frozen deuterium and tritium into the plasma (using pellets allows the fuel to be injected right into the centre of the plasma rather than into cooler edge. A new high frequency pellet injector has recently been installed on JET to develop this technique.
Lots of other problems to solve - this is not easy or we would have done it a long time ago - but if we don’t try we won’t know if they can be solved. Given the potential benefits, a concentrated, non-carbon producing, power source with virtually unlimited fuels and without the inherent dangers of fission, it’s well worth the investment. ITER will cost about 10 billion Euros - say 15 billion USD - over ten years. In a global energy market of around 3 trillion dollars a year this is a pretty small investment. (For comparison, one terminal at Heathrow Airport cost about 5 billion Euros!)
Hi guys, I’ve followed Polywell about as closely as anyone the last couple years, so I thought I’d chime in.
Fusion is a tough cookie. There are a few concepts out there that might pan out in the next 5-10 years. In order of likelihood (imho), they are Polywells (EMC2, funded by US Navy), field-reversed configurations (Tri-Alpha, backed by Paul Allen), dense plasma focus (Focus Fusion), and General Fusion’s concept, which is a sort of steampunk dream – it involves a thousand or so pistons all firing with microsecond precision to compress a sphere, each such shot generating fusion power (I hope they get funded, because even if it doesn’t work I’d like to see that puppy in action!)
The problem with the ITER>DEMO tokamak path is plant power density: even if everything works the way it’s supposed to going forward (including some pretty challenging materials work) even the most advanced designs would not be competitive with fission LWRs because the plant would be about ten times as large for the same power production. This is (very basically) because toks have to operate at low beta (plasma pressure vs magnetic field) due to having poor magnetic curvature (in some places the field gets weaker as you move away from the plasma). Polywells were designed to overcome this problem by having good curvature everywhere (but of course that also introduces its own challenges) – according to the PW scientists, at ITER conditions (magnet power and size) a PW should in theory produce about 62,500x more power because it operates at higher beta.
Polywell is being carried on from Bussard’s work by a team led by Richard Nebel. They validated Bussard’s WB-6 findings with their own similar WB-7 machine, and have moved on to a larger machine, WB-8, which is apparently steady state and actively cooled (someone at T-P drove by and saw a liquid nitrogen tank in back). That contract finishes up in April, and that’s when things may get interesting, because there are two add-ons – one is to modify WB-8 to fuse p-B11, which appears to be the first time anyone has done so in this kind of machine, and the other add-on is a full-scale 100MW net power reactor, which could be world-changing if it works, the design for which is to be delivered under the current contract.
The big question mark for PW is how losses will scale. If they scale at something like the B^.25 * r^2 Bussard predicted, these things could be competitive with nuclear power, or even cost as little as a tenth as much if they can get p-B11 working too. If scaling looks more like B^2, well, it was an interesting science project, and it only cost about 1/1000th of what we’ve spent on toks. There’s also a Talk-Polywell website with discussion if you’re interested in more technical details like the mechanics of wiffleball confinement.
Some other trivia: interestingly, Polywells also don’t ignite – they require a constant input of power, basically an electron flow from the guns to the anode Magrid and the wall, which create a virtual cathode along the way with a non-Maxwellian distribution that lets you accelerate ions electrostatically instead of heating them. Another neat aspect is that if they can beat brem in a p-B11 reaction, all the power will come out in the form of charged alphas at MeVs, which can be funnelled into a sort of reverse particle accelerator to generate current directly and avoid all those ugly neutronicity problems.
The Navy seems optimistic, and ONR (Office of Naval Research) has done some other good work. If they pan out, PWs would certainly be a great fit for that kickass free electron laser they’re developing. We’ll see!
Drexler is going for a very negative reading of the ARIES report and your quote is misleading. The reports suggests “orders-of-magnitude reductions in costs” are needed in some sub-systems, not the whole device. I believe these are the specific issues I identified above - low activation materials (at present only made on laboratory scales so obviously - if it can be done - the costs will fall) and super-conducting materials (again not previously made on the scales required).
To say that “fusion as just a false front for people who don’t want any sort of nuclear power and know there is no chance of a useful fusion reactor in their lifetime.” is completely mistaken. I don’t know anyone in the fusion community that is anti-nuclear. Every fusion supporter I know (or know of) fully recognises that fission is essential in the short to medium term. If fusion works it will be for the second half of the century.
Investigating thousand to one long shots is fine and, at low levels worthwhile, but the main lines of fusion research (magnetic confinement and inertial confinement) are - at worst - 50-50 bets and so worth a much bigger investment. Investment alongside fission, renewables, and clean coal - not instead of them. The world needs multiple options for the future. As I pointed out above the world energy market is >USD 3trillion pa - to have clean and reliable energy supplies into the future all possibilities needed to be researched and developed.
Just seen TallDave7’s post: Polywells are certainly on the list to be researched but I suspect they will prove to be more difficult in practice than in theory - if not, that’s great, but let’s not stop the development of the one technology we have been working on for the longest and know the most about.
Regarding the further development of tokamaks, there are possibilities for more compact devices with higher power densities. The one I know most about is the spherical tokamak (developed a Culham with the START and MAST devices) that essentially compresses the torus from a doughnut shape to a cored apple. For a second generation magnetic confinement power plant it has great potential.
Thanks for the info! Is there a website where an interested EE could keep up to date? Sounds like some interesting things are about to happen.
The Polywell FAQ has a lot of good technical details.
http://ohiovr.com/polywell-faq/index.php?title=Main_Page
For a good tech overview, Bussard’s Valencia paper was my bible for a few years.
http://www.askmar.com/ConferenceNotes/2006-9%20IAC%20Paper.pdf
Talk-Polywell is the main site for news and discussion.
http://www.talk-polywell.org/bb/index.php
A lot of engineers and a few physicists (Dr. Nebel himself commented there for a while; you can search his old comments which are quite fascinating) come by T-P and argue over various things related to theory, design, or etc. A couple people have been by the lab; the one they let in had to sign an NDA though. The Navy seems to want to keep a lid on things, and of course EMC2 has their IP to consider, but there’s some independent research too – a PhD student Joel Rogers has done some great simulation work, and there’s a guy in NY Mark Suppes who’s been in the news for the Polywell he’s trying to build in his garage (he did measure some fusion from a fusor so he’s made some progress).
Marcus – yeah, scaling is where these things tend to run into trouble, if toks are any guide. Heck, Bussard himself thought he was going to get a tok to ignite a few decades ago. So, we’ll see. I don’t mind seeing toks get funded, but sometimes they seem to suck all the air out of the room. Livermore once built a $500M mirror machine and it was cancelled the same day it was turned on. It’s hard to see toks having a customer in a reasonable timeframe unless something changes dramatically, given that fission fuels will last thousands of years, but it’s true we know more about them, and ITER will probably work.
The sun is a giant naturally occurring fusion reactor. The fuel will last for several billion years. Power can be harvested using photo-voltaic cells.
Thanks.
Certainly, we can and should harvest energy from the sun - not just with photo-voltaics but through solar thermal as well - but it is no panacea. Solar energy is pretty low density - particularly in more northern regions where the population is concentrated. To produce significant impact on our energy mix you need to cover significant fraction of the country with solar farms.
For a full discussion see David MacKay’s Sustainable Energy - Without the Hot Air.
Exactly many kinds of unobtainium do you need, before it isn’t practical? Remember the quote is orders of magnitude. How many technologies, besides electronics, have seen orders of magnitude improvement during a human lifetime? Going from Trains to Jets was about one order and that was a revolution.
I’ll agree that working fusion scientists aren’t anti-fission. They seem to be too busy trying to cut off the air supply for other fusion approaches like inertial confinement. I’m talking more about experts you see on television, like Michio Kaku. It also seems to be hard to have a thread on nuclear power, without someone saying that we should stop building fission power plants and wait for fusion power.
In the real world, there isn’t an infinite amount of R&D money. There certainly isn’t an infinite number of engineers capable of the kind of creativity it will take to make some of the approaches work. Fusion Tokamaks just don’t have the NPV to justify spending billions of dollars, when we have things like Uranium breeders and Thorium reactors that we know will work
You’re welcome. Working, self-sustaining fusion reactor. Now let’s harvest the energy. We’ve got a working fusion reactor that never has down time, divides its energy over the entire globe, never needs refueling or cooling (in the next billion years). But we barely use it for generating electricity. Isn’t the world filled with non-arable land we can half fill with solar plants of varying types?
But the world isn’t filled with an infinite supply of gallium, germanium, cadmium, selenium, indium, copper, tin, and manufacturing plants capable of producing miles and miles of semi-conductor grade electronics at a pace that would out match the rate at which solar panels lose their power producing capacity not to mention that they don’t take well to physical damage from winds storms and the other elements.
I understand that sometimes you got to cut your losses, but whats the story on THAT?
Surely they could have afforded to play with a bit before killing it.
Panels do degrade over time, but slowly and not completely. At the end of that time all the materials used to make it are still in it and can be recycled.
There are also mirror solar heating plants that continue to produce after dark due to heat retention.
The amount of resources that could be spent on research are finite, but we’re still very far from saturating that potential. Until we get close, it’s not really accurate to speak of different research projects competing with each other for funding and manpower.
Is he referring to the NIF (National Ignition Facility), a giant laboratory laser which will (hopefully) perform nuclear fusion in a laboratory for the first time? Because I can’t find anything saying that the project was killed.