The Bizarre Reactor Scientists Hope Will Save Fusion Research (sciencemag.org)

sciencehabit writes: In a gleaming research lab in Germany's northeastern corner, researchers are preparing to switch on a fusion device called a stellarator, the largest ever built. The €1-billion machine, known as Wendelstein 7-X looks a bit like Han Solo's Millennium Falcon, towed in for repairs after a run-in with the Imperial fleet. Stellarators have long been dark horses in fusion energy research but the Dali-esque devices have many attributes that could make them much better prospects for a commercial fusion power plant than the more popular tokamaks: Once started, stellarators naturally purr along in a steady state and they are not prone to the potentially metal-bending magnetic disruptions that plague tokamaks. Unfortunately they are devilishly hard to build.

Comments

Re:that One Weird Trick which will make you click

[Anonymous Coward]

"Tokamak researchers HATE them!"

Re:Shouldn't these things ...

[benjfowler]

Nope. With these kind of magnetic confinement machines and the way they scale, the bigger the better (quite literally).

This is why we need to build a stupendously huge and expensive machine like ITER to demonstrate anything approaching economic power output for the energy required to confine and heat the plasma.

Re:Title is misleading

[viperidaenz]

Title doesn't mention "new", neither does summary.

The summary also correctly implies stellarators are in fact old. Stellarators have long been dark horses

Just stop.

[X0563511]

looks a bit like Han Solo's Millennium Falcon, towed in for repairs after a run-in with the Imperial fleet.

Sure, in the same way a croissant does.

Meaning, not at all.

Presses button and...

[SuperKendall]

Whirr Whir Whir Whir CLUNK.

"They told me they fixed it! It's not my fault!" as they furiously poke at buttons.

Re:Title is misleading

[knightghost]

We blew $5 trillion on useless wars and $20 trillion so that wall street could get some short term bonuses. A billion dollar fusion engine isn't even a rounding error.

Re:Q: heat

[benjfowler]

Heating (and confinement) are now basically solved problems in magnetic confinement machines. The Wikipedia article says that they'll be using bog-standing microwave heating (they don't say exactly what), and neutral-beam heating in W-7X.

Both tokamaks and stellarators have to 'twist' the magnetic field around the torus (since paths around the inside of the torus are smaller than the outside, leading to instabilities). Tokamaks achieve this by inducing a current through the plasma to induce the twist in the magnetic field using a huge solenoid or other means; stellarators use external coils.

The former are prone to catastrophic disruptions (which in extreme cases, can unleash strong forces that could, in the absolute worst case, physically break the machine); the latter are more stable, but much harder to manufacture.

DOE report says fusion is likely uneconomical

[PeterM from Berkeley]

Went and looked for answers to my own question:

This report from DOE
http://web.ornl.gov/~webworks/...

has figures showing that they forecast the cost of fusion power to be between 68 to 80 "mill/kWh", (apparently mills are thousandth's of a 1999 dollar) which is more expensive than any alternative they examined. Wind power they forecast to cost between 20 to 40 "mill/kWh".

If the people at DOE who wrote that report are good forecasters, then fusion is DOA. Alternatives will be less expensive.

Yes, you can make "technology advancement" arguments that the DOE forecasters are wrong, but the cost of wind and solar generators are dropping all the time, too, and storage options might get radically cheaper as well. I think investment in solar + wind + storage actually dwarfs investments in fusion, so the market seems intent on fulfilling DOE's prophesy.

Fusion may really only come into its own when we go live in the asteroid belt or the outer solar system.

--PeterM

Re:DOE report says fusion is likely uneconomical

[Opportunist]

Price has never been a good indicator of whether an energy source is viable. Especially not current price. If you suggest things like fracking or even oil sands to someone from the 70s he'd probably look at you like you're suggesting mining iron on the moon. Far too expensive to do, for there are far cheaper sources of oil.

Just because something is cheap today doesn't mean it is going to be cheap tomorrow. Resources like coal, oil and gas are getting more and more expensive as the cheap sources run dry. Nuclear (fission) power may well jump in cost if countries decide that companies running them should be responsible for disasters and waste disposal. And wind and solar power are dependent on there being areas where putting them actually makes sense. Real estate can actually become the issue here in the future.

Whether a power source is economically viable is by no means static.

Re:DOE report says fusion is likely uneconomical

[blindseer]

Yes, you can make "technology advancement" arguments that the DOE forecasters are wrong, but the cost of wind and solar generators are dropping all the time, too, and storage options might get radically cheaper as well. I think investment in solar + wind + storage actually dwarfs investments in fusion, so the market seems intent on fulfilling DOE's prophesy.

Wind and solar will never compete with coal and fission. Part of this is because wind and solar require viable (read that as cheap, reliable, etc) storage to provide 24/7 power. Any energy storage system that can make wind and solar reliable will also serve to make coal and fission cheaper.

A big problem with any power plant that works by steam power, which coal and fission do, is that it does not respond well to large daily swings in power demands. To rectify this there are a large number of solutions, the most popular one because it is cheap is natural gas turbines. In this case "cheap" is relative because even though natural gas turbines cost three times that of coal and fission it is still the cheapest solution we have. Right now that is the same for wind and solar, to make wind and solar "work" there must be a ready reserve of natural gas turbines.

If we develop a technology that can store energy cheaper than it takes to produce it by natural gas turbines then all we'd need to do to get cheap and reliable power is to couple that storage with coal and fission. To compete with that wind and solar would have to be a fraction of the cost of operating a coal or fission power plant. Why a fraction of the cost? Because coal and fission can operate with better than 80% up time. Wind and solar can only operate with something like 30% up time. To compete with a one GW fission power plant would require three GW capacity wind and/or solar, along with this as yet undeveloped storage technology that is cheaper than natural gas.

I believe that after all the gains we've made in wind and solar in the last few decades we're seeing diminishing returns. We're getting real close to theoretical maximum efficiencies already, there just isn't much more room for improvement. If wind and solar require some cheap storage system to be viable then they are both fool's errands. While wind, solar, and storage are all noble efforts in solving our future energy needs none of them can compete with fission. Our future is a fission powered one, nothing else we've seen so far can compare, and that includes fusion.

Re:DOE report says fusion is likely uneconomical

[blindseer]

Disasters and waste disposal issues for fission are only a concern if we keep doing it like we've done for the last 40 years. We've seen liquid fuel fission that promises to not only be "disaster" proof but can also "eat" the radioactive waste from the reactors we've used for decades.

Liquid fuel fission reactors like liquid fluoride thorium reactors (LFTRs) can be made to be walkaway safe, where any damage would be limited to the destruction of the reactor. LFTRs have safety mechanisms that prevent the possibility of "China Syndrome" style meltdowns. This is primarily because the fuel is already melted, loss of containment means removal of the mechanisms that maintain fission. If the reactor runs too hot a normal "scram" operation involves dumping the core fuel into a drain tank that removes the fuel from the core, the tank is designed in such a way that just air cooling prevents further damage. Thermal failure of the core, as in it gets so hot that it melts, mean the fuel spills onto the floor of the reactor building, and then flows into that same drain tank. It is impossible for a LFTR failure to result in a massive release of radiation.

Once the powers that be in the federal government realize the value of LFTR we will see fission not only get cheaper but also prove that fission does not mean we have to pile up radioactive waste. That "waste" we have now exists only because of federal government policies that prevent the reprocessing of spent fuel into new fuel and valuable industrial material. LFTR could prove to be a means for making reprocessing of "spent" fuel that is both economically and politically feasible. Much of what makes up "spent" fuel from current reactors is unburnt uranium, stuff that is no more radioactive than what was dug from the ground. If we can get that uranium out and turn it into something useful then not only have we just solve 90% of the "waste" problem but we've also solved an energy problem.

There's two ways to dispose of radioactive waste. One way is to store it away until it decays, which can take hundreds of years. (Anything that takes longer than hundreds of years to decay is "radioactive" only in the theoretical sense, it's not a hazard to life.) Another way to dispose of radioactive material is in a reactor. If we do it right then that reactor can not only destroy radioactive material but we also get valuable energy from it.

Like you say, if you ask someone from the 1970s about nuclear power they'll tell you about The China Syndrome. The reason we still think of fission power like we do in the 1970s is because not much has changed in fission technology since then. Why haven't we seen anything new in fission technology since the 1970s? Likely because we have the same people in the Department of Energy that we did in 1979. Time will prove that nuclear fission is safe, cheap, reliable, and the only option we have. That time may come, sadly, only because the people that are holding the technology back have died of old age.

Re:DOE report says fusion is likely uneconomical

[Zak3056]

Wind and solar will never compete with coal and fission.
But actually they do. In Germany coal planets get decomissioned because they can no longer compete.

The reason that coal is not competitive in Germany is because the playing field is severely tilted in favor of wind (wind power gets a premium price that is, IIRC, funded by fossil, and also has priority in the grid. If there is renewable available, the fossil plans have to spin down). That climate makes it absolutely uneconomical to run a large powerplant that is slow to respond to changes in supply and demand.

Please note that I'm not saying this is necessarily a bad thing (though some of my German colleagues think the situation is untenable for various reasons), but your argument above is not nearly as simple as you frame it.

Re:DOE report says fusion is likely uneconomical

[CaptainLard]

Whether a power source is economically viable is by no means static.

Can't argue that but this brings up an interesting question (for me anyway). What could make wind and solar more expensive in the future? The raw material costs are basically nothing compared to fossil fuels (where they are essentially basically 100%). There is plenty of silicon just lying around on the surface. Some of it may be easier to process but I think that problem is largely solved.

I don't know what the global lithium supply looks like but I do know LiIon batteries can be recycled. The reason China has all the rare earth mines is because their government subsidized them to corner the market in the short term. Rare earths aren't really that rare.

For wind you need resins and what not but again, the material input is minuscule compared to the lifetime energy output. You mentioned real estate and places that make sense....but there are a LOT of those places where it does make sense. Often the real estate is pretty cheap (deserts, etc) and hey, the solar panels covering just a little over 1/3 of my roof provide 110% of my yearly electricity use! (yeah storage...that's being resolved faster than even I thought it would)

Given all that I know about wind and solar it seems that if anything, prices will only get cheaper.

Re:Even if ITER or W7X works, is it economical?

[david_bonn]

For all of this, in the very best case W7X will only sustain fusion for thirty minutes (according to Wikipedia). That is an extremely long way from being practical.

Even assuming it works very well, we are an extremely long way from solving all of the problems required to build a practical working fusion reactor.

Some of the problems remaining to be solved:

• Neutron flux (part 1). Most of the energy from the deuterium-tritium reaction is in the high-energy neutron produced by the reaction. The best estimate is that the neutron flux from a 1GW fusion reactor would be one or two orders of magnitude higher than from a fission reactor. No known material can withstand that neutron flux. One other way to look at it is that in five years of operation, every atomic nucleus in whatever radiation shield you build will be hit hundreds of times over a five year period.
• Neutron flux (part 2). the deuterium-tritium reaction produces one neutron. That neutron has to (1) heat a working fluid that can be used to run a turbine, and (2) strike a lithium nucleus with enough energy to breed tritium. You need to do that with every damned neutron to have a self-sustaining system. This is made even more challenging by the fact that neutrons will be emitted isotropically from the reactor. Yes, there are materials that can act as neutron amplifiers, but no one has ever done that on a large scale and it probably won't be easy or simple.
• Lithium. You are going to need a lot of it. A 1GW reactor will probably need around 10000 tons of lithium. At $7/kg, that is seventy billion dollars worth of lithium. That is also a significant percentage of the world's annual production of lithium.
• Tritium. Once you've made the tritium from the lithium, you need to get it back into the plasma where it can do some good. I note that both tritium and lithium will easily react with each other and separating them will be tricky.
• Helium removal. Your fusion reaction will produce helium. Too much helium in the plasma will interfere with the reaction and lower the efficiency of the reactor. You need a system to get the helium out of the plasma without cooling it down. This system must operate continuously.
• Scaling. W7X has a plasma volume of around 30 cubic meters. A 1GW fusion plant would need a plasma volume on the order of 1000 cubic meters. W7X will cost around a billion dollars -- straight-up extrapolation implies a cost north of 30 billion dollars. That doesn't include all of the systems described above or a turbine to actually generate electricity. I also point out that scaling up isn't necessarily cheaper either.

I'd also note that solving each of the above problems is not going to be cheap. It is hard to imagine how a fusion plant can be made for less money than an existing fission plant, and those plants are already not competitive. Chances are it would be better and cheaper to build lots of batteries with all that lithium and a lot of wind turbines and solar panels. That would get you the same amount of energy, probably.

Sources: matter2energy, Do The Math

Re:Dat Title

[fisted]

Dat device tho.

Re:What's the big deal?

[backslashdot]

They havent been given the budget needed to build a breakeven facility -- basically people like you set them up to fail and then say look it failed!

Re:Even if ITER or W7X works, is it economical?

[Anonymous Coward]

The bullet points where you give numbers make no sense. 10000 tons of lithium? Design studies for DEMO, which would have several GW of thermal output, have a blanket volume on the order of 500 m^3. Even if assuming that was all lithium, you are talking about 300-400 tons, much smaller than 10000 tons. 10000 tons would be a block of lithium about 27 m on a side, which is much larger than the whole reactor vessel design.

Scaling the costs is very difficult to do. A production reactor would be far cheaper in many ways, because you don't need as much diagnostic access. A lot of compromises have to be made to just get enough space between the magnets of many designs for diagnostics, plus the costs of diagnostics (millions of dollars each for the many of them), plus the costs to use, maintain and analyse them. This is part of why designs for DEMO are only about 15% larger than ITER, but of a much more compact design considering it is producing nearly 4-8 times as much thermal output.

"Built it" my ass!

[arglebargle_xiv]

As any student of history knows, Greifswald was the location of assorted secret Nazi research projects during WWII. This thing wasn't built recently, they dug it up from the mine where it was buried in 1945 to hide it from the advancing Russians. Look at the photo of the cryostat, that's classic 1940s engineering design. The reason for the "schedule slips" mentioned in the article is because they've had problems disarming all the booby traps left to kill Russian investigators. Next thing you know a previously unknown German research institute in the Owl Mountains will invent an antigravity device, and another heretofore-unknown research group at Hillersleben will announce the creation of a death ray.

Remember, you read it first on Slashspot.

Re:No need for storage

[blindseer]

Getting 10% of your electricity from wind is trivial. Daily demand varies more that 10% so all you have to do is what you've been doing for the current mix of coal, gas, nuclear, and hydro. People smarter than the both of us have spent a long time looking at this and have convinced me that having more than 30% of power from wind and strange things start to happen with the grid.

We can make wind power work but it would involve massive changes to how the national power grid works, which would be very expensive. Not only would it be expensive, because putting large power cables over or under the Mississippi river is not easy, but it would create a vary fragile network. If there was a catastrophic loss of connection on one of those Mississippi crossings we'd see blackouts and brownouts nationwide.

Even if we could power the world with wind we would not want to. Making wind power work means relying on wind in California to power a Florida with calm winds. There's a lot of ways that could fail, badly.

Wind power, right now, costs three times what nuclear power costs, right now. Even a quantum leap in wind technology cannot make it cheaper than what nuclear fission could cost if only the Department of Energy would allow the building of a modern liquid fuel fission reactor. The Department of Energy has been subsidizing wind power for decades and it still cannot compete with fission power from the 1970s. I don't see a great future for wind power. Wind power will never go away, it's just too easy to get in many places, but it cannot power a first world economy.

Re:Q: heat

[An ominous Cow art]

And if it melts down, falls over, and sinks into the swamp, we'll just build another, which will be the strongest reactor in all the lands.