Z Machine Advances Fusion Race

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.

20 years off?

[Firethorn]

Wasn't it 20 years off 20 years ago?

I think that I'll stand by my idea that even if/when we crack fusion enough to be able to build a fusion power plant it'll have to be so big to be worth it, that they won't be able to get the funding to do so.

Basically, Containment costs go up by the square, while energy release goes up by the cube. To make it worth it, we might be looking at a 100 gigawatt reactor*, of which half goes towards sustaining the reaction.

*1-2 gigawatts is a pretty big reactor today.

20 year off == 20 good funding years

[i_should_be_working]

Well, since every comment here is about that "20 years off" quote, I'll add mine.

That twenty years (here and decades ago) assumes that governments won't pull funding for fusion research. But they did, and will again. ITER could have been built years ago. It wasn't a lack technology holding it back, it was a lack of money. So don't blame the scientists who give those 20 year estimates, blame your governments.

Re:20 years off?

[inviolet]

Weren't we closer 30 years ago?

Yeah. I came here to make the same quip.

Then I realized a possible explanation. Perhaps every time another milestone is passed, the new understanding moves us closer to fusion and thus on to the next unexpected hurdle. Sort of like being able to see the second mountain that was previously obscured by the first.

Or maybe it's just researchers looking to grab headlines in order to obtain more funding. Either way. :)

Do we need such "estimates"?

[Nuffsaid]

Wouldn't be more honest to say "We have no clue when fusion energy will be practical. Maybe some fundamental research breakthrough will make it doable next year, maybe we need to struggle with the current approach for another thirty years. Please fund research" ?

Re:20 years off?

[Anonymous Coward]

From TFA:

"It's like building a tinker toy," says Matzen. "We think we need 60 megamperes to make large fusion yields. But though our simulations show it can be done, we won't know for certain until we actually build it."

Depends on what you mean by containment

[mdsolar]

Fusion reactors could produce some short lived waste, but they are not prone to melt down and so don't need the heavy containment that fission reactors require in most countries. Table top fusion is also advancing so I'm not so sure things have to be big to be useful. For Tokomaks this probably is a requirement but not neccessarily for other methods.
--
Mr. Fusion on your roof: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html [blogspot.com]

Re:Do we need such "estimates"?

[Firethorn]

Even if we had a breakthrough and suddenly we had all the equations and knowledge to build practical fusion reactors, fusion power would still be at least a decade away.

5 years to design it into a power plant, find and obtain a site, necessary permits, etc... Then 5 years to actually build the thing.

I'll believe that it's twenty years away when we have a working plant sustaining a fusion reaction for testing purposes. IE operating the thing for days/weeks, not seconds/minutes.

We had [umr.edu] the first nuclear pile in 1942. The first nuclear reactor to produce electricity came online in 1951. It wasn't until 1957 when the first commercial fission plant came online. 15 years from the first pile until a commercial plant. All signs point towards fusion being bigger and more difficult, so I figure one will take even longer to build than a fission plant.

Re:Do we need such "estimates"?

[AWeishaupt]

"Besides, I doubt that a fusion reactor will solve the radioactive waste problem. More than likely it will add to the waste problem because all it takes to create radioactive particles is to heat any matter to extremely high temperatures." Please excuse me for putting this a little bluntly. What the fuck are you talking about?! If you don't know anything about the physics involved, then please don't pretend that you do.

Re:ICF, not MCF

[obaloney]

During ICF, each fusion reaction has a duration short enough that it isn't necessary to hold the plasma back against the forces of gravity.

Er, not quite. A fusion plasma must be confined against its own internal pressure, which for ICF is driven sky-high by compression, shock heating, etc., as well as the energy released by fusion reactions. The idea of ICF is simply to get a decent fraction of the target to fuse before the whole thing blows itself apart. In other words, the plasma can be in effect held together—temporarily—by its own inertia.

Earth's gravity matters not one whit. There is, however, an effective local gravity that is created across the surface of the pellet by the inward acceleration. This makes "out" look like "down", and it can drive Rayleigh-Taylor (buoyancy-type) instabilities. So in that sense, there is a race against "gravity", because the target compression rate must beat the rate of growth of the instability. But that's a whole 'nother story.

Re:20 years off?

[Anonymous Coward]

Well, build a really big one. Welcome to the future.