A consequence is that the reaction chamber walls lose their physical integrity, i.e. become brittle, so leaving them in place is not an option. Thus, when operating a fusion reactor, you're constantly forced to replace crunchy, fusion-baked, radioactive reactor wall debris with newly built wall plates.
I admit to having no idea about which isotopes would be produced and what their half-life would be. If anyone can shed some light or correct me, I'd be indebted.
That's a researcher working in mainstream fusion, so that would be for deuterium-tritium fuel, which is the easiest but produces very high-energy neutrons. More advanced fuels are mostly aneutronic. Helion is attempting D-D/D-He3, which would release only 6% of its energy as neutron radiation. Tri-Alpha and LPP are attempting boron fusion, for which neutron radiation is only 1% of the released energy.
I'm glad to see that neutron blasting is being taken into consideration. I suppose not wasting most of your energy output as destructive radiation makes excellent sense economically, too.
Thanks!
Yes, radioactive waste will be produced - unless an aneutronic fusion process can be handled - but the goal is to have low-halftime waste that is manageable and does not have to be contained for millions of years. And fission reactors also have this problem to some degree, although their neutron radiation has very different energy profiles compared to fusion. When they are dismantled their reactor cores also have to be treated as waste. But unlike fusion plants you have to deal with the structural materials AND the actual spent fuel. So fusion plants will generally be better than fission, no matter what you end up doing.
Additionally the high energy neutrons of fusion reactors may prove useful to transmutate radioactive waste from fission plants so they might actually lead to a net reduction in radioactive waste.
[1] http://en.wikipedia.org/wiki/International_Fusion_Materials_...
I'd bet on thermal solar, that is proven to work. Also smart energy management with wind and solar are all proven to work. Electric cars have big batteries which are proven to work as energy storage.
That said, I favor the continued R&D and I hope one of these approaches pans out. Research is rarely wasted.
But I guess there are very few more mundane applications.
Now I worked on nuclear plants and not on fusion research but I heard that the main issue with fusion power is the non-linearity that comes along when scaling up small experiments. Things like not being really able to predict plasma behavior at industrial scale even if it works fine in the lab. Could anyone with a better understanding of the physics expand on this ?
People call it 'wind tunnel scaling', so I presume this is an empirical method borrowed from aerodynamic modeling. Nowadays we can actually do computational fluid dynamics to some extent, but a full-on electromagnetic plasma simulation remains intractable on the macroscopic/machine scale. And we remain limited on theoretical approaches, so we are stuck with actually having to build the darn things before we know they'll work.
The only new fission plant being built in Western Europe, Olkiluoto 3 in Finland, was supposed to go online in 2010 but is still unfinished: http://en.wikipedia.org/wiki/Olkiluoto_Nuclear_Power_Plant#U...
Estimates suggest it may not be done until 2020, and the budget has overrun to about $10.6 billion USD versus the original cost estimate of about $3.75B USD. (This reactor is now more expensive than the Large Hadron Collider!)
When a fission plant costs $10B+ today, I wonder how much the first working fusion plant will cost -- if we ever get that far.
Now I was referring to the inherent difficulty to scale fusion up due to the underlying physics. So when the article says:
> The next steps for the dynomak are straightforward. The experimental device [...] is about one-tenth the size that a commercial dynomak fusion reactor would be. [...] the group hopes to construct HIT-SIX [...] that will be twice as large as HIT-SI3. >At that size, things start to get interesting, says Sutherland. If imposed-dynamo current drive works well in HIT-SIX, he’ll be “much more confident going forward that our development path will be successful,” he says.
I don't know if it will be that straightforward because they're building a 1/10 prototype to build a 1/5 proto and then if all goes well they could be more confident about building a full scale plant. Does someone know how scaling up 1/10 → 1/5 → 1/1 is or isn't such a big issue ?
They all work if we're assuming spherical, frictionless cows in a vacuum.
Regardless, I would be excited no matter who did it first and I want it yesterday.
Aside from the potential for aneutronic fusion (essentially zero radioactive waste), and reactors small, cheap and safe enough to put in residential neighbourhoods, it's the way that they're using the instabilities in the plasma to their advantage. Reactors like the tokamak try to control the plasma, whereas dense plasma focus reactors use the natural instability in order to compress the plasma in a way that leads to fusion. So instead of fighting against nature, you make use of what nature gives you.
If any investors are reading, you really are looking at potentially the best investment you've ever made. If I was a millionaire I'm absolutely sure I'd invest. Even if a different fusion device wins the race, you'd still have a device capable of exploring the dynamics of plasmas, as well as a useful tool to explore magnetic fields. It's almost a no brainer.
I'm curious if that's just some kind of perception filter thing, though, or if not what's causing it.
http://physicsworld.com/cws/article/news/2014/sep/30/us-targ...
That said, I read the papers on the UW design and the design seems a lot more credible than the Lockheed press release. The optimist in me believes that if you work at the problem long enough, eventually you will discover something of use. And of course once we do, well then a lot of intractable problems become tractable.
Fusion energy replaces coal powerplants, and probably fuel bunkers on container ships/air craft carriers. No concept is small enough or dense enough to replace oil, although cheap fusion energy would make all sorts of crazy synthetic hydrocarbon schemes viable.
BTW, there have been numerous proposed improvements over the Tokamak reactor type over the years, such as the "Stellarator" (https://en.wikipedia.org/wiki/Stellarator), most of them have proven too complex to be of practical use though.
Not that that makes me think it's any more likely to work....
[1] http://absimage.aps.org/image/DPP14/MWS_DPP14-2014-000198.pd...
I thought it did exist but wasn't efficient (i.e., energy in > energy out)?
When people talk about "doing" fusion, it's usually implied to mean "in a commercially viable way."
http://www.nature.com/news/laser-fusion-experiment-extracts-...
For only a hundredth of a second, and not even remotely economically viable yet. But it's a step in the right direction.
