Our current civilization basically revolves around ‘boiling water’…so finding a fancier way to do that is sort of a good thing.
Hoping it’s a whoosh…
-XT
Correct me if I’m wrong, but I thought one of the long term problems was that the reactor materials became extremely radioactive and problematic to dispose of. Of course, much less of it to deal with than the the current fission plants generate, but there is still ‘hot’ waste.
And no, people, this isn’t a woosh. It’s “Og build better fire” technology, and I guess in my old age I’m getting a bit dubious about ever more dangerous fire technology.
Ok, I admit, I’m being a little snarky about the whole thing.
I would be very interested in learning more about this, however;
There is some radioactive waste produced, but less as you say, and its not long-lived, so you don’t end up with stuff you have to seal away for 100,000 years.
That’s one of the theoretical benefits to fusion, it’d be considerably less dangerous then a fission reactor, both because of the smaller amount of radioactive material and the fact that “run-away” reactions aren’t possible, once the confinement is broken the reaction will stop.
There’s is a meaningful debate about whether money is best spent on fusion, which is unlikely to be a cost-effective method of generating power in our lifetimes, as opposed to researching energy sources that are more likely to be useful in the nearer future, but I don’t think your objection about it being more dangerous is valid.
I’m curious. What kind of power generation are you advocating in its place? Solar power is a chimera. Wind and tide and other power that depends on motion is unreliable. We have no good large-scale means of storing power. The world runs on power that can be generated at will in the desired amounts. There is literally no alternative to turbines for that today, or for as far out as any predictions can be made.
Or is your complaint a lament against the lack of magic technology and our forced submission to the laws of physics?
You like to use that computer thingy and have cold drinks? That whole fire technology thingy may be a bit more important than you think…and finding new fancy ways to do it without producing GHG is kind of a priority today, ehe? Nuclear fusion may not be the best way…it might not even be possible on a commercial scale. But it’s worth attempting because the potential rewards if we DO figure it out are beyond calculation for abundant and clean power. Unless you figure clean and abundant power is a bad thing of course…
-XT
Looks at own user name, looks at sentence again… :dubious:
Now let’s not go around cranking up the straw men factories. This is not
If (don’t grasp his position)
Then
Assume (improbable position).
We’re never going to get away from generated power, and like you say, all the “green” methods are unpredictable and unreliable when you need a constant flow. To be sure, they will be factors in long term production, but they will NEVER be the be-all-end-all of electric production. Therefore, yes we do need long-term high capacity plants, and although we have enough Coal for a very long time, we should probably be getting away from Oil, and until we get our butts in gear with a solid plan to store the waste, Fission is becoming problematic.
One of the concerns I do have is scalability. We have large numbers of small power plants precisely because we need local availability and we need to handle local variations in supply/demand. I am concerned with minimum size and power generation issues and how these will impact local power grids and long-distance power transmission, with has always been a huge NIMBY issue. I’m concerned about cost effectiveness, I’m concerned about reliability.
These are designs that use the rotating confined charged plasma to directly induce a current in a surrounding coil - it’s a tricky balance between magnetic confinement of the plasma, maintaining the temperature and pressure need to achieve ongoing fusion, adding fresh reactants, and tapping the generated energy. This is why better than breakeven has been so hard to achieve.
As for the neutron flux, the problem is not just the induced radioactivity, it is the physical and chemical changes in the containment. Neutrons are neutral, so are not confined by the magnetic fields. Neutron impacts with the containment can be absorbed by nuclei, changing them to different isotopes or atoms (possibly radioactive). Nuclei can also be displaced, storing additional energy within the containment (Wigner Energy). This can affect the structure of the containment material, making it brittle and prone to failure, and the Wigner energy must be regularly dissipated, otherwise a thermal cascade can occur and cause uncontrollable heating. Given the extreme conditions in a fusion reactor and the materials requirements, these sorts of issues (problematic in a nuclear reactor) are far more difficult to solve for fusion systems. Containments may need to changed more regularly, introducing design difficulties.
Just to illustrate - a recent New Scientist article looked at a recent trend in fission reactors of running with “hotter” fuel that can stay in the reactor for longer, and gives more energy. Great idea. But running fuel for longer damages (via neutron flux and thermal effects) the fuel cladding more, increasing the risk of fuel failure. And the waste fuel is more radioactive, as well, requiring longer cooldown and better cooling. It’s not an easy balance to strike.
Si
The solution to that might not be fusion, but superconducting power cables, allowing lossless transmission. Some promising work is being done along these lines.
True, that’s why one of the keys to commercial fusion power plants is the development of low activation steels (low activation and reduced damage from neutron bombardment tend to go together). Along with the new large tokamak, ITER, there are plans well underway to build IFMIF (the International Fusion Materials Irradiation Facility) in Japan. This will be a source of high energy neutrons used to test materials as they are developed.
Funded mainly by Europe and Japan (with some input from the USA and Russia) this is one of the times when politics worked for the scientific community. When they were trying to decide where to build ITER, Europe (primarily France) and Japan got into a bidding war, offering bigger and bigger inducements for ITER to be built in their territory. Eventually it was pointed out that the money on the table was enough to build ITER plus other key facilities so, in return for Japan agreeing to ITER in France, France and the EU are part funding the rebuilding of Japan’s largest facility, JT60, and the construction of IFMIF.
On the question of scalability, most of the conceptual reactor designs I’ve seen are in the 1 - 2 GW range - the same as new gas, coal, or fission plants. I don’t see why local production is an issue - most industrialised countries have electricity grids precisely to manage local variations in supply and demand - and if anything, fusion plants are easier to site than wind, wave, tidal, or large scale solar facilities.
It is a mistake to think of fusion as an alternative to other energy sources. Look at the rate demand is going up in China, India, all over the developing world; project European per capita energy use (don’t even think about US per capita use!) to the whole world population and you soon realise you will need every source of energy you can get - fusion, fission, wind, wave, tidal, PV, coal with carbon capture, etc, etc. Any source that does not release CO2 into the atmosphere.
R&D is needed for all of these: some more research, some more development. There have been comments up-thread about the “billions and billions on a fancier way to boil water” but it is worth baring in mind that the total cost of building ITER is likely to be less than the profit one oil company - Shell - made last year.
This is why we need fusion.
In terms of the amount of energy available (MJ) per Kg of fuel:
Nuclear Fusion - 645,000,000
Crude Oil - 42
Anthracite Coal - 32.5
We also can get the fusion fuel directly from the ocean, or any other source of water, like a tap, or rain, where you have to dig giant mines to get coal, or dig holes in politically unstable regions of the world to get oil.
When fusion comes, and works, it’s going to usher in an entirely new age of man.
Boiling water is a method of energy transfer. You need to do something to convert heat into electricity. Is there a reason why we shouldn’t boil water in general?
Possibly you are arguing that there is a more efficient method of converting heat to electricity that we should use in our nuclear reactors, is this what you are saying?
These are reasonable concerns. They also have absolutely nothing to do with how you expressed yourself earlier, which is why you’re getting this grief. 
I’ve been around long enough that I’m jaundiced myself on the issue. Call it Mapcase’s Fifth Law.
Any announced future technology will never arrive. The future will always surprise us.
That implies that we shouldn’t be surprised by some breakthrough in energy production or storage that none of us are talking about now. It also makes the this discussion too futile to have, which is a down side. :smack:
One of the things that’s always bothered me about Inertial Confinement Fusion (the laser beam-induced kind of fusiomn, where you’ve got a battery of ultra-high pulse , carefully synchronized lasers shooting at a single microballoon of deuterium/tritium suspended in a chamber) is how it’s supposed to work as a regular system. All the work so far has been on single, carefully suspended single microballoons carefully centered in the test chamber with all the lasers pointing at it. There’s a lot of time taken up with making vast numbers of such targets so that you can find a handful (not even, in fact) that are good enough to use, setting up the lasers, placing it carefully in the center, charging up the capacitor banks for the lasers and their control systems, then, finally, firing, and measuring the results.
You don’t want the target to be off-center. You don’t want any dirt or detritus to get on the optics. You’re pouring Terawatts of power through them, and any dirt will heat up and destroy the optics. Even “ghost” reflections from improperly coated surfaces can screw up the system. Back-reflections going through the amplifier rods will gouge out great swaths of expensive neodymium glass. I used to live next door to the LLE (Laboratory for Laser Energetis) and work with people who spent part of their time in there, and I’ve seen photos of laser damage.
Considering how ANYTHING gets dirty in use, you have to wonder how you can turn this into a practical system. More to the point, in a practical power generator you can’t spend time setting up a single shot and charging for it. You need to get some sort of rapid turnover, if not steady-state operation. The most I’ve seen from LLE on this is a single slide in one presentation that showed material flowing through the nexus of all those laser beams. It didn’t look as if they were very serious about it.
I’m not putting down the effort, which I think is worthwhile, but I’ve never had a satisfactory explanation about how it would be implemented practically, let alone “scaled up”.
It makes you understand why people got so exvcited about Pons and Fleischmann’s “testtube fusion”, involving platinum and palladium rods infused with deuterium. The goal of fusion is to get your nuclei really close together for long enough to interact. Nuclei don’t like to get close together, so you need to force thm, using high-temperature plasmas to provide the conditions that regularly ram some of them close together, or the laser-based inertial confinement, in which you use laser-induced shock waves to compress a small pellet even tinier. The idea of pushing the deuterium into platinum elevctrodes, which act as a "sponge’ and can hold a surprising amount of hydrogen (or its isotopes) must have seemed like a nifty and low-tech “end run” that gave you the high density of nuclei without all the bother. But it didn’t work (except, arguably, on a small scale – the group at Brigham Young University was working on this independently and simultaneously, and claimed MUCH more modest reactions in deuterium in their metal electrodes). One difference is that I could, in fact, see how to scale up a Pons/Fleischmann apparatus, or a Tokamak-style apparatus, if they worked.
Eh, people following the equation I gave earlier are never more than a minor annoyance.
But it is kind of funny, in an outside-the-box kind of way, to see people get all worked up about questioning the ‘boil the water’ method. 
(See your own statement about the future surprising us and consider that vis major changes in technology over time.)
Sorry, you’re reading that wrong.
I do say that when the future comes it’s usually a surprise. That does *not * mean that changes are automatically going to arrive. Cars haven’t changed. (They may, but I bet it won’t be the predicted hydrogen technology.) Housing hasn’t changed. Lots of technologies stay the same.
We can’t sit around and wait for the future to dump some magic technology in our laps. We have to work with what we have now.
Right now, turbines are like democracy; the worst of all choices except for all the others. We know they’re not perfect. (Who ever said otherwise?) Trying to make them better is mandatory. Simply decrying them, though, will get you ignored, and rightly so.
Well, that’s why there are Engineers…
Seriously, the “dirt” issue would probably be solved by having a completely solid beam path from end to end. This would eliminate dirt on the optics, and any convection distortions also. Mass producing the targets, and being able to ignite them at a practical rate is a hug problem, but is it insurmountable?
No hug problem is insurmountable. [insert cuddly smilie]
We might make it mad?
Well, if it got mad then that would probably be a hug problem after all. Though I’m not volunteering to hug boiling water…
-XT
You misunderstood me, or it is an attitude issue showing. I’m not waiting for magic. I’m simply stating that there is an expectation that a new technology will look like the old technology, and that this isn’t necessarily the case. Internal Combustion technology did not involve steam engines bioling water. It replaced them with something different. Likewise with many other technologies. It’s like projecting the future of computers based on better and better vacuum tubes (as was frequently done) because that’s your current base technology and you can only imagine improving it, not replacing it with something as yet unimagined (which is then dismissively labeled as “magic” by people inclined to be dismissive. hint hint.)
This being an example that I like. Instead of relying simply on the heat generated in order to boil water to turn a turbine (convert to convert to convert), use the rotation of the plasma itself to BE the turbine. Which in itself does not also rule out using the heat in a more traditional manner.