Hey I just wanted to get your guys opinion about fusion mainly...

1) I know that containment is the main problem... what do you guys think will be the soultion?

2) What kind of design do you see as being as the best?

3) In what kind of timeframe do you think we will a) achive fusion with a positive energy ouput and b) construct the first reactors

Also if there are any interesting devlopments, or new ideas that you stumble upon let me know....

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The first principle is that you must not fool yourself - and you are the easiest person to fool.
~~~ Richard Feynman ~~~
There is no harm in doubt and skepticism, for it is through these that new discoveries are made.
~~~ Richard Feynman ~~~

Well the ITER experimental fusion reactor won't be running until 2018. If it takes an optimistic two years of experiments and five years to build a demonstration reactor then it will be 2025 before electricity is produced. And that's just a demonstration plant. A commercial plant might be at least another seven years away.

A problem with fusion is that while it seems quite possible to use it to generate electricity, it may never be profitable to use it. This is because other forms of energy may be cheaper. For example the cost of solar energy could drop dramatically over the next couple of decades.

yes, it would be very costly, but can produce alot of power with no poulltion, and we may find cheaper ways to construct plants in the future... especially with Global Warming...

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The first principle is that you must not fool yourself - and you are the easiest person to fool.
~~~ Richard Feynman ~~~
There is no harm in doubt and skepticism, for it is through these that new discoveries are made.
~~~ Richard Feynman ~~~

Practical fusion power is 50 years away. Just as it's been since the '50s.

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Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

Why do you say that pratical fusion is still 50 years away? Is it because we don't yet have a model which can contain the plasma? Is that the time you think it will take for us to proper test and experiment with the current fusion "devices"? Or is there another reason?

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The first principle is that you must not fool yourself - and you are the easiest person to fool.
~~~ Richard Feynman ~~~
There is no harm in doubt and skepticism, for it is through these that new discoveries are made.
~~~ Richard Feynman ~~~

It's just a joke. It's because some people were overly optimistic about fusion power in the past. But it does seem likely that the ITER will work and that after that a working demonstration plant could be built, so there is now a timetable at least. So maybe 20 years to generate power, maybe 30 years to become commercial if it is capable of ever becoming commercial. Of course there could be problems that slow everything down and unexpected advances are also possible. Expect delays, that way you'll be pleasently surprised when things go to plan.

The big problem with fusion is that plasma physics is really really complex.

Seriously, fusion research has kinda boiled down to finding the next order instability in the plasma and manipulating it into not being a power loss. Hopefully, computing power has gotten good enough that simulations can start showing suspected instabilities instead of experiment.

even then tho, fusion may not be pollution free. You could end up with alot of secondary radiation due to neutrons escaping the plasma and interacting with the reactor structure.

As a note tho question 3A has already been achived

I wonder if the concept tested over the last 50 years, actually works, i mean ..the toroidal confinement (tokamak)....i wonder if it will work, is not the fusion research stucked with the same idea?

Any kind of for ultra-hot fusion confinement (not inertial) other than tokamak ?

I have my doubts about the ITER success

I think fusion reactors have reached for 1-2 seconds fusion energy output, but total brute energy output hasnt been achieved yet (meaning that the input power was still higher than the generated)

Nothing has "no pollution". Fusion plants in particular would have some radioactive waste.

I'm also very sceptical it will be possible to build them at anything like an acceptable cost. 10% of the Sahara desert covered in solar panels would supply our present electricity needs, without reducing land for food growing, and would be technically far easier. (Though obviously we need to worry about what to do at night). But that is also far too expensive at present. But roughly speaking, if fusion isn't cheap enough to compete with solar, then it's a waste of time.

By "containment" do you mean confinement - as in keeping the plasma at a high enough pressure and temperature? If so, I would agree, this is the biggest problem (at least to the best of my limited knowledge). If you mean containment, as in fission power and keeping radioactive materials contained, I would not.

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At night the stars put on a show for free (Carole King)

One Earth, One Sky - IYA 2009

yes, confinement is the correct term

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The first principle is that you must not fool yourself - and you are the easiest person to fool.
~~~ Richard Feynman ~~~
There is no harm in doubt and skepticism, for it is through these that new discoveries are made.
~~~ Richard Feynman ~~~

In the description of the sun given in http://www.nineplanets.org/sol.html , the energy output is given as: These values seem plausible and they describe a powerful fusion energy plant. A fusion plant of whatever size will have to have its energy harnessed by some interfacing equipment to get the power in usable form. I suggest we take the fusion plant nature has provided and work on harnessing its energy which seems more easily obtained than building a fusion device from scratch.

The implication from the description is that fusion produces energy primarily in the form of gamma rays (I had assumed that it was scattered across a larger bandwidth) which are exceedingly difficult to confine/shield and this will add to the difficulty of the design of less powerful fusion devices. I'm not a fan of fusion power (except as produced in stars) for interstellar transportation.

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For those inclined to oppose human meddling with the structure of the universe or the composition and configuration of objects and groups of objects within the universe, consider:
Whether there is a limit to the magnitude of a modulation of chaos below which order remains invariant? Or, is order but a fiction invented by perspectives applied over finite, however large, time intervals?

There are other techniques, which each have their own issues. I went through a brief obsession with the Polywell confinement method, a hybrid of an inertial fusor and electrostatic confinement.

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Do try not to take me too seriously.

I agree with your assessment.

Although without a doubt the sun is a powerful fusion plant in the sense of the size of its output in relation to any other energy output device in the near vicinity, it is also in another sense a very weak one. It will take a time period measured in billions of years to consume all of its fuel. So the conclusion is that at temperatures and pressures in the sun the probability of fusion for any given hydrogen atom is actually exceedingly low. In the case of an earth-bound fusion plant, we can't wait that long to fuse the quantity of material we will put into that plant. That is why a fusion plant on the earth has to have substantially more extreme conditions than the core of the sun, so as to achieve fusion at much higher rates than the sun. Only that way can we achieve a useful output for a small scale device.

Hmm, really the difference is in the confinement technology. The Sun uses gravitational confinement, which has the significant advantage of not requiring a structure. It has the significant disadvantage of being so bloody massive we cannot build our own. At the distance we are from the sun the energy available is about 1000 to 1500 W/m^2, a relatively low density. To match the electrical output of a modern ESBWR nuclear plant would take a 306 acre solar farm, even assuming it was 100% efficient and used 100% of the available space for PV cells (which is impossible).

I ran the numbers once for solar thermal tower technology, and even the most advanced projected plant with the best of future technology (Solar 220) would have required 24000 acres to match a single ESBWR, not even counting capacity factor.

Obviously being a lot closer to the fusion reactor makes a big difference. Space based solar with microwave transmission anyone? (can't wait for the "oops" disaster from SimCity 2000 to come true)

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Do try not to take me too seriously.

Not too many details...

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