ITER and all things fusion.

[sgt_flyer]

one of the things though, is there was a lot of develloped theories and small scale tokamaks built before. so, as they more or less know what to expect, they can concentrate on testing additionnal things - other type of fusion reactors were much less studied, so we have to make them work first.

ITER is built not to try and make fusion work - but to study the problems around it, by having a lot of known values taken from experiments with other tokamaks.

when you start from unproven, little studied technologies, studying these additonnal problems on top of having to control the technology is much harder

 

we should not oppose the various fusion technologies   most of the fusion technologies (notably all D-T reactors) will benefit from the researchs that will be made with ITER. (even if we don't keep tokamak tech in the end - the data on sustained operation at these temperatures, tritium breeding (for D-T fusion reactors) and neutron absorption.

 

afterall, they have also Wendelstein 7-X tested in europe, which will test the stellarator concept. both tokamaks and stellarator are very similar in their operating principles, so who knows if DEMO will not end using a stellarator, combined with whatever technique they devellop from ITER

 

[Nuke]

as i understand it the next step for polywell is a demo equivalent reactor, and it will only cost 200 million.

[Elthy]

Is there anyone actualy building one?

[Nuke]

emcc has some transitional funding but i think its trying to find investors right now.

Edited December 17, 2015 by Nuke

[Bill Phil]

Fusors are actually pretty cool devices.

[Nuke]

problem is those grids let all the energy out and contaminate the plasma. thats why the polywell config was done. physical electro static grids are replaced by magnetic coils that confine electrons. this draws ions into the center where they can collide. it takes natures solution to the fusion problem and replaces gravity with a potential well. its elegant (its literally a star in a jar) and i like it. its certainly better than the brute force solutions.

Edited December 19, 2015 by Nuke

[PB666]

4 hours ago, Nuke said:

problem is those grids let all the energy out and contaminate the plasma. thats why the polywell config was done. physical electro static grids are replaced by magnetic coils that confine electrons. this draws ions into the center where they can collide. it takes natures solution to the fusion problem and replaces gravity with a potential well. its elegant (its literally a star in a jar) and i like it. its certainly better than the brute force solutions.

Just keep in mind that a stars energy production density is unacceptably low for a power generation scheme on earth, Such a scheme on earth would have to increase that density by a million-billion to be useful here on earth

[Bill Phil]

15 hours ago, Nuke said:

problem is those grids let all the energy out and contaminate the plasma. thats why the polywell config was done. physical electro static grids are replaced by magnetic coils that confine electrons. this draws ions into the center where they can collide. it takes natures solution to the fusion problem and replaces gravity with a potential well. its elegant (its literally a star in a jar) and i like it. its certainly better than the brute force solutions.

Yeah I know. It's still pretty cool.

[sgt_flyer]

mmh. one thing about magnetic fields , they lose strength fast as the distance from the coils increase. i wonder how well fusion reactors can scale up (if you want to have more plasma volume) - in tokamaks / stellarator's case you can use a longer torus (to avoid increasing the plasma conduit diameter - thus your power requirements to maintain your magnetic field strength might be lower)

now, on polywell's case though, if you build a bigger one, the energy requirements are going to ramp up quite significantly in order to maintain the desired magnetic field strength and size - so would a polywell be able to generate that much excess power ?

 

on the other end, i could see a polywell style design much more easily used as a fusion rocket engine  (basically keep trapping atoms to keep the fusion going, and have a weaker side in the magnetic field act as a directed magnetic nozzle for allowing the excess fusion products to escape)

though, you'd still need another generator to power the magnetic fields.

Edited December 19, 2015 by sgt_flyer

[Nuke]

superconducting coils is the usual go to solution for that problem. i dont think any polywells to date have been build with superconductors. dr bussard got fusion out of wb6 on just copper coils.

Edited December 20, 2015 by Nuke

[sgt_flyer]

yes, but even with superconductors, the magnetic field intensity will drops with the distance  - you'll need to pump in more power to sustain a larger (and maybe farther away)magnetic field

so what i'm wondering is up until which size can those reactors still generate enough power to sustain their own magnetic fields and still output some net energy  i doubt the amount of power needed to sustain the field increase linearly with the reactor's power output

[Nuke]

in the world of fusion bigger is usually better. larger volumes mean a higher rate of fusion, and less energy lost from failed particle collisions (this actually sets lower limits on how small certain types of reactors can be). higher rate of fusion means more energy out and more power for coils (which by the way use less energy than heating the plasma does). we do know that magnetic fields can be the size of planets and keep charged particles away from places where we dont want them to be.

[Bill Phil]

1 hour ago, Nuke said:

in the world of fusion bigger is usually better. larger volumes mean a higher rate of fusion, and less energy lost from failed particle collisions (this actually sets lower limits on how small certain types of reactors can be). higher rate of fusion means more energy out and more power for coils (which by the way use less energy than heating the plasma does). we do know that magnetic fields can be the size of planets and keep charged particles away from places where we dont want them to be.

It is better, true. But from an engineering and design standpoint it's less practical. If it's smaller it's easier to handle and there's less building time, reducing costs. A happy medium is what we need.

[PB666]

1 hour ago, Bill Phil said:

It is better, true. But from an engineering and design standpoint it's less practical. If it's smaller it's easier to handle and there's less building time, reducing costs. A happy medium is what we need.

You first have to have a working scale before you can scale up or down. I would predict that the fusion reactor that comes online first will prolly be the one closest tonits optimal scale. The german reactor seems to be on a faster track than iter, only because they seem to have a physical design that is specifying precisely wher particles are going to be and they have defined velocity and period within a cylce of l5. Either its going work or flop in great misery, but either case it should be soon. 

Though in all the design stuff i still dont see how they are going to carry energy and waste particles out of the system. 

 

[Bill Phil]

I think that only large reactors are going to be practical for quite some time.

[PB666]

http://news.mit.edu/2016/heat-loss-fusion-reactors-0121

Maybe help speed up getting a working fusion reaction.

[sgt_flyer]

guess they'll have to recompute all their plasma models after that, if only to check that this new model is much closer to the experimental results they got. (would be interesting to see how wendelstein 7-X plasmas behave compared to a more classic tokamak in this regard.)

Edited February 15, 2016 by sgt_flyer

[PB666]

They haven't done a fusion test yet, they know they can safely generate a tight plasma stream.

[sgt_flyer]

yup, just reread, after the helium plasma test last year, they have just done an hydrogen plasma test a few days ago. (80 millions degrees celsius for 1/4th of a second)

i just meant, that if they indeed have a more accurate fusion model now, seeing how it will behave in stellarators will be interesting  - if a stellarator design can mitigate this problem in addition to the other problems it was built for

(though of course, they'll need quite some time to analyse this new model and refine it anyway. - so they might have a much better model to check against in 2019 for wendelstein first planned fusion tests )

http://www.gizmag.com/wendelstein-7x-stellarator-hydrogen-plasma/41651/

Edited February 16, 2016 by sgt_flyer

[Nuke]

Dr Park of emcc recently answered a bunch of questions for the talk polywell forum.

http://www.talk-polywell.org/bb/viewtopic.php?f=7&t=6139&start=45#p124371

there are supposidly more to come so keep checking the thread.

 

[Nuke]

On 2/19/2016 at 4:08 AM, Nuke said:

Dr Park of emcc recently answered a bunch of questions for the talk polywell forum.

http://www.talk-polywell.org/bb/viewtopic.php?f=7&t=6139&start=45#p124371

there are supposidly more to come so keep checking the thread.

 

...and part2.

[sgt_flyer]

ouch, read a bit part 2 - for polywells they need a structure able to handle 30 metric ton compression loads ! they sure need very powerful electromagnets

Edited February 22, 2016 by sgt_flyer

[fredinno]

On December 15, 2015 at 11:55 AM, wumpus said:

I'd really like to complain that re-processed nuclear fuel rods and fuel from breeder reactors should be considered "renewable".  Using this stuff hasn't different issues (don't let another Ken Lay control the stuff), but isn't the same doom as fossil fuels.

It's not really "renewable" though, as E=Mc2, which atomic energy gets energy by, basically means that any nuclear fuel is nonrenewable, as the isotopes used will disappear for good once used.

[Nuke]

5 hours ago, sgt_flyer said:

ouch, read a bit part 2 - for polywells they need a structure able to handle 30 metric ton compression loads ! they sure need very powerful electromagnets

i figured the forces were high, after all all your north poles face inward. magnets generally dont like that. its probibly why wb6 shorted out after just 3 shots. but 30 metric tons is kind of nuts.

3 hours ago, fredinno said:

It's not really "renewable" though, as E=Mc2, which atomic energy gets energy by, basically means that any nuclear fuel is nonrenewable, as the isotopes used will disappear for good once used.

this is true but technically we can use anything up (but not including) iron and come out energy positive. obviously we are gonna start with the easy stuff. when we start running out of fuel for fusion reactors we will have more pressing problems, like all the stars dying.

Edited February 22, 2016 by Nuke

[PB666]

6 hours ago, Nuke said:

i figured the forces were high, after all all your north poles face inward. magnets generally dont like that. its probibly why wb6 shorted out after just 3 shots. but 30 metric tons is kind of nuts.

this is true but technically we can use anything up (but not including) iron and come out energy positive. obviously we are gonna start with the easy stuff. when we start running out of fuel for fusion reactors we will have more pressing problems, like all the stars dying.

If you play the neutrons correctly you can breed deuterium from hydrogen, and there is literally an ocean of hydrogen atoms to breed from, might have to figure what to do with the left-over oxygen.