Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 14/02/2014 16:32:10

Title: How can fusion reactions be made to yield more energy than they take in?
Post by: thedoc on 14/02/2014 16:32:10

Powerful lasers have managed to create a fusion reaction that releases more energy than was put in...

Read the whole story on our  website by clicking here (http://www.thenakedscientists.com/HTML/news/news/1000444/)

 

Title: Re: Fusion experiment breaks crucial energy
Post by: evan_au on 16/02/2014 20:13:40

To approach being a practical energy source, the National Ignition Facility (http://en.wikipedia.org/wiki/National_Ignition_Facility) will need to increase its rate to perhaps hundreds of laser shots per second.
At present they can achieve around 2 shots per day, with a laborious inspection process after each shot. Skipping the inspection step could cause one of the laser amplifiers to explode on the next shot - the energies involved are incredibly high.

Magnetic confinement, the other major approach to controlled fusion, is working towards a very large demonstration project at ITER (http://en.wikipedia.org/wiki/ITER).

There has been some theoretical analysis recently about combining magnetic and laser heating (http://arstechnica.com/science/2012/02/a-crushing-magnetic-field-combined-with-a-laser-may-make-fusion-more-efficient/).

Title: Re: Fusion experiment breaks crucial energy
Post by: Ian Scott ZL4NJ on 17/02/2014 18:49:24

This sounds like an important milestone in the search for practical exploitation of fusion - "proof in principle" is now established, and future progress towards harnessing similar reactions to those used by stars is possibly inevitable. It is unfortunate the the recent "Jade rabbit" rover on our moon has suffered a mishap - especially since the moon is a far richer (potentially) source of Tritium than Earth, useful in fusion reactors (from memory, Tritium is more efficient that fusing hydrogen)  :)

Title: Re: Fusion experiment breaks crucial energy
Post by: syhprum on 17/02/2014 20:36:41

As a practical source of power I have always considered ITER type fusion reactors a wild pipe dream what can we say about laser types they make ITER types mundane and practical in comparison !
I remember well when the Sellafeild  Plutonium plant was coaxed into producing 20GW we had he worlds first revolutionary nuclear power station.
Laser fusion can only be a thinly disguised military project as for producing power its nonsense.

Title: Re: Fusion experiment breaks crucial energy
Post by: crimsonknight3 on 24/02/2014 23:02:10

Quote

For the first time, the experiments have released more energy from the fuel than was put in by the X-rays – about 1.2 to 1.9 times more. Although this amounts to only 1% of the original laser energy, because most of that was absorbed by the hohlraum

Enough said? They would need to be able to ignite roughly 40-50% MORE fuel in ONE burst in order to produce more energy than was put in, as said in the OP. I still believe that magnetic fusion is A LOT more promising if they can create a self sustaining reaction, then over time it would produce more than it took to start the reaction, although then the problem is learning to stop the reaction quickly incase of emergency! THAT would be a big explosion!

Title: Re: Fusion experiment breaks crucial energy
Post by: crimsonknight3 on 24/02/2014 23:52:28

I answered myself about the quick stopping in case of an emergency already lol, if the magnetic field broke down it would damage the interior of the reactor contaminating the reaction and stopping it