Would this make nuclear fusion work?

[Josiah]

TL;DR Summary

Would this make nuclear fusion work?

If the gas in the fusion reactor was compressed as much as possible wouldn't that increase the efficiency of the reactor and therefore make nuclear fusion possible. It would significantly increase the chances of hydrogen atoms colliding with each other and therefore creating much more power.

 

[berkeman]

Are you familiar with the Lawson Criterion? The pressures are much higher than you can achieve by just "compressing the hydrogen gas"...

https://en.wikipedia.org/wiki/Lawson_criterion

 

[Astronuc]

If the gas in the fusion reactor was compressed as much as possible

Therein lies the challenge, to compress a heated gas as much as possible. One has to look at the stresses within the structural components to see that a confined pressure is limited by the maximum stress a system can achieve without failure. Magnetic confinement is used to keep a plasma from contacting the walls of the vacuum chamber that would otherwise quench the plasma through rapid conduction of the heat, not to mention the atoms of the structural material contaminating the plasma and causing substantial radiation losses.

Magnetic materials cannot withstand much stress, so they are supported by structural alloys that bear the loads/stresses, and those stresses must be below the yield stress of the material.

 

[confusedhome]

Also currently LASERS are being utilized to increase pressures, also with limited success.

 

[Josiah]

So, the issue is the strength of the structure? Surely if you could build a structure strong enough then, you could increase the pressure significantly and there create more power.

 

[Josiah]

What about if you increased the volume of hydrogen?

 

[etudiant]

Interesting report on the Lockheed fusion project. Seems to be ongoing and making progress, albeit slower than initially planned.
https://aviationweek.com/defense/lockheeds-skunk-works-building-bigger-fusion-reactor

 

[PeterDonis]

What about if you increased the volume of hydrogen?

That doesn't help unless you have a way of compressing even more hydrogen to sufficient pressures. Having more hydrogen actually makes the issues that @Astronuc mentioned even worse.

Also, when you look at the rate at which you would actually have to burn hydrogen in a fusion reactor to give an output comparable to other commercial power reactors (roughly a gigawatt), the amount that needs to be in the reactor at any given time is very small. So increasing the volume wouldn't really gain anything since there is no need to burn very much of it at a time.

 

[jartsa]

Summary: Would this make nuclear fusion work?

If the gas in the fusion reactor was compressed as much as possible wouldn't that increase the efficiency of the reactor and therefore make nuclear fusion possible. It would significantly increase the chances of hydrogen atoms colliding with each other and therefore creating much more power.

Sure. If a hydrogen atom collides 1000 times with another hydrogen atom before colliding with the reactor wall, then there is a good chance that it fuses before reaching the wall. So there should be as many hydrogen atoms as possible between some random hydrogen atom and the wall.If we talking about tokamaks, then we don't know yet how to increase the number of fuel atoms without causing instabilities. See page 91 here: (I mean chapter 10 or page numbered 81 in the text )
http://www.euro-fusionscipub.org/wp-content/uploads/2014/11/JETR99013.pdf

 

[jartsa]

If we talking about tokamaks, then we don't know yet how to increase the number of fuel atoms without causing instabilities.

We don't know, but we are guessing that stronger magnets would help. But there are problems with stronger magnets, as explained by other posters.

 

[Josiah]

"If we talking about tokamaks, then we don't know yet how to increase the number of fuel atoms without causing instabilities"

What if there was some sort of stabiliser. What if there was some sort of inert gas which could help stabalise the reaction

 

[berkeman]

What if there was some sort of stabiliser. What if there was some sort of inert gas which could help stabalise the reaction

It seems like the inert gas would just cool down the plasma. Here is an interesting PF thread about other approaches to stabilization:

https://www.physicsforums.com/threads/new-approach-to-stabilize-fusion-plasmas.963896/#post-6116441

 

[Josiah]

What if there was some sort of chemical gas which could stabalise the reaction

 

[DEvens]

question about fusion snipped

I know you are keen and want to make positive suggestions. But it's necessary to do this sort of thing with more knowledge. It's hard for me to give you an example because I don't know what subjects you are familiar with so you would see things from my point of view.

But imagine a 9 year old child asking "why can't the gas in a car be special gas that makes it go faster?"

Here is a very intro-level article on fusion. Scroll down and you will see a graph that shows that fusion really gets going at a few 100 million degrees K. No material structure is going to hold that.

https://en.wikipedia.org/wiki/Nuclear_fusion
So there are a number of approaches that people are pursuing. One is magnetic confinement. There are a number of variations on the theme of a magnetic torus that will, it is hoped, confine the plasma long enough to get useful amounts of energy.

https://en.wikipedia.org/wiki/Tokamak
Another approach is intertial confinement.

https://en.wikipedia.org/wiki/Inertial_confinement_fusion
The basic idea is to blast a target with lasers, and heat it fast enough that it does not have time to fly apart before some fusion takes place.

There are some other approaches. The folks at General Fusion are working on an interesting approach of using collapsing metal to compress a "smoke ring" of plasma. There are a lot of engineering challenges, but it's interesting. At the very least it will be an interesting research tool if they can even get it to pulse once an hour.

https://generalfusion.com/https://en.wikipedia.org/wiki/General_Fusion
There are several other potential methods that you can read about in the first wiki article I linked.

Most of these approaches are looking at producing very hot and very high pressure plasma. A very few are doing other interesting things such as trying to use muons or even more exotic materials.

 

[etudiant]

It may be that commercial fusion requires some novel insight to make it work.
The example of the H bomb is perhaps illustrative, none of the early approaches worked at all, as summarized by the 'Icicles are beginning to form' quip made by one of the frustrated researchers. It was not until Ulam conceived the idea of radiation compression that a solution was found.