Sustainable fusion reaction, basic question.

[ArmyOfAll]

I am an ordinary guy, no academic, I am just curious about something.

 

At present we can't get a self sustaining reaction for long, this much I understand. And I realise its of no practical use, but can we sustain a fusion reaction if we sustain the input power (ignition)? I realise the output would be lower thus rendering the point of it useless.

 

Cheers.

[KipIngram]

I'm sure others will reply, but I have a general observation to offer. The problem isn't getting the reaction to sustain per se - the problem is maintaining the very high temperature, very high pressure conditions required for ignition in the first place. I think they'd still have to maintain those conditions for fusion to occur, whether they were below or above break-even. So I'm guessing no - if we could do that reliably we'd probably also be able to sustain a net-positive process.

 

I'm not an expert in the area, and I thought about not posting. But I decided to go ahead and caveat it properly because this way if it's nonsense someone will teach me something.

[Raider5678]

I am an ordinary guy, no academic, I am just curious about something.

 

At present we can't get a self sustaining reaction for long, this much I understand. And I realise its of no practical use, but can we sustain a fusion reaction if we sustain the input power (ignition)? I realise the output would be lower thus rendering the point of it useless.

 

Cheers.

The hard part is maintaining the high temperatures required, and making the plasma float.

[mistermack]

I believe that they can maintain fusion for well over a minute now, and records are being broken all the time.

That's with the existing machinery, but once the giant ITER project gets going, they should be into a different scale of fusion.

 

It now looks like the first plasma from that will be produced in ten years time. Shame they can't get their act together, and move it on a bit quicker. I'm sure that fusion will be the answer to fossil fuel problems in the long run. Maybe when ITER is pushing out power, the real investment will start, and things well really speed up.

[KipIngram]

Yes, if we can get there then our energy problems ought to be permanently dealt with. I think passively safe fision reactors (pebble bed, etc.) can buy us a big chunk of time (centuries at least), but ultimately that still leaves us steadily exhausting something that there's a limited supply of. I think the fission era would be very much an "oil era #2." Though if recently announced glass battery tech pans out we could really make EVs work, and at least we'd be treating the environment a lot better during that era as compared to now.

[swansont]

I'm sure others will reply, but I have a general observation to offer. The problem isn't getting the reaction to sustain per se - the problem is maintaining the very high temperature, very high pressure conditions required for ignition in the first place.

 

 

Seems to me that's at the very heart of the "maintaining" issue

[DrP]

I still cannot find that you-tube vid that claimed that the Russians had this new tokomak that promised producible fusion power in a few years... I suppose it could have been a hoax or Russian propaganda, but the documentary has been taken down since (or I can't find it at least). It was very small in comparison to JET or ITER.. sort of room/lab sized - the more I think about it the more I reckon it was wishful thinking on my part to see it as anything but a fake or a Russian dick waving exercise.

 

The program claimed new improved magnetic shielding which could hold a plasma at sustained fusion temps for ages. Still looking out for it.

[swansont]

People have been promising that sustainable fusion is imminent for 60 years.

[mistermack]

Once you've cracked the problem of sustaining the plasma, you have to crack the materials problem, of making hardware than can handle the high energy particles that are emitted.

Until you can run the reactor for serious intervals of time, you are guessing what will happen to the surrounding materials.

 

As soon as ITER is running at serious power levels, the problems of maintaining the hardware kick in, and they might be deal breakers. Or not.

 

Of course, there are other projects on the go. They might achieve a surprise breakthrough before 2026.You never know, but it doesn't look likely.

 

Maybe solar energy will get there first, with cheap reliable energy on tap. If they can develop efficient storage, that could happen.

[ArmyOfAll]

I've been away for a couple of weeks, I just wanted to say thank you all for taking the time to answer my basic questions in such a comprehensive manner. I now know a little more about not only my own question but the difficulties and possibilities.

 

Cheers.

[pavelcherepan]

I think one other major issue with the current and proposed designs in terms of commercial energy production is that a large part of the energy of the reaction is carried away by neutrons, which makes it hard to collect this energy and transfer into a usable form. This is especially a big issue with D-T fusion reaction.