Fusion?

[Dexter Sinister]

Helium and neutrons. How many neutrons depends on what the fuel is, deuterium or tritium, and electromagnetic energy (heat and light). In the traditional model, energy is extracted from the electromagnetic energy and from a screening substance (usually water), that is used to absorb the free neutrons. That absorption produces heat.

I'm no nuclear engineer, but tritium seems unlikely to me, it's pretty rare, produced by cosmic rays in the upper atmosphere, nuclear explosions, and nuclear fission, about 1 in every 10,000 hydrogen atoms produced if memory serves. It's also poisonously radioactive, half life of about 12 years I think.

I've been hearing my whole life that commercial use of fusion is 30 to 50 years away, maybe this brings it down to 20 to 30, not soon enough to solve our short term energy problems. This is a breakthrough in the sense that it's the first time a fusion reaction has produced more energy than it took to create it, but it wasn't very much, about enough to boil a kettle of water according to what I read in this morning's newspaper. The problem is containment, the stuff's so hot that no physical vessel can hold it, it has to be confined by magnetic fields somehow so it doesn't contact anything, that cools it and the reaction stops. There are serious engineering difficulties involving the stability of the fields. I'll believe it when it happens.

 

[Tecumsehsbones]

I'm no nuclear engineer, but tritium seems unlikely to me, it's pretty rare, produced by cosmic rays in the upper atmosphere, nuclear explosions, and nuclear fission, about 1 in every 10,000 hydrogen atoms produced if memory serves. It's also poisonously radioactive, half life of about 12 years I think.

I've been hearing my whole life that commercial use of fusion is 30 to 50 years away, maybe this brings it down to 20 to 30, not soon enough to solve our short term energy problems. This is a breakthrough in the sense that it's the first time a fusion reaction has produced more energy than it took to create it, but it wasn't very much, about enough to boil a kettle of water according to what I read in this morning's newspaper. The problem is containment, the stuff's so hot that no physical vessel can hold it, it has to be confined by magnetic fields somehow so it doesn't contact anything, that cools it and the reaction stops. There are serious engineering difficulties involving the stability of the fields. I'll believe it when it happens.

As I understand it, that's correct. As deuterium is vanishingly rare, less than 1% of hydrogen on Earth, tritium is less than 1% of deuterium. I've always heard deuterium as the fuel for fusion.

Agreed on the rest. This was a significant breakthrough, but we're a long way yet from Fusion Energy, Inc.

 

[Dexter Sinister]

I've always heard deuterium as the fuel for fusion.

Yeah, that's what they use in hydrogen (fusion) bombs, though that process doesn't seem readily adaptable to power production. Deuterium and tritium are both gases, which are difficult to work with, they both fuse more readily than plain old garden variety hydrogen, but it takes the heat and pressure of a fission bomb to set an H-bomb off. Lithium deuteride is the fuel of choice, it's a heavy gray sand, and when its bombarded by neutrons lithium fissions readily and produces all the tritium required for a really BIG explosion. The overpressure from a fission bomb is enough to compress the lithium deuteride, and the radiation is enough to ignite the fusion process, but the effects come in the wrong order. The radiation travels faster than the shock wave and you have to compress the fuel first, so they build a heavy metal buffer around the fuel to shield it from the radiation long enough to get compressed. If you want a nasty bomb, use uranium for that, for a "cleaner" bomb use some metal that doesn't fission readily, like tungsten.

Now you know how to build your own. Somewhat to my surprise, all that and more is public knowledge.

 

[The_Foxer]

Now you know how to build your own. Somewhat to my surprise, all that and more is public knowledge.

The 'how to' has never really been the issue since the 60's. The issue has always been obtaining the precise isotopes required and the precision engineering of the bomb. But considering how many countries have nukes these days obviously it's not THAT hard either i suppose.

 

[Taxslave2]

The 'how to' has never really been the issue since the 60's. The issue has always been obtaining the precise isotopes required and the precision engineering of the bomb. But considering how many countries have nukes these days obviously it's not THAT hard either i suppose.

Difference being, those nukes are designed to blow up. Building something that falls apart isn't that difficult. Look at the shit that comes out of Detroit. WE need something that is going to hang around and produce more than it costs to run for 5 decades or so.

 

[Tecumsehsbones]

Wind turbines.

On Mars.

No kidding. That's NASA's latest brainwave.

 

[Taxslave2]

Did the Chinese already buy up all the best wind sites on the moon?