If I cook it on the reactor, is it fusion cuisine?

[Janx]

It is created naturally in very small amounts by cosmic ray interaction with the upper atmosphere (it eventually falls as rain, and gets to the ocean), but he concentrations are very low.

Just brain storming here, but would it work if we took a bucket of water up to the ISS and left it outside the airlock for a few days, to turn it into tritium?

Obviously, when I say bucket, I mean NASA designed vessel for bombarding H20 with cosmic rays in space...

 

[Umbran]

Just brain storming here, but would it work if we took a bucket of water up to the ISS and left it outside the airlock for a few days, to turn it into tritium?

Obviously, when I say bucket, I mean NASA designed vessel for bombarding H20 with cosmic rays in space...

In theory, somewhat. We get tritium on the ground because the atmosphere is *big*, and has a wide area to catch cosmic rays. A small bucket isn't a large target, and won't catch many cosmic rays. Plus, water is heavy, so taking it to orbit and back isn't cheap. I'd have to work out the density of cosmic rays at ISS height to be sure, but I don't think that's a win.

You could put the bucket in the beam of a particle accelerator, and get much the same result, without all the mucking about in orbit. Of course, running a particle accelerator costs money/energy, so this may not be a win.

Having the tritium be a *byproduct* of something else profitable (say, running a fission power reactor) is probably a better bet - you're getting the tritium almost for free, then.

 

[Mustrum_Ridcully]

Reality check:

- LM wouldn't straight-up lie about such a discovery, but they WOULD leverage it to gain investor (stock market) interest.

- I highly doubt that fusion would "save" us from problems, because the problems are in human decisions, not capabilities. We already have the technology for a green earth and to end world hunger. We're just not using it until it's profitable.

And so it is a question of capabilities - we must have the capability to do it at profit.

 

[Umbran]

- I highly doubt that fusion would "save" us from problems, because the problems are in human decisions, not capabilities. We already have the technology for a green earth and to end world hunger. We're just not using it until it's profitable.

Not true - some of them are already profitable, but we still aren't using them. And if we did use them, they'd become even more profitable, but still we don't use them. Discussing why that is goes to politics, I'm afraid.

It isn't the fusion itself which saves us, it is the total package Lockheed is suggesting, which would be profitable enough to be a no-brainer, and get past many of our current political issues.

Lockheed is talking about a 100 megawatt power plant on a truck.

A quick web search tells me that an average, an American home utility customer uses about 11,000 kilowatt hours of electricity each year, so a sustained power use of about 1.3 kilowatts, on broad average. If my quick math is correct, then just one of Lockheed's reactors puts out enough power for tens of thousands of homes. It could power, for example, the entire residential customer base of the town I live in!

Fuel costs would be the stickler here. We don't currently produce tritium on industrial scales....

 

[Dannyalcatraz]

Come on down to Terawatt Tom's Tritium Emporium! We got solutions to ALL your fusion fuel confusions! And we're blowing up the competition with our new low, low, LOW pricing!

 

[Umbran]

As a note - when I said one of these could power my town - that was in a theoretical sense. It would require running the thing at or near full output, which is not normally something you want to do with a power generating plant. With one and a half, you'd be running with more suitable margins. Or maybe one, with a nice offshore wind turbine farm as a supplement...

That brought me to another point. Several folks in other places have asked why a company as big as Lockheed would need partners to help develop this. Lockheed knows power generation, after all - they build nuclear power plants for navy vessels. I suspect the first concept for the fusion reactor was similarly for large navel vessels. So, why does Lockheed need partners?

The answer is in my point above. Assume Lockheed has cracked the basic fusion issue, and they can fit in in a 7'x10'(x10') space*. Think, for just a moment - how do you get all that electric power *out* of that tiny space? With a normal power plant, you have much more space, you don't have to crowd the outgoing cables together. For this, all that power has to come out of a very small surface area. The currents would be enormous. If you use classic copper wire, the heat would similarly be enormous. If you get it out on superconducting cables... well, you need superconducting cables. Either way, with the enormous current would come enormous magnetic fields as well, which would put physical stresses on the thing...

So, there are some engineering and materials challenges implied by that power output and size that nobody, Lockheed or otherwise, has ever tried to meet.



*The power plants on modern nuclear vessels are more like 30' to 40' per side.

 

[Mishihari Lord]

Fuel costs would be the stickler here. We don't currently produce tritium on industrial scales....

So the next trick is how do we produce or harvest tritium using less energy than we get out of the fusion plant. Or modify the process to use fuel that's more readily available. One idea that immediately comes to mind is to run water through a fission plant and purify out the tritium produced.

 

[Umbran]

So the next trick is how do we produce or harvest tritium using less energy than we get out of the fusion plant. Or modify the process to use fuel that's more readily available. One idea that immediately comes to mind is to run water through a fission plant and purify out the tritium produced.

As I mentioned above - tritium is a known byproduct in heavy-water cooled fission reactors. It isn't enough to "run water through" - you need to start with deuterium or the yield will be too low to be economical.

 

[Scott DeWar]

I saw something about a thorium powered car on you tube. Is that a possibility?

http://blogs.cars.com/kickingtires/2011/08/a-car-that-could-go-1000000-miles-without-refueling.html

 

[Umbran]

I saw something about a thorium powered car on you tube. Is that a possibility?

http://blogs.cars.com/kickingtires/2011/08/a-car-that-could-go-1000000-miles-without-refueling.html

Um, no. That article, and a bunch of others I read in searching around on this topic, are pseudoscientific gobbledigook. Complete nonsense. The various articles about the thorium-powered car are not self-consistent, but if I try to piece them together, I get the following:

They take some Thorium, heat it up to "energize" it, make it put out laser light, and use that laser light to heat water, and run a steam turbine. And, while the Thorium is radioactive, they say there is no actual nuclear reaction going on here.

So, I ask, where does the energy come from?

Can you make a laser out of thorium? Probably. You can make a laser out of just about any material. But lasers are based on a quantized electrodynamic process. You put some energy in (often in the form of just normal, non-coherent light, but you can use other ways), and excite the electrons in the material. When the electrons drop down to their original places, they emit very specific frequencies of light, and when one atom does it, there's a cascade so they all do - and you get out a bunch of very specific, coherent light. But this is just turning some energy put in into a different form of energy out - it is merely conversion. If you make a laser out of thorium, you still have to plug that laser into the wall, or a battery, or something. So, what's powering your thorium laser?

Can you make a nuclear reactor that runs on thorium fuel? Yes. And there are some reasons why you might want to do that. But it isn't all that much different from one that runs on uranium - it is still a big old nuclear reactor. You can't (and don't want to) put one under the hood of your car. Even if you made it small enough, the reactor would put out some pretty hard radiation that would not be stopped by a few thin layers of aluminum foil. I am pretty sure nobody wants a car that gives them radiation poisoning or cancer.

You can probably also make a "nuclear battery" out of thorium, but those don't have sufficient power output to run something like a car - you typically use such to run the electronics on spacecraft for long journeys.

All that stuff about how thorium is dense, and so 8 grams of it can power your car for a century? That's flimflam designed to sound all sciencey. Thorium isn't particularly dense - gold and uranium are more dense, for example. Moreover, grams are a measure of mass. Density is a measure of mass per volume. 8 grams of thorium will be 8 grams, no matter the density! If it is super dense, it'll take up small space, if it is not dense, it'll take up more space. But it will still be 8 grams!

So, all in all, that Thorium powered car is stuff and nonsense. Pay it no mind.