Fusion Power

[billvon]

No way was it politics. One man made the decision, the POTUS under War Power Act.

Right. He was a . . . politician. That's what they do.

(To put it in your perspective, imagine if Obama signed an executive order that pumped billions of tax dollars into wind energy. For the good of the country of course. Would you claim that he had finally removed politics from the energy debate?)

[Sunking]

Right. He was a . . . politician. That's what they do.

(To put it in your perspective, imagine if Obama signed an executive order that pumped billions of tax dollars into wind energy. For the good of the country of course. Would you claim that he had finally removed politics from the energy debate?)

He does not have the authority to do that. Presidents only get blank checks under War Powers Act. It is Congress that makes spending bills, not the POTUS.

[russ]

He does not have the authority to do that. Presidents only get blank checks under War Powers Act. It is Congress that makes spending bills, not the POTUS.

He just shovels money of the back of the truck using executive orders - he will be known as the executive order president!

[billvon]

He just shovels money of the back of the truck using executive orders

Thank you for making my point. Yes, many presidents shovel money at things - and it's always political. As Sunking pointed out, often such political moves are good ones.

[russ]

Thank you for making my point. Yes, many presidents shovel money at things - and it's always political. As Sunking pointed out, often such political moves are good ones.

Get off it - Wartime powers in 1940 are one thing.

Freebies, advantages and favors for votes like today are quite another.

[billvon]

Freebies, advantages and favors for votes like today are quite another.

Yep. When you like what the government pays for, it's a great idea, and not political at all. But when you don't like what the government pays for, it's political freebies, advantages and favors for votes. Been that way for the last 236 years.

But back to energy -

One of the more promising fusion reactions is the DT-HE3 reaction. Most fusion plants rely on a plain old Carnot cycle to extract energy from heat (i.e. a boiler, a turbine, cooling towers etc.) The DT-HE3 reaction produces high speed protons. As high speed charge carriers, you can extract electrical energy directly from the reaction without any intermediate thermal step. Potential efficiencies are much higher, although you still have the problem of initiating and sustaining the reaction in a manner that uses less energy than is produced. You'd also still have to cool the reaction chamber but that would be secondary to direct electrical production.

[russ]

Yep. When you like what the government pays for, it's a great idea, and not political at all. But when you don't like what the government pays for, it's political freebies, advantages and favors for votes. Been that way for the last 236 years.

Sorry but I don't see it that way at all. The government does many things that I will never benefit from but I consider to them as OK for the greater good. It does many things that I don't agree with but then I am not the only one around.

Don't confuse that with blatant vote buying - whichever party does it.

Both extremes are bad about the slippery/slidy motion and Bill - there is no question but that you are of the rather far left group.

But then I have come to consider 'democracy' where everyone gets to vote as more than stupid. If one does not have a stake in the system, meaning contributing, they have no reason to vote. That would be the 47% in the news recently. In the 1700's only rich white guys could vote - a bit restrictive but closer to good than what we have today.

[inetdog]

The DT-HE3 reaction produces high speed protons. As high speed charge carriers, you can extract electrical energy directly from the reaction without any intermediate thermal step. Potential efficiencies are much higher, although....

Not saying nay, but I am sure that handling extremely high DC voltages (~10MegaVolts?) in a highly radioactive environment will require some interesting technology and engineering too. Would the means of extraction of the energy be magnetic or electrostatic? What is the state of that art at the moment?
(I know I could look it up, but it is easier to ask you, since you appear to be following the topic.)

It is attractive that by extracting the energy from the escaping protons, you are, in effect, cooling the reaction chamber. Or at least leaving less heat to be removed by other means.

[billvon]

Not saying nay, but I am sure that handling extremely high DC voltages (~10MegaVolts?) in a highly radioactive environment will require some interesting technology and engineering too. Would the means of extraction of the energy be magnetic or electrostatic?

From what I understand, neither one exclusively. There's been a lot of work in MHD over the past few decades, and extracting energy from charged particles within magnetic fields has become something of a black art that I don't understand completely. From what I understand, doing it purely electrostatically wastes a lot of energy for the same reason that PV wastes a lot of energy - you optimize for one energy. (In the case of PV it's energy of photons, and in the case of fusion it's energy of protons.) Any proton without enough energy to overcome the coulombic barrier is repulsed, any proton with more energy makes it to the target but 'wastes' its extra energy in the form of heat. At least one research center is working on a solid state device that is supposed to overcome that problem but I don't know how they do it.

Again, all this is assuming we can get fusion to work at all. HE3 reactions are even harder to get started than D-T reactions, so it likely won't be the first reaction they consider for power generation. Also the only "local" source of significant amounts of HE3 is the moon which presents some logistics problems.

[inetdog]

At least one research center is working on a solid state device that is supposed to overcome that problem but I don't know how they do it.

If you are referring to PV, is it conceptually simple but again the engineering has some tricky steps:
You add additional dopants to the silicon which provide a limited number of excitation sites that are roughly halfway to the full energy on the other side of the band gap. Once you have done that, photons with only half of the band-gap energy can step the electrons up one stair-step at a time.
Among the problems are making sure that the "halfway" electrons do not fall back to the ground state before they get hit again.
Trying to use more than one intermediate level (fish ladder) seems to be impractical at the moment.

Also the only "local" source of significant amounts of HE3 is the moon which presents some logistics problems.

"Been there, haven't done that." ...yet...

[billvon]

If you are referring to PV, is it conceptually simple but again the engineering has some tricky steps:
You add additional dopants to the silicon which provide a limited number of excitation sites that are roughly halfway to the full energy on the other side of the band gap. Once you have done that, photons with only half of the band-gap energy can step the electrons up one stair-step at a time.
Among the problems are making sure that the "halfway" electrons do not fall back to the ground state before they get hit again.
Trying to use more than one intermediate level (fish ladder) seems to be impractical at the moment.

No, I was referring to a device intended to capture protons of varying energies. I don't know anything about it yet, just that they're working on it.

Yeah, for PV triple junction cells have been around for a while, and they substantially solve that problem by having three separate bandgap energy levels. I think they've hit over 40% efficiency in the lab.

[inetdog]

No, I was referring to a device intended to capture protons of varying energies. I don't know anything about it yet, just that they're working on it.

Somehow, I am having problems figuring out how a solid-state device could operate in that energy regime. But then again, metallic lead is in the solid state too.