What is the state of decelerator R&D?

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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chrismb
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Post by chrismb »

KitemanSA wrote:To me, the fact that a battery HAD been made and had worked to a degree consistent with it's design makes it no longer "fantasy".
No 'battery' has been made. The NASA paper shows charging up of a plate in a containment volume, with a flux of 10^-8 amps finding its way to the 'anode'. This does not satisfy a description of 'a battery' I know of.

D Tibbets
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Post by D Tibbets »

Another link to a paper (abstract) about direct conversion applied to a Tokamak (the diverter I assume)

http://adsabs.harvard.edu/abs/1976llnl.reptR....B

Dan Tibbets
To error is human... and I'm very human.

Jded
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Post by Jded »

Just registered an account to throw in my 2 cents:
jmc wrote:(...)ultimately the problem of converting fusion products to electricity is the same as the problem of converting decaying alpha particles to electricity, so the question stil stands: if its easy to convert fusion products to electricity at an efficiency of 80%, then why is the efficiency of state-of-the-art nuclear batteries 20%?
Accidentally, a few days ago I came across an article that mentions direct conversion from nuclear rector:

http://thefutureofthings.com/articles.php?itemId=26/64/

I did not find any follow-up for this design, and I can't judge validity of concept, by what I find interesting is this:
The new battery concept benefits from the distinctive properties of Am-242m (the most stable of the eight meta states of Americium), enabling design of a critical reactor with ultra-thin fuel elements on the order of one micron. Such thin fuel enables the fission products to escape from the fuel and to be used for direct conversion of their kinetic energy into electricity. One of the major advantages of the improved nuclear battery is its simplicity.
I don't know if it's valid, but it would appear that current reactors and batteries don't use direct conversion because most alphas and betas don't escape fuel rods. You need to work with heat cause this is all you get. Anyone in the know can confirm this?

Edit:

This probably has more details, but I can't access it:

Ronen Y., Kurtzhand M.., Droizman L.., Shwageraus E., Conceptual design of americium nuclear battery for space power applications, Journal of Propulsion and Power, 23, 4, 874-880, (2007).

The abstract says something about 4% efficiency, though - not good.

jmc
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Post by jmc »

Efficiency only matters if your fuel is expensive, limited in supply, or both, no?
or if your reactor design requires large amounts of recirculating energy to break even (like p-B designs do)

KitemanSA
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Post by KitemanSA »

chrismb wrote: No 'battery' has been made. The NASA paper shows charging up of a plate in a containment volume, with a flux of 10^-8 amps finding its way to the 'anode'. This does not satisfy a description of 'a battery' I know of.
You speak Brit and I speak Merkin. Your speak is fairly pessimistic. Mine more optimistic. Kind of describes the difference between Ook and Merka, no?

jsbiff
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Post by jsbiff »

jmc wrote:
Efficiency only matters if your fuel is expensive, limited in supply, or both, no?
or if your reactor design requires large amounts of recirculating energy to break even (like p-B designs do)
But, do note, that my original comment was in the context of using D-D or D-T fusion, and thermal conversion. My understanding is a little bit fuzzy on this point, but it seems like, from what I've read, D-D or D-T are considered much 'easier' fusion to achieve, and require less energy? So, with D-D or D-T fusion, the problem is conversion efficiency of using gas or steam turbines, yes? But, with D-D or D-T, if Polywell works out, it's believed that it will release a lot more power from fusion than it takes to initiate and sustain the fusion, right?

So, my point was that if we are getting 500MWt of thermal power output from the reactor, and a gas turbine then generates 250MWe of output power, using virtually unlimited D and T, that would be an awesomely good power plant, yes?

Giorgio
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Post by Giorgio »

jsbiff wrote: So, with D-D or D-T fusion, the problem is conversion efficiency of using gas or steam turbines, yes? But, with D-D or D-T, if Polywell works out, it's believed that it will release a lot more power from fusion than it takes to initiate and sustain the fusion, right?

So, my point was that if we are getting 500MWt of thermal power output from the reactor, and a gas turbine then generates 250MWe of output power, using virtually unlimited D and T, that would be an awesomely good power plant, yes?
You gave the answer by yourself.
In any type of power plant the issue is the energy coming our VS the energy going in to keep the plant working.

So, IF the input energy will be a fraction of the generated heat we will have a good power plant, otherwise no.
The reference value here will come from a "power" equivalent nuclear plant.

D Tibbets
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Post by D Tibbets »

Having excess power with a plentiful fuel is of course essential. Having low pollution concerns is also nice, but that does not necessarily mean it is a good power source. That is the major problem with Tokamaks. Even if it works the cost of generating the power is tremendous. You could run your air conditioner and electric car, but at perhaps 100 times the cost of coal derived power. This is even worse than current solar and wind costs. The only saving grace may be that a Tokamak may better serve baseline loads, but even that in uncertain. To always have two plants online, you may need to build three plants, increasing the costs even further. This is one of the major advertising advantages of the Polywell. You would have an inexhaustible power source, AND reduce the end users cost per KWH (ignore the shouts about free energy- there would always be some finite production and transmission costs).

Dan Tibbets
To error is human... and I'm very human.

ladajo
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Post by ladajo »

Sounds like Nuclear.
The Rock gets really hot, and is pretty darn efficient in energy conversion. However, taking that energy across multiple heat exchange boundaries significantly reduces Efficiency. Thus you may generate 100MW Nuclear in the core, but you only get 25MW usable out. However, as the relative plant and fuel costs are low, when compared to usable power, it makes it worthwhile. That is why France has the cheapest electricity in the world.

Giorgio
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Location: China, Italy

Post by Giorgio »

Exactly, in the end is just a matter of costs.
If energy from Fusion technology will cost more than the one from equivalent Nuclear plant I doubt it will get spread.

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