The Boys At Talk-Polywell Have Struck Paydirt

IECFusion Blog ^ | June 17, 2009 | MSimon

[B-Chan]

It’s the specification for a test-model nuclear fusion reactor called a Polywell reactor. If all goes well, the next model will produce more power than it consumes. If built at a commercial scale, such a reactor would not only be a revolutionary source of waste-free grid electrical power, but would be a perfect power source for submarines, aircraft, and spacecraft.

Fun Fact: the basic technology behind this design was originally developed by Philo T. Farnsworth — yes, the same guy that invented electronic television.

[Technocrat]

This isn’t just news of the first order, it makes everything else pale to insignificance. If they pull this off, the game changes completely, and it looks like they are about to pull it off. I would put it in breaking if I were the mod.

[nomorelurker]

Google up Fusor.net

It's a good place for layman to get started understanding this stuff.

[Cobra Scott]

I saw the wiki poage was updfated a few weeks ago after a very long period of practically no news. Great times. Philo would be proud; the Tokamak folks still don’t have a usable neutron source and he built one 50 years ago.

I still have not grasped how the power is to be reliably harnessed though. Still way off IMO, but visible as opposed to the tokamak boondoggle.

[Wonder Warthog]

"I still have not grasped how the power is to be reliably harnessed though."

If the polywell runs one of the neutronic fusion cycles (D-T, D-D), it will extract energy just like the ITER (i.e neutrons lose energy in a moderator---like water--heat up the water, make steam, and drive a generator). This is limited by the Carnot cycle, but no worse than a fission reactor or other fossil fueled power plant. The large number of neutrons tends to "make things radioactive", so there will be some radwaste associated with the process.

If they succeed in running one of the higher energy aneutronic fusion cycles (PB11), then they can design the electrostatic confining fields to "leak" ions at a specific point and do magnetohydrodynamic conversion by "slowing down" the high energy particles, which can be up to 80% efficient.

[Cobra Scott]

If they succeed in running one of the higher energy aneutronic fusion cycles (PB11), then they can design the electrostatic confining fields to "leak" ions at a specific point and do magnetohydrodynamic conversion by "slowing down" the high energy particles, which can be up to 80% efficient. Thanks, I wondered how you eventually turned it into shaft work, I didn't realize they could funnel the neutrons. Then you have a standard moderator-to-heat solution. You are saying the neutrons can be funneled, right? Or am I missing something? I looked up MHD from your post, and now I think I understand the debate over whether it is Maxwellian and for how long. Thanks for that! Incidentally I did read some speculation on trapping alpha in the chamber and using it as an additional source of current, like a giant pacemaker battery I guess. Just speculation I know.

[ASOC]

Here is a link to a neutron trap.
http://www.aip.org/png/html/neutrap.html

magnetic trap for neutrons
http://www.nature.com/nature/journal/v403/n6765/full/403062a0.html

So-called cold neutrons are used for cancer treatment. Cool use of N physics.

[Cobra Scott]

I saw that when I started investigating the fusor. But unlike a fusor, I wasn’t sure how you get the neutrons out of the polywell. I guess you want to “leak” them through a cusp? Or are they directional at all?

[Rifleman]

The proton/Boron 11 reaction (PB11) produces almost no neutrons. Instead alpha particles are generated. These are charged particles and so can be steered out of the reactor and can directly generate a very high voltage dc current. So you don’t need a steam plant(20 to 30% efficiency and expensive), just a tall stack of high voltage semiconductor switches and some transformers (85 to 95% efficiency and MUCH cheaper) to make 60Hz electrical power for the grid.

Assuming no show stoppers of course.

[Wonder Warthog]

"Thanks, I wondered how you eventually turned it into shaft work, I didn't realize they could funnel the neutrons. Then you have a standard moderator-to-heat solution. You are saying the neutrons can be funneled, right? Or am I missing something?"

Not really. They need to use the "moderator" approach with neutrons because they CAN'T "be funneled". They have to be "slowed down" and lose energy by collisions with a light nucleus (like the protons in water).

But with the PB11 reaction, the products are two high energy alpha particles, which can most definitely be funneled and slowed either by electric or magnetic fields.

[Cobra Scott]

Thanks to both of you! I love these threads.

[ASOC]

LOL

Gravity?

I failed fisiks... I can ‘do’ electronics, tnat follows some pretty well established rules. Fisiks OTOH is full of strange things, colors and charms - almost magic, eh?

[Osage Orange]

And I thought it was a spoof on playing whiffle ball....

Something I enjoyed immensely as a kid.........

[Wonder Warthog]

"And I thought it was a spoof on playing whiffle ball...."

Actually, it is. They call the reactor a "wiffle ball" because a 3D map of it's magnetic fields looks like (you guessed it), a wiffle ball. Who says genius physicists don't have a sense of humor???

[Osage Orange]

Most people I know that are successful, happy, and generally conservative...have a great sense of humor!!

So it figures......

Thanks!