Neutron & radioactive waste production in p11B polywells

Discuss how polywell fusion works; share theoretical questions and answers.

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MSimon
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Post by MSimon »

So explain how you keep electrons from hitting the grid?

Without magnetic shielding?

MSimon
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Post by MSimon »

Uh.

Electric fields are used to confine the charged particles.

http://powerandcontrol.blogspot.com/200 ... nd-it.html

http://powerandcontrol.blogspot.com/200 ... tails.html

http://powerandcontrol.blogspot.com/200 ... -well.html

If you read these three articles it should give you the basics.

TallDave
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Good discussion

Post by TallDave »

Good discussion. Hope no one got their feelings hurt too much. BTW Simon, I think anticarrot said he was an aerospace engineer, not a nuke engineer, which might explain some of his questions. I found them interesting, but then I'm just a humble programmer/entrepeneur.

As a programmer, I know new things rarely work right the first time (it's easier to recompile than rebuild tho; in your face 'neers!). We all know Bussard has thrown out an estimate of $100-$200M for a full-scale reactor. Based on our guesstimated costs of around $10M for The Great Convincer, am I correct in assuming only about $50M of that is actually the cost to build it, and the rest is included because there are going to be serious engineering challenges/failures, as one would expect with such a novel, revolutionary tech? Or should the estimate be higher to take that into account?

MSimon
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Re: Good discussion

Post by MSimon »

TallDave wrote:Good discussion. Hope no one got their feelings hurt too much. BTW Simon, I think anticarrot said he was an aerospace engineer, not a nuke engineer, which might explain some of his questions. I found them interesting, but then I'm just a humble programmer/entrepeneur.

As a programmer, I know new things rarely work right the first time (it's easier to recompile than rebuild tho; in your face 'neers!). We all know Bussard has thrown out an estimate of $100-$200M for a full-scale reactor. Based on our guesstimated costs of around $10M for The Great Convincer, am I correct in assuming only about $50M of that is actually the cost to build it, and the rest is included because there are going to be serious engineering challenges/failures, as one would expect with such a novel, revolutionary tech? Or should the estimate be higher to take that into account?
The $200 mil is for a 100 MW demo. I think.

I'm betting that a few more research reactors will have to be built along the way.

To build the 100 MW job without a small demo running continuously is folly. IMO.

I'm thinking about the early fission program ('41 to '45) where at least 5 or 6 demo reactors were built.

BTW I program and design (because you had to in the early days). A good designer can save a programmer a LOT of sweat. And vice versa.

TallDave
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Re: Good discussion

Post by TallDave »

Right, when I said "full-scale" I meant net power: the Phase II 100MW demo Bussard talks about. I probably should have been more explicit.

http://www.emc2fusion.org/
Fusion R&D Phase 2 - Design, Build and Test
Full Scale 100 MW Fusion System
5 years, $200M
Testing is the big question. I'm wondering if the estimate should be more on the order of an order of magnitude rather than 2x, or if this is really simple enough engineering-wise that the estimate can be as tight as he makes it.

I'm trying to pick up a little more 'neering. Discussions like this sure don't hurt.

MSimon
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Re: Good discussion

Post by MSimon »

TallDave wrote:Right, when I said "full-scale" I meant net power: the Phase II 100MW demo Bussard talks about. I probably should have been more explicit.

http://www.emc2fusion.org/
Fusion R&D Phase 2 - Design, Build and Test
Full Scale 100 MW Fusion System
5 years, $200M
Testing is the big question. I'm wondering if the estimate should be more on the order of an order of magnitude rather than 2x, or if this is really simple enough engineering-wise that the estimate can be as tight as he makes it.

I'm trying to pick up a little more 'neering. Discussions like this sure don't hurt.
Dave,

You know engineers, a more sneering, conceited bunch I have never met. A lot more Zen Masters than usual too!

In any case:

I think a lot of the proposed cost has to do with the amount of custom engineering required. Plus custom manufacturing.

Take High voltage insulators. The highest quasi off the shelf voltage offered is 100 KV. If the Dr. wants to go to 200 KV a custom mfg set up may need to be developed.

Or superconductors. That is going to be custom from top to bottom.

The reactor will need a building. The test reactors may need their own building(s).

Personally, my next effort will be to see if we can't cut development time from 5 years to two or three. That will require more funds than $200 mil (in part to buy places at the head of the line).

Getting the initial funds was just the first in a long line of required successes. We must be more relentless than ever.

We need to keep gathering supporters.

ANTIcarrot
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Post by ANTIcarrot »

MSimon wrote:ITER running at 500 MW will produce around 250 MW or more of neutrons. My recollection may be off but it is the right order of magnitude.A Polywell running at the same power production rate will produce 5 kW of neutrons.
Closer to 80% for ITER's D-T reaction, so emphasis on the 'or more' there. ITER has a peak capacity of 500MW. 0.1% of this is 500kW, not 5kw. ITER is also designed to run for short periods of time, unlike a p11B reactor, which runs continuously.

Since many of your fellow nuclear engineers seem concerned for ITER's vulnerables, this amount of exposure (however slight and preferable in comparison to other forms of nuclear energy) may turn out to be non-trivial; and a source of potential problems.
Overall neutron damage will be in proportion to total neutron power.
I think you'll find that total exposure (power * time) will also be a factor.
Now consider a fission plant.
Yes yes. The steel and concrete will last donkeys years. I've never questioned this for those materials.
Damage to the superconductors is another question. That will take operational experience. It may also be mitigated by proper design. We shall see. It may just be a matter of adjusting current densities to allow for damage. i.e. take a coil capable of 10T and run it at 1 or 2T.
Nice of you to say so. Eventually.
BTW anti in what country do you practice nuclear engineering?
I never said I did. 'Aerospace' is not spelled with an 'n'. But then again it shouldn't matter. When speaking to members of the public, or politicians, or grant committees, "Trust me, I wear a big impressive white lab coat," is a good and useful answer to many concerns, because many in such groups want simple reassurance rather than actual information. But when it comes to science and engineering, facts, figures, and/or accessible-references should matter more than CV swinging contests.

I'm quite happy to admit you are a better qualified nuclear engineer than I am, but your PR skills need work.
Will the B10 explode if bombarded by neutrons?
No.

Though there may be some inevitable proton leakage from the polywell. This could cause minor but steady erosion problems which could lead to periodic maintenance requirements. Possibly a problem to watch for during R&D and presumably something clever designing can mitigate.

And while the neutrons might be 2MeV when they enter the boron shield, they may well have much lower energy levels by the time they reach the other side. Some of them could get low enough to count as thermal neutrons.

Besides which, this is also another one of those 'PR issues' which you don't do too well with.
The above is a joke right? Do you live in a country where the 'net is filtered?
Okay. How about you do an experiment? Right now.

Go to google and type in '12Boron decay products' and see how long it takes you to find the answer. Any question even half as technical as this just turns up dozens of 'buy this paper on a completely unrelated subject which may or may not contain the answer you're looking for for a low low bargain price of $500' pages. That kind of information is generally not readily publicly available online. Or try it with super conductors.

Or here's one you probably won't be able to answer off the top of your head Mr 'technical information is easy to find': Maximum RL10 engine performance envelope.

The public pages contain very little technical information, or they contain highly technical samples from the middle of university textbooks, or they want you to 'buy one of our papers for the low low price of...'. Wikipedia is not the world's best source but it pretty much represents everything easily accessible. And I'm well aware of how dismal a statement that is.

As for suggestions I was hoping for something better than a blog site which you write yourself. "Cause I said so somewhere else," is hardnly a technical answer. And when I did search your blog for 'superconducting magnets' I only find this:
http://iecfusiontech.blogspot.com/2007/ ... ances.html

Which is one of the two (count 'em: only two) papers I have already been able to find! Neither of which state that HSC can't make good magnets. Even 'magnet' turned up a sorry list of subjects which sounded very interesting and which I intend to read, but had nothing to do with explaining why high temperature super conducting magnets are theoretically or practically impossible.
Some light reading material: Half Way To Anywhere, The Rocket Company, Space Technology, The High Fronter, Of Wolves And Men, Light On Shattered Water, The Ultimate Weapon, any Janes Guide, GURPS Bio-Tech, ALIENS Technical Manual, The God Delusion.

MSimon
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Post by MSimon »

You are correct on the math.

Now compare .5 MW of neutrons from Polywell to a running 500 MWe Fission Nuke. That nuke will be producing about 1,500 MW of neutrons (most of which will be thermalized by the time they strike any structure).

However, the damage from high energy neutrons is probably comparable.

Yep. There are problems.

That is why I'm an engineer.

As to superconductors. The best place to get free info on products is from the people that make them.

And yes. Proper shielding will need to be worked out. If the calculations show too many neutrons/gammas/x-rays we add another 6" to 12" of concrete. We know how to do this even if personally I'm only able to give correct results within a foot or two. I think 8" of concrete (ROM) will cut down the neutron/gamma/x-ray flux by a factor of 10X.

Roger
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Post by Roger »


Will the B10 explode if bombarded by neutrons?
PB11 fuel for a polywell would be a gaseous form, no? B2H6 .. ?

Di-Borane gas ...... ?

Maybe if I strike a match......
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.

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