Talk-Polywell.org

Hi All--

This topic emerged over on another thread here:. Seems like it really belongs over in this forum.

Here's the issue:

Today, there are two ways to make stuff for nuclear weapons:

1) You can enrich uranium to produce highly enriched U-235 (often abbreviated HEU). This is hard because you have to have centrifuge cascades or other high-tech, expensive, and easily detectable industrial equipment.

2) You can put U-238 into a breeder reactor to produce Pu-239, then chemically purify the Pu-239 to produce bomb-grade stuff. This is actually a lot easier to do than producing HEU, but it requires a nuclear reactor, which is in turn, large, high-tech, expensive, and easily detectable.

The US, EU, Russia, China, and even the good ol' IAEA all know how to find states that are attempting to get weapons through either of these methods, because the industrial footprint is unmistakable.

But notice that method #2 works equally well with any high-density neutron source. Fortunately, the only neturon source that's dense enough to be workable is a fission reactor.

Or at least it is until you get a high-power D-D or D-T fusion reactor going. Then you've got plenty of neutrons. Instead of a lithium thermal blanket, you jacket your fusion reactor with a water blanket to slow down the neutrons to thermal energies, then a U-238 blanket on top of that. Marinate for a while, then take your U-238 + Pu-239 away to be refined.

Now, nobody's going to worry too much about somebody sneaking a tokamak or a laser inertial confinement plant into the outskirts of Islamabad or Khost. Such a facility would cost billions of dollars, take up at least a city block, and require all sorts of exotic metallurgy. Again, it's highly detectable.

But what about a polywell or even a focus fusion plant? It seems reasonable that you could fit such a plant into an ordinary warehouse or even a large garage. We think that the materials to construct such a plant (especially one where you weren't generating electric power) are fairly mundane. Would a polywell be detectable from a non-proliferation standpoint?

So, two problems emerge that we need to consider. First, what does a compact fusion reactor mean for non-proliferation enforcement? Are there actually ways of detecting them? Is there some sort of technological secret sauce that will be easily traceable or put the technology out of the hands of rogue states and non-state actors? Will a polywell be so cheap to deploy and so simple that it's acquirable by a rogue state? By a terrorist group?

But the second problem may be more interesting to this group: If I were a legislator that was faced with funding research into a technology that might have huge power applications but also came with a substantial proliferation risk, I might equivocate, especially if that technology wasn't yet a slam-dunk. This might be silly, but legislators are in the business of getting re-elected, which doesn't always translate into doing the right thing. We obviously want the funding to occur. (I think the proliferation risk is real, but it's dwarfed by the possibility of a permanent solution to our energy problems.)

What are some of the arguments that we'd put in front of legislators (or any other potential funders) that would assuage their proliferation fears?

Even chemical separation will be radiation intensive.

There will be a lot of fission products to go with the Pu239.

Radioactivity can be detected from a distance.

The cat is already out of the bag.

We are headed for a dark and uncertain future WRT nuke bombs.

Our main hope is that cheap energy improves world conditions quickly enough that the desire for domination (local or world) declines fast enough.

It will be a race and may require robust military action. Sadly.

The IAEA isn't going to do anything except wring its hands.

BTW neutron pulses would be good for finding hidden nuclear material.

I think the starting point has to be pBj reactors. D-D jobs should be experimental only.

In any case extracting Pu chemically from U is going to be radiation intensive. That is some help.

As neutron sources IEC devices are old hat. As far as a rogue group building an IEC device as a neutron source... if all you want is a bomb.... why go the route via IEC.

Does this represent a shortcut compared to the traditional ten thousand centrifuges ?

My guess is no.

Let me add that since you are working with solutions that have the potential to go critical due to water moderation you have minimum size requirements to maintain a dilute enough solution to prevent criticality problems.

MSimon wrote:Even chemical separation will be radiation intensive.

There will be a lot of fission products to go with the Pu239.

Radioactivity can be detected from a distance.

Several objections:

First, you'll get no isotope sniffing hits off of the fusion machine itself. If I were a savvy terrorist, I'd do a nice long breeder run, then divide my U-238/Pu-239 blanket into multiple chunks prior to separation. That way, you'd have to run a whole bunch of sniffing hits to ground.

Next, imagine you've got small separation ops running all over Central Asia (or Paraguay, or Indonesia...). That's an awful lot of area to cover with sniffing operations.

The directionality of sniffing is only so-so.

Roger wrote:As neutron sources IEC devices are old hat. As far as a rogue group building an IEC device as a neutron source... if all you want is a bomb.... why go the route via IEC.

Does this represent a shortcut compared to the traditional ten thousand centrifuges ?

My guess is no.

To do Pu-239 breeding, you need a lot of neturons. Current IECs are fine for neutron activation analysis, but not for breeding. But a power-producing fusion reactor would be a different animal. (NB: I have no clue whether the neutron flux from a power-generating D-D or D-T reactor would be dense enough to do decent breeding. Can anybody do that calculation?)

MSimon wrote:Let me add that since you are working with solutions that have the potential to go critical due to water moderation you have minimum size requirements to maintain a dilute enough solution to prevent criticality problems.

On the other thread, I thought you were describing a system where you'd have a 4-6" water blanket to thermalize the fast neutrons, followed by a blanket of solid U-238. Did I misunderstand? Wouldn't the U-238 itself be enough of a moderator to avoid criticality?

Fusion reactors burning deuterium will produce 10X to 20X as many neutrons as an equivalent fission reactor.

Extracting Pu is not going to be done by terrorists. Too much science, too much eqpt., too much radioactivity.

The power supply for a non-power producing (neutrons only) 100 MW reactor will consume 1 to 10 MW. Not a lot. Not trivial.

Proliferation will be about as hard as doing it with a fission nuke.

A distributed system increases the chances of detection by accident if nothing else. Plus terrs are sloppy. Radioactives blowing in the wind will get detected.

TheRadicalModerate wrote:

MSimon wrote:Let me add that since you are working with solutions that have the potential to go critical due to water moderation you have minimum size requirements to maintain a dilute enough solution to prevent criticality problems.

On the other thread, I thought you were describing a system where you'd have a 4-6" water blanket to thermalize the fast neutrons, followed by a blanket of solid U-238. Did I misunderstand? Wouldn't the U-238 itself be enough of a moderator to avoid criticality?

Uranium does not slow neutrons much per collision. Water slows them from 10 MeV to .025 eV (thermal) in 22 collisions on average.

Optimum is a water blanket with U in solution as a salt. A nitrate or a sulfate. U does not slow down neutrons and as Dr. Mike points out you want to expose the U to a flux that has all the energies in the range of 10 KeV to .025 eV. Best way to do that is to have the U in solution with the (water) moderator.

We are indeed heading into uncertain times. Having large fusion reactors acting as neutron sources to produce weapons grade material is a worry. But people have been worrying for years. The damage has already been done, missing American suitcase nukes, broken arrows, and Profiteering Russian nuclear inventory after the fall of the soviet union.

The fear bought on a generation of people from the cold war is getting lost in todays technocratti.

Why the F#(K do America keep on insisting on undermining Mutually Assured Destruction with aspirations of missile shields ?

Portable (6 to 10 truckloads) of a 1,000 MW laser blaster should keep the rocket guys busy for a few years with countermeasures.

It will buy time.

A portable Bussard Reactor operated in a semi pulsed mode (1 hour out of every 2) or maybe draw in more trucks and have 3 or 4 lasers in a battery.

MAD is not the optimum strategy. The optimum is we do not have to strike first. Or simultaneously. Only a shield gives that option.

Sorry to get off topic TheRadicalModerate. But all that talking about lasers Msimon has got me thinking.

What would happen if you put a platform with a Polywell and a Free Electron Laser in space ? This would give you the power to erase anyone or anything off the map with the push of a button. Nuclear Smuchlear. This is the sort of godlike power our power crazed new world order elite have in their wet dreams. Now i see it all within reach. Add to this a micro chipped population in a super connected society where anyone who misbehaves simply gets vaporised from above. 25 years could see a system like this operational. Now that is definitely some scary shit. While i would hate to bring another weapon of fear and destruction into this into the world, flogging a system like this on capitol hill would definitely get us all the funding we need, and then some.

Pardon my cynicism, but it seems that genuine, high tech, physics savvy, engineering terrorists are a bit thin on the ground. We've had nukes for some time, yet no nuke has gone off (as yet) from a terrorist attack. The tech required to crank out a functioning polywell, along with the physics and chem required to refine the plutonium from a breeder associated with it ... sorry, my credibility indicator indicates it's very unlikely.
If you want real-life scenarios (think Glasgow, the London Underground, the Bali Bombing) good-ol fertiliser has done the job so far, and it's unlikely to change anytime soon. It's just too much trouble.
I personally think that sufficient intelligence engenders prosocial behaviour. And you need a lot of intelligence to iron the kinks out of a polywell.
Note:- Ed Teller worked on the hydrogen device (fusion bomb) and seems to have had plenty of intelligence, so the postulate isn't absolutely cast-iron; but Teller would have gotten nowhere without a serious industrial effort behind him.

^agreed. Although Teller wasn't a shining example of humanity. His real contribution to the H-bomb in collaboration with Ulam is still disputed. He testified that Openhiemer was communist for a power grab. He wanted to nuke part of alaska to build an artificial bay. He is a shining example of how absolute power corrupts absolutely. Once people get control of viable polywells who knows what mania it could induce. I also heard Teller was inspiration for Dr Strangelove, but i believe that award should go to Robert McNamara.