Welding of Plutonium (1958) [pdf] | Hacker News Reader

Welding of Plutonium (1958) [pdf]

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120 pointssohkamyung90 comments

"Just prior to welding the plutonium surfaces are cleaned in the inert atmosphere of the welding box to remove oxide and foreign material. If the oxide film is light, it can be removed by wire brushing. If this is not satisfactory, sanding or an abrasive wheel can be used."

In case you are wondering what you'd do with tools, consumables, entire workspaces and ductwork contaminated by that kind of dust, well, these folks buried it in a trench on a mesa overlooking the Rio Grande [1]. The dump is large enough to contain the Empire State Building and, by one account, whole machines like forklifts were just pushed right in [2]. No "highly esteemed deed" was commemorated there, indeed.

1: https://n3b-la.com/area-g-tru/

2: Los Alamos, Hidden Colony, Secret Truths by Chuck Montaño (2015)

Reminds me of what they did near me at Rocky Flats - well: before it was raided by the FBI, shut down, cleaned up, an reopened as a nature reserve. e

Every single time I come across information like this, I hate humanity just a little bit more.

Near my hometown, an army train depot closed in the 60s. I imagine some sergeant tasked with making shit go away just dumped barrels of TCE and burned various materials in pits.

Today, a plume is contaminating groundwater at quite a distance.

When I think of Hunters Point I think of Gommer Pyle pouring a bucket of expired radium paint into a hole dug in the base commanders flower garden.

I think all railroad maintenance facilities have similar groundwater problems.

Why hate yourself? Violence is a part that makes us human. Without it we are not human If we will not learn to control it, we will die. But in the end everything does. Also, being prepared is important. Si vis pacem, parabellum.

Most of us manages very well not being violent, and have no desires or urges to be violent. Aren’t we humans then?

It is not what I said. I meant violence is part of being Human. If you do not use it does not mean that you do not have it. It is not about blindly applying it. It is not only a negative thing, it is an evolutionary advantage versus species which is not violent. It is just another tool of enforcing you will over the will of others. For example some people have to obey the law because of a threat of violence of the state. I mean if you remove all our societal conditioning and learning, it all boils down to violence, like it was for first humans. I do not advocate violence, I think hating humanity for it is not rational. Clauzewitz said: "War is the continuation of policy with other means". So essentially violence is the continuation of policy when you can not achieve your goals by other means. This is just my view on it, take it or leave it.

I just had another thought about this: without violence - you cannot have peace. Sure, you can threaten violence if peace is not kept, but if you are not prepared to use violence to uphold your threat - your threat is useless. I think Putin is a great example for this. He showed us, that violence is actually a valid tool to achieve your goals nowadays. I mean sure I and people like me don't like violence but just because we don't, doesn't mean others somewhere else also don't and won't use it. We cannot avoid being confronted with violence at least at some points in society. We need to understand that it is also part of us and be able to deal with it or channel it. When I read the definition of violence I found on google: "behavior involving physical force intended to hurt, damage, or kill someone or something." Is there really any human who at least in some way didn't somehow use force to hurt someone, even as a kid? Don't we actually nurture application of violence in soldiers? I just have a feeling, that there is some insight here, that violence is not all that useless and maybe is a trait that made humans at least in part successful. OK, it make bring our downfall through nuclear war, but what other catastrophes wouldn't? We will fall down one way or another if we will not prepare. Also, what is a benchmark for success here? Is humanity that survived 300,000 years better than the one that survived 400,000 and who will be there to measure it?

Plutonium half life is like 90 years. It wouldn't get to the top 10,000 list of bad things we did in the last 100 years.

24000 years actually

See

https://en.wikipedia.org/wiki/Isotopes_of_plutonium

The main reason people believe a nuclear waste dump needs to last a stupendously long time is because of the long lifetime of Plutonium 239 and some related actinides.

Reactors with a fast neutron spectrum could consume those actinides, the remaining waste becomes less radioactive than the original uranium in 1000 years which is within the time that we've had buildings last, social structures last, etc. In that scenario you have little fear that carefully buried waste incorporated in glass will leach out.

If you are looking 100,000 years down the road like you are with Yucca Mountain it is likely the facility has long been flooded and soluble Uranium will migrate in the direction of Death Valley whereas the Plutonium will not migrate because it is insoluble in water. I think it is sublime that the Pu239 decay chain goes through U235 which retains the nuclear fuel value.

In the "once-through" fuel cycle almost all of the waste buried is unburned U and Pu fuel, the fast reactor cycle could consume all of that starting with the waste that is cooling out now.

That is the Pu238 isotope that is used in thermoelectric generators.

Most of the plutonium produced in nuclear reactors is Pu239. This is the isotope that is useful as nuclear fuel and for nuclear bombs. As another poster has already written, it has a half-life of 24 thousand years, so there is no chance to get rid of it easily, unless it is recovered and used as fuel.

There exists also the Pu244 isotope, with a half-life of 80 million years.

This isotope is produced only in negligible amounts in nuclear reactors, but it is produced in supernova explosions, so the Solar System and the Earth had contained plutonium besides uranium and thorium in the beginning, during the first few hundred million years of their history, but the plutonium has decayed until now.

The creation of contaminated tooling continues at the Pantex plant in the Texas panhandle. The plutonium pits for the US nuclear arsenal are serviced there. When cores get recycled a ton of nuclear-contaminated waste gets created. Oil, lathes, air filters, etc. The existence of the plant makes the recent musings on secession by the Texas legislature a hilarious thought.

I don't understand the connection there

I think they are stating the odds of the federal government actually allowing secession to go through would be...minimal at best, given these assets in the state.

Bingo. 100-200 physics packages go through the facility annually, and if you think Uncle Sam got mad when someone touched his boats, try touching his nukes.

Nothing a treaty won't solve. Access to West Berlin through the Iron Curtain was a thing.

West Berlin was of minimal strategic importance though. It had highly symbolic value of course.

First, we take Manhattan. Then, we take Berlin.

And I don't like those drugs that keep you thin

I too am sometimes guided by the beauty of our weapons.

(Though to be honest: usually I'm just guided by the beauty of our tools...)

One could also compare with Russia's Baikonur Cosmodrome being in Kazakhstan.

The NY Air National Guard has B-52s and tankers. Hopefully they would launch a disarming strike on any attempt by Texas to go nuclear.

Nobody serious thinks Texas secession is a good idea. It’s performative nonsense to rile up idiots.

For an international analogy it’s along the same lines as Putin claiming the sale of Alaska was not valid.

Every single piece of nuclear ordinance goes through that area. There are likely hundreds of near functional nuclear warheads under maintenance at any moment.

They're a larger nuclear power than China, England, France, or any country other than Russia and the US. What they don't have are delivery systems.

SpaceX launches out of Brownsville.

Just because SpaceX has rockets that go to space doesn't mean those rockets are ICBMs.

Any rocket that can put a payload in orbit is an ICBM capable of launching at least that payload at another continent.

If a continent is your target, sure...

I mean spaceX can drop a booster on a 20m wide barge without much fuss...

Land, not drop... And the boister is not coming in hot from a ballistic trajectory...

Dropping seems a lot easier than landing though. And I imagine if your payload is a nuke, missing your target by even a hundred meters doesn't matter much..

Convincing SpaceX to go along with it on the other hand, I think is going to be really hard.

Yes, of course, guidance systems for ICBMs and with multiple warheads are easy, I forgot.

Um yes they are, that's the point. It might have been hard 40 years ago, but it's not today. SpaceX could build a rocket to park a nuke on your front lawn[0], wherever that is, inside about 30 minutes, without breaking a sweat.

[0]Read: at an optimal altitude and velocity for air detonation.

guidance systems for icbms are literally the exact same guidance systems used for launching satellites into orbit. that's what the 'b' stands for: 'ballistic' means that the reentry vehicles go where i, the launch vehicle, throw them (βαλλω) rather than guiding themselves to the target with onboard thrusters or airfoils or something. the only difference is that you fall short of orbit

https://en.wikipedia.org/wiki/Ballistic_missile

in the 01950s, guidance systems for orbital launch were a very significant engineering challenge. a rocket is almost an inverted pendulum in the sense that it's a long, stiff thing being pushed up from below; even going to space instead of arcing back into the turf near the launch site requires active negative-feedback control. even the smallest programmable computers were too big and heavy to put into space, so they had to use circuits wired up specifically for the guidance and control task. inertial measurement units were artisanally-produced gimbal-mounted things the size of a small child, there was no gps, and cybernetics was in its infancy. my grandfather built guidance systems for icbms at the time, and it was very difficult indeed

now, every twenty-dollar cellphone contains the necessary ingredients, although some of them are artificially crippled by export restrictions, and control theory is a standard course in any undergraduate engineering curriculum, using the inverted pendulum as a homework exercise. and if you're going to spend a few thousand bucks, and aren't north korea trying to circumvent other countries' export restrictions, you can easily get lower-noise imus than the ones that go into cellphones

so yeah, it's easy, even if it wasn't a problem spacex had already solved

So, ICBMs are easy, hm? Just slapp in some smartphone components? Then why is, e.g. North Korea struggling so hard with them? Sure they have access to some Samsung Galaxy 12 over there.

they're struggling with the rockets, not the imus or guidance algorithms. rockets that can launch things into orbit are at the boundary of being physically impossible; if earth was a bit bigger, we'd have to use a different space launch method

It's p̶a̶r̶t̶i̶c̶u̶l̶a̶r̶l̶y̶ pretty hard to obtain guidance systems and components or certain types of ruggedized electronics that haven't been deliberately gimped to prevent them from being used in supersonic or exoatmospheric missiles while on the USA Naughty List, and North Korea doesn't yet seem to have an advanced manufacturing base for this that I'm aware of, whereas Texas or Japan would be a different story.

while this is true, the resulting difficulty is often overstated for both political and historical reasons. itar was conceived in a very different technological, political, and economic world

It's not so much that they are easy per se, but compared to what SpaceX does regularly, it's peanuts. A simplified version of what they already do.

Assuming the warhead itself can handle the detonation part, what part of "fly to these coordinates fast, don't brake" do you think would be difficult for SpaceX based on their current capabilities?

Sarcasm truly is the lowest form of wit, doubly so when you’re in fact wrong.

Do you really think ICBMs are difficult conditional on being an entity with the infrastructure and degree of expertise and experience in both launching stuff to orbit and bringing it down from orbit (not just from a suborbital trajectory) that SpaceX now has? Ballistic missiles were first developed and deployed by Nazi Germany. Before transistors were invented. They were already developing ICBMs capable of reaching New York. The war just happened to end before they managed to deploy them.

Oh, sure SoaceX could do it. Right now, they cannot. And yes, guidance systems for multiple warheads, single warheads are a thing of the past, is not easy to get right. At the very least, it is a major development project.

The people who know how to do that are in California not Texas.

In one piece?

It does though. Any rocket that can go into leo can fall within a mile without trouble.

And that's with 1950s guidance technology. Add modern controls and a SpaceX can crash into a site with 100 m no problem

Or the codes to make the Permissive Action Links (PAL) work.

If they have the physics package they don't need the codes. Those codes to deter a grunt or rogue commander. A place like Texas can easily make bombs out of the physics packages

I’d imagine that they have everything they need to make devices without a PAL.

I believe you need a code in order to disassemble a PAL protected device without it self destructing, presumably these disassembly codes are different from the arming codes.

"sure you can secede"

"sweet! look at this nuclear weapons plant that's now ours"

"sure, enjoy!"

"HEY...you just left us the giant nuclear waste dump, where's the boom booms?"

Also look into the glovebox and exhaust duct fires at Rocky Flatts.

There is a famous news clip where the DOE representative is denying there is a fire on live TV with a big fire visible behind them.

It's also the only time one federal agency (FBI) raided another (DOE).

They also had a bunch of the kind of radioactive waste your talking about sitting in 50 gallon oil drums that just rusted away in the open air.

Most of these bizarre properties can be traced to the mixed valent character of plutonium - that is the electrons in the partially filled 5f shell of the plutonium atom hybridize in the solid phase with the valence electrons, and thus for some properties they are valence like and others they are core like. This is quite similar to some lanthanide (4f) elements like cerium, which also show strange variety of allotropes. The mixed valent character causes plutonium to have a variety of exotic physics effects, completely unrelated to it's most notorious use in nuclear weapons. Examples of these include heavy fermion metals, novel superconductivity, etc..

It would be extremely funny if the room-temperature superconductor we're searching for is some plutonium-based compound or alloy.

See https://en.wikipedia.org/wiki/Gas_mantle for a an unusual property of Thorium which must have to with having so many electrons.

Is it specifically the emissivity that's so unusual and makes it the preferred material? I don't know that "low emissivity in infrared + high emissivity in visible" is a rare property—I recall reading about space satellite thermal engineering and seeing long lists of common materials sorted by visible/infrared emissivity ratios [0]. And there are a lot of them, in every category. I suspect the key thing is ThO2 is a super-refractory with a melting point of (approximately—these are hard to measure!) 3,350° C [1]. (About the same as the tungsten filaments in the old-school type of lightbulbs—something with pretty similar considerations). I suspect "things that maintian structural integrity in hot gas flame" is really the key discriminator here, the rare property that prunes out most candidates.

I'm not any sort of expert on this, to make very clear! Just a curious geek.

[0] (That's basically a proxy for the radiative equilibrium temperature in space: visible emissivity measuring absorption of sunlight, infrared emissivity measuring emission of waste heat. (To those unfamiliar, absorption and emission are exactly the same, at a specified wavelength: the physics is reversible). ThO2 for example, you'd expect would get extremely hot in space).

[1] https://en.wikipedia.org/wiki/Thorium_dioxide

Small bit of background:

https://en.wikipedia.org/wiki/Allotropes_of_plutonium#Stabil...

What do you mean I can't wear my lucky beryllium welding gloves?

Not so lucky.

If what you're working on is close enough to a critical mass, just your body might do. Otto Frisch nearly fried himself by standing too close to a stack of bars when trying to determine the critical mass for enriched uranium. His own body was reflecting neutrons back at the stack.

https://en.wikipedia.org/wiki/Otto_Robert_Frisch#Manhattan_P...

Unless I missed it the PDF doesn't explain why you would want to weld plutonium.

I suppose you would need to weld two hemispheres of plutonium together to make the hollow pit[1] for an implosion device. Or it could be safer to work on smaller pieces and then weld them together.

[1]: https://en.wikipedia.org/wiki/Pit_(nuclear_weapon)

My guess is the same: that to add structural integrity during the first phase of implosion, so as to guide the implosion process better (rather than having a piece of the pit fly out, say), you'd want to weld the pieces with little plutonium columns between them. I doubt that's how modern bombs work.

This seems like the best possible place for me to repeat one of my favorite quotes about technologists: Never ask a geek, "why?", just nod your head and back away slowly.

Sure, but I think the people that published this were doing the exact opposite of geeking out and had the most deadly serious of intentions with the work.

Looks like this is the welder they used, for anyone wanted to try it at home:

https://hgrinc.com/productDetail/Welding/Used--Welder/022017...

If you want to try it at home, read this first: https://myaccount.ans.org/s/product-details?id=a1B5f000003nS...

“Topics span the history of the discovery of plutonium, properties of plutonium isotopes, chemistry and properties of plutonium metal and alloys, plutonium aging, thermodynamic trends of plutonium, plutonium in nuclear fuels, waste forms, and heat sources, packaging, storing, and transportation of plutonium, nuclear security and safeguards, and techniques for working with plutonium.”

I guess chances are that ordering that product puts you on a few lists.

Unfortunately, no. It requires something with a little more kick.

Take a hike, you shady used pinball machine parts hustler. :)

Why the heck are we welding plutonium ?

Because some people think the world needs nuclear weapons :-(

We conceded that part. The question is: What about nuclear weapons needs welding?

According to

https://discover.lanl.gov/publications/national-security-sci...

    Pieces of cast plutonium are then welded together to form a pit

Note if the world (ex. Russia) ever gets interested in the fast breeder reactor, or even if we try to get the absolute most out of the LWR

https://www.neimagazine.com/features/featurean-advanced-fuel...

there may be revived interest in casting fuel elements out of mixed U, Pu and Zr like so

https://www.youtube.com/watch?v=KEfhx5ovuYk

a technology which has been quietly used in marine nuclear reactors for years. This competes with the oxide fuels ordinarily used in civil LWRs and that the French have developed to make mixed-oxide (part U, part Pu) fuels. Problem with that is that quality MOX fuel is made of U and Pu alloyed in a high-energy ball mill but that makes nano particles that are highly effective at getting in your lungs and causing cancer. That is a problem with casting too, but making MOX fuel means you need to pick up fuel pellets with gloves and carefully stuff them in a tube whereas you don’t have to get anywhere near a cast fuel rod.

Was wondering the same, I would not have expected welds in places where plutonium is used and assumed things like casting, forging, and machining is what you do to plutonium. Maybe this was just for research, just in case the need ever arises? Or for experimental setups?

Addative manufactering (welding) has the advantage of working towards a critical mass. Where as subtractive requires getting even closer to it then moving away from it, as you make the desired part.

Interesting point but would that really be relevant? If you have a hollow pit or one with an initiator in the center, you will be making two half-spheres, so you will be far away from the critical mass. And even if you are making a solid pit, I would have assumed that you are quite a bit away from the critical mass without neutron reflectors and the compression from the detonation.

I think you'd want to weld the two half spheres together to give a more consistent mechanical fit to help with your implosion efficiency.

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