"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.
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 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.
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.
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.
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
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
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.
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.
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.
It's nothing to do with violence and everything to do with the charade they put on. They didn't forget the plant exists. They allocate for it in appropriations every year, and they accept federal funds every year because the aforementioned contamination has made it an EPA superfund site. They know it would be a political impasse, and they could push Pantex out of the state to avoid the problem - but they don't. The idea of secession was and is, to the majority of the legislature, a tool for agitation. That is why it is hilarious, it's an elaborate exercise in "hear what I say, see not what I do". To think my comment was about "using violence to force other people to be chained to a political union" is to play right into their trick.
I find an interesting philosophical subject in that the last time states seceded from the union for misrepresentation the remaining states declared them in rebellion to the agreement and spent a million lives(on both sides) forcing them back into union. Why not just let them go?
Today given the outcomes of said conflict, it is generally agreed that this was the correct thing to do. Are there guidelines for when a secession is a genuine need to preserve local representation and when it is a gross attempt to preserve local culture that right thinking people have deemed illegal and are trying to stamp out?
> Are there guidelines for when a secession is a genuine need to preserve local representation and when it is a gross attempt to preserve local culture that right thinking people have deemed illegal and are trying to stamp out?
I think the Civil War is a rare, almost singular, example of the latter.
Because a poltical union is not just something where you get things, but also a commitment (some would say: duty) as e.g. demonstrated by such infrastructure the union put there.
If you want to get out without causing decades of conflict you have to at least get even with them, return things you have gotten through the union and esentially make your secession meaningless.
Seceeding when you hate your neighbours is a dumb and dangerous move, that has historically caused more than one war.
We live in a world where few nations would voluntarily give up their landmass. If we want this changed we need to make it so that borders don't matter anymore (e.g. an overarching governing entity — at least in Europe this has eased tensions between language barriers an places that yearned to receed — but that is a Union).
But the fact remains, just because you live in your own room in that shared rental doesn't mean your flat mates have to tolerate everything you are doing in there if it starts affecting them. We are all connected and pretending that we are not creates situations of tension. The metaphor stops working at some point, because "moving" out doesn't work for countries, at least not on human timescales.
This means there will always be the tradeoff between having binding deals (less freedom to do as you like), but good terms with your neighbours and having no binding deals (more freedom), but being in bad terms with them (on the upper end of that scale we have North Korea).
So freedom for geographic landmasses is always paradox in a sense. Cutting all ties to your neighbours will make you more free to decide laws and regulations they or your deals with them wouldn't allow, but it comes with consequence that you are on your own and interacting with them now becomes very much non-free, extremely bureaucratic and burdensome. Just look at Brexit, and there the seceeding part was at least a nation, so that was easy mode.
In the case of Brexit mostly the English laboured under the illusion that you can get the freedom to decide yourself while keeping all the good stuff they gained by being within the union.
Maybe now you might ask why the union wouldn't let them keep the good stuff?
1. It makes the union meaningless. If you allow one part to ignore the rules of the union, but still keep the good stuff, all nations can ignore the rules of the unions and keep the good stuff
2. Part of the good stuff you gain through unions you gain because your law and regulations are aligned with them. E.g. if your food safety standards are compatible you can get food that has been checked at your place and sell it all over the union without having to check again. This kind of compatibility has to exist in many places. If you are out of the union you got the freedom to have your standards diverge, but if you let it come to that guess what, you got the freedom to fuck up your ability to export things and reap the benefits of compatibility. So either you eat it up and live with much more bureaucracy, regulation and checks at your (now: hard) border or you closely mirror union law, without having a seat at the table — call me stuborn, but both do not sound like freedom to me.
Don't get me wrong, real secession can be a legitimate decision, but I think sometimes people wanting it have the wrong idea of what this would mean, which freedoms are gained and which things they would be able to keep.
IMO the best thing is to accept you are part of the world and try to gain favourable terms with those around you, without pretending they have nothing to do with you, just like in real life.
> Seceeding when you hate your neighbours is a dumb and dangerous move, that has historically caused more than one war
Secession is sometimes necessary for freedom and self determination. People should do it more often, instead of trying to live in unworkable Byzantine unions. My home country exists because we seceded from Pakistan. Yes it meant war. Folks like my uncle has to kill a bunch of Pakistanis to do it. But it was totally worth it. We now navigate our own destiny instead of being tied to an overbearing neighbor.
If the US split into 2 then China would offer to help one of the 2 pieces defend itself against the other piece, which greatly strengthens China's position in the world with potentially drastic effects on billions of people, so I hope that anyone talking about secession from the US is at least taking that effect into account.
And: most of the US population is so used to the US dominance of geopolitica, they don't know how much it gains them.
E.g. one of the consequences might be that world business might decide to do business in EUR instead of USD, ending a lot of the ways in which the US currently exploits the situation.
Now don't get me wrong, I don't live in the US, and my place might geostrategically profit from such a split in the long term. But it will be a rude awakening for all the "rugged individualism"-people out there to see just how rugged things get once the US isn't in a position of privilege anymore.
>>>We are all connected and pretending that we are not creates situations of tension.
...among other damage. Believing you're not connected to Rest of World is a symptom of narcissism - an irrational moral blindness where you're trapped screaming with rage inside your own skull because you lack any genuine connection to the world outside, and only ever experience it through a narrow filter of opportunism and antagonism.
Just because you acknowledge some sort of “connection” to others doesn’t mean you want to enter into a political arrangement in which those people can vote on the laws that are binding on you.
True, a necessity to form political unions does not arise. But my point was about the notion of freedom. If we look for example at freedom of speech, the naive assumption would be that people would most free in their speech if everybody ignored others and just spoke their minds. In reality however this leads to people yelling at each other. Turns out the best room for speaking freely (e.g. without having to censor yourself or without pretending you are of your ingroups opinion) is in places where you can trust the participants to both understand you and them wanting to understand you. The point here being that the goal of communication is to have others understand you, not to win against them by yelling them into submission.
A similar paradox applies to the freedom to decide your own laws without having to regard others. You can of course decide to do that, but then you have to be aware that this symbolic act of freedom might in fact have a detrimental effect on your actual freedom (as in: the number of choices you can make).
Most people who operate on a "I won't let them tell me what to do"-mindset don't care about actual freedom, they care about something symbolic. Brexit being a big example of the whole thing. There are whole phone-in radio shows filled with guests unable to answer the question which EU-law violates their freedom.
We need to be aware that a big fraction of The Bad Stuff™ that has ever occured in the political history of the world was due to regular people being whipped into a violent frenzy over purely symbolic problems, which on closer analysis don't have any impact on people's life at all.
The symbolic plane of politics is how they get you — get you to do things you thought you never would — for things that wouldn't even impact your life if you just ignored them. Stay aware of that.
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.
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.
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?
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.
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 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.
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..
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).
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.
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.
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.
“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.
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.
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.
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)