An atomic bomb works, roughly, by compressing a critical mass of fissionable material until it is dense enough that the emitted neutrons are sufficient to set off the chain reaction that “breaks” nuclei and leads to the explosion.
So what is the hardest part of making an A-bomb? Is it getting the material, or making the detonator?
My friend says that making the detonator is very difficult, and many nations haven’t the technology. It seems to me, though, that this is a problem in conventional explosives (setting off explosives over the surface of a sphere such that there is an implosion in the center of the sphere). It seems to me that getting the plutonium or at least the proper isotope of uranium (242 was it? something like that) would be the hardest part.
In case you’re wondering, I don’t have a do-it-yourself project going in my basement; the topic arose while discussing the ability of third world countries to join the nuclear club. That’s relevant, I guess, since I am interested in the hardest part of making a bomb for someone with the resources of a small nation, and not cousin Joe the roofing contractor from Idaho. Presumably some expertise with explosives is not that hard for a nation to come by, but a breeder reactor might be.
Am I wrong? Are there impenetrable subtleties to the detonator?
Not that this is any kind of good answer, but it’s always been my understanding that everything to get the chain reaction started is done with conventional explosives, or at least something any loser nation could come by. I always heard it was the Uranium/ Plutonium that was the hard thing to come by.
At least that’s what you get from movies like ‘The Manhattan Project’
The hardest part is the delivery system. How do you get your bomb where you want it to go off? To set it off you gotta have the explosive force just strong enough and directed enough to fuse all the Uranium in the hollow sphere into critical mass without blowing it past the “other side”, or just all over the place.To get a breeder you ask one of the super powers to fund an atomic electrical plant so you poor lil country doesn’t have to deplete its natural resources,then send some bright young students to the universities and have them modify it. You can always just pack a bunch of radioactive’waste’ into a conventional explosive and blast the stuff over a fairly wide area. But again the problem is how do you deliver it?
“Pardon me while I have a strange interlude.”-Marx
Well, delivery is only a problem if you actually intend to shoot it at someone. If you’re India or Pakistan, you just want to tell the world you can make a big bang. So you can carry the thing out to the desert or wherever and just set it off.
So in fifty years, we have as nuclear powers the U.S., Russia et al., China, Britain, France, India, Pakistan (sort of), and several states that haven’t acknowledged it but certainly can build one (like Israel). The Japanese could probably go through the dumpster behind Pizza Hut and cobble one together if they really wanted to.
The main roadblock to nations becoming nuclear powers is…
Difficulty getting fissionable materials
Difficulty setting it off (the detonator)
Political pressure by other nations
An internal desire not to destroy the world.
Any others? Obviously, it’s a combination of all of these, with some being more persuasive to some countries than to others. I tend to think that the technical roadblocks, 1 and 2, are really not that difficult for almost any nation with a real desire to blow up the world.
Are 3 and 4 really enough to stop, say, Libya from making a nuclear bomb? I tend to think they are pretty immune from external pressure, and I’m not sure we can count on their wisdom and forebearance. So is it really a knowledge of the finer points of configuring conventional explosives that they lack, or is it nothing more than getting a handful of radioactive beans?
IIRC, one of the WWII bombs was a “gun-type” device, with half the fissionable material mounted in a lead slug at each end of a tube. Chemical explosive behind one or both slugs slammed them together. I do recall seeing an outline of how to build one by filling a house with concrete around a vertical pipe.
It doesn’t seem that there’s any great explosives skill needed for either.
Bob the Random Expert
“If we don’t have the answer, we’ll make one up.”
Well, the definition of “hardest” is pretty vague.
Getting the fissionable material is supposedly the major obstacle, but this is questionable at best. The security of Russian states is weak, and even American nuclear security has proven to be imperfect, Sandia et al. So getting, making, or storing the material is difficult, but not as impossible as the US wants its citizens to think. The plan is to track evey scrap of it, and insure that it doesn’t fall into enemy hands. So depending on you’re monetary resources this could pose a very major obstacle, but I presume that if you have the money you can get it.
The obstacle for the Manhattan Project crew was finding a deliverable method of detonating the core. Now the obstacles back then may have become obsolete due to computer and electric technology. I know that the engineering of the detonator required a extremely precise method of construction, and some very sensitive calibrating equipment. This I presume is still a major problem for most nations that are not technologicaly advanced and practiced in fine crafted machinery.
Don’t underestimate the influence of the global community, a nation dependant on other countries is very hesitant to risk tade embargos and the such. This is a moot point for some nations that have totally alienated the world already, but for nations like Japan and Israel it proves a very dangerous prospect.
Delivering the weapon isn’t difficult, using ICBMs and Long Range bombers is high profile and a engineering feat of its own, but there are many simple ways to deliver them. A overseas cargoship, or SUV would do just fine with a little creativity avoiding border security.
So it really depends, some nations are too poor to afford the raw materials, and in such see that as the biggest obstacle. Others have the money, but not the skill and expertise to build what is a extraordinarily complex and low tolerance piece of equipment. Others have all of the above but see the repercussions as being to severe, and note that as the biggest challenge, and I would incorporate the lack of desire in this group. All in all I’d guess that the majority of nations fall into the second group. The ones in the first group would likely not afford the machining either and therefore can be added to the total. In short, if I needed to choose an answer it would be that the detonator is the most challenging step and therefore the most prohibitive. But, as with all subjective questions it depends on how you look at it.
I believe part of the problem is also insuring that the fissile material is properly prepared. A simple lump of plutonium stuck in a case of exposives would not be a very reliable device, so the material is shaped into a sphere to be encased in explosives.
This obviously requires machinery of some sophistication, because, you know, you can’t stick some plutonium in a vise and go to work on it with a wood lathe. You might end up like that one guy in that movie, “Fat Man and Little Boy.” (Or maybe I was the only one who saw it?)
I was told that Israel already has nukes, but doesn’t admit it. This is the reason no-one has tried to invade them since the Six-day War. If this is true, it’s pretty likely those warheads have U.S. flags painted over with the Star of David.
–It was recently discovered that research causes cancer in rats.
The Little Boy uranium gun is so simple a concept that the Americans didn’t even feel the need to test it before they dropped it on Hiroshima. The problem is that you don’t get the same bang for your buck as you could get with the more complex plutonium implosion bomb (like that dropped on Nagasaki).
With enough uranium, I think any well supplied and staffed machine shop with a few UC Berkley Physics and Engineering grads could throw together a Hiroshima bomb.
The practical problem for nuke wannabe nations is getting the several pounds of fissionable uranium needed.
The engineering and design difficulties of an implosion device might well be beyond the means of a small country, even if they had the material.
Getting any old uranium isn’t exactly difficult, it’s getting the right isotope. Unenriched uranium is no good in atomic weapons. However, unenriched uranium is fairly easy to obtain from supply companies in the United States. You can order the stuff through the mail. But, once again, this Uranium isn’t good for atomic weapons in its unenriched form.
However, you can actually enrich it yourself (if you know what you’re doing) through a complex series of chemical reactions involving flourine (you can order that too) to make uranium hexaflouride (which is very dangerous to handle, of course). After several more reactions, you have your uranium plus several neutrons, giving you the correct isotope to make primative atomic weapons.
It is my understanding that the complexity and accuracy requirements of machining the core of a nuclear weapon were – and still are – the major stumbling blocks on the road to making a nuclear explosive device. This is one of the reasons that the Feds, to this day, seek to control the dissemination to other nations of certain types of ‘high technology.’
Getting your hands on uranium – enriched or otherwise – and enough conventional explosives to trigger the necessary reaction is not that much of a problem. Precision-crafting the core IS.
I don’t know why fortune smiles on some and lets the rest go free…
I was under the impression that we had nuclear devices in Israel, just as we have them planted in other parts of the world. Am I wrong on this? If they were there, have we since removed them? I realize that our having nuclear weapons there wouldn’t make them a nuclear state, but it would give them ample chances to see how we do it and make a few of their own.
“I guess one person can make a difference, although most of the time they probably shouldn’t.”
Disclaimer: my information is based on rumors and investigative reports whose details are out of date and half-forgotten by me. However, many friends and relatives, including military folk and regular visitors to Israel, have heard similar tales. No citation is available at this time.
AFAIK, the nuclear weapons that Israel has are of their own design – I believe the delivery system is a missile called the Jericho, and the warhead yields top out well below 1 Mton, probably about 250-300 Ktons.
However, Israel’s arsenal is kept disassembled and unfueled, so as not to provoke any of the surrounding aggressor nations. By the same token, the Israelis haven’t tested any of their weapons – people tend to notice that sort of thing.
–Da Cap’n
“Playin’ solitaire 'til dawn
With a deck of fifty-one.”
Thank you all for the interesting replies. If I can hijack my own thread a little, what is the minimum size one can make a nuclear bomb? Or more specifically, what is the minimum size anyone HAS made a nuclear bomb? (Filing cabinet, steamer trunk, suitcase, bread box?)
