Why have so few countries managed to produce Nuclear Weapons?

If we could do it in the 40's, why can't these other countries do it now?

What is the holdup?

Why EXACTLY doesn't Iran produce them? I guessing EVERONE knows how....it is just the process right? What is so hard about the process?

There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task.

There is nothing particularly hard about it.

If you don't happen to have uranium deposits in your country getting hold of it can be somewhat difficult without lots of strings attached though.

The most difficult part is the somewhat precise engineering that it takes, and the original bombs were far from small and light like the modern ones. To produce a WWII style bomb is perfectly feasible. But what use is that? Its too big to stick on the end of a missile, and aircraft delivery is a bit problematic these days.

Many countries probably have the knowlege/capacity to start atomic weapons production quite quickly if the want/have to, but there is little incentive to do so, it tends to piss off the USA, who is of the opinion that only it "is professional enough to handle an a-bomb fourty".

it requires the processing of a lot of ore to get enough enriched material for a fission weapon.

in the 40's we did it with massive plants to diffuse gaseous material and seperate fissionables that way.

they use high tech cenrifuges today (for the most part)

Iran has to
1) get enough / produce enough in breeder reactors ( last I heard they have enough)
2) enrich it
3) build it (easiest of the 3 steps)
4) test it

all without us or the Isreali's dropping a hammer on them

the biggest stumbling block is we do everything we can to prevent them from acquiring technology to allow easy enrichment

Its not that hard.  Most physicists have the knowledge to make one work.  One graduate student actually designed one that would work and was offered money for it by the Libyians.  The problem is getting the amount of military grade fissionable material to make the core.   You need thousands of centrifuges to get a small amount.   You can get spent radioactive materials and make a dirty bomb. Thats much easier.  

Many technically advanced countries could do it in their sleep, but don't want to. Japan,
Switzerland, and Germany, for example.

The third world countries who want them also need substantial technical
infrastructure to refine the materials and to create delivery systems,
such as ballistic missiles.

Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task.

Thats not true.  If you use the gun method, you can have the explosives drive the fissionable materials together to get a detonation.   You dont need the spherical or implosion design.  

Here are the specs for Little Boy, as you can see it will be a PITA to deliver one.  Its easy to make but its another to get it to where you want it.  Also 140lbs of uranium will make sensors go wild.

Weight: 9,700 lbs
Length: 10 ft.; Diameter: 28 in.
Fuel:  Highly enriched uranium; "Oralloy"
Uranium Fuel: approx. 140 lbs; target - 85 lbs and projectile - 55 lbs
Target case, barrel, uranium projectile, and other main parts ferried to Tinian Island via USS Indianapolis
Uranium target component ferried to Tinian via C-54 aircraft of the 509th Composite Group
Efficiency of weapon: poor
Approx. 1.38% of the uranium fuel actually fissioned
Explosive force: 15,000 tons of TNT equivalent
Use:  Dropped on Japanese city of Hiroshima; August 6, 1945
Delivery:  B-29 Enola Gay piloted by Col. Paul Tibbets

Making a nuclear bomb is pretty durn easy, really.  Put two spherical halves of uranium-235, each weighing 25kg, and it will go boom.  A neutron reflector and implosion can reduce the amount of material you need significantly.

Making implosion designs work efficiently, however, is difficult.  Requires very precise machining, and very precise timing.

Making thermonuclear weapons is much more difficult.  Especially since most of the open literature is supposedly corrupted.

Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task.

Yes.
Lotsa math.
Makes my head hurt.

is not hard to make nukes.. we used to do it all the time when i was a kid, but you have to have a really long fuse..

its the thermo-nukes, hydrogen-bomb city busters that are hard to make...

OK, I'm a dumbass.

What is the difference in the bombs we dropped on Japan and the modern thermonuclear weapons we use have now.

Is it simply the amount of fissionable material we are able to explode, there by making the blast bigger while using less "nuclear" material?

We have fusion bombs now.

Quoted: OK, I'm a dumbass. What is the difference in the bombs we dropped on Japan and the modern thermonuclear weapons we use have now. Is it simply the amount of fissionable material we are able to explode, there by making the blast bigger while using less "nuclear" material?

I believe that "thermo-nuclear" are fusion bombs, whereas normal atomic bombs are fission.  

Fusion bombs basically set off a fission bomb next to fusable fuel such as deuterium (I may be wrong).  Lighter elements are capable of fusion, and the heavier they get, the more energy required to set the reaction off.  

Quoted: OK, I'm a dumbass. What is the difference in the bombs we dropped on Japan and the modern thermonuclear weapons we use have now. Is it simply the amount of fissionable material we are able to explode, there by making the blast bigger while using less "nuclear" material?

Fission bombs.

As I understand it, Hydrogen, or Fusion, or thermonuclear bombs yield a much heigher energy release.

Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task.

 The triggering the fission bombs is the least of your worries.  The first ones weren't even implosion triggered, they just fired a U235 "bullet" into another mass of U235 to make it supercritical.  Simple as that.

The hard part is enriching the Uranium/Plutonium.  There are many different methods to enrich, none of them are easy and all require specialized knowledge, equipment, and raw materials.

Quoted: One of the problems is that some of the important components degrade over time.  Hence the "live' testing long ago. Some of the older bombs, assuning no maintenance,  including the suitcase nukes, are probably no more lethal now than their constituent components.

Would that mean that a "suitcase nuke" if not maintained, would be a "dirty bomb" or a dud?

Quoted: Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task. Thats not true.  If you use the gun method, you can have the explosives drive the fissionable materials together to get a detonation.   You dont need the spherical or implosion design.   Here are the specs for Little Boy, as you can see it will be a PITA to deliver one.  Its easy to make but its another to get it to where you want it.  Also 140lbs of uranium will make sensors go wild. Weight: 9,700 lbs Length: 10 ft.; Diameter: 28 in. Fuel:  Highly enriched uranium; "Oralloy" Uranium Fuel: approx. 140 lbs; target - 85 lbs and projectile - 55 lbs Target case, barrel, uranium projectile, and other main parts ferried to Tinian Island via USS Indianapolis Uranium target component ferried to Tinian via C-54 aircraft of the 509th Composite Group Efficiency of weapon: poor Approx. 1.38% of the uranium fuel actually fissioned Explosive force: 15,000 tons of TNT equivalent Use:  Dropped on Japanese city of Hiroshima; August 6, 1945 Delivery:  B-29 Enola Gay piloted by Col. Paul Tibbets

Does that meen that the damage could have been 98.62 % greater ? If so holy shit.

Quoted: Quoted: OK, I'm a dumbass. What is the difference in the bombs we dropped on Japan and the modern thermonuclear weapons we use have now. Is it simply the amount of fissionable material we are able to explode, there by making the blast bigger while using less "nuclear" material? I believe that "thermo-nuclear" are fusion bombs, whereas normal atomic bombs are fission.   Fusion bombs basically set off a fission bomb next to fusable fuel such as deuterium (I may be wrong).  Lighter elements are capable of fusion, and the heavier they get, the more energy required to set the reaction off.

Thermonuclear devices are Fission-Fusion-Fission devices.  

The hardest part of making a Thermonuclear devices is making the fission primary.

Quoted: Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task.  The triggering the fission bombs is the least of your worries.  The first ones weren't even implosion triggered, they just fired a U235 "bullet" into another mass of U235 to make it supercritical.  Simple as that. The hard part is enriching the Uranium/Plutonium.  There are many different methods to enrich, none of them are easy and all require specialized knowledge, equipment, and raw materials.

you need lots of centrifuges...

from : http://www.globalsecurity.org/wmd/intro/u-centrifuge.htm

A single centrifuge might produce about 30 grams of HEU per year, about the equivalent of five Separative Work Unit (SWU). As as a general rule of thumb, a cascade of 850 to 1,000 centrifuges, each 1.5 meters long, operating continuously at 400 m/sec, would be able to produce about 20-25 kilograms of HEU in a year, enough for one weapon. One such bomb would require about 6,000 SWU.

A typical centrifuge facility appears to have a capacity of 10-20 SWU/meter square, and to consume in the range of 40-50 kWh per SWU. A facility capable of producing one bomb per year would thus require about 600 square meters of floor space, and consume in the range of about 100 kWe.

Quoted: Quoted: Quoted: One of the problems is that some of the important components degrade over time.  Hence the "live' testing long ago. Some of the older bombs, assuning no maintenance,  including the suitcase nukes, are probably no more lethal now than their constituent components. Would that mean that a "suitcase nuke" if not maintained, would be a "dirty bomb" or a dud? Most likely dirty bomb.

Suitcase nukes are highly specialized pieces of ordnance.  Not to mentio they are really difficult to maintain. And they need regular maintance or they will not go boom.  They have them in Korea right now.  Basically if the South is invaded again and is being over run, a SEAL will hide and leave one behind.  BOOM! when the commies are in the thick of things.

Quoted: Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task. Thats not true.  If you use the gun method, you can have the explosives drive the fissionable materials together to get a detonation.   You dont need the spherical or implosion design.   Here are the specs for Little Boy, as you can see it will be a PITA to deliver one.  Its easy to make but its another to get it to where you want it.  Also 140lbs of uranium will make sensors go wild. Weight: 9,700 lbs Length: 10 ft.; Diameter: 28 in. Fuel:  Highly enriched uranium; "Oralloy" Uranium Fuel: approx. 140 lbs; target - 85 lbs and projectile - 55 lbs Target case, barrel, uranium projectile, and other main parts ferried to Tinian Island via USS Indianapolis Uranium target component ferried to Tinian via C-54 aircraft of the 509th Composite Group Efficiency of weapon: poor Approx. 1.38% of the uranium fuel actually fissioned Explosive force: 15,000 tons of TNT equivalent Use:  Dropped on Japanese city of Hiroshima; August 6, 1945 Delivery:  B-29 Enola Gay piloted by Col. Paul Tibbets

True, ARDOC, but the 'gun' design is NOWHERE near as efficient as the implosion method.  that said, it is ALOT easier to do.

Quoted: Why have so few countries managed to produce Nuclear Weapons? If we could do it in the 40's, why can't these other countries do it now? What is the holdup? Why EXACTLY doesn't Iran produce them? I guessing EVERONE knows how....it is just the process right? What is so hard about the process?

Well, this is instructive; I read all the posts and they are about evenly split between how easy it is and how hard it is!!

For a VERY good discussion of some of the intricacies of constructing the "suitcase nuclear bomb" please read 'The Sum Of All Fears' by Tom Clancy. Although it is fictional, he did an amazing amount of research to pin down the details. In the Afterword he even says he deliberately fudged some technical points so terrorists could not use any of his info to help them construct a(fictional, so far)  'backpack nuke". Forget trying to learn anything constructive from that abortion of a movie that was made with the same name. The only resemblance they share is the title. The book is a 'bible' of possibilities, and you can bet prudent national security agencies studied it with a close eye.

Quoted: Quoted: Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task. Thats not true.  If you use the gun method, you can have the explosives drive the fissionable materials together to get a detonation.   You dont need the spherical or implosion design.   Here are the specs for Little Boy, as you can see it will be a PITA to deliver one.  Its easy to make but its another to get it to where you want it.  Also 140lbs of uranium will make sensors go wild. Weight: 9,700 lbs Length: 10 ft.; Diameter: 28 in. Fuel:  Highly enriched uranium; "Oralloy" Uranium Fuel: approx. 140 lbs; target - 85 lbs and projectile - 55 lbs Target case, barrel, uranium projectile, and other main parts ferried to Tinian Island via USS Indianapolis Uranium target component ferried to Tinian via C-54 aircraft of the 509th Composite Group Efficiency of weapon: poor Approx. 1.38% of the uranium fuel actually fissioned Explosive force: 15,000 tons of TNT equivalent Use:  Dropped on Japanese city of Hiroshima; August 6, 1945 Delivery:  B-29 Enola Gay piloted by Col. Paul Tibbets Does that meen that the damage could have been 98.62 % greater ? If so holy shit.

Most modern fission bombs top out at ~50%.  Little Boy wasn't very efficient, but it was still pretty powerful and I'm sure many countries would still love to have one.

Quoted: Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task.  The triggering the fission bombs is the least of your worries.  The first ones weren't even implosion triggered, they just fired a U235 "bullet" into another mass of U235 to make it supercritical.  Simple as that. The hard part is enriching the Uranium/Plutonium.  There are many different methods to enrich, none of them are easy and all require specialized knowledge, equipment, and raw materials.

Not exactly, Duke.  Gas centriguges to separate isotopes of U from UF6 samples are not that hard to produce.  Iraq had scores of them.  Perfect implosion is a FAR more difficult task to achieve than productiion of sufficient quantities of HEU....your rolleyes notwithstanding.

Bombs aren't too hard to make through the U-235 gun method, if you've got the uranium.  The hard part is getting the uranium.  Mining the ore, refining it, turning it into UF6, and then centrifuging or diffusing it to get that U-235.  That takes a lot of money, and it's goddamn near-impossible to do secretly. The South Africans managed to develop their bomb secretly though.  They announced the dismantling of their nuclear arsenal (which they made in cooperation with the Israelis, SA was probably where they got the fuel for their bombs), which few in the world were aware they had.

Just so you know:  You don't enrich Plutonium, you make it in a nuclear reactor.  The design of which is different than a reactor made primarily to make electrical power, althoug electrical power is a byproduct of the plutonium reactors.  That's how we know someone is making nuke bomb fuel and not just trying to lower their power rates with a reactor.

Merlin

Quoted: ...  One graduate student actually designed one that would work and was offered money for it by the Libyians...

Did you spend the money on hookers and blow and M193?

Quoted: Quoted: Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task.  The triggering the fission bombs is the least of your worries.  The first ones weren't even implosion triggered, they just fired a U235 "bullet" into another mass of U235 to make it supercritical.  Simple as that. The hard part is enriching the Uranium/Plutonium.  There are many different methods to enrich, none of them are easy and all require specialized knowledge, equipment, and raw materials. Not exactly, Duke.  Gas centriguges to separate isotopes of U from UF6 samples are not that hard to produce.  Iraq had scores of them.  Perfect implosion is a FAR more difficult task to achieve than productiion of sufficient quantities of HEU....your rolleyes notwithstanding.

 And how exactly does that disprove what I said?  Having gas centrifuges is all there is to enriching Uranium?

krpind asked what is the obstacle that is stopping other countries from making nukes.  You're right though, I'm sure Iran has made tons of weapons grade uranium/plutonium, they're just too proud to use the gun triggering method and are sitting around trying to make the "perfect implosion."

It costs alot of money and PLENTY of electricity to provide the constant energy needed to enrich the fuel.

here ya go.  this should clear up alot of questions about nukes for ya.

people.howstuffworks.com/nuclear-bomb.htm

Quoted: Its not that hard.  Most physicists have the knowledge to make one work.  One graduate student actually designed one that would work and was offered money for it by the Libyians.

[Doc Brown]Lybians! Run Marty![/Doc Brown]

Quoted: OK, I'm a dumbass. What is the difference in the bombs we dropped on Japan and the modern thermonuclear weapons we use have now. Is it simply the amount of fissionable material we are able to explode, there by making the blast bigger while using less "nuclear" material?

Sheesh...Google is your friend.

Go here and study.  Lots to learn.  When you're done you'll even understand what makes a thermoculear weapon an H-bomb.

Nuke Design

And here...

Nuclear Weapons Archive

Look fellas...it REALLY isn't as easy as some of you are postulizing.  In fact making any type of nuke is very expensive and a BIG engineering challenge.  It is also dangerous.  Lots of stuff there that can kill.

Quoted: Quoted: Quoted: There are several obstacles to making an efficient implosion device.  Among them are the incredibly precise timing needed to detonate all the explosive material simultaneously around the Pu core.  Making the hemispherical pieces of explosive material into shaped charges whose wave front much reach the core at the exact same time is another.....  There are several others.  It's a daunting technological task. Thats not true.  If you use the gun method, you can have the explosives drive the fissionable materials together to get a detonation.   You dont need the spherical or implosion design.   Here are the specs for Little Boy, as you can see it will be a PITA to deliver one.  Its easy to make but its another to get it to where you want it.  Also 140lbs of uranium will make sensors go wild. Weight: 9,700 lbs Length: 10 ft.; Diameter: 28 in. Fuel:  Highly enriched uranium; "Oralloy" Uranium Fuel: approx. 140 lbs; target - 85 lbs and projectile - 55 lbs Target case, barrel, uranium projectile, and other main parts ferried to Tinian Island via USS Indianapolis Uranium target component ferried to Tinian via C-54 aircraft of the 509th Composite Group Efficiency of weapon: poor Approx. 1.38% of the uranium fuel actually fissioned Explosive force: 15,000 tons of TNT equivalent Use:  Dropped on Japanese city of Hiroshima; August 6, 1945 Delivery:  B-29 Enola Gay piloted by Col. Paul Tibbets Does that meen that the damage could have been 98.62 % greater ? If so holy shit.

Yes the Hiroshima bomb was roughly 15 Kilotons or roughly 15,000 tons of TNT +-20% if the bomb had been 100% effitient then the maximum theoretical yeild would be approximately 1.4793 Megatons or about 14,793,000 tons of TNT +-20%....

As was said nukes requir constant maintainence, more so as they age, and thats virtually all Los Alamos is doing these days, most people don't realize that when they panic that Alquida might get a suitcase nuke (If they had one they would have used it already anyway....), it takes knoledge, and equipment to maintain nukes, and theres no way those ignorent half evolved apes have eighther, if they did detonate one it would just be a "dirty bomb", and a small one at that, ineffitient to, as nukes are desighned to direct there blast in twards the core rather than outward, so they radiation would likely be confined to the immediate area....

Nukes are actually very easy to make, pretty bone headedly simple actually, the trickiest parts are the electronics, and the shape of the blast plates, the electronics can be done by most anyone with even a passing knoledge of electronis, and the shape of the blast plates can be discovered by triel and error with dummy bombs which is how the manhatten prodgect did it, there are to basic types of atomic bombs the implosion type, and the gun type, I'll describe each below:

Gun Bomb:



A gun bomb is the simplest type, and does not requir the complex electronis or blast plates of an implosion bomb, it works by fireing a Uranium 235 "bullet" into a Uranium 235 target fuseing the wo togethor makeing a critical mass, a neutron generator ensures that it becomes super critical, this type is very inefficient though, and only one was ever built "Little Boy", it was dropped on Hiroshima Japan on August 6th, 1945....

Implosion bomb:



An implosion bomb is much more complicated, but is much more efficient it uses shaped charges to compress, and fuse togethor segments of a Plutonium 239 Sphere to form the critical mass....





There are also Fusion or Hydrogen bombs, which are much more powerful, and efficient:

Quoted: Many technically advanced countries could do it in their sleep, but don't want to. Japan, Switzerland, and Germany, for example. The third world countries who want them also need substantial technical infrastructure to refine the materials and to create delivery systems, such as ballistic missiles.

Once you build it, you then have to guard it and make sure it's only used when properly authorized. That's a big hassle and doesn't play into the defense schemes of smaller nations. Not when we could whack the entire world 10 times over as the anti-nuke people claim.

Quoted: One of the problems is that some of the important components degrade over time.  Hence the "live' testing long ago. Some of the older bombs, assuning no maintenance,  including the suitcase nukes, are probably no more lethal now than their constituent components.

Yes. Radioactivity is the nuclear material decaying. The more radioactive it is, the faster it decays. When you have a really small nuke device, the radioactive bits that make it go boom decay to the point where they won't go boom properly (fizzle) in a reasonably short amount of time. The smaller the device, the sooner it goes bad. Larger devices stay good longer, but there's no such thing as a maintenance free nuclear weapon. They all need regular checks and after a while the core material is replaced with a fresh core while the old core is sent somewhere for re-processing-repurification. How often you need to do that depends on how big the core is and how pure it is. The smaller and less pure it is to begin with, the sooner it will go bad and need attention.

Originally posted by krpind OK, I'm a dumbass. What is the difference in the bombs we dropped on Japan and the modern thermonuclear weapons we use have now. Is it simply the amount of fissionable material we are able to explode, there by making the blast bigger while using less "nuclear" material?

Apart from what other people have said, there is also the "efficiency" of the design. The Hiroshima bomb is estimated to have only turned approx 5% of it's nuclear material into energy in the explosion. The other 95% became fallout, it was a very inefficient design. Nagasaki wasn't much better even though it was a different design. These days the designs have improved to the point where the efficiencies are the complete opposite. A modern warhead is capable of converting almost all of it's nuclear material into energy, so you can either make an explosion of the same size with much less material, or a much bigger explosion using the same amount of material as the Hiroshima bomb used, and have very little material left over as fallout.

This improved efficiency has a lot to do with how the device initiation (detonation) occours at the very beginning. Control the initiation in the right way and you improve the efficiency enourmously. There are some not so obvious tricks involved in making sub-critical amounts of nuclear material go critical (properly timed implosions are part of it, but there are other details that help improve things a lot more even with a proper implosion). The more of these "tricks" you use, the more sophisticated the design has to be, and that makes building one that will work the way you want it to much harder.

There are quite a few countries that have the technology/know how to build their own nukes if they wanted to, but mostly for political reasons or trade restrictions on critical technology/materials have not done so. South Africa is the only country which is believed to have developed useable nuclear weapons but then decided that they caused more political problems than they solved, so they dismantled and disposed of their weapons.  The Australian government of the 60's wanted nukes and tried to buy some off the shelf from the US who said no, then from the UK, who said no after the US asked the UK not to say yes to Aust. As a consolation for blocking Australian attempts to buy some nukes the US agreed to sell F-111's to Australia. If the Aust govt had been really determined to get it's own nukes, it could have spend the money required to develop it's own weapons, but assurances from the US that Aust would be under the US's "nuclear umbrella" helped discourage Aust nuclear ambitions.

Quoted: Making a nuclear bomb is pretty durn easy, really.  Put two spherical halves of uranium-235, each weighing 25kg, and it will go boom.  A neutron reflector and implosion can reduce the amount of material you need significantly. Making implosion designs work efficiently, however, is difficult.  Requires very precise machining, and very precise timing. Making thermonuclear weapons is much more difficult.  Especially since most of the open literature is supposedly corrupted.

A big +1 here...

The German design for a nuke didn't need precisely cast exposives, didn't have any timing issues, didn't require a CRAY supercomputer to design the pit of the weapon etc. All they had to do was the mass calculations for the stack of uranium plates, the plate spacing and amount of kerosene (inhibited the plates from going critical due to being close to each other), and come up with a way to make the pieces....

You have to understand that it takes a lot of doing to take a lump of a highly radioactive material, machine it to some EXACT dimension and shape  that a physicist thinks it should be, find a way to measure it, move it, assemble it etc. in a way that not only is safe for everyone involved, but doesn't give off a radioactive signature to prying eyes like we have. I'd venture to say that this is how we know where Iran's assets are, and how far along they are with their device.

Dave

There are some other considerations, but most of what has been said is basically correct.

It isn't really that technically daunting... IF you can do it in the open.  It's hiding all of the research that's so hard.  Centerfuges, Uranium purchases, Breeder reactors... It's a dead givaway, and the rest of the world no longer tolerates it.  

Plus, if you don't do a lot of complex math, the only way to be sure it will work is to blow one up.  And you just can't hide that.

Gun type units are MUCH easier to make than implosion bombs.  But they are nowhere near as efficient... Which means you need more material per bomb, and get less blast.  Given the cost of the material, basically you don't go that way.

As a nuclear operator, I can tell you that while the technology to build a nuclear weapon isn't all that trying in today's world of computer-controlled machinery, the real problems are in:

- Make it small enough to be useful and
- Making a delivery system capable of carrying it.

Not hard to make the weapon itself, as others have said--the hard part here is getting the weapons-grade uranium, then machining it and the other components to very tight tolerances.


So, now you have a nuke....now what?  As others (like TheOtherDave) have said, you have to move, store, maintain and guard the thing, without poisoning your own people.  That takes a lot of resources and personnel, some with VERY expensive technical capabilities.

And then comes the REALLY hard part--you have to have the means to use it.  Contrary to popular belief, making a nuke that will fit in a missile nosecone is VERY hard.  There's a lot of arming and fuzing equipment needed to make that happen, and THAT is where it gets difficult.  You could drop it from an aircraft, but the same applies--it's got to be small enough to be carried by your aircraft, and not many countries have full-fledged bombers anymore.  Face it, Chile isn't going to be able to develop a nuke capable of being dropped by one of their F-16s any time soon......

Quoted:  The triggering the fission bombs is the least of your worries.  The first ones weren't even implosion triggered, they just fired a U235 "bullet" into another mass of U235 to make it supercritical.  Simple as that. The hard part is enriching the Uranium/Plutonium.  There are many different methods to enrich, none of them are easy and all require specialized knowledge, equipment, and raw materials.

+1

Enriching U or Pu is EXTREMELY difficult.  This involves purifying it and obtaining critical mass...

Quoted: The Hiroshima bomb is estimated to have only turned approx 5% of it's nuclear material into energy in the explosion. The other 95% became fallout, it was a very inefficient design.

It was much worse, about 1.5% of the U235 *went under fission* (more on this later).

Nagasaki wasn't much better even though it was a different design.

Fat boy had about 17% of its Uranium(?) go under fission IIRC, I'd say MUCH better than 1.5%.

These days the designs have improved to the point where the efficiencies are the complete opposite. A modern warhead is capable of converting almost all of it's nuclear material into energy

Unless they are making anti-matter bombs now, not even close.  Nuclear bombs convert only a small percentage of its "nuclear material" to energy.  Modern bombs may have a high percentage (~50%) of its uranium/plutonium go under fission, that's a far cry from having it converted into energy.  Fusion is more efficient but whether the atom is split or fused, it's still forming other types of matter, not being converted directly to energy.  Take a typical fission bomb with say 40 pounds of fissible material.  If you converted 40 pounds of matter into energy, that would yield a bomb of about 400 megatons!  As reference...

* The typical nuclear bomb nowadays is about 1 megaton
* The high end of modern nukes is ~ 20 megatons
* The most powerful bomb ever detonated was a Russian multi stage thermonuclear bomb which was 58 megatons

Regardless, "rogue states" aren't worried about the having the most efficient and shiniest nuke, they'd be happy with any nuke.  Their problem is making the uranium/plutonium.

Put it this way, if a country is gonna develop a nuke- they are gonna get help from a country that already has produced one- unless of course they have one of these guys in their country running around:

The knowledge of how to do it is readily availalable.  In that way it is "easy".  Putting it together the right way is the "hard" paart.

A simpler analogy is putting men on the moon, OK and bringing them back, OK and back alive.    Just accelerate them to a certain velocity such that they can escape the earth's gravitational pull.  that sounds easy.  

But you got to do it in the right direction, and a heavy enough capsule to hold the men, their supplies and the launch machine to get them off the moon, and working back from that you get the size of the launch vehicle.  And then you go OH SHIT!

Quoted: Why have so few countries managed to produce Nuclear Weapons? If we could do it in the 40's, why can't these other countries do it now? What is the holdup? Why EXACTLY doesn't Iran produce them? I guessing EVERONE knows how....it is just the process right? What is so hard about the process?

Here are a couple of (fiction) books that will answer both the building and the enrichment answers for you. Both are very good reading, and both are very accurate (I've asked a few engineer friends about this).

Building a bomb: The Sum of All Fears, by Tom Clancy. (MUCH better than the movie.)
Enrichment: The Winds of War and War and Rememberance, by Herman Wouk.

In both books the bomb is part of the sub-plot.

The most interesting about Clancy's book is the relevation of the precision requirements of machining the radioactive surfaces and the reflectors: no more than you'd need to grind a pair of lenses for eyeglasses!

Hell, high school kids do it all the time!

us.imdb.com/title/tt0091472/

Also we are not considering what will happen if they try to launch or fire their nuke on a missle.   If its not properly built to withstand the Gs and shock of launch and travel, it may not go boom on the other end.  Or worse may go boom on the launch pad.

Same with aircraft.  

Most likely scenario would be a large primative bomb in a shipping container.  They would detonate the bomb at a port city.

The question is do we have the ability to detect nukes from orbit?  I really doubt our port defenses would be able to do anything.  Especially of the nuke is a mile or more off shore.

As an interesting side note, the big Russian bomb was scalable to 150 megatons, and would've gotten most of it's explosive power from the fast neutron fissioning of a U-238 (depleted uranium) layer.  

I wonder how many 'red flags' this thread is sending up......"how to make a nuclear bomb" "suitcase nuke" etc....

Quoted: I wonder how many 'red flags' this thread is sending up......"how to make a nuclear bomb" "suitcase nuke" etc....

Even if we all got togwther and devoted our lives, I doubt we could make a nuke privatektely, independently, on our own.

It's just impossible.  And not worth it. Assuming we all here agree with lineralism and the western mode  of thinking.

Why would peolple like us even want to make a rogue nuke?  We dont hate the Muslims.  Nuking them wouldn't eliminate them or make us safer.