7 ms·

so the explosives cause the jawbreaker like layers of radioactive materials to compress creating nuclear fission that unleashes ton of energy? So what stops so

so the explosives cause the jawbreaker like layers of radioactive materials to compress creating nuclear fission that unleashes ton of energy? So what stops so many other countries from creating such seemingly simple device? Is it the trouble in acquiring the materials?

tdicola 12y ago
Making enough plutonium is pretty difficult from what I understand. In WW2 some of the biggest buildings ever built were necessary to house all the equipment to make just enough material for a few bombs (see http://en.wikipedia.org/wiki/K-25 http://en.wikipedia.org/wiki/K-25). Nowadays you need a nuclear reactor and fancy equipment like uranium centrifuges. See the Stuxnet worm and how it targeted Iran's uranium centrifuges in an attempt to disable their ability to make bomb material.
nate_martin 12y ago
Yep, also enriching uranium to anything near weapons grade is a cumbersome process.
sehugg 12y ago
Yes, in fact the website in the OP is for a book which advocates for a disarmament approach based on eliminating weapons-grade fissile material stockpiles: http://unmakingthebomb.com/sample/ http://unmakingthebomb.com/sample/
JanezStupar 12y ago
Plutionium is one problem, but AFAIK not the greatest for this type of device. Greater problem is precise machining and fuse technology necessary, which makes it an enormous and expensive project even today. The rifle design is just the reverse. There technology is a lot simpler, but rich enough Uranium 235 is a lot harder to come by.
- sgdread 12y ago
  another complexity is that the plutonium core is not just any weapon-grade plutonium: it has to be casted in unstable delta phase (which has unusually low density; the implosion's task is to switch it into alpha-phase which is much dense: this process makes core critical and explosion happens). Not to mention toxicity of the material itself.
droopybuns 12y ago
While this looks simple, many of the details of the construction of the first nuclear devices are still classified. So part of the reason is that simple explanations of the design do not necessarily reflect a simple construction. On the other hand, you get a taste of a story about how John Phillips got his Undergraduate senior thesis classified for being to informative on how to resolve some important technical details around the actual explosive design for a pit based weapon. http://www.universitypressclub.com/archive/2013/02/the-a-bomb-kid-and-hows-your-senior-thesis-going/ http://www.universitypressclub.com/archive/2013/02/the-a-bom... Plutonium is difficult to handle and accumulate in significant quantities. Here is a fun video that gives you an appreciation for the danger and rarity of the element: http://www.youtube.com/watch?v=XLufmakbiU0 http://www.youtube.com/watch?v=XLufmakbiU0 *Edit: I linked the wrong youtube video. While the above is fun, this one gives you a better idea about the manufacturing difficulties of working w/ Plutonium: https://www.youtube.com/watch?v=89UNPdNtOoE https://www.youtube.com/watch?v=89UNPdNtOoE The bottom left corner of the periodic table is apparently filled with wildly interesting elements that do super bad things to your body. They get hard to come by- and in some cases they only get created in the laboratory. Maybe that's for the best.
mikeash 12y ago
It's not quite as easy as it looks. The implosion has to be perfectly symmetrical, or else the core will pop out the side instead of being crushed. Think trying to spear a cherry tomato with your fork. That in turn means that your chemical explosives have to be carefully arranged and they have to be detonated at the precise correct times. In fact, one theory of how the Permissive Action Links (basically, the stuff that makes it so a bomb needs a code to be detonated instead of any random person just pushing a button) work is by encrypting the timing sequence, so that without the code you don't have the information needed to detonate the bomb, rather than relying on some physical lockout. Working out the timing and building the device accordingly are both tough. Additional difficulty comes in when you want to either increase the bomb's power or decrease its size and weight, both of which are important for making them practical to use against an enemy. There's a lot of work between Fat Man, which weighed 10,000 pounds had a yield of 21kt, and a modern weapon like the W88 which weighs 800 pounds and has a yield of 475kt. But still, once the basic research was completed and available, producing the materials becomes the primary difficulty in building a bomb.
th0ma5 12y ago
Here's a TEDx talk from 2009 that goes into some of the difficulties: https://www.youtube.com/watch?v=AeodWP0B-pw https://www.youtube.com/watch?v=AeodWP0B-pw The TLDR is that you have to do a whole bunch of things that give away that you're doing it, take a lot of time and money, make you an easy target to be disrupted in your task, and failing all of that, can kill you pretty easily along every step of the way.
tjradcliffe 12y ago
Nothing. Remember: this was done the first time in less than four years, from 9 October 1941 to 16 July 1945, using technology from the stone age. No solid-state electronics beyond crude diodes. No electronic computation. Approximate estimates on most of the cross-sections. Hopeful guesses on many of the processes (including multiply redundant approaches to some things, including the basic design, because people weren't sure what would work or what would be possible to build.) Today, a team of reasonably intelligent engineering students with a budget of a few billion dollars could build a bomb in a year, simply because they would know vastly more than the original team. Again: it took three years and $2 billion ($30 billion in today's dollars) to build the very first bomb from scratch knowing almost nothing about the process and having to custom build and design and invent almost every component. To suggest that any particularly rare expertise today would be required or that the cost would be more than a tenth of the original development is implausible. Remember this the next time you hear about Iran's nuclear program, which has been going on for twenty years, supposedly in mad pursuit of nuclear weapons. It's a ridiculous claim: if the Iranians wanted a Bomb very badly they would have one by now. If they don't have one by now the only reasonable conclusion is that they don't want one very badly. The extreme disapprobation they get from the rest of the world on this issue may well contribute to their tepid enthusiasm, but no amount of Stuxnet and the like is going to put a dent in a strongly committed program. The Iranian's commitment just isn't that strong. Gas centrifuge technology in particular has been a game-changer in the lowering the nuclear bar over the past couple of decades. People were warning about it in the '80's, and their warnings seem to have had some prescience. It makes practical enrichment of natural uranium to weapons grade, bypassing the need for a reactor program to breed plutonium, and all the nasty, difficult chemistry involved in plutonium extraction. And unlike plutonium weapons, uranium weapons are ridiculously easy to detonate. Trinity was a plutonium test. Little Boy was one of the very few uranium weapons ever detonated, and it was live tested because the scientists were as certain as anything it would actually explode. There are uraninite (pitchblende) ores that are getting on for 10% uranium, or 0.07% 235U, so a tonne of ore would yield 7 kg of 235U. It'll only get worse as seawater extraction gets better (it's already capable of producing macroscopic amounts of uranium from the relatively uranium-rich Japan Current, although post-Fukushima the primary research, which was Japanese, has likely been curtailed.) Processing a couple of tonnes of ore is sub-industrial. It isn't that hard to hide. On the other hand, if countries want to go the plutonium route, plutonium producing reactors aren't hard to hide either: the Russians were running them underground--a few hundred metres below the surface--in the 80's and 90's.
sytelus 12y ago
Main thing that stops any country is availability of refined fission material. First you need to have access to Uranium mines which US and Russia pretty much has covered all over the world. Second, you need to dig tons of ore and go through very tedious and complicated refinement process that is very expensive and requires very large scale operation. To avoid these, countries like Iran would just use the material generated from reactor fuel that can be obtained more easily.
sean-duffy 12y ago
Not much at all, and an interesting consequence of this is that manufacturers of high-precision CNC machines have to be very selective about which countries they're willing to sell to, and many of these machines carry GPS trackers and other sensors which will alert the manufacturer and prevent the machine from functioning if somebody tries to move it.[1] [1] https://www.techdirt.com/articles/20140109/03060325817/latest-twist-drm-lockdown-geolocation.shtml https://www.techdirt.com/articles/20140109/03060325817/lates...
- BrandonMarc 12y ago
  From reading about Stuxnet, I believe they also have something involving IP address pings and feedback.
BrandonMarc 12y ago
See this article from Der Spiegel [1]. Many methods are outlined - including getting unwitting cooperation (wink wink, it's just for energy / research, we promise [2]) from developed nations - along with the caveat that until the bomb is ready it's best to deny, deny, deny and avoid all the headache. The article discusses Israel, South Africa, Brazil, Libya, and of course Iran. That said, being part of the nuclear club means a huge responsibility - assuming you just want influence and don't want to kill somebody, now you've got to make sure nobody messes with your new toy or tries to take it. [1] http://www.spiegel.de/international/world/the-bomb-for-beginners-a-diy-guide-to-going-nuclear-a-681525.html http://www.spiegel.de/international/world/the-bomb-for-begin... [2] "Um ... we just want to learn more about submarine propulsion, nothing else. Trust us."
InclinedPlane 12y ago
What stops so many other countries from building nuclear weapons? That's an interesting question, perhaps the best answer is simply affluence, the perception of geopolitical safety, and the perception of unwanted negative repercussions of obtaining nuclear weapons. Any developed country with a significant industrial base can build nuclear weapons. Trivially so for countries with significant local nuclear power industrial infrastructure such as fuel reprocessing or Uranium enrichment. Brazil, Mexico, Canada, Japan, South Korea, Germany, all these countries, and more, could build nuclear weapons quite rapidly and in great quantity just by deciding to do so. For everyone else, well, one hopes that it is sufficiently difficult and costly that it's just not worth it for most countries, and difficult to hide as well, though mostly that's a lie we tell ourselves to make us feel safe. The hardest part is acquiring the fissile materials, which turns out to be slightly tricky. Plutonium requires production in reactors, but more so it requires a rather inefficient process to produce weapons grade Plutonium in reactors. Reactors are hard to hide, and if a reactor is under IAEA observation it's non-trivial to use the reactor to produce Plutonium. I say non-trivial but it is certainly far from impossible, as it's been done, but it makes it difficult to produce in large quantity while under the IAEA's eyes. Uranium enrichment is a bit of a different story, and not a particularly heartening one either. It does require very sophisticated equipment and significant industrial resources to enrich Uranium, but it turns out that this equipment can be hidden fairly well and it actually takes much less of an investment to create enrichment facilities for making weapons versus for making reactor fuel (the enrichment level needs to be much higher, but the quantity needs to be vastly smaller). For example, to process natural Uranium into 5% enrichment takes about 75% of the work as to process it into 90% enrichment (weapons grade), and you only need perhaps 16kg or so of highly enriched Uranium to make a bomb. Getting back to observability, these facilities can be easily hidden and operate without notice since they blend in well with other industrial facilities externally. The world learned of Saddam's vast Calutron facilities only due to the first Gulf War. And the world learned of North Korea's centrifuge cascades only when that regime announced their existence. In the last 50 years half a dozen countries have acquired nuclear weapons without sanction from existing nuclear powers and in most cases without the world being certain of the existence of those nuclear programs until they were announced (such as through weapons tests). That gives some perspective on the true difficulty of preventing nuclear weapons proliferation. As a side note, if the entire worldwide civilian Uranium enrichment capacity was diverted from making reactor fuel to making nuclear bombs it could produce around 400 nuclear bomb cores per week.

tdicola 12y ago

Making enough plutonium is pretty difficult from what I understand. In WW2 some of the biggest buildings ever built were necessary to house all the equipment to make just enough material for a few bombs (see http://en.wikipedia.org/wiki/K-25 http://en.wikipedia.org/wiki/K-25). Nowadays you need a nuclear reactor and fancy equipment like uranium centrifuges. See the Stuxnet worm and how it targeted Iran's uranium centrifuges in an attempt to disable their ability to make bomb material.

nate_martin 12y ago

Yep, also enriching uranium to anything near weapons grade is a cumbersome process.

sehugg 12y ago

Yes, in fact the website in the OP is for a book which advocates for a disarmament approach based on eliminating weapons-grade fissile material stockpiles: http://unmakingthebomb.com/sample/ http://unmakingthebomb.com/sample/

JanezStupar 12y ago

Plutionium is one problem, but AFAIK not the greatest for this type of device. Greater problem is precise machining and fuse technology necessary, which makes it an enormous and expensive project even today. The rifle design is just the reverse. There technology is a lot simpler, but rich enough Uranium 235 is a lot harder to come by.

sgdread 12y ago
another complexity is that the plutonium core is not just any weapon-grade plutonium: it has to be casted in unstable delta phase (which has unusually low density; the implosion's task is to switch it into alpha-phase which is much dense: this process makes core critical and explosion happens). Not to mention toxicity of the material itself.

droopybuns 12y ago

While this looks simple, many of the details of the construction of the first nuclear devices are still classified. So part of the reason is that simple explanations of the design do not necessarily reflect a simple construction. On the other hand, you get a taste of a story about how John Phillips got his Undergraduate senior thesis classified for being to informative on how to resolve some important technical details around the actual explosive design for a pit based weapon. http://www.universitypressclub.com/archive/2013/02/the-a-bomb-kid-and-hows-your-senior-thesis-going/ http://www.universitypressclub.com/archive/2013/02/the-a-bom... Plutonium is difficult to handle and accumulate in significant quantities. Here is a fun video that gives you an appreciation for the danger and rarity of the element: http://www.youtube.com/watch?v=XLufmakbiU0 http://www.youtube.com/watch?v=XLufmakbiU0 *Edit: I linked the wrong youtube video. While the above is fun, this one gives you a better idea about the manufacturing difficulties of working w/ Plutonium: https://www.youtube.com/watch?v=89UNPdNtOoE https://www.youtube.com/watch?v=89UNPdNtOoE The bottom left corner of the periodic table is apparently filled with wildly interesting elements that do super bad things to your body. They get hard to come by- and in some cases they only get created in the laboratory. Maybe that's for the best.

mikeash 12y ago

It's not quite as easy as it looks. The implosion has to be perfectly symmetrical, or else the core will pop out the side instead of being crushed. Think trying to spear a cherry tomato with your fork. That in turn means that your chemical explosives have to be carefully arranged and they have to be detonated at the precise correct times. In fact, one theory of how the Permissive Action Links (basically, the stuff that makes it so a bomb needs a code to be detonated instead of any random person just pushing a button) work is by encrypting the timing sequence, so that without the code you don't have the information needed to detonate the bomb, rather than relying on some physical lockout. Working out the timing and building the device accordingly are both tough. Additional difficulty comes in when you want to either increase the bomb's power or decrease its size and weight, both of which are important for making them practical to use against an enemy. There's a lot of work between Fat Man, which weighed 10,000 pounds had a yield of 21kt, and a modern weapon like the W88 which weighs 800 pounds and has a yield of 475kt. But still, once the basic research was completed and available, producing the materials becomes the primary difficulty in building a bomb.

th0ma5 12y ago

Here's a TEDx talk from 2009 that goes into some of the difficulties: https://www.youtube.com/watch?v=AeodWP0B-pw https://www.youtube.com/watch?v=AeodWP0B-pw The TLDR is that you have to do a whole bunch of things that give away that you're doing it, take a lot of time and money, make you an easy target to be disrupted in your task, and failing all of that, can kill you pretty easily along every step of the way.

tjradcliffe 12y ago

Nothing. Remember: this was done the first time in less than four years, from 9 October 1941 to 16 July 1945, using technology from the stone age. No solid-state electronics beyond crude diodes. No electronic computation. Approximate estimates on most of the cross-sections. Hopeful guesses on many of the processes (including multiply redundant approaches to some things, including the basic design, because people weren't sure what would work or what would be possible to build.) Today, a team of reasonably intelligent engineering students with a budget of a few billion dollars could build a bomb in a year, simply because they would know vastly more than the original team. Again: it took three years and $2 billion ($30 billion in today's dollars) to build the very first bomb from scratch knowing almost nothing about the process and having to custom build and design and invent almost every component. To suggest that any particularly rare expertise today would be required or that the cost would be more than a tenth of the original development is implausible. Remember this the next time you hear about Iran's nuclear program, which has been going on for twenty years, supposedly in mad pursuit of nuclear weapons. It's a ridiculous claim: if the Iranians wanted a Bomb very badly they would have one by now. If they don't have one by now the only reasonable conclusion is that they don't want one very badly. The extreme disapprobation they get from the rest of the world on this issue may well contribute to their tepid enthusiasm, but no amount of Stuxnet and the like is going to put a dent in a strongly committed program. The Iranian's commitment just isn't that strong. Gas centrifuge technology in particular has been a game-changer in the lowering the nuclear bar over the past couple of decades. People were warning about it in the '80's, and their warnings seem to have had some prescience. It makes practical enrichment of natural uranium to weapons grade, bypassing the need for a reactor program to breed plutonium, and all the nasty, difficult chemistry involved in plutonium extraction. And unlike plutonium weapons, uranium weapons are ridiculously easy to detonate. Trinity was a plutonium test. Little Boy was one of the very few uranium weapons ever detonated, and it was live tested because the scientists were as certain as anything it would actually explode. There are uraninite (pitchblende) ores that are getting on for 10% uranium, or 0.07% 235U, so a tonne of ore would yield 7 kg of 235U. It'll only get worse as seawater extraction gets better (it's already capable of producing macroscopic amounts of uranium from the relatively uranium-rich Japan Current, although post-Fukushima the primary research, which was Japanese, has likely been curtailed.) Processing a couple of tonnes of ore is sub-industrial. It isn't that hard to hide. On the other hand, if countries want to go the plutonium route, plutonium producing reactors aren't hard to hide either: the Russians were running them underground--a few hundred metres below the surface--in the 80's and 90's.

sytelus 12y ago

Main thing that stops any country is availability of refined fission material. First you need to have access to Uranium mines which US and Russia pretty much has covered all over the world. Second, you need to dig tons of ore and go through very tedious and complicated refinement process that is very expensive and requires very large scale operation. To avoid these, countries like Iran would just use the material generated from reactor fuel that can be obtained more easily.

sean-duffy 12y ago

Not much at all, and an interesting consequence of this is that manufacturers of high-precision CNC machines have to be very selective about which countries they're willing to sell to, and many of these machines carry GPS trackers and other sensors which will alert the manufacturer and prevent the machine from functioning if somebody tries to move it.[1] [1] https://www.techdirt.com/articles/20140109/03060325817/latest-twist-drm-lockdown-geolocation.shtml https://www.techdirt.com/articles/20140109/03060325817/lates...

BrandonMarc 12y ago
From reading about Stuxnet, I believe they also have something involving IP address pings and feedback.

BrandonMarc 12y ago

See this article from Der Spiegel [1]. Many methods are outlined - including getting unwitting cooperation (wink wink, it's just for energy / research, we promise [2]) from developed nations - along with the caveat that until the bomb is ready it's best to deny, deny, deny and avoid all the headache. The article discusses Israel, South Africa, Brazil, Libya, and of course Iran. That said, being part of the nuclear club means a huge responsibility - assuming you just want influence and don't want to kill somebody, now you've got to make sure nobody messes with your new toy or tries to take it. [1] http://www.spiegel.de/international/world/the-bomb-for-beginners-a-diy-guide-to-going-nuclear-a-681525.html http://www.spiegel.de/international/world/the-bomb-for-begin... [2] "Um ... we just want to learn more about submarine propulsion, nothing else. Trust us."

InclinedPlane 12y ago

What stops so many other countries from building nuclear weapons? That's an interesting question, perhaps the best answer is simply affluence, the perception of geopolitical safety, and the perception of unwanted negative repercussions of obtaining nuclear weapons. Any developed country with a significant industrial base can build nuclear weapons. Trivially so for countries with significant local nuclear power industrial infrastructure such as fuel reprocessing or Uranium enrichment. Brazil, Mexico, Canada, Japan, South Korea, Germany, all these countries, and more, could build nuclear weapons quite rapidly and in great quantity just by deciding to do so. For everyone else, well, one hopes that it is sufficiently difficult and costly that it's just not worth it for most countries, and difficult to hide as well, though mostly that's a lie we tell ourselves to make us feel safe. The hardest part is acquiring the fissile materials, which turns out to be slightly tricky. Plutonium requires production in reactors, but more so it requires a rather inefficient process to produce weapons grade Plutonium in reactors. Reactors are hard to hide, and if a reactor is under IAEA observation it's non-trivial to use the reactor to produce Plutonium. I say non-trivial but it is certainly far from impossible, as it's been done, but it makes it difficult to produce in large quantity while under the IAEA's eyes. Uranium enrichment is a bit of a different story, and not a particularly heartening one either. It does require very sophisticated equipment and significant industrial resources to enrich Uranium, but it turns out that this equipment can be hidden fairly well and it actually takes much less of an investment to create enrichment facilities for making weapons versus for making reactor fuel (the enrichment level needs to be much higher, but the quantity needs to be vastly smaller). For example, to process natural Uranium into 5% enrichment takes about 75% of the work as to process it into 90% enrichment (weapons grade), and you only need perhaps 16kg or so of highly enriched Uranium to make a bomb. Getting back to observability, these facilities can be easily hidden and operate without notice since they blend in well with other industrial facilities externally. The world learned of Saddam's vast Calutron facilities only due to the first Gulf War. And the world learned of North Korea's centrifuge cascades only when that regime announced their existence. In the last 50 years half a dozen countries have acquired nuclear weapons without sanction from existing nuclear powers and in most cases without the world being certain of the existence of those nuclear programs until they were announced (such as through weapons tests). That gives some perspective on the true difficulty of preventing nuclear weapons proliferation. As a side note, if the entire worldwide civilian Uranium enrichment capacity was diverted from making reactor fuel to making nuclear bombs it could produce around 400 nuclear bomb cores per week.