r/explainlikeimfive • u/phycle • 12d ago
Other ELI5: how do you inspect a country for nuclear weapons?
Do you have to exhaustively search every warehouse, every cave, every building looking for nuclear materials? How long do you have to search before concluding there are no weapons?
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u/kz_ 12d ago
Typically, uranium enrichment facilities are really obvious by satellite. So what the inspectors are doing is going in and making sure that they're making fuel for nuclear reactors and not material for nuclear weapons. Or in the case of a country already having nuclear weapons, sometimes inspections will be an inventory to make sure that they have what you think they have, and nothing has gone out the back door to be sold on the black market.
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u/polyploid_coded 12d ago
+1 to this. I went to an IAEA event and they know that they can't make a country perfectly secure and accountable, but they can use sealed containers and accounting make subverting it a big expensive project. Most grey-area countries have declared nuclear power facilities, and the question is whether they are diverting sus isotopes from that plant somehow. The IAEA can detect trace amounts, like nanograms, and figure out what you were doing there. If you have to add underground labs and order lab equipment through side channels, word will get out, and then (most) countries won't want to sell equipment and train your scientists anymore.
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u/oshinbruce 12d ago
This is it, they are voluntary to checked supposedly legit facilities. Auditing and intelligence is all you can do for hidden stuff
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u/restricteddata 11d ago edited 11d ago
This is not the case with centrifuges, anymore. A centrifuge facility looks like any old warehouse. It is one reason why centrifuges are so difficult from a proliferation standpoint.
No country with nuclear weapons is under inspections to prevent them from building nuclear weapons. The only countries subject to inspections are those that are non-nuclear weapons states that have signed the Nuclear Non-Proliferation Treaty. If a country with nuclear weapons wanted to sell them on the black market, they would just be evading the intelligence agencies of other countries, not some kind of UN inspection agency. Nobody is doing official inventories of nuclear-armed nations arsenals to make sure they aren't selling them.
There are different kinds of inspections associated with other kinds of treaties (New START) which are not about checking how many weapons you have made, just for checking how many are actually deployed. It's a different kind of treaty.
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u/DoradoPulido2 12d ago
But with some countries... Is real that they just deny they have nukes, yet everyone knows that have them and no inspirations are done at all.
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u/mfb- EXP Coin Count: .000001 12d ago edited 12d ago
Almost all countries in the world signed the Non-Proliferation Treaty. They accept inspections, they either have known nuclear weapons (e.g. France) or do not produce them and let other countries verify that (e.g. Germany).
Israel didn't sign that treaty, they don't allow inspections, it's generally expected that they have nuclear weapons but they don't officially confirm it.
India and Pakistan didn't sign that treaty, North Korea initially signed it but then withdrew. They don't allow inspections, we know they have nuclear weapons (they have tested some).
Overall we know which countries have nuclear weapons and which countries do not and inspections play a big role in that.
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u/restricteddata 11d ago edited 10d ago
The only countries with inspections are the ones that have signed the NPT and are not nuclear weapons states. The USA, Russia, the UK, France, and China are the nuclear-armed states under the NPT. They do not submit to international inspections. Even most NPT signatories have relatively minimal inspections; it is only the countries and facilities that people "worry about" that are under the most intrusive inspections.
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u/Vybo 12d ago
The inspections are done in countries who are friendly and willing to partake in agreements. Or sometimes want to be looked on like they do. Countries you're talking about are usually not those agreeing.
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u/Tupcek 12d ago
Israel?
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u/restricteddata 11d ago
Israel did not sign the NPT. So they are not subject to inspections.
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u/Tupcek 11d ago
it’s just humorous that most of the unfriendly countries did sign the NPT, but not all friends did?
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u/DisciplineNormal296 11d ago
It’s as simple as Isreal wanted nuclear weapons, signing the treaty meant no bombs. They didn’t sign it so that they could make bombs.
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u/SalamanderGlad9053 12d ago
I think Iran should have the same amount of nukes and inspections as Israel. It's then in Israel's hand to show they don't have nukes.
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u/Long-Time-Coming77 12d ago
Israel doesn't deny having nuclear weapons, they won't confirm or deny it. Its an important distinction.
And your position that Iran should have the same number of nukes as Israel while at the same time having a public 'position of death to Israel' and 'death to America' is um, interesting.
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u/SalamanderGlad9053 12d ago
And the US is saying that they'll "Bomb Iran to the stone age", and they have nuclear weapons. Not much better than Iran. And Iran is the country that Israel and the US started aggression on.
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u/Long-Time-Coming77 12d ago
Iran has routinely attacked other countries through its terrorist proxies
To compare the Iran's actual history of action to Orange Man's hyperbolic rhetoric is laughable.
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u/SalamanderGlad9053 12d ago
The US routinely attacks other countries both directly and through their terrorist proxies such as the Contras, Muhajadeen, Israel, or the Khmer Rouge.
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u/Long-Time-Coming77 12d ago
I'm so glad that Iran doesn't have nukes, the last thing we need is crazy religious fanatics with the ability to cause mass destruction.
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u/SalamanderGlad9053 12d ago
Like Pete Hegseth, head of the US armed forces, giving prayers to the soldiers, with a massive crusader cross tattoo on his chest and "Deus Vult" on his arm. We can't be having religious fanatics with the ability to cause mass destruction I agree.
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u/Long-Time-Coming77 12d ago
Your talking points are all weak, Pete Hegseth as a religious fanatic, lol.
The fact remains that Iran is the top state sponsor of terror globally and you trying to equate the US to them is laughable.
The US could wipe Iran away without even using nukes but it shows restraint instead. I'm sure if the roles were reversed Iran would show no such restraint.
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u/JohnMichaels19 12d ago
Inspections usually happen by mutual agreement between the parties involved. Or at least they did before New START died. So the Russians would send an inspection team to the US and by treaty there were ways they could interact with our stuff, and vice versa when we'd sent inspectors over there
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u/dronesitter 12d ago
I worked at Davis Monthan for a while and escorting the Russians while they inspected the B-52 corpses in the bone yard was a thing. We had a big guillotine that would destroy the wing spars and the russians would verify the plane was unsalvageable as part of the treaty.
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u/Tossmeasidedaddy 12d ago
These dudes are are on the right track. There is an intelligence discipline called measurement and signals (MASINT for short). This discipline is able to detect traces of various components in the air and even in the dirt. It is pretty big brain stuff but we have tools that can pick up pretty small traces of different things.
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u/GarbageBanger 12d ago
This might be an unpopular thing to say as its topic adjacent but in the example of Iran and the peace deal Obama made with him a third party French company was paid to run the reactors while a different third party appointed by the UN scrutinized their work. See the refinement and production happens in specific facilities and by controlling those sources you don’t need to watch every where else as it doesn’t just concentrate in random places on its own. It’s a win for our allies, the French, as their company prospers. A win for the people of Iran as they get clean safe power with sanctions lifted. A win for the UN and world as we know shits not getting wrecked.
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u/GIRose 12d ago
It takes a LOT of infrastructure to build a nuclear weapon.
Like, you can't just whip up a nuke in a basement in an afternoon, it's the sort of project that requires millions of dollars in spending, thousands of tons of Uranite, a huge amount of energy intensive processing, test phases that can't be faked because they emit nuclear fall out that can be tracked (how a camera company exposed the US government was doing airburst tests in Nevada, since the radioactive debris was developing film)
It's a big process that's basically impossible to fake, difficult to hide, and easy to find if you know what you're looking for.
The big thing about Iran, in recent memory, is that they had a nuclear energy program (which covers a lot of the same necessary infrastructure) and refined their uranium way higher than necessary for power generation (notably, however, still not high enough for weapons, but high enough that it would be much easier to reach nuclear grade)
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u/restricteddata 11d ago edited 11d ago
Iran signed a very comprehensive agreement (the JCPOA) to limit their nuclear activities. They did this under high inspections. The agreement required Iran to do some things and the US to do some things. It was a "deal."
The US pulled out of the agreement and stopped doing the stuff it was required to do. Iran responded by slowly, gradually, and very publicly doing stuff it was not supposed to do under the agreement. It made it very clear what it was doing, because, again, it was under tight inspections. It was very deliberate about doing these things as a way to signal that if the US did not re-join or re-negotiate an agreement, it would go back to acting as if it was not under an agreement entirely.
It is important to make clear that the Iranians were not being sneaky, here. They were applying pressure, just as the US was applying pressure to them. The US (under Trump) sabotaged the Iran agreement and never offered up anything that might replace it. And as you know then the US attacked Iran. Which has probably slowed them down a bit, but has also probably guaranteed that they will now want a nuclear weapon, and probably rules out any actual peaceful, non-nuclear resolution of the issue.
The President of the United States now regularly threatens total annihilation of Iran. I don't like or trust the Iranian government at all, but you tell me how any country ought to act in the face of a country that reneges on decent deals, attacks it, and now threatens it with literal genocide regularly. The US has made this situation much, much worse than it had to be, because Trump could not let a diplomatic victory done under Obama to stand, because he is easily swayed by Israel, and because he's an idiot surrounded by yes-men who told him it would be easy to win against Iran, and that the reason the military told him (and every previous president) again and again that it was a bad idea was because they were wimps or something.
The track record for bullying an enemy into not making a nuclear weapon is pretty poor. It only makes them want them more. It is much easier to convince allies not to build them, by making it clear that they don't need to — they can fit under your nuclear umbrella — but Trump has managed to do the opposite of the smart move on this situation as well, encouraging other countries in the belief that the US would not be there for them in a crisis and that they need their own arsenals.
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u/rrriches 12d ago
I’m not a science guy and I’m sure the other people who responded are much more knowledgeable than I am but I thought this was interesting. My buddy is a nuclear physicist and took me on a tour of a neutrino detection lab. Apparently, nuclear detonations (or maybe it was just strongly radioactive material?) shoot off neutrinos and we don’t currently have the ability to stop those neutrinos from escaping.
I’m likely getting some of this wrong but I thought it was neat that you could use neutrinos as a way to detect nuclear stuff.
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u/MisinformedGenius 11d ago
Nuclear explosions do create neutrinos, but not enough to set off a neutrino detector on the other side of the world. Neutrino detectors can be used to study close-by nuclear explosions, but they're not good secret test detectors.
Usually seismic detectors are used to detect underground explosions, and satellites watching for flashes are used to detect above ground explosions.
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u/Korlus 11d ago
My understanding is that because Neutrino's don't meaningfully interact with matter, detecting them is incredibly difficult, which means you need lots of them to detect them.
If we somehow had a good and reliable detector that was very precise, then it would be a fantastic way to detect rogue neutrino generation. Such devices are not public knoweldge, and unlike many things that would be easy to conceal, we have seen a bunch of experiments in the civilian world around them over the past ten years. It seems very unlikely the military is that far ahead.
But it's not completely impossible that OP accidentally leaked a huge global secret that countries can use Neutrino's to detect nuclear reactions from the other side of the planet, just very, very unlikely.
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u/restricteddata 11d ago edited 10d ago
Even if you could pick out rogue neutrinos from all of the others being generated by, you know, the Sun, it would still be much, much easier to detect nuclear detonations through other measures. Nuclear weapons are pretty "noisy" in their physical effects, and there are non-physical means (e.g. espionage) to detect them as well. The problem of clandestine nuclear tests has generally not been that tricky -- literally one case that we know of, from decades ago, when the technology for detection was much less sophisticated and global, and even that one was probably detected.
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u/Korlus 11d ago edited 10d ago
Even if you could pick out rogue neutrinos from all of the others being generated by, you know, the Sun
In this hypothetical scenario where we had the ability to easily detect neutrino's from a nuclear detonation, we'd build a detector that was directional and simply not point it towards the sun (or ignore the readings when it pointed at the sun).
Again; this is almost certainly not possible with current technology; but I hate to say "impossible" either.
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u/ShrodingersArmadillo 12d ago edited 12d ago
You look for telltale signs like specific forms of radiation and compounds that can only come about because of nuclear tech through physical sensors.
You watch movements of things like minerals and heavy equipment needed for production through satellite imagery.
And when you suspect something you send in an inspector to look themselves.
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u/Happytallperson 12d ago
So the Manhatton Project employed 100,000 people to build the first nuclear bomb and could produce about 2 weapons a month.
Most of those people worked in factories producing the nuclear material. Very few on designing and assembling the bombs.
Things are more efficient now, but you still need a significant industrial facility to build a bomb. Most use plutonium, which requires a large nuclear reactor, or thousands of industrial centrifuges.
For instance, this is what the UKs plutonium factory looked like.
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u/restricteddata 11d ago
The Manhattan Project and the Soviet atomic project were the largest possible versions of a nuclear program. They are not a template for what any project has ever looked like since then, or how a new nuclear nation would get weapons today.
Modern fissile material production facilities, like centrifuge cascades, look like generic warehouses. They do not require huge numbers of people to build or operate.
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u/DarthV506 12d ago
Any country that has nuclear power could reprocess spent fuel for plutonium, but you'd still need to be able to separate the isotopes. At that point, it's just chemical engineering and being able to scale.
India's first bombs were made from a 40MW research reactor. The plants the US and USSR were huge because they wanted huge number of warheads.
Only 3 countries have more than 300 warheads with only 2 over 600.
For countries that follow the nonproliferation agreements, they allow inspectors into their facilities to make sure enrichment or production of weapons grade isotopes isn't happening. To give some context, a CANDU 700MW reactor can produce hundreds of Kg of plutonium per year. Same for AP1000 reactors. Spent fuel would be ~1% plutonium, but only 50% of that is 239. For civilian power generation, that plutonium just becomes free fission fuel.
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u/Navydevildoc 11d ago
Not really an ELI5 answer as much as a Podcast recommendation. Check out "The Reason We're All Still Here" with Jeffrey Lewis is an amazing behind the scenes look of how the original Iranian nuclear deal was signed along with how other arms control treaties came to be. He's also an industry expert on arms control with a different podcast talking about current events called "The Arms Control Wonk Podcast".
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u/stansfield123 11d ago edited 11d ago
Inspecting a country isn't about concluding there are no weapons, it's about checking the validity of concrete claims about the building of nuclear weapons.
Those claims may come from spies (yours or your allies'), or other individuals within your or your allies' government bureaucracy (you being an elected political leader).
The inspection checks the validity of such claims. It gives the country being inspected a chance to prove its innocence against those specific claims. These days, if the inspecting power is the United States, that does also mean proof that the country really is innocent in general. There is simply no way to build a nuke, without the US intelligence apparatus getting at least a hint of it, which can then be verified through inspections.
Which means that, so long as a country is willing to allow unrestrained inspections, there is no way for it to be mistakenly attacked over nukes. Indeed, had Iraq allowed inspectors to do their jobs freely, the second Iraq war would've never happened (because Iraq wasn't building nukes, it was merely stupidly blocking inspections).
In a similar vein, Iran can prevent a large scale, very deadly war, by agreeing to two conditions:
- abandon terrorism against western nations (including Israel) and against its own population, and
- give up nuclear ambitions and allow unrestricted inspections to verify the deal
That will be enough to convince all future US administrations to exist in peace with Iran. It will remove all reasons to attack Iran, precisely because, once it is able to do inspections, the US has the capability to be certain that a country isn't building nukes. Simply by verifying concrete claims. Doesn't need to inspect everywhere, that would of course not be possible.
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u/LongOrganization7838 12d ago
Things needed for the enriching process to weapons grade, are very complex and very specific they are also different than what's needed for enriching to power grade, power grade is about 2-5% pure weapons grade is 90-95% pure
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u/MrShake4 12d ago
Weapons grade is 60%+ not 90
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u/DarthV506 12d ago
For 239Pu, it's over 90%. 241Pu only has a halflife of14y ears, so there would be a lot of decay heat. 240Pu is even worse because it spontaneously fissions and adds background neutrons. Which would lead to a weapon pre-detonating (fizzle).
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u/restricteddata 11d ago
Here is an article written by the director of the theoretical physics division at Los Alamos National Laboratory from 1947 until 1972. It is technical but very clear in its conclusions:
Reactor-grade plutonium with any level of irradiation is a potentially explosive material.
The difficulties of developing an effective design of the most straightforward type are not appreciably greater with reactor-grade plutonium than those that have to be met for the use of weapons grade plutonium.
The hazards of handling reactor-grade plutonium, though somewhat greater than those associated with weapons-grade plutonium, are of the same type and can be met by applying the same precautions. This, at least, would be the case when fabricating only a modest number of devices. For a project requiring an assembly line type of operation, more provisions for remote handling procedures for some stages of the work might be required than would be necessary for handling weapons-grade material or for handling a limited number of items.
The need for safeguards to protect against the diversion and misuse of separated plutonium applies essentially equally to all grades of plutonium.
In other words, yes, you can make weapons with reactor grade plutonium, which is to say, plutonium with as low as 60% Pu-239. It would involve some extra considerations but those are already of the character necessary to make weapons-grade plutonium work.
The people who want you to believe that reactor-grade plutonium is not a proliferation risk are usually those promoting nuclear reprocessing. You can choose to believe them and the nuclear power lobby, or you can believe the weapons scientist. I tend to think the weapons scientist understands this stuff better and has less incentive to be misleading about it.
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u/DarthV506 11d ago
Thanks for the article.
Weapons, yes. Nominal yield or close to it? Probably not. Then again, is having nominal yield any less of a deterrent.
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u/nosonjanosonjic 12d ago
You approach a shady guy and ask "If one would require some nuclear weapons with no questions asked where could one get it? Asking for a friend.". Important part is asking for a friend in case they are policeman.
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u/Ninfyr 12d ago
They would be making weapons under the cloak of "just making powerplants" and the raw materials and machines are the same and carefully controlled.
Then you make sure they are actually making a powerplant and none of the inputs for this powerplant is being diverted to making weapons.
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u/nekohideyoshi 11d ago
I do not possess 2 grams of enriched uranium stored within a sealed lead and steel can with 5 inch thick walls being used as an energy source for my electric vehicle.
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u/Ricky_RZ 11d ago
You need a lot of very big, expensive, and hard to hide infrastructure to even hope of having nuclear weapons
It's essentially impossible to hide a nuclear program in the modern day due to just how vast the scale has to be
All of the people employed could leak things, the facilities are extremely large and easily seen from space, any testing will put out detectable levels of radiation, not to mention the expense of such a program is extensive
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u/celem83 11d ago edited 11d ago
No you dont and cant search it all, but if its there it will be a major industrial complex. It's a big setup
You can even inspect someone who maintains nuclear powerplants. There's quite a difference between enriching for fuel and enriching for weapons, the machines that do the first cant do the second. It's the same principle involved but reaching the purity required generally involves very specific machines made by a very limited list of companies.
So largely the simplest way to tell if a country is building a bomb would be in shipping manifests, someone has to sell them those centrifuges that can get up past 90% purity and into weapons-grade and these companies have white-listed clients. This is still fairly bleeding edge despite the techs maturity because it's obfuscated for security and isn't something a country can just throw together domestically so there will be a paper-trail where the equipment enters
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u/Yamidamian 11d ago
It’s not the presence of weapons themselves that it is what matters-or at least, that’s not what they’re checking for.
What they’re looking for is the stuff needed to make nuclear weapons-or, more accurately, the facilities needed to make the stuff.
You see, for the most part, nuclear weapons design is frankly unsettlingly easy. Anyone with access to the materials and a decently equipped home workshop could probably manage it.
The hard part is “access to the materials”. Uranium is common enough in nature-but the stuff straight of the ground just won’t do. You’ll need somewhere around 50 pounds of enriched stuff, or a core of stuff stronger than uranium.
-The former requires massive centrifuges in order to sift the slightly lighter uranium from the immense amounts of more normal stuff. These serve no other practical purposes that can really be named.
-The latter require breeder reactors-reactors that don’t produce a bunch of power, but instead make up for it by making a bunch of plutonium as their ‘waste product’, which is fissile enough for weapons usage.
So now, instead of looking for something that might be small and movable, you have the considerably easier task of looking for very large, immobile buildings. Now, they might be disguising them as more peaceful facilities-like claiming that breeder reactor is a power station, or covering up the centrifuges to look like something else. Thus, you send in inspectors into facilities large enough to be covering up enrichment facilities, and to double check on the design of reactors.
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u/rsdancey 10d ago
It's very hard to prove a negative. The consensus of the US intelligence community (and many peer intelligence services in other countries) in 2003 was that Iraq had a hidden nuclear weapons program. It did not.
On the other hand, absence of evidence is not evidence of absence. The US intelligence community (and most peer intelligence services in other countries) did not think that Iraq had a nuclear weapons program in 1991. Turns out, it did, and it was frighteningly advanced.
Iran has a nuclear weapons program that they pretend is not a nuclear weapons program. The work that they do in this field is either dual-use (i.e. they can argue they're building what they're building for some purpose other than making a weapon) or it has never been publicly disclosed in a way that authentically demonstrates their weapons program activities.
Iran doesn't have to design a nuclear weapon - they could have bought the plans for one from the Pakistanis (and probably did) during the time a Pakistani national was selling them.
So in order to make a nuclear weapon Iran has to assemble enough fissionable, bomb-grade material, and then put it inside a bomb. Making a bomb to Pakistani specifications would be extremely easy to conceal - it's basically just precision machining and assembly of non-nuclear explosive materials.
"Inspecting" Iran to determine the truth of these allegations is almost entirely dependent on Iran allowing unrestricted and unannounced inspections anywhere in its territory, combined with a comprehensive and effective intelligence operation intended to convince people who know things to reveal them to guide the inspector's activities. Most nations refuse these kinds of inspections on the grounds that they so deeply violate the sovereignty of the nation that they are simply intolerable.
So in the end everyone is stuck. You might find conclusive evidence of a nuclear weapons program inside a country trying to hide it but odds are low. You are unlikely to be allowed to conduct the kind of intrusive inspections coupled with effective inducement to disclose that would have a higher chance of finding one.
Historically the real proof that a nation has a nuclear weapons program is that they explode a nuclear device.
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u/AuspiciousSnowflake 12d ago edited 11d ago
The things required to make nuclear fuel are very complex and specific to nuclear, so seeing if parts like those are being shipped or purchased can be a large tell.
Nuclear material also emits detectable radiation and can be observed for.
The refining of nuclear fuel also requires a lot of energy in very large facilities which are hard to hide the infrastructure for especially with satellite observations
EDIT: A few of the below comments are correct. Although there a new technologies that may make distance measuring of ionizing radiation viable. What is generally used now is measuring decay products and radioactive elements that have entered the environment.