Did North Korea really just detonate a hydrogen bomb? Probably not At 0130 UTC on Wednesday, the United States Geological Survey recorded a magnitude 5.1 seismic event in North Korea, and shortly afterwards the Nork state media delivered the message that the country had exploded its first thermonuclear device. An H-bomb, in other words. "Let the world look up to the strong, self-reliant …
That the Norks built a hydrogen bomb, but when they tested it only the fission first stage fired correctly, and some design flaw prevented the fusion portion of the device from working.
I remember that the Nork's first fission weapon test seemed to underperform, so maybe they are having the same experience with their first H-bomb test.
AIUI the difficult bit about a thermonuclear device is getting the secondary to go off properly rather than just being a fission explosion, not the basic principle of the thing which is well understood (there's even a diagram on Wikipedia!), so even if it was intended as an H bomb if it didn't perform as such that doesn't necessarily mean they're any closer to one than before...
I really don't understand why the Chinese continue to put up with him. He must be a bigger danger to them than anyone else.
The Chinese don't want 20 million starving North Koreans wandering across a very long and hard to police border, and buggering up their economy. Of course there's a thriving industry in China in exploiting those who manage to escape, as cheap labour, sex workers or even brides (given what the one-child policy has done to the male/female ratio). So they probably don't try too hard to stop them coming across the border - and the threat of having your entire family sent to Labour Camps for the rest of their lives is enough to deter most from trying to escape.
But I guess the Chinese prefer the relative stability - rather than the uncertainty of having a border with a united Korea. But in comparison to North Korea, East Germany was a positive paradise on earth - so I'm not sure the South are up to re-unification anyway. The levels of poverty, suffering, terror and brainwashing are an order of magnitude worse.
>But I guess the Chinese prefer the relative stability - rather than the uncertainty of having a border with a united Korea.
On the other hand, having the lunatic just over the border running around with nuclear and chemical weapons can't be much fun either.
Isn't this the choice we've struggled with, and so often failed, in Cold War and Middle East policy? Sure that dictatorship is horrible (Saudi, Egypt wherever) - but they're relatively stable, so at least we don't have much of a foreign policy headache. Followed by Oooh! This Arab Spring is exciting. Then almost immediately, Oh God, this Arab Spring is scary! Perhaps an Egyptian military dictatorship isn't so bad after all.
Look at Iraq, Libya and Syria for 3 diffferent places where we've intervened a lot, a little and not much. And how they've all turned out quite badly. At least if you do nothing, fewer people will blame you when it all turns to shit.
And as the old Yes Prime Minister joke went, "the Foreign Office's job is to tell you all the reasons why you shouldn't do anything. Then when it's clear that something ought to be done, that there's nothing you can do. Then to say that there might be something that we could do, but it'll be terribly complicated - and will need lots of time to study. Then hopefully whatever bad thing will have already happened, so they can then tell you that there probably was something that we could have done, but it's too late now.
That show really was a documentary not a comedy... And I bet the Chinese diplomats are just as cautious as our Foreign Office ones.
One strange old colleague of mine had worked in Cuba/Russia/North Korea putting up satellite links (I've met some strange people in my time). He said that North Korea was the only place he felt truly scared. This was in the time of Kim Il-sung and he said that the satellite station was done in the most basic of ways - apart from the gold-leafed control room where Kim Il-sung would see.
The advice he got when going to North Korea was: a) take two suitcases, one for your clothes and one for food, because there wasn't any; b) most importantly, never ever interact with the shadows that dogged your every step whenever you left your hotel, they are the security services.
Uh-yeh. If that was a really useful diagram, it wouldn't be there. Maybe that's where North Korea started with its research program, and why their H-bomb fizzled. Get Jimbo to cough up the web server logs!
Edit: beaten to it by Fred Flintstone. Story of my life, maybe others!
I think the yield is too small to be close, the initiator of the Castle Bravo bomb was claimed to be 60kt or 10x the apparent yield of the Korean device. Even the Hiroshima and Nagasaki bombs yielded double this device leaving open the possibility that they actually just got 6000 tonnes of TNT together.
Even the Hiroshima and Nagasaki bombs yielded double this device leaving open the possibility that they actually just got 6000 tonnes of TNT together.
I remember that theory being put around for their first test, which was even smaller than the last three 5-10 kt ones. But I read about the last one that the detectors placed around North Korea detected the expected nuclear material in the atmosphere.
Unless of course they're also releasing trace elements of that at the same time.
But this does seem too small for fusion.
Also I don't know why all the speculation that not only have they made the leap to fusion (as they claim) - but also managed to miniaturise at the same time.
Although I suppose it's possible that this was actually a test of a mini A bomb, and they're lying about the H bomb bit.
Still they haven't yet managed a successful large missile test launch have they? So they'd still have to put the things on aircraft or ships. Or a suicide sumbarine. Surface in New York harbour and kaboom.
Have they managed to sell enough fake Viagra to afford to pay SpaceX, now the price has come down? Perhaps try to buy a cheap launch on a re-used Falcon first stage through a false company?
I'd say the bigger risk is Elon Musk. He's got his rocket that can now land vertically. He's got the new space capsule coming in by 2017-18. He's got electric car capability - so should be able to master the monorail with ease. I bet he can get from a standing start to an H bomb, before the Norks can go from A bomb to miniaturised A Bomb. The moment he buys a private island or dormand volcano is the time to take him out - just to be sure...
It doesn't have to be a volcano..
There are some nicely refitted missile silos on the market.
Personally, I think Musky will hang on in there until he has his own space station, after all he probably has more chance of building one.
Dormant volcanoes are so last year!
He should be able to get to it in his own black (for baddy) Iron Man suit.
Making an A bomb is extremely difficult and it is not the physics which is the issue, it is the chemistry part.
An A bomb and especially the Plutonium variety requires the ability to manufacture shaped explosives which detonate simultaneously around the entire fission core and have very clean and well defined shockwave front propagating at several of Mach speed. As a comparison most normal industrial explosives have explosion front propagation speed around 1M. If it does not blow up simultaneously you get a dud (especially with Plutonium).
Once you have made an A bomb, making it into an H bomb is graduate level chemistry and engineering.
You already have heavy water from working on the A bomb, all you need is to make it into D2 and synthesize LiD. It is compact by design and "just works".
Getting from an H bomb (100s of Ktn) to a three stage device (10s of MTn) is village garage engineering. You just pile non-enriched Uranium around the H core.
So frankly, I see no reason not to believe them that they blew an H device and dialed back the yield. Their nuclear test site is only 300 km or thereabouts from one of Russia main naval bases on the Pacific. Blowing up anything above 50Ktn would get them a Xmas present from Putin (they blew it up spot on for Orthodox Xmas).
Once you have made an A bomb, making it into an H bomb is graduate level chemistry and engineering.
Absolute rubbish, a H-bomb is a very complex fission-fusion-fission sequence which is just as difficult as the A-bomb to get right. It took the UK 4 attempts with Operation Grapple to get a yield significantly greater than the secondary fission device alone. So it's unsurprising that NK's device has a similar yield to its previous tests.
is a very complex fission-fusion-fission - that is 3 stage. First 4 British thermonuclear tests were TWO STAGE designs and they yielded exactly what you would expect from a weaponized 2 stage design - 100s of Ktns.
THREE stage is from Grapple X onwards
A pure 2 stage H bomb (not a true 3 stage variety) is relatively trivial once you have A bomb and you know to use LiD as an "accelerant". Example - https://en.wikipedia.org/wiki/Joe_4 and the like - all several 100s of Ktn when cranked to full dial. The design is known, the caveats are known, once you have working A and the tech for it you can manufacture one.
The NK explosion when looking at the quake-to-Ktn tables is ~ 30-50Ktns. (4.9 - 5.1 Richter scale, surface blast). That matches this type of device fairly well. It is also likely to be deploy-able as a warhead too. First American efforts were not weaponizable because they did not figure out to use LiD and used liquid D2 instead. The "use LiD" idea (I believe the russians came up with it first) has been non-secret for 50+ years now.
As I said before, they are so close to Vladivostok and Nahodka that if they are stupid enough to test a 3 stage device cranked to full dial they will get whacked by their northern neighbor. So trying a 2 stage device and dialing the yield as far back is all they can do at that site. They will not get multi-Mtn range with this type device, but even the 300-500Ktn design maximum is more than enough and it matches their delivery capabilities as well.
Whacked by their northern neighbor
Hmmm. That could be made to look like a botched NK test, couldn't it...? After all, it's the nuclear capability that is the target, not Pyongyang.
Then turn the tin-foil hat inside out: a botched test could equally be blamed on a neighbor-whack, or on others further away. This is why developing nuclear weapons is a dangerous business.
"An A bomb and especially the Plutonium variety requires the ability to manufacture shaped explosives which detonate simultaneously around the entire fission core and have very clean and well defined shockwave front propagating at several of Mach speed. As a comparison most normal industrial explosives have explosion front propagation speed around 1M. If it does not blow up simultaneously you get a dud (especially with Plutonium)."
That's only one way of initiating the reaction. They could have used the old fashioned "big enough lumps of XXXXX" and just explosively thrown the lumps together.
That's only one way of initiating the reaction. They could have used the old fashioned "big enough lumps of XXXXX" and just explosively thrown the lumps together.
The "rifle" design is very low-yield; as the halves get close to each other, the beginnings of the explosion tend to throw the fissile material around, rather than let it detonate. That's why the slappy explosive lens thing was created in the first place...
Vic.
"world's smallest thermonuclear detonation"
Not necessarily. If you get good at multiple-stage device design, you can do cute things like selectable-yield, and other general tuning of the second stage. The devices proposed for the later bigger Project Orion craft would have been designed to generate the minimum of fallout and be selectable-yield up to about 5kt. It's entirely possible the US tested a weapon along those lines prior to adoption of the nuclear test ban.
Selectable yield is available from the boosted fission design, by way of selecting the amount of boost. I would guess this is what they've tried. Full thermonuke design is the next step.
Also I suspect our decadent western governments have underplayed the threat.
As someone pointed out its the delivery method that matters. Their working bomb is going to be at least dustbin sized and tonnes in weight.
@Tomato42 "let's assume for a second that what they say is true, wouldn't that make it the world's smallest thermonuclear detonation?"
JUST AS WE CLAIMED -- A MAGNIFICENT TECHNICAL ACHIEVEMENT, UNEQUALED IN ITS GLORIOUSNESS BY ANYTHING ACCOMPLISHED BY DECADENT WESTERN PARIAH STATES, EVER!!! BOW DOWN BEFORE US, PUNY RUNNING DOG CAPITALISTS!!!
'The basic nuclear weapon is a fission device that either fires two chunks of material, typically types of plutonium, uranium, or neptunium, into each other to set off a chain reaction, or uses carefully coordinated explosives to compress the mass of material and cause fission.'
Ahem, while you can use uranium in a gun barrel approach to nuclear weapons, plutonium can't be. It will pre-detonate before a useful yield is achieved. In fact even uranium benefits from an implosion method of compression. It's just for Hiroshima they wanted something that would be *guaranteed* to go bang and the implosion method wasn't tested yet so they built a gun-barrel weapon. In fact Hiroshima was that test - but they were confident that it would in fact explode.
Not that I have a comprehensive knowledge on this - but has anyone ever used Neptunium in a tested weapon?
If North Korea wanted to develop a thermonuclear weapon a more reliable design for implementation is the sloika design (reputedly what the Israelis implemented). It's crude but easier to construct.
If it was an open-air weapon as various pictures on TV screens seem to imply then radioisotopes driven by the wind will give a quite accurate idea of the design. If it's an underground explosion as I suspect, I guess that we'll have to guess.
ZSn wrote "It's just for Hiroshima they wanted something that would be *guaranteed* to go bang and the implosion method wasn't tested yet "
Trinity test July 1945 was an implosion device, a big ball with detonators sticking out all over the place.
They actually didn't bother test firing the Little Boy gun method, as used at Hiroshima. As you stated, it was essentially guaranteed to work.
So the implosion method *had* been tested before Hiroshima. And Fat Man was dropped on Nagasaki just a few days after Hiroshima in any case.
ZSn "If it was an open-air weapon as various pictures on TV screens seem to imply then radioisotopes driven by the wind will give a quite accurate idea of the design. If it's an underground explosion as I suspect, I guess that we'll have to guess."
Atoms are small; they'll leak. Even from underground. Especially if somebody has recently exploded a nuclear warhead, ah, nearby. Detection methods for unusual isotopes can be exquisitely sensitive (Ding! "Hey. Found another one!"). I guess they'll be up gathering samples, and hopefully finding the info they want.
All the other tests were underground, and I read a news report in November / December that they were carrying out digging works at or near one of the previous test sites. So I don't quite know why most of the stories I've seen in the papers said that this test was a surprise. And this is likely to have been underground too.
Admittedly China say they weren't told in advance. But then if you remember in December Kim withdrew his girlband from Beijing, because they were only getting a Politburo member in the audience, rather than Xi Xinping himself. And I read speculation then that this was because the Chinese might not want to be seen to endorse an upcoming test.
The neptunium thing was interesting. I didn't realise it was useable in weapons. But according to that authoritive source of knowledge Wiki (as I quickly Googled it on reading the article) - the US released info that it could be used for nukes in the 90s. The same article said that no-one has been known to try, as it's harder to isolate enough of the stuff than uranium/plutonium.
@ Mark 85 - Given NORK has not real trade with the world selling anything would bring in cash. Most analysts assume the primary reason a terrorist group has not gotten a nuke and used it has been the cost of buying one on the black market. If the NORKs are willing to play "Let's Make a Deal" then all bets are off and some terrorist group will get and use a nuke. A fission device in any major city would be very nasty and a real fusion device could be devastating.
Therein is the real problem. Their "current state of the art" if reports are to be believed, is that what they have hasn't been miniaturized enough to work as an ICBM warhead. Once they hit that point, it will be easy enough to be transported by boat, lorry, etc. If, say ISIS wanted one and could cough up the cash, the Middle East may very well turn into a sea of glass depending where it was detonated and who retaliates. As I recall, many (but not all) of Saddam's Scuds came from NK so there is precedent and yes, NK is cash-hungry after all these years of sanctions.
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