Bestest Korea Icbm Test Launch

[Stuart Galbraith]

 

Ultimately the emplacement of the ABM system in Eastern Europe is irrelevant because it cannot intercept Russian missiles.

And again, they are not irrelevant, cause interception of ICBMs for them is not singe purpose. You want to bitch about russian facilities on russian soil that can be used as IRBMs? You can bitch about Pioner. Oh wait...

 

 

Lets see you want to complain about ABM making your own nuclear strike capability ineffective, but dont give a toss about your own system doing it for Britain or France.

 

You want to complain about GLCM, overlooking your own military is going to introduce them, and can in fact already strike as far as London with shipborne ones whilst parked in the Harbour in Kaliningrad.

 

You want to complain about SS20, and but we dont actually have an analogue.

 

 

Basically you want your cake and to eat it. Which is fine. I mere suggest watching your waistline as you do so. Nothing like biting off the unchewable.

 

 

 

 

 

The truth of the matter is, the Russians are perfectly happy to have BMD themselves, they just dont want anyone else having it.

Bullshit, and you know it. Russia has absolutely nothing against BMD facilities anywhere on NA continent. It is against BMD facilities in Eastern Europe for number of reasons, not least of them is one that any ABM can be easily used in anti-ground role, which is moving game in pretty different direction.

 

How? I'd have thought the guidance not remotely suitable (picking out a hot target against sky background vs land) and the lack of warhead rather a poor choice for a land attack weapon?

 

Russia has been complaining about the Use of Aegis which having the same cell launcher is (In theory) capable of mounting Tomahawk. Which is a groundless complaint because we wont mount it, but if so one that could easily be resolved through an inspection routine if they would stop whining for 5 minutes enough to seriously propose one. I seem to recall the Americans have actually suggested having inspections. The poles didnt like it, but they arent the ones putting the money into the facilities.

 

As an indirect bombardment weapon, I have to suggest the poles could just as easily do that today with their SA2 missiles, and nobody seems to complain about those. More to the point, I gather the Lithuanians are introducing an air defence system based on AMRAAM, which you could use as a bombardment weapon I guess in theory. Is anyone complaining about it? No. They want to complain about ABM for political reason's, not its military utility. Again, completely predictable 15 years ago, and like chumps we didnt think of it.

[GARGEAN]

Blah

Anther pile of irrelevant stuff. I'm not complaining about CMs(and don't understand those complains cause West has this ability since 70s). I'm not complaining about ICBMs or anything, in fact. Your words about S-75 or GLAMRAAM is comparing eggs with roaches(in other words - BSh), cause this is absolutely uncomparable with ABMs as whole.

In the end I'm not ehining about ANYTHING. I'm not even GaF about ABMs in Europe. This is YOU who said that Russia wants its own ABM system and want anyone else without it. This is lie. And you know it.

[Stuart Galbraith]

Its not a lie if I actually believe it you know. I might be wrong, insane, carpet biting, or a whole host of other things, but a liar I am not. I would hope nearly 20 years of posting on Tanknet would have established this point, but clearly not.

 

Ultimately Russia DOES have an ABM system. Yes? And it complains about their being one in Eastern Europe. Yes? A system that is designed to provide security to the US and Nato. Yes? It has (and i regret I cant find the link to prove this, but my memory suggests its true and you will have to roll with me on this one) complained about the presence of American THAAD systems in South Korea and Japan, as has China. So basically, anyone that is not the US, Europe, Japan or South Korea can have ABM systems. Yes?

 

I stand corrected and admit my fault.

[GARGEAN]

Its not a lie if I actually believe it you know. I might be wrong, insane, carpet biting, or a whole host of other things, but a liar I am not. I would hope nearly 20 years of posting on Tanknet would have established this point, but clearly not.

 

Ultimately Russia DOES have an ABM system. Yes? And it complains about their being one in Eastern Europe. Yes? A system that is designed to provide security to the US and Nato. Yes? It has (and i regret I cant find the link to prove this, but my memory suggests its true and you will have to roll with me on this one) complained about the presence of American THAAD systems in South Korea and Japan, as has China. So basically, anyone that is not the US, Europe, Japan or South Korea can have ABM systems. Yes?

 

I stand corrected and admit my fault.

USSR or Russia complained ZERO times about ABM facilities on US soil. Yes?

 

Glad that you admit it.

[Stuart Galbraith]

 

Its not a lie if I actually believe it you know. I might be wrong, insane, carpet biting, or a whole host of other things, but a liar I am not. I would hope nearly 20 years of posting on Tanknet would have established this point, but clearly not.

 

Ultimately Russia DOES have an ABM system. Yes? And it complains about their being one in Eastern Europe. Yes? A system that is designed to provide security to the US and Nato. Yes? It has (and i regret I cant find the link to prove this, but my memory suggests its true and you will have to roll with me on this one) complained about the presence of American THAAD systems in South Korea and Japan, as has China. So basically, anyone that is not the US, Europe, Japan or South Korea can have ABM systems. Yes?

 

I stand corrected and admit my fault.

USSR or Russia complained ZERO times about ABM facilities on US soil. Yes?

 

Glad that you admit it.

 

No, it has not. It just complains incessently about American ABM facilities to protect the US from missiles coming from the other direction, or indeed anywhere else on the globe. A small matter, but I dont think im out of order in pointing this out.

 

You are a nice guy Gargean, but you really need to work on those Irony appreciation skills.

[Stuart Galbraith]

http://www.telegraph.co.uk/news/2017/09/02/south-korea-agrees-revise-missile-treaty-face-north-korean-threats/

Donald Trump agreed with South Korean President Moon Jae-in to revise a joint treaty capping the development of the South's ballistic missiles, Moon's office said on Saturday, amid a standoff over North Korea's missile and nuclear tests.

M Trump also gave "conceptual" approval to the purchase by the South of billions of dollars of US military hardware, the White House said.

The South wants to raise the missile cap to boost its defences against the reclusive North, which is pursuing missile and nuclear weapons programmes in defiance of international warnings and UN sanctions.

"The two leaders agreed to the principle of revising the missile guideline to a level desired by South Korea, sharing the view that it was necessary to strengthen South Korea's defence capabilities in response to North Korea's

Impoverished North Korea and the rich, democratic South are technically still at war because their 1950-53 conflict ended in a truce, not a peace treaty. The North regularly threatens to destroy the South and its main ally, the United States.

North Korea sharply raised regional tension this week with the launch of its Hwasong-12 intermediate-range ballistic missile that flew over Japan and landed in the Pacific.

That followed the test launch of two long-range ballistic missiles in July in a sharply lofted trajectory that demonstrated a potential range of 10,000 km (6,000 miles) or more that would put many parts of the U.S. mainland within striking distance.

North Korea has been working to develop a nuclear-tipped missile capable of hitting the United States and has recently threatened to land missiles near the US Pacific territory of Guam.

South Korea's development of its ballistic missiles is limited to range of 800 km (500 miles) and payload weight of 500 kg (1,100 pounds) under a bilateral treaty revised in 2012.

South Korea has said it wants to revise the agreement to increase the cap on the payload.

The two countries agreed to the cap as part of a commitment to a voluntary international arms-control pact known as the Missile Technology Control Regime, aimed at limiting the proliferation missiles and nuclear weapons.

The two leaders pledged to continue to apply strong diplomatic and economic pressure on North Korea and to make all necessary preparations to defend against the growing threat by the North, the White House said.

The White House did not mention the voluntary bilateral agreement but said the two leaders agreed to strengthen their defence cooperation and South Korea's defence capabilities.

Trump "provided his conceptual approval of planned purchases by South Korea of billions of dollars in American military equipment", the White House said.

Trump, who has warned that the U.S. military is "locked and loaded" in case of further North Korean provocation, reacted angrily to the latest missile test, declaring on Twitter that "talking is not the answer" to resolving the crisis.

North Korea defends its weapons programmes as necessary to counter perceived U.S. aggression, such as recent air manoeuvres with South Korean and Japanese jets.

[GARGEAN]

 

 

 

Its not a lie if I actually believe it you know. I might be wrong, insane, carpet biting, or a whole host of other things, but a liar I am not. I would hope nearly 20 years of posting on Tanknet would have established this point, but clearly not.

 

Ultimately Russia DOES have an ABM system. Yes? And it complains about their being one in Eastern Europe. Yes? A system that is designed to provide security to the US and Nato. Yes? It has (and i regret I cant find the link to prove this, but my memory suggests its true and you will have to roll with me on this one) complained about the presence of American THAAD systems in South Korea and Japan, as has China. So basically, anyone that is not the US, Europe, Japan or South Korea can have ABM systems. Yes?

 

I stand corrected and admit my fault.

USSR or Russia complained ZERO times about ABM facilities on US soil. Yes?

 

Glad that you admit it.

No, it has not. It just complains incessently about American ABM facilities to protect the US from missiles coming from the other direction, or indeed anywhere else on the globe. A small matter, but I dont think im out of order in pointing this out.

 

You are a nice guy Gargean, but you really need to work on those Irony appreciation skills.

Why? You was flat out wrong, I pointed that directly. And no, not "unnecessarily". There was no complaints about simple ABM facilities like Patriots or stuff. There was real complains about heavy ABM facilities in close approach that can be used in anti-ground work. And what "other directions" ABMs in Eastern Europe covers?

[Jeff]

Some info on BMD conversions of Arleigh Burke DDGs.

 

https://news.usni.org/2014/06/03/navy-altered-destroyer-upgrade-plan-due-budget-pressure-demand-ships

[Stuart Galbraith]

I give up. It like playing good samaritan to a lemming.

 

North Korea appears likely to have another atomic 'test'.

http://www.dailymail.co.uk/news/article-4846054/Kim-Jong-poses-Korean-People-s-Army-youth-league.html

[GARGEAN]

I give up. It like playing good samaritan to a lemming.

Pretty fair. Those lemmings who irrationally believe in "EVIDENCES" and ivel Russia that want whole world without BMD, jees...

[Stuart Galbraith]

http://www.telegraph.co.uk/news/2017/09/01/north-korea-will-able-send-long-range-missiles-within-months/

 

France's foreign minister said on Friday that North Korea would have capability to send long-range ballistic missiles in a few months and urged China to be more active diplomatically to resolve the crisis.

North Korea fired a missile that flew over Japan and landed in waters off the northern region of Hokkaido early on Tuesday, marking a sharp escalation of tensions on the Korean peninsula.

"The situation is extremely serious... we see North Korea setting itself as an objective to have tomorrow or the day after missiles that can transport nuclear weapons. In a few months that will be a reality," Jean-Yves Le Drian told RTL radio.

 

"At the moment, when North Korea has the means to strike the United States, even Europe, but definitely Japan and China, then the situation will be explosive," he said.

His comments came as Russian President Vladimir Putin warned of a "major conflict" looming on the Korean Peninsula, calling for talks to alleviate the crisis.

"The problems in the region will only be solved via direct dialogue between all concerned parties, without preconditions," Mr Putin said.

"Threats, pressure and insulting and militant rhetoric are a dead end," a statement from his office said, adding that heaping additional pressure on North Korea in a bid to curb its nuclear programme was "wrong and futile."

North Korea v US

[JasonJ]

Some info on BMD conversions of Arleigh Burke DDGs.

 

https://news.usni.org/2014/06/03/navy-altered-destroyer-upgrade-plan-due-budget-pressure-demand-ships

 

Just to add, one more difference between Baseline 9 and older Baseline versions IIRC is that SM-3 block 2A requires Baseline 9. AFAIK, currently the Burkes use SM-3 Bk 1B for BMD and the Kongos use SM-3 Bk 1A, although SM-3 Bk 1B is in the 2018 budget request, so maybe the Kongos will be switching to the Block1Bs soon.

 

3 Kongos use Baseline 4 and 1 Kongo uses Baseline 5. Don't know how that fits into what BMD version.

 

JMSDF also has the 2 Atago. Upon completion, they were fitted with Baseline 7.1J but with no SM-3 missiles, so they only had the ability to detect and track BMs. But they are being upgraded to Baseline 9 and BMD 5. SM-3 Bk2A was in this years defense budget and more are in the budget request for 2018.

 

Two more Aegis destroyers (8200 tons standard weight) were payed for in earlier fiscal years with the first one to begin construction this year. They will also have Baseline 9 and BMD 5. Planned to be completed in 2020 and 2021.

 

And finally, Japan's MOD is to begin the process of implementing Aegis Ashore. I recall seeing one source saying two of them. But its too early to say details and cost estimations are not ready yet. But something functionally similar to at least Baseline 9 and BMD 5 should be expected from it.

 

As of now, as far as BMD goes, Japan has 4 (the 4 Kongos) that are like the Burke MILSPEC, and currently zero that are like Burke COTS but in about 5 years from now, will have perhaps 6 (the 2 Atagos, 2 8200 ton class, and 2(?) Aegis Ashore) that are like the Burke COTS.

[Adam_S]

There are a couple of interesting images on teh interwebz this morning showing Fat Boy Kim viewing what is allegedly a nuclear warhead being loaded into an ICBM.

 

 

 

 

Assuming this is an actually a warhead and not a dummy of some kind, a few things stand out.

 

First of all, North Korea appears to have made a fair amount of progress in terms of miniaturization. Compare with the size of the "gadget" device from the first nuclear bomb test.

 

 

This would also be a pretty major requirement given the apparently limited throw weight of North Korea's current ICBM design.

 

The other noteworthy feature is the shape of the warhead. An implosion design is basically spherical in shape, something like this.

 

 

The shape of the warhead in the picture is actually quite suggestive of a two stage Teller-Ulam type design with a separate primary and secondary. Here's a W-80, the warhead from GLCM as a comparison.

 

 

North Korea claims to have developed and tested a hydrogen bomb, although the apparent yields from their tests to date do not support this claim. To design a proper H bomb with this level of miniaturization would represent a significant technological achievement. All countries that have produced designs of this nature to date have started with relatively large and crude designs with typically megaton range yields. Reducing the size of a warhead to this degree requires sophisticated computer modelling and a very precise knowledge of the fission and fusion processes. Going from a basic fission design to a miniaturized Teller-Ulam type device in a single step would be virtually impossible without some very significant technological help.

 

The other two possibilities would therefore be that either the warhead shown in the pictures is just a dummy, or at best a kind of mockup for future RV development, Alternatively, it is really just an implosion type design, most likely in the larger sphere section at the rear with additional equipment of some sort packaged in the front.

 

As an aside, if North Korea has succeeded in producing a miniaturized implosion design, presumably through some combination of a levitated pit and/or tritium boosting, this could mean that it could greatly increase the size of its warhead arsenal without having to produce additional nuclear material. A Fat Man type design is very inefficient and uses a great deal of fissile material. A more efficient design uses less, so North Korea could potentially dismantle older, less efficient designs and rework them into a greater number of smaller, more efficient warheads.

[Luckyorwhat]

There are a couple of interesting images on teh interwebz this morning showing Fat Boy Kim viewing what is allegedly a nuclear warhead being loaded into an ICBM.

 

 

 

 

Assuming this is an actually a warhead and not a dummy of some kind, a few things stand out.

 

First of all, North Korea appears to have made a fair amount of progress in terms of miniaturization. Compare with the size of the "gadget" device from the first nuclear bomb test.

 

 

This would also be a pretty major requirement given the apparently limited throw weight of North Korea's current ICBM design.

 

The other noteworthy feature is the shape of the warhead. An implosion design is basically spherical in shape, something like this.

 

 

The shape of the warhead in the picture is actually quite suggestive of a two stage Teller-Ulam type design with a separate primary and secondary. Here's a W-80, the warhead from GLCM as a comparison.

 

 

North Korea claims to have developed and tested a hydrogen bomb, although the apparent yields from their tests to date do not support this claim. To design a proper H bomb with this level of miniaturization would represent a significant technological achievement. All countries that have produced designs of this nature to date have started with relatively large and crude designs with typically megaton range yields. Reducing the size of a warhead to this degree requires sophisticated computer modelling and a very precise knowledge of the fission and fusion processes. Going from a basic fission design to a miniaturized Teller-Ulam type device in a single step would be virtually impossible without some very significant technological help

Luckily for them over half a dozen counties have done it already, so they can just read the notes. Actually NK is being very responsible, watching time lapses of us good white western countries blasting test after test for decades is stomach-churning. Suuuure, it's hairspray that blasted a whole in the ozone layer, AND the fucking magnetosphere. Suuure.nothing to do with fuking hbombs.

 

Be funny if China stole the blueprints for bombs at the same time as stealth.

 

We just refuse to give oours up, so we can never get this non nuclear peacemovement going, wester myopia is just too much

[JasonJ]

6th nuke test today.

 

 

 

Two quakes were detected in North Korea in North Korea on Sunday, touching off speculation that Pyongyang has conducted its sixth nuclear test despite mounting international pressure.

According to the Korean media, a termor with the 5.6 magnitude was detected in Gilju-gun, North Hamgyeong Province around noon on Sunday. Another quake on scale of 4.6 was detected an hour and a half later on the test site.

The United States Geological Survey (USGS) said the first tremor was 6.3 on the exponential scale, suggesting a far bigger test than before. The location of the epicenter was near the site where the North had detonated nuclear explosions in the past.

Chinese authorities also confirmed the detection of a quake, measuring its magnitude at 6.3.

South Korean military has raised alert level following the reports of North Korea's apparent nuke test. The miilitary said the North might have conducted its sixth nuclear test.

The latest quakes are raising fears that the North is accelerating its nuclear test amid the growing tension on the Korean Peninsula.

The tremor's detection came after North Korean leader Kim Jong-un inspected the loading of a hydrogen bomb into a new intercontinental ballistic missile.

http://www.koreaherald.com/view.php?ud=20170903000121

[Adam_S]

So, if it was a magnitude 6.3 seismic event, then we can do a quick back of the envelope calculation using a formula from here, https://nautilus.org/napsnet/napsnet-special-reports/technical-analysis-of-the-dprk-nuclear-test/:

 

Mb = 4.262+0.973 logY

 

Where, Mb: Richter seismic scale,

and Y: yield of nuclear explosion.

 

If my dodgy maths is correct then that gives about 120kt for the yield, which is fairly significant for a fission only design, although there is a lot of potential error there. The Brits got up to several hundred kilotons using only boosted fission with no secondary so it doesn't have to be a true hydrogen bomb. Nevertheless, to get to a 100kt class yield means that they've got something a bit more advanced than a common or garden variety implosion design going on.

[Adam_S]

A couple of news articles on Reuters worth a read.

http://uk.reuters.com/article/uk-northkorea-nuclear/north-korea-earthquake-points-to-sixth-most-powerful-nuclear-test-idUKKCN1BD0VY

 

The first confirms the previous North Korean nuclear test as in the low 5's on the Richter scale. Since this is a logarithmic scale, an increase of 1 on the scale to the 6.3 reported today corresponds to an order of magnitude increase in the energy released. Again, this points at a 100kt class detonation.

[Adam_S]

The Guardian thinks the USA should fly a cruise missile over Pyongyang.

https://www.theguardian.com/world/2017/aug/29/how-can-world-respond-north-korea-military-action

 

The only problem might be that the North Koreans might not actually notice it.

[Simon Tan]

Better to fly cruise over London.

[Stuart Galbraith]

So, if it was a magnitude 6.3 seismic event, then we can do a quick back of the envelope calculation using a formula from here, https://nautilus.org/napsnet/napsnet-special-reports/technical-analysis-of-the-dprk-nuclear-test/:

 

Mb = 4.262+0.973 logY

 

Where, Mb: Richter seismic scale,

and Y: yield of nuclear explosion.

 

If my dodgy maths is correct then that gives about 120kt for the yield, which is fairly significant for a fission only design, although there is a lot of potential error there. The Brits got up to several hundred kilotons using only boosted fission with no secondary so it doesn't have to be a true hydrogen bomb. Nevertheless, to get to a 100kt class yield means that they've got something a bit more advanced than a common or garden variety implosion design going on.

 

 

You were thinking exactly what I was thinking, yes, this might be a real hydrogen device. Or no, it isn't, its a very large atomic bomb designed to impress the Americans, just like we did.

 

If its a very large atomic device (and I think we got something up to 700KT if I recall correct) it may be simply unusable unless you want to deliver it via a cargo ship. Clearly its progress though all the same.

[Stuart Galbraith]

The Guardian thinks the USA should fly a cruise missile over Pyongyang.

https://www.theguardian.com/world/2017/aug/29/how-can-world-respond-north-korea-military-action

 

The only problem might be that the North Koreans might not actually notice it.

 

 

I love the way they talk of inconsistent messaging from Trump. If anything, he has been wholly consistent. The problem for him is that he is coming on top of 9 Presidents whom have been wholly inconsistent in their rhetoric towards North Korea. Im not surprised for NK thinking they can push the US around with enough firepower. Its all they have been doing since 1968. Why are the newspapers assuming this is a new development?

[Der Zeitgeist]

Here's the KCNA press release.

 

Interesting points:

 

-They go into some detail to describe what they did and what that should show to the outside world.

-They claim the warhead is ready as a payload for the Hwasong-12 and -14.

-They claim no venting or other "ecological effects" occured, probably as a signal to South Korea and Japan.

 

[Adam_S]

 

So, if it was a magnitude 6.3 seismic event, then we can do a quick back of the envelope calculation using a formula from here, https://nautilus.org/napsnet/napsnet-special-reports/technical-analysis-of-the-dprk-nuclear-test/:

 

Mb = 4.262+0.973 logY

 

Where, Mb: Richter seismic scale,

and Y: yield of nuclear explosion.

 

If my dodgy maths is correct then that gives about 120kt for the yield, which is fairly significant for a fission only design, although there is a lot of potential error there. The Brits got up to several hundred kilotons using only boosted fission with no secondary so it doesn't have to be a true hydrogen bomb. Nevertheless, to get to a 100kt class yield means that they've got something a bit more advanced than a common or garden variety implosion design going on.

 

 

You were thinking exactly what I was thinking, yes, this might be a real hydrogen device. Or no, it isn't, its a very large atomic bomb designed to impress the Americans, just like we did.

 

If its a very large atomic device (and I think we got something up to 700KT if I recall correct) it may be simply unusable unless you want to deliver it via a cargo ship. Clearly its progress though all the same.

 

 

Green Bamboo was the rainbow code name for it. It had something like 70kg of plutonium in it, which rather concerned the RAF at the time because the critical mass for plutonium is about 6kg. For safety, it was full up with ball bearings which had to be removed before the bomb could be armed.

 

It is possible that North Korea has built something similar or perhaps some kind of layer cake design, but there are a couple of reasons why they might not want to do that. Firstly, any large device like that is completely unsuitable for the limited throw weight of North Korea's ICBMs. Secondly, if they have relatively limited stocks of nuclear material, a large, inefficient design used for a test could use up a significant fraction of their stockpile.

 

If they were to build something like that, it would represent a complete waste of both time and resources. It's not inconceivable that they might do this just to piss the West off, but I'm not sure.

 

Something else to consider is that the recent series of tests would be consistent with a country seeking to produce a Teller-Ulam type device. A Fat Man type bomb is apparently unsuitable for the primary so the first step would be to get an advanced design of fission weapon working correctly. This requires much more precise detonation than a more simple implosion design and it would not be unexpected for them to have a few goes at getting it right. Once they're happy with the yield from that, the next logical step would be to add a secondary and see if they could get that to work too, which may be what we have seen today.

 

If they have a working two stage device it may be possible to significantly increase the yield further. Here's a diagram of a W-88, pretty much the state of the art in Western warhead design.

 

 

The relevant feature here is the U-238 casing around the warhead. Because of the large number of fast neutrons produced by the explosion of the primary and secondary, the normally non-fissile U-238 also undergoes fission, dramatically increasing the yield. U-238 is cheap and easy to obtain so this is a very effective way of increasing the yield of a bomb. If NK really does have a working two-stage device, and if this was tested in its "clean" configuration without the U-238 case, it is possible they could get up close to half a megaton by re configuring the device with a "dirty" casing of U-238 around it.

Edited September 3, 2017 by Adam_S

[RETAC21]

That diagram seems off in a number of points, but regardless, current warhead design required a lot of testing and computer power to arrive at, IIRC. I doubt the NKs have been able to reproduce a state of the art warhead with the limited testing they have done so far, all of which points more to fizzles rather than working nukes. They are able to leverage a lot of literature, but, if what they show is an actual warhead, it's shape is quite exotic. More on this here:

 

http://blog.nuclearsecrecy.com/2016/04/22/bomb-silhouettes/

[Stuart Galbraith]

 

 

So, if it was a magnitude 6.3 seismic event, then we can do a quick back of the envelope calculation using a formula from here, https://nautilus.org/napsnet/napsnet-special-reports/technical-analysis-of-the-dprk-nuclear-test/:

 

Mb = 4.262+0.973 logY

 

Where, Mb: Richter seismic scale,

and Y: yield of nuclear explosion.

 

If my dodgy maths is correct then that gives about 120kt for the yield, which is fairly significant for a fission only design, although there is a lot of potential error there. The Brits got up to several hundred kilotons using only boosted fission with no secondary so it doesn't have to be a true hydrogen bomb. Nevertheless, to get to a 100kt class yield means that they've got something a bit more advanced than a common or garden variety implosion design going on.

 

 

You were thinking exactly what I was thinking, yes, this might be a real hydrogen device. Or no, it isn't, its a very large atomic bomb designed to impress the Americans, just like we did.

 

If its a very large atomic device (and I think we got something up to 700KT if I recall correct) it may be simply unusable unless you want to deliver it via a cargo ship. Clearly its progress though all the same.

 

 

Green Bamboo was the rainbow code name for it. It had something like 70kg of plutonium in it, which rather concerned the RAF at the time because the critical mass for plutonium is about 6kg. For safety, it was full up with ball bearings which had to be removed before the bomb could be armed.

 

It is possible that North Korea has built something similar or perhaps some kind of layer cake design, but there are a couple of reasons why they might not want to do that. Firstly, any large device like that is completely unsuitable for the limited throw weight of North Korea's ICBMs. Secondly, if they have relatively limited stocks of nuclear material, a large, inefficient design used for a test could use up a significant fraction of their stockpile.

 

If they were to build something like that, it would represent a complete waste of both time and resources. It's not inconceivable that they might do this just to piss the West off, but I'm not sure.

 

Something else to consider is that the recent series of tests would be consistent with a country seeking to produce a Teller-Ulam type device. A Fat Man type bomb is apparently unsuitable for the primary so the first step would be to get an advanced design of fission weapon working correctly. This requires much more precise detonation than a more simple implosion design and it would not be unexpected for them to have a few goes at getting it right. Once they're happy with the yield from that, the next logical step would be to add a secondary and see if they could get that to work too, which may be what we have seen today.

 

If they have a working two stage device it may be possible to significantly increase the yield further. Here's a diagram of a W-88, pretty much the state of the art in Western warhead design.

 

 

The relevant feature here is the U-238 casing around the warhead. Because of the large number of fast neutrons produced by the explosion of the primary and secondary, the normally non-fissile U-238 also undergoes fission, dramatically increasing the yield. U-238 is cheap and easy to obtain so this is a very effective way of increasing the yield of a bomb. If NK really does have a working two-stage device, and if this was tested in its "clean" configuration without the U-238 case, it is possible they could get up close to half a megaton by re configuring the device with a "dirty" casing of U-238 around it.

 

 

I dont disagree, but if the objective is as others have said to try and browbeat the Americans into acting (or perhaps more subtly, helping Trump by making it appear he has no other options than to negotiate) then it does make some kind of sense. I guess it comes down to whether Kim thinks he is actually going to need nuclear weapons, or just using them as a bargaining tool.