North Korea detonates a Nuclear bomb

[billvon 3,120]

Useless fact of the day:

The smallest deployed nuclear weapon was the Davy Crockett, a recoilless rifle (think Stinger) projectile that yielded between .02 and .5 kilotons. There were a few thousand made. It could be launched with a three man crew using one of two tripod launchers.

Since the weapon could be launched with its smallest launcher about 1 mile, and lethal radiation dosage occurred within about 1/4 mile - one might imagine that launching one was a bit "sporty" for the crew.

[nerdgirl 0]

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Marg, is there a conclusive estimate for yield on the second test?

No. Because we don't know the specific geological rock formation of the area, there will never be an exact estimate. An estimate +/- a couple kT is highly dependable.

, the plausible range is narrowing.

If/once Xe & Kr are picked up ... probably at Japan's monitoring station, then it will be 99.99% conclusively a nuclear test. It took 2 weeks for the Oct 06 fizzle gas to be picked up ... at the monitoring station in Yellowknife, CA, iirc.

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Can there be, or is it extrapolated from inprecise information?

Yes, there can be.
Some of the starting conditions have to be estimated. Much of the information (seismic waveforms, location {close to the Oct 06 fizzle}) is quite precise.

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Reports range from fissle #2 to Hiroshima class, which is still a big range. One end would seem to negate the deterrent value, and make the large number of soldiers at the DMZ the primary concern still.

Afaik, the only ones still putting forth >10kT are the Russians. (And they may have backed off that (?).)

/Marg

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying

[kelpdiver 2]

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Reports range from fissle #2 to Hiroshima class, which is still a big range. One end would seem to negate the deterrent value, and make the large number of soldiers at the DMZ the primary concern still.

Afaik, the only ones still putting forth >10kT are the Russians. (And they may have backed off that (?).)

/Marg

Well, you know the media. The headline in the SF Chronicle repeated the Hiroshima line, and people run with it as fact. A lot of people don't realize that the yield on little boy and fat boy were pretty low by later standards (esp russian designs).

[kelpdiver 2]

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Useless fact of the day:

The smallest deployed nuclear weapon was the Davy Crockett, a recoilless rifle (think Stinger) projectile that yielded between .02 and .5 kilotons. There were a few thousand made. It could be launched with a three man crew using one of two tripod launchers.

Since the weapon could be launched with its smallest launcher about 1 mile, and lethal radiation dosage occurred within about 1/4 mile - one might imagine that launching one was a bit "sporty" for the crew.

I thought I had read of at least one model whose blast radius exceeded the range, but one would hope that was a bad joke. Sorta feels like the mustard gas era where a shift in wind could screw you.

[happythoughts 0]

Events have pushed things to an entirely new level.

The SOS has move from merely characterizing NKs actions as "reckless" and "non-smiling" to that of "dangerous" and "egregious". This adjective-brinksmanship has given strengthened the search for new and stronger words that will
threaten the NKs.

This new level of adjectives may force the administration to
advance an offer of aid again. With the acceptance of money,
the NK govt will agree to not do what they plan to do anyway.
(This is based on their past strict adherence to stuff written on
stacks of paper with official-sounding names).

[FreeflyChile 0]

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Most seismic estimates seem to be putting the yield at 2-8kT. The Russian estimates (10-20kt) are way whacked … & they stubbornly seem to be sticking to them. Using the Nevada Test Site “underground explosions of announced yield” data for correlation, Monday’s yield corresponds to ~1.6 kT.

AFAIK, the DPRK has chosen a plutonium-based design.

Last June, the Yongbyon water cooling tower was blown up. Without the cooling tower, the DPRK can’t produce more Pu. (They can rebuild the tower, but they haven’t.)

Estimates of DPRK plutonium produced range from 7kg (low-end) to 40kg (high-end). US estimates are ~30kgs. Sig Hecker (formely LANL now Stanford), who’s been to the DPRK’s nuclear facilities, estimated 35 kg.

A Pu-based nuclear device requires 4 to 8 kg.

The October 2009 test fizzled. The yield of this one appears to be small. By comparison, the first test of a US Pu-based nuclear device, Trinity, had a yield of 20kt. Why can’t the North Koreans get at least 10kT? What’s so screwed up there? … (okay, maybe that latter question is more rhetorical.)

Most folks estimate the DPRK to have enough Pu for 4 to 8 tests/devices.



Play out one scenario: they’re using up their deterrent capability.

Given the more recent down-estimates of the yield of this recent test, a couple technical security folks have tossed around the idea that this was large conventional explosive. Conventional explosives can create 1-8 kt yields, albeit that’s a lot. I don’t think so … but it plays to the regime’s brinkmanship behavior, and it does push the metaphorical buttons of some.

The Xenon & Krypton cloud (two long-lived atomic tracers) should be reaching monitoring stations outside of DPRK soon, if not already.

VR/Marg

Marg,

If these tests aren't really high-yield, could it just be that they're testing the process of creating the explosion with a small amount of plutonium - so they're not seeing how big a blast they can get but instead just that they have the process of causing the blast down? Or do nukes not work in this scalable way?

[LongWayToFall 0]

Yeah I figured NK did not have nuclear warheads specifically, but was trying to answer the question of "why we should be concerned." It honestly would not surprise me if they did in fact have ICBMs and warheads small enough to fit on them, you never know what they are working on underground, and the technology certainly is out there.
Thanks for all the cool data, btw. Can we establish from the gas clouds how powerful the blast was? Also, using plutonium, what sort of blast would be expected from the size warhead that is capable of being small/light enough to fit onto a short or long range missile?

[nerdgirl 0]

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If these tests aren't really high-yield, could it just be that they're testing the process of creating the explosion with a small amount of plutonium - so they're not seeing how big a blast they can get but instead just that they have the process of causing the blast down? Or do nukes not work in this scalable way?

Notionally, they could be; there's always a danger in mirror-imaging our program/the Iranian program/the Pakistani programs/etc. Based on my experience, understanding, and knowledge, I judge it to be very, very, highly, highly, really unlikely, however.

Getting plutonium is relatively easy *compared to* enriching uranium. They're both difficult; one is harder than the other. An HEU bomb design is easy compared to the Pu-based bomb design. The most likely explanation is they’re having problems with test device design and manufacture.

If that is true (which I judge it likely), it also means that they are unlikely to be able to produce a physically smaller device (even more complicated design) for a warhead.

It’s not evident that they “have the process of causing the blast down.” A fizzle and this most recent test do not suggest that.

Intentionally making small nukes – both ones really are intended be sub-kT or very low kT yield and ones that can be carried on a ICBM – is a lot harder than making a 10-20kT … or even a 50kT nuclear device.

/Marg

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying

[nerdgirl 0]

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Can we establish from the gas clouds how powerful the blast was?

One can make estimates but they are not as precise as the ones based on data from the 20 or so seismic stations, including at least one in the US. Estimations will be done from the Xe radioisotopes (assuming they’re detected); the error bars will be larger than the seismic data.

The crucial part of the Xe and Kr isotope detection is showing that it was *really* a nuclear test not just a big heap o’conventional explosives.

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Also, using plutonium, what sort of blast would be expected from the size warhead that is capable of being small/light enough to fit onto a short or long range missile?

Ours? The Russians? Or the DPRK? We have multiple W62, W78, & W87 warheads on Minutemen ICBMs w/yields of 150 to ~500kT for each warhead in our current arsenal. At one point, the Soviet Union had ICBM with 20MT warheads. It was really heavy.

If the DPRK can get a TD-2 to work - & that’s a really, really, really big *if*, imo – the largest estimated payload is ~500kg for long range estimates. (Shorter range =’s smaller payload.) For comparison, the bomb dropped on Nagasaki was about 4,500 kg.

/Marg

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying

[champu 1]

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It honestly would not surprise me if they did in fact have ICBMs and warheads small enough to fit on them, you never know what they are working on underground, and the technology certainly is out there.

It would floor me if they had any such technology capability that was indigenously produced.

The DPRK (Democratic People's Regime of the Kims) literally has nothing but problems right now.

[nerdgirl 0]

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(Democratic People's Regime of the Kims)

I'm stealing that ... w/permission, of course?

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying

[champu 1]

Granted.

[nerdgirl 0]

Interesting note to me & I suspect some others - the expected noble gas isotopes of xenon & krypton haven't been detected yet. Based on the wind patterns, monitoring stations in ROK and Japan were in direct path.

There are multiple possible reasons ... among them -- but not the only explanation -- is that it wasn't a nuclear detonation. Radioactive isotopes from the Oct 2006 'fizzle' (estimated ~1/2 kT) were detected w/in 9 days, iirc.

/Marg

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying

[happythoughts 0]

clicky

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Secretary of State Hillary Clinton, in her first foray into the Sunday talk show circuit as a Cabinet secretary, delivered a tough and blunt message to North Korea and Iran, saying that diplomacy as well as “consequences and costs” are both on the table.

Clinton said that North Korea could once again be added to the list of states that sponsor terrorism, a move that several senators backed in a letter to President Barack Obama.

“Well, we're going to look at it. There's a process for it. Obviously we would want to see recent evidence of their support for international terrorism — we're just beginning to look at it. I don't have an answer for you right now,” she said Sunday on ABC’s “This Week with George Stephanopoulos.”

Support for international terrorism and possible
possession of weapons of mass destruction.

Senators writing Obama about this.

Clinton using harsh words.

[nerdgirl 0]

The topic of the undetected Xe & Kr nucleotides was discussed at last week’s CTBTO mtg.

On Monday, the DNI released a concise statement, which largely matches my own assessment:

“STATEMENT BY THE OFFICE OF THE DIRECTOR OF NATIONAL INTELLIGENCE ON NORTH KOREA’S DECLARED NUCLEAR TEST ON MAY 25, 2009 [capitalization in original; it’s also bolded and underlined too - nerdgirl]

“The U.S. Intelligence Community assesses that North Korea probably conducted an underground nuclear explosion in the vicinity of P'unggye on May 25, 2009. The explosion yield was approximately a few kilotons. Analysis of the event continues.”

The “probably” is due to the undetected nucleotides, imo. Altho' likely to generate speculation in some parts.

Most likely nuclear test … but the remote possibility of detonation of *a lot* of conventional explosives remains. Less plausible, imo (& others).

/Marg

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying

[PhreeZone 20]

The one thing that stood out to me on the theory of the non-nuclear device being used was that from my understanding the physics for detonating such a large pile of ordnance with the correct timing and being able to use it to generate a seismic P wave that matched a nuclear device would be almost as difficult as creating a medium yield nuclear device to start with. It would have been far easier to just create the nuclear device then trying to build and use a hoax bomb.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[billvon 3,120]

>The “probably” is due to the undetected nucleotides, imo.

At what yield would no nucleotides be released? There must be a level below which the reaction products don't make it to the surface.

[nerdgirl 0]

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The one thing that stood out to me on the theory hypothesis, speculations, etc [sorry … that’s one thing about which I get pedantic because it’s used incorrectly by so many … & since this is getting technical …] of the non-nuclear device being used was that from my understanding the physics for detonating such a large pile of ordnance with the correct timing and being able to use it to generate a seismic P wave that matched a nuclear device would be almost as difficult as creating a medium yield nuclear device to start with. It would have been far easier to just create the nuclear device then trying to build and use a hoax bomb.

The conventional explosives hypothesis is less plausible, imo. It’s still a fascinating, again imo, footnote.

The isotopes from the October 2006 ‘fizzle’ were detected and that test was conducted in the same area, which is a factor that strongly suggests one would detect them again.

W/r/t seismic patterns – the ratio of S-wave to P-waves is used to differentiate from natural earthquakes, which you probably/may already know. E.g., the May event in DPRK, the P-wave component was ~five times the S-wave, iirc. In natural earthquakes, the S-wave component is usually larger than the P-wave (integrated across the entire seismic curve). It’s not impossible that a natural earthquake might generate a seismic signal that looks like a nuclear device, the probability is very, very, very low, i.e., much more plausible that it’s a non-natural. Something similar was used to differentiate a 1997 Russian earthquake that happened to be about equidistant to the Finnish monitoring station from a previously used nuclear test site (see pages 3 & 5 of the pdf).

As far as P-waves from conventional explosives, you’re right that it is possible, although more difficult, to distinguish large chemical explosions from nuclear generated explosions. I haven’t heard anyone previous suggest that as a means to differentiate at the DPRK site. Might be … I just haven’t heard of it.

The DPRK has been doing conventional explosive tests, presumably of firing sets under development, since the early 1990s. In September 2004, seismic monitors picked up large explosions in DPRK (unannounced) that are considered (highest probability) to be from conventional explosives.

W/r/t ease … might be for a Uranium-based device, significantly less certain w/r/t a Pu-based device. Mostly because I’m not as familiar with construction of large conventional explosions.

As I originally wrote, a number of folks (myself included) were “surprised that it took *this* long for them to do another ‘test.’”


Shifting from technical to policy, one can ask why would DPRK want to stage an elaborate hoax? Brinkmanship? Attention? One can generate speculations, but the most likely, imo, are that it is more likely to have been a nuclear device.

/Marg

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying

[nerdgirl 0]

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At what yield would no nucleotides be released? There must be a level below which the reaction products don't make it to the surface.

In the event there was no nuclear chain reaction, there would be no nucleotides. Nucleotides were detected from the October 06 ‘fizzle,’ which had a smaller yield (as calculated based on seismic info) than May’s event.

There are possible, although very low probability, scenarios in which nucleotides either are trapped or aren’t detected. Detection is an almost absolute confirmation that an explosion really was nuclear, but lack of detection does not implicitly mean the converse. It just leaves some room for doubt, i.e., “probaby.”

/Marg

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying

[kelpdiver 2]

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Shifting from technical to policy, one can ask why would DPRK want to stage an elaborate hoax? Brinkmanship? Attention? One can generate speculations, but the most likely, imo, are that it is more likely to have been a nuclear device.

/Marg

??

If your last test was a fizzle and you can't solve the problem, a fake test at least maintains your status as a nuclear member. The news reported the next morning that this was a blast equivalent to the bombs in WW2.

Of course, if you get caught faking it, the damage is huge, and leaves NK much worse off than not doing anything. Recall Iran and its photoshop screwup, and and a big multiplier.

Given the disparity in downside versus gain, it would seem improbable and irrational, but this isn't the healthiest of nations by most measures.

[1969912 0]

Radionuclides, not nucleotides.

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

[1969912 0]

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At what yield would no nucleotides be released? There must be a level below which the reaction products don't make it to the surface.

In the event there was no nuclear chain reaction, there would be no nucleotides. Nucleotides were detected from the October 06 ‘fizzle,’ which had a smaller yield (as calculated based on seismic info) than May’s event.

There are possible, although very low probability, scenarios in which nucleotides either are trapped or aren’t detected. Detection is an almost absolute confirmation that an explosion really was nuclear, but lack of detection does not implicitly mean the converse. It just leaves some room for doubt, i.e., “probaby.”

/Marg

...Which prompts this thought: What if they intentionally limited the emission of fission products in order to mask the source of the fissile material (by doing a small test really deep, well sealed, etc.) Not sure if world enriched uranium stockpiles are (or are able to be) catalogued based on source, but plutonium can be and is, AFAIK.

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

[nerdgirl 0]

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Radionuclides, not nucleotides.

Yep … thanks for the correction.

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... What if they intentionally limited the emission of fission products in order to mask the source of the fissile material (by doing a small test really deep, well sealed, etc.) Not sure if world enriched uranium stockpiles are (or are able to be) catalogued based on source, but plutonium can be and is, AFAIK.

That’s another possible speculative scenario. I would rank it lower in probability than conventional explosives. A physical sample would be required as well.

Yes, there are catalogs of trace impurities of fissile materials (e.g., uranium isotopic composition and impurities according to where it was mined and processing). The IAEA has probably the most complete one; it's not publically available. Stanford's Michael May (formerly director LLNL) has been advocating for international collaboration on nuclear material databases and nuclear forensics.

/Marg

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying