So, my initial speculation about the cause of failure for North Korea’s nuclear test—remember that I thought the NORKS tried to reduce the size of the warhead with fancy implosion techniques—seems to have gained some credibility. (See So, Like, Why Didn’t It Work?, October 10, 2006)
Andrew Koch called my hypothesis “the most popular working assumption inside the U.S. intelligence community at the moment” which, you know, is kind of cool.
Underground facility at Hagap, once thought an HE testing site.
Anyway, this was something I’d been thinking about since the IC began noticing that the NORKs were doing an assload of implosion testing and Lowell Jacoby confirmed North Korea “had ability to arm a missile with a nuclear device.” (See also “Can North Korea Mate a “Simple Fission Weapon to the Taepo Dong 2?, April 30, 2005.)
As an aside, I gave Jacoby a hard time about that, but he’s actually a pretty nice guy. Sorry about that.
Something else that makes me sorry: How quickly the news that North Korea tried and failed to design a warhead small enough for a missile gets translated into, “N.K. can put warhead on mid-range missile – experts.” Or so sayeth David Morgan with Reuters:
North Korea has the ability to put a nuclear warhead onto a medium-range missile and threaten its regional neighbors, especially Japan, some U.S. experts believe.
[snip]
U.S. intelligence determined over a decade ago that Pyongyang was trying to develop a warhead for its medium-range arsenal but had yet to overcome the engineering obstacles.
[The experts] said those hurdles appear now to have been surpassed.
What? It. Didn’t. Work.
The NORKs didn’t jump the hurdle; they ran smack into it.
The bomb did produce a yield of a couple hundred tons—something I wouldn’t want dropped on my house or even in my neighborhood. And, maybe dud was a somewhat careless description. But given the inaccuracy of a Nodong and the small yield, the nuclear threat recedes below that posed by the hundreds of North Korean artillery pieces that “threaten all of Seoul with devastating attacks.”
Claiming that North Korea can arm a Nodong with a nuclear weapon is the same as claiming the Tapeodong-2 can fly thousands of kilometers. No, it can’t. The range of the Taepodong is about 40 seconds of powered flight before it explodes. North Korea can arm a Nodong with a nuclear weapon that is little more than a gi-normous dirty bomb.
I don’t mean to say that the North Koreans will never solve these problems. With enough testing they will, which is a reason to seek North Korea’s return to the NPT, adherence to the CTBT, the Clinton-era moratoria on missile testing and some sort of nouvelle Agreed Frameworok. The Reuters headline doesn’t help those efforts by giving an exagerrated picture of North Korea’s capabilities relative to the actual performance of North Korea’s strategic programs.
“No, it can’t. The range of the Taepodong is about 40 seconds of powered flight before it explodes. ”
Let us also remember that we—certainly the public and probably non-NK governments—don’t know what kind of missile the “TD-2” that failed actually was. Was it an ICBM? Maybe. Was it an IRBM? Maybe. Was it an R&D vehicle like DIA now assesses the “TD-1” to have been? Maybe.
Dr. Jeff wrote:The bomb did produce a yield of a couple hundred tons—something I wouldn’t want dropped on my house or even in my neighborhood. And, maybe dud was a somewhat careless description. But given the inaccuracy of a Nodong and the small yield, the nuclear threat recedes below that posed by the hundreds of North Korean artillery pieces that “threaten all of Seoul with devastating attacks.”
The NK device was a FULL-SIZED, massively destructive, real honest-to-pete atomic bomb. It was NOT some pathetic damp squib. Altho likely a fizzle, it was still a weapon from hell.
For scale, here is an image of Boston with a red bracket showing the area the NK device would blanket with prompt radiation of greater than 500 REMs, essentially killing EVERY EXPOSED PERSON in that zone.
Beyond the bracketed area massive numbers of people would be injured and killed by burns, flying debris and radiation.
A diagram of the effects over Manhattan is found here:
Half-Kiloton-NYC
=================================Compare the lethal zones between the NK fizzle, its probable minimum design yield of 4kt, and the Hiroshima bomb:
Distances are in kilometers outward from the point of detonation:
Yields are in kilotonsRadiation is greater than 500 remThermal is 3rd degree burnsBlast is greater than 4.6 psi==================================
If the NK design is missile capable, then with a 2 km CEP, aimed at the center of a Japanese or Korean city, the devastation would be unspeakable.
Here is a distant image of the “Wheeler” 1957 airburst test, roughly 1/3 the size of the NK “failure”.
Yale,
While I agree that low-yield weapons are certainly very deadly, their precise effects are variable depending on a host of factors. The bracketed picture of Boston you provide above is interesting, but not really accurate. The urban terrain would absorb much of the initial radiation and greatly reduce the radiation lethality radius. Unfortunately, my math skills are too rusty to make much use of my copies of Bridgman, Northrop and Glasstone to calculate somewhat more precise values.
The picture of the Wheeler test is pretty cool, though I don’t think it’s that distant. The device was tethered 150m above the ground, so the fireball looks to be about 75m in diameter at the time the picture was taken. Scale is often hard to determine based on photographs.
Here’s another cool little calculator for various weapon sizes against several cities.
http://www.fas.org/main/content.jsp?formAction=297&contentId=367
In the final analysis, I completely a agree that a sub-kiloton weapon is still very deadly, but the real question, to me at least, is how much deterrent value will such a device have? So far most military planners are unimpressed, and the test apparently did not generate the expected reaction from Japan and South Korea.
Andy wrote:
“The urban terrain would absorb much of the initial radiation and greatly reduce the radiation lethality radius.”
My goal was to provide a familiar scale, not a particular target. Thus I wrote:
As I wrote:“FOR SCALE, here is an image of Boston with a red bracket showing the area the NK device would blanket with prompt radiation of greater than 500 REMs, essentially killing EVERY EXPOSED PERSON in that zone.”
This is to demonstrate the wide area of destruction. Any particular target would have varying results. In the case of high-rise Boston, the damage is shorter range, but possibly more severe. People are exposed not only in a horizontal dimension, but vertically up the skyscrapers.
In addition to the radiation pulse, the blast and thermal pulses also extend over a 1 kilometer diameter and also may be enhanced in damage by the 3-dimensionality of the target. In all cases, “shadow” and “canyon” effects exist.
In any event, the point being made is that the explosion is vast and destructive.
Andy wrote:“I don’t think it’s that distant. The device was tethered 150m above the ground, so the fireball looks to be about 75m in diameter at the time the picture was taken.”
My eyeball trig makes out the range at about 1 kilometer plus, which I see as “distant”.
The 75 meter fireball of the 0.2 kt Wheeler shot seems about right. A 10 kiloton blast creates a 400 meter fireball at one second, and one kiloton explosion has a 150 meter fireball. The NK device at ~0.6 kt would be intermediate between the 1 kt and Wheeler fireball.
As to military planners being unimpressed, I’m not privy to their non-public reactions.
BTW, the hypothesis about a smaller warhead tested by North Koreans is shared in Russia by some experts too.
See a comment by Gennady Yevstafiev, former Russian senior inteligence official
http://pircenter.org/index.php?id=1248&news=2822
If they get working warheads, delivery will be a minor problem. In addition to nodongs they can put them on torpedoes, for instance, too