HUA HIN, Thailand - It is probably unwise to taunt a man who commands a
million-strong army. It is also probably unseemly to make light of the man's
ballistic and nuclear weapons, even if they don't work.
Right now people around the world are running around in circles, pulling their
hair and wringing their hands over North Korea's reported underground
atomic-bomb test, when it ought to be the
subject of late-night television comedians.
In the old days opposing armies faced each other in an open field, war paint on
their faces, feathers in their helmets, rattling their
shields and making rude comments about their opponents' manhood.
Today global leaders rattle their ballistic missiles and nuclear weapons rather
than spears and battle-axes, but it is still a
macho world. And in macho terms, Kim Jong-il is a man who literally can't get
it up.
In July, North Korea tried to launch a multi-stage ballistic missile that
fizzled out over the Sea of Japan (called the East Sea by Koreans) minutes
after it was launched. This was the second test-firing in eight years and it
was even less successful than the one in 1998, which at least flew over Japan,
landing somewhere near the Aleutian Islands.
Two months after the July test, North Korea conducted a purported
nuclear-weapon test, which may not have been an obvious fizzle, but its
extremely low yield of less than a kiloton of conventional explosives (it was
the equivalent of about 550 tons) strongly suggests it was a dud.
Sub-kiloton nuclear tests are not unheard of. Pakistan set off five bombs in
1998, three of which were supposedly of sub-kiloton yield, although that has
never been confirmed.
It is confirmed that the British in a series of above-ground tests in South
Australia in the mid-1950s set off a half-dozen explosions ranging from 27
kilotons down to less than 1 kiloton (930 tons).
The United States has conducted numerous sub-kiloton tests in its quest to
miniaturize atomic bombs to put in artillery shells and other delivery systems.
But no nuclear-weapons state - from America's "Trinity" test in July 1945 (20
kilotons) to Pakistan (40 kilotons) - has ever made its world debut with such a
low yield.
Initial detonations have all been in the 10-60-kiloton range. So North Korea's
explosion was lower than the lowest by a factor of nearly 20. "No one has ever
dudded their first test of a simple fission device," said Defensetech.org.
"North Korea's nuclear scientists are the worst ever."
There are several reasons that a nuclear test might fizzle. Indeed, "fizzle
yield" is a recognized nuclear term, indicating the complexities of igniting a
fission bomb, especially one that is made from plutonium.
A fizzle can happen when the bomb literally blows itself apart too fast for the
nuclear chain reaction to take place properly and generate the large amount of
energy needed for a full-scale explosion. Should that happen, a bomb meant to
be in the Nagasaki range (20 kilotons) may yield only about a kiloton.
There are two ways this can happen. One is contamination with plutonium-240.
The key ingredient for a plutonium bomb does not exist in nature; it is
manufactured in a nuclear reactor when atoms of uranium-238 capture loose
neutrons and are converted to plutonium-239, the stuff of bombs. But these
plutonium atoms can, in turn, capture neutrons, becoming Pu-240 and even
Pu-241. They are not fissionable.
With a bomb contaminated with Pu-240, the probability of a fizzle is very
large. The US maintains a standard that none of its bomb-grade plutonium will
have more than 6% Pu-240.
Presumably North Korea's physicists, not to mention their Russian and Chinese
advisers, understand this problem. But whether they applied the skill needed to
suppress Pu-240 buildup is another question.
North Korea could avoid the problem of contamination entirely by using uranium
as the basic ingredient of its bomb. Much less is known of Pyongyang's
purported uranium-enrichment program, but it very unlikely that it progressed
to the point of producing sufficient weapons-grade material.
The other problem concerns detonation. Plutonium bombs work on the "implosion"
principle. A sub-critical core of plutonium about the size of a softball (30
centimeters in circumference) is surrounded by conventional explosives. The
pressure from the explosion squeezes the plutonium into a critical mass,
setting off the nuclear explosion.
But the shaped charges must be precisely engineered so that they go off
simultaneously. If even one charge explodes prematurely, even by a nanosecond,
it may blow the bomb apart, cutting short the chain reaction and reducing the
yield.
Of course, even a sub-kiloton bomb can cause a lot of damage. A 1-kiloton bomb
will have the radius of destruction of about a third of the Hiroshima bomb, not
exactly a city-flattener but perhaps something that could work as a terrorist
weapon.
North Korea should understand the destructive power of even sub-kiloton
explosions from experience. On April 22, 2004, in Ryongchon, near the Chinese
border, an explosion presumably of ammonium nitrate killed or injured about
3,000 people (roughly the same number as killed in the September 11, 2001,
terror attacks in the US) and flattened hectares of houses.
Some speculate that last Monday, North Korea may have skipped the debut stage
and moved directly to testing a deliberately weaponized bomb. Such a low-yield
bomb would be more suitable for export to terrorists. If that was the case, the
test might not have been aimed at world opinion in general but was, in fact, a
demo for potential buyers. So one is left really with two possibilities: was it
meant to be a normal, moderate-to-high-yield test that fizzled out, or was it a
deliberate low-yield test, a subtle advertisement for the atomic marketplace?
If, as seems likely, the test was designed for show or for its purported
deterrent effect on the US, then it was almost certainly a failure. A yield so
small as to leave the world wondering what really happened should not count as
a major propaganda victory.
A deliberately low-yield test is oddly more nefarious but also so difficult to
pull off that it would seem to be beyond the competence of North Korea in view
of its shortage of top-tier physicists and engineers.
Of course, Pyongyang may set off more nuclear tests (using up its limited
stocks of plutonium). Someday it might build a multi-stage ballistic missile
that really works; someday it may conduct a successful nuclear test; someday it
may marry the two. Yes, and Kim Jong-il may live to be 100.
Todd Crowell is a Thailand-based correspondent for Asia Times Online.
