If
getting international attention is North Korea's goal, then there is
nothing quite like detonating a nuclear device to make your adversaries
sit up and take notice. But experts say North Korea probably has a long
way to go before it will be able to actually deploy a nuclear weapon.
While
North Korea is adept at getting political mileage out of showy military
displays, Pyongyang's attempts to show off its strength are, just as
often, reminders of its weaknesses — and a nuclear test would likely
fit that pattern.
Fears
that such a test may be imminent were heightened last month, when North
Korea marked an important anniversary with a long-range rocket launch.
Its two previous tests came soon after such launches. Satellite imagery
also suggested stepped-up activity at the North's Punggye-ri nuclear testing site.
Little
progress at the site has been reported since, which could mean the
activity was a ruse or the device is simply not ready yet. It also
could mean that the new regime headed by Kim Jong Un,
who assumed power after the death of his father in December, is having
second thoughts about whether to risk international sanctions by
forging ahead.
Sooner or later, however, a test is highly likely.
"The
North Koreans clearly value the demonstration effect of nuclear and
missile tests, even if the test is only partially successful," said Jeffrey Lewis, of the Center for Nonproliferation Studies at the Monterey Institute of International Studies. "North Korea gets a tremendous amount of leverage from our fear that these weapons might work someday."
But
he noted that Pyongyang failed miserably in its attempt to launch an
ICBM-style rocket last month, then capped off a lavish military parade
with the unveiling of a half-dozen ominous-looking new missiles that
analysts now believe were low-quality mockups of a design that could
never fly.
"They are trying to run before they can walk, with the predictable outcome of tripping," Lewis said.
A test could have two practical goals.
North
Korea may be developing devices that use highly enriched uranium,
instead of the harder-to-obtain plutonium it has relied on in the past.
If so, it needs to try one out and see if it works. Either way, the
North has to shrink its warheads down to fit them on a missile — so it
needs to test that capability as well.
"There can be a huge difference between a nuclear explosive 'device' and a weapon," said Ivan Oelrich,
a nuclear weapons consultant and former head of strategic weapons at
the Federation of American Scientists. "We have no idea how large North
Korea's bombs are, or even whether they have anything that would be
described as a 'bomb.'"
North
Korea's devices are likely along the lines of the first plutonium bomb
the U.S. built — Fat Man, which was dropped on Nagasaki in 1945. That
bomb was 3 meters (10 feet) long and weighed more than 4.5 tons.
Such
a bomb could be loaded on a ship or an airplane, but without
significant "miniaturization," which requires difficult technological
redesigning, it would be useless as a missile payload.
"A
weapon has to be light and compact, a more or less self-contained
package," said Oelrich. "To fit on a missile, they would have to be
less than a few hundred kilograms (about 600 pounds) and smaller than a
cubic meter or two."
Though
estimates vary, outside experts say the North has enough plutonium for
about four to eight "simple" bombs, more if it can employ uranium. But,
so far, North Korea's attempts to demonstrate it has mastered the
technology — with tests in 2006 and 2009 — have not been entirely
successful.
The
first produced a yield of less than 1 kiloton of TNT, and the second
was equivalent to only 4 kilotons, both quite small by nuclear
standards, though some experts believe North Korea in the second test
may have been trying out the smallest device it could put on a missile.
Success
or failure, the tests provide an opportunity for North Korea's nuclear
scientists to learn valuable lessons. That's why the international
community has imposed harsh sanctions after each of its previous
underground blasts. But turning those lessons into a viable weapon is
no easy task.
"Testing
a device underground is relatively easy, as one can initiate the test
once everything is in order and verified to be ready," said Michael Elleman, of the International Institute for Strategic Studies. "A military or strategic nuclear weapon must be able to detonate on demand, with little forewarning."
Then there is the other problem — how to deliver it to a target.
South
Korea and Japan — and the more than 70,000 U.S. troops based in those
countries — are already within range of the North's Nodong weapon,
which was test fired in 1993 and can travel up to 1,300 kilometers (800
miles) with a 1,200-kilogram (2,600-pound) payload.
If tipped with nuclear weapons, they would put millions of lives at risk.
But
all of North Korea's long-range rocket launches have ended in failure,
meaning it is 0-4 since 1998. That has led some experts to doubt
whether North Korea, lacking in resources and expertise and hamstrung
by stringent international trade sanctions, will ever succeed in
fashioning an ICBM of its own.