South Koreans Say Secret Work Refined Uranium
By DAVID E. SANGER and WILLIAM J. BROAD
Published: September 3, 2004
The South Korean government has admitted to the International Atomic
Energy Agency that a group of the country's scientists secretly produced
a small amount of near-weapons grade uranium, raising suspicions that
South Korea may have attempted a secret program to counter North Korea's
The revelation, made 11 days ago and disclosed by the agency yesterday,
could greatly complicate the confrontation with North Korea over its own
nuclear weapons program. President Bush regularly calls for a
"nuclear-free Korean peninsula," and those calls have been endorsed by
South Korea, one of Washington's closest Asian allies.
In a statement, the South Korean government said the highly enriched
uranium was produced by a group of rogue scientists in 2000, without the
knowledge of the government. But many details of the effort, which was
an apparent violation of the Nuclear Nonproliferation Treaty, remain
murky, and the method the scientists used was so expensive that it is
normally associated with government-directed weapons programs. Richard
A. Boucher, the State Department spokesman, said yesterday that it "is
important that all such activity be investigated," adding that after the
I.A.E.A. completed a review the United States "will be able to draw the
According to international diplomats with knowledge of the South Korean
disclosure, the government admitted to the experiment only after energy
agency inspectors began asking pointed questions about a piece of
equipment in a building in Taejon, a South Korean scientific center,
that they had been barred from visiting. It was unclear how they had
learned of the existence of the equipment. "It became clear to the South
Koreans that there would be environmental samples taken, and the truth
would be discovered," one of the diplomats said. "So they decided they
better disclose it first, themselves." That disclosure took place on
Aug. 23. The South Korean government has not yet explained how it
learned of the work of the scientists.
While the amount of uranium that South Korea has admitted to enriching
was very small, about two-tenths of a gram, it was enriched to nearly 80
percent - a level so high that experts said it was difficult to imagine
that it would be useful for anything other than making nuclear weapons.
It would take several kilograms to make even a crude nuclear weapon.
When it was disclosed last year that Iran used a similar method to try
to enrich uranium - though with significantly larger quantities - the
Bush administration said that effort was clear evidence that Tehran was
seeking to build a nuclear weapon.
Mr. Boucher declined to draw that conclusion on Thursday about South
Korea, noting that it had disclosed its own violation. But a team from
the International Atomic Energy Agency was rushed to the country last
week, and is now conducting tests to determine if the country has fully
disclosed what it produced.
South Korea recently agreed to a set of more intensive inspections by
the agency, and the inspectors were in the country to perform them.
It was unclear whether the scientists who were involved in what South
Korea called a "laboratory experiment" were government employees or
workers for the country's civilian nuclear industry. A South Korean
government statement said the experiment was intended for research on
civilian fuel production, but outside experts said that seemed
There was no response yet from North Korea, and Mr. Boucher said it was
not clear that the discovery would hinder the diplomatic effort to
pressure the North to disarm. But several other administration officials
disagreed, saying the disclosure would probably have significant
propaganda value for the North, which withdrew from the nonproliferation
treaty 18 months ago. It can now claim that the South had also
introduced weapons-grade material to the Korean peninsula.
North Korea is estimated to have enough plutonium to produce two to
eight nuclear weapons, and Washington has accused it of having a second,
secret uranium enrichment program of its own. North Korea denies it has
such a program.
At the time of the South Korea experiment in the year 2000 - which Seoul
insists was never repeated - the country was led by President Kim Dae
Jung. Mr. Kim was known for his "sunshine policy" of seeking increased
engagement with the North, and traveled to North Korea the same year
that the enrichment experimentation reportedly took place. "I would
doubt it is anything that Kim Dae Jung condoned," said Donald P. Gregg,
a former American ambassador to South Korea. "But that doesn't mean it
hadn't been condoned by some previous government" or parts of the
The method chosen by South Korean scientists to enrich uranium, through
the use of lasers, is considered easy to hide. Though pioneered by the
United States and pursued for decades around the globe, laser enrichment
appears to have remained a laboratory curiosity. "None of the big
players use lasers," said Thomas B. Cochran, a senior scientist at the
Natural Resources Defense Council in Washington, a private group that
tracks nuclear arms. "They all use centrifuges, " referring to the
devices that concentrate uranium by spinning it at high speed. Low
levels of enrichment are necessary for electricity production; high
levels can be used for weapons.
To date, the laser technique has been so expensive that experts assume
its only usefulness would be for a military program where costs are no
obstacle. It uses different colors of laser light to separate different
forms of the same element, like uranium 238 from uranium 235, which in
atomic reactions easily splits in two in bursts of energy.
"Given its lack of commercial application, the only conclusion you can
reach is that any nation pursuing this technology is doing it for
military uses," said Paul Leventhal, president of the Nuclear Control
Institute, a private group in Washington that has campaigned against
nuclear facilities whose waste could be used for weapons.
Last year, the International Atomic Energy Agency revealed that Iran had
worked in secret for 12 years to develop lasers for purifying uranium.
In a report, it said Iran established a pilot plant for laser enrichment
in 2000 and used it from October 2002 to January 2003 to conduct
experiments. The Iranian authorities said they disassembled the plant in
Mr. Leventhal of the Nuclear Control Institute said the laser technology
was so costly and difficult that only governments had the means to try
to exploit it, undermining South Korea's disavowals about unsupervised
scientists doing the experiments on their own.