South Korean nuclear experiments revealed earlier this year produced minute amounts of highly enriched uranium and plutonium but there is no evidence to link them to an attempt to make weapons, the UN atomic watchdog said.
The report, drawn up by the International Atomic Energy Agency and made available Thursday to The Associated Press, followed up on revelations that South Korea sporadically dabbled in uranium enrichment and plutonium reprocessing from the early 1980s to 2000.
Uranium enriched to weapons grade and plutonium can both be used to make nuclear warheads. Officials acknowledged the experiments earlier this year amid pervasive IAEA queries about past activities but insisted they were small-scale and conducted by scientists who never informed the government.
Beyond establishing that those experiments appeared to have produced only small amounts and had been restricted to the laboratory, the report also revealed a separate attempt at uranium enrichment that it said had not been previously reported to the agency.
But the report said this attempt -- to enrich uranium chemically -- resulted in extremely low enrichment, far below the 90 percent minimum normally considered weapons grade.
South Korea has scrambled to deny it has ambitions for a nuclear weapons program following the first revelations in late August, and the government has sought to downplay its role in what it says were unauthorized experiments.
The report -- prepared for a Nov. 25 meeting of the IAEA's board of governors -- noted government assertions that the highest official aware of enrichment experiments between 1993 and 2000 was the head of a government nuclear research agency in the city of Dajeon and that the activities included only 14 scientists.
But such claims were questioned by diplomats familiar with the investigations of the Vienna-based IAEA. The fact that uranium metal normally used in enrichment was produced nearly two decades before the laser enrichment experiments were carried out four years ago suggests long-range planning that was targeted to enrichment, said one diplomat, on condition of anonymity.
Action by the IAEA board on the report could set a precedent for Iran, which the United States accuses of trying to develop nuclear weapons.
If the board decides that the South Korean violations need to be reported to the UN Security Council, then the US case for similar action against Tehran -- with a much more serious record of nuclear transgressions -- would likely receive a boost.
The report, written by IAEA head Mohamed ElBaradei, said failure by South Korea to report the experiments were "a matter of serious concern," because they violated agreements signed with the IAEA linked to the Nonproliferation Treaty.