During an IAEA inspection last week, South Korean officials could not produce documentation or several scientists who were involved in the work, the diplomats said. That portrayal differs significantly from those offered by U.S. officials who have repeatedly praised South Korea for coming clean voluntarily and cooperating with the IAEA.
South Korea says it has cooperated fully with the IAEA and has not been obstructionist. South Korean officials say they have produced reports for inspectors as quickly as possible given the sketchy details remaining about the 1982 plutonium experiment and the February discovery of the 2000 uranium enrichment program.
South Korean workers dismantle the facilities of a research reactor belonging to the Korea Atomic Energy Research Institute in Seoul.
(Kang Chang-kwang -- Hankyoreh News Via AP)
The IAEA investigation revealed South Korea's work on uranium enrichment, plutonium reprocessing and the production of nuclear equipment including uranium metal for laser technology.
When Iran was found to have been working on uranium metal, suspicions were immediately raised about its intentions. "Anytime a country makes uranium metal in secret, you have to worry that they are trying to make nuclear weapons components," said David Albright, a former IAEA nuclear inspector and the current president of the Institute for Science and International Security.
Iran was far less successful than South Korea at laser enrichment, according to diplomats and IAEA reports. In 2002, Iranian scientists enriched uranium to about 15 percent while the South Koreans, working two years earlier, enriched uranium to 77 percent, well within the range necessary for a nuclear explosive.
South Korea acknowledged the achievement in written statements to the IAEA this summer, the diplomats said. South Korean officials publicly deny uranium was enriched to high levels. The IAEA is conducting tests, and the results are expected soon.
Much of Tehran's enrichment work has been done with centrifuges, and officials there said they will continue to assemble the large-scale operation to enrich low levels of uranium for a nuclear energy program. Iran has enriched uranium to 2 percent using the centrifuges but, once mastered, the technology could be used to make highly enriched uranium suitable for bombs.
Iran's secret nuclear work was exposed two years ago, and since then IAEA inspectors have been trying to understand how and why Iran hid 18 years of effort. Iran maintains that its goal is to develop a nuclear energy program and that it worked in secret because it feared it would not be believed.
South Korea agreed, under U.S. pressure in the 1970s, to give up its nuclear weapons program. In 1991, it and North Korea agreed to ban uranium enrichment and plutonium reprocessing on the Korean Peninsula. The North is believed to have violated that agreement, and U.S. intelligence estimates indicate Pyongyang may have up to eight nuclear weapons.
In the past month, U.S. spy satellites have observed activity in North Korea that some intelligence officials believe could be a sign that Pyongyang is preparing to conduct a nuclear test, an administration official who had been briefed on the matter said last week. But he said that while the evidence, such as increased movement of vehicles at suspected test sites, was suspicious, officials were reluctant to draw firm conclusions because assumptions drawn from similar activity observed in Iraq had turned out to be wrong.
North Korea said yesterday that talks with Washington and others aimed at ending its nuclear ambitions must be tied to a full investigation of South Korea's work. Talks were to have resumed this month in Beijing, but many analysts think the next round could be delayed until after the U.S. presidential election in November.
Staff writer Glenn Kessler in Washington and correspondent Anthony Faiola in Seoul contributed to this report.