Reports that South Korean scientists secretly -- and unbeknown to the government -- conducted experiments to enrich uranium are another blow to the nuclear nonproliferation regime. News of the tests is proof that nuclear standards have to be toughened and that the Additional Protocol needs to become mandatory for Nuclear Nonproliferation Treaty (NPT) signatories. Most importantly, Seoul must fully disclose what happened four years ago, and end all doubts and suspicions about the country's nuclear program, capabilities and intentions.

Two weeks ago, Seoul notified the International Atomic Energy Agency (IAEA) that scientists working at a government laboratory had enriched uranium to amounts far beyond the levels needed for energy production. According to Seoul, four years ago scientists used lasers to enrich less than a gram of uranium. The government said that it was a one-off experiment, using equipment that was intended for other purposes, and which was subsequently destroyed because of radioactive contamination. The government first became aware of the experiment in June and reported it to the IAEA last month. International nuclear inspectors have already visited South Korea to look into the claims and will continue their investigation.

Seoul denies that it has or had a nuclear-weapons research program or a uranium-enrichment effort. One South Korean nuclear expert said other experts "would probably laugh" at claims the experiment was a step toward building nuclear weapons.