South Korea first became interested in nuclear technology in the 1950s but did not begin construction of its first power reactor until 1970. Changes in the international security environment influenced South Korea's decision to begin a nuclear weapons program in the early 1970s. Under significant pressure from the United States, Seoul abandoned the program and signed the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) in April 1975. In 1981, South Korean engineers produced five test fuel rods using depleted uranium. The unapproved fuel rods were placed in a research reactor and irradiated between July and December 1981. The spent fuel rods were removed and scientists conducted experiments in hotcells to extract 0.3 grams of plutonium. These experiments were not revealed to the public until the summer of 2004 when South Korean nuclear facilities would soon be subject to more detailed inspections under the Additional Protocol, which the National Assembly ratified in April 2004. In the summer of 2004, South Korean scientists were also revealed to have conducted laser isotope separation experiments to enrich about 0.2 grams of uranium.  Both the plutonium extraction and uranium enrichment experiments were in violation of Seoul's safeguards commitments, but the government has been cooperating with the IAEA to account for these violations and to ensure there are no violations in the future.

In November 1991, President Roh Tae Woo declared that South Korea would not "manufacture, possess, store, deploy, or use nuclear weapons." Two months later, North and South Korea signed the Joint Declaration on the Denuclearization of the Korean Peninsula. However, both sides have failed to implement its provision for a bilateral inspection regime. North Korea has since declared the agreement is no longer valid. South Korea is an executive board member of the Korean Peninsula Energy Development Organization (KEDO) and is providing most of the financial support for the construction of two light water nuclear reactors in North Korea under the Agreed Framework. South Korea has 19 nuclear power reactors in operation and one more under construction.

	Updated February 2006