South Korea also allows the United States to maintain nuclear weapons on its territories, which the US first brought to the peninsula in January 1958.
In August 2004, South Korea revealed the extent of its highly secretive and sensitive nuclear research programs to the International Atomic Energy Agency (IAEA), including some experiments which were conducted without the obligatory reporting to the IAEA called for by South Korea's safeguards agreement.
Under the direction of South Korea's Weapons Exploitation Committee, the country attempted to obtain plutonium reprocessing facilities following the pullout of the 26,000 American soldiers of the 7th Infantry Division in 1971.
[6] However, under pressure from the United States, France eventually decided not to deliver a reprocessing facility to South Korea in 1975.
[5] In 1982, scientists at the Korean Atomic Energy Research Institute performed an experiment in which they extracted several milligrams of plutonium.
In exchange, the US agreed to transfer reactor technology and give financial assistance to South Korea's nuclear energy program.
It was revealed in 2004 that some South Korean scientists continued some studies; for example, in 1983 and 1984 Korea Atomic Energy Research Institute was conducting chemical experiments related to the handling of spent fuel that crossed the reprocessing boundary.
[10][11] Highly enriched uranium with a purity of 20% or more is usable in a weapon, but this route is less desirable as far more material is required to obtain critical mass.
[7] Following Seoul's disclosure of the above incidents, the IAEA launched a full investigation into South Korea's nuclear activities.
[24] In the late 1990s, a notable minority of South Koreans supported the country's effort to reprocess materials, although only a small number called for the government to obtain nuclear weapons.
[32][33][34] In February 2023, Leader of the People Power Party Chung Jin Suk said that South Korea might need nuclear weapons.
NHK-1 was by South Korea touted as completely indigenous development though in fact some of the technology was supplied and obtained from the United States.
Seoul agreed to not extended range of the missile beyond 180 km under South Korea Ballistic Missile Range Guidelines with the U.S. with development of its successor NHK-2 that was tested in October 1982 with development being halted in 1984 until resumption couple years later with completion in 1987 when it entered service, its guidance system was supplied by United Kingdom.