Weapons of Mass Destruction (WMD)

South Korea Special Weapons

Nuclear Weapons

Seoul had no plans to obtain nuclear weapons and would rely on an extended deterrence of North Korea in an alliance with the United States, South Korean Prime Minister Han Duck-soo said on 07 March 2023. "From the point of view of deterring senseless provocations on the part of North Korea, we need to work more closely with the US in terms of joint planning or some kind of joint operations and implementation," the minister told a meeting with foreign journalists in the city of Busan. "We need a stronger extended deterrence, including with nuclear weapons. Therefore, we do not have any solid plans to obtain nuclear weapons in any timeframe."

Seoul will continue holding joint military drills with Washington despite Pyongyang's reaction, the minister said. "We will continue our joint exercises and continue strengthening our deterrence capabilities regardless of what North Korea does or how it reacts to our just actions to defend ourselves," Duck-soo said, adding that Seoul will not compromise on the issue.

As a member country of the Nuclear Non-Proliferation Treaty, South Korea is prohibited from having a nuclear arsenal. South Korea has the technical engineering personnel for the development of nuclear weapons. Acquisition of the facilities for the development of nuclear weapons is not beyond the financial reach of South Korea, but the expense would require a major re-allocation of existing resources that are presently devoted to other priorities.

In the absence of the US-Korea alliance, support for a South Korean nuclear weapon could grow, but it could come with economic costs. The South Korean economy is dependent upon trade, and it could face significant economic sanctions to pressure it not develop nuclear weapons. And it could see its access to fuel for its nuclear power plants cut off by the Nuclear Suppliers Group.

Even if South Korea develops nuclear weapons, where is it going to put them? The land mass is restricted and any nuclear installations would be near a population center. That will draw more protests. Thus, it seems likely that any South Korean weapons program would have to be sea-based.

South Korea began a nuclear weapons program in 1970, in response to the Nixon Doctrine's emphasis on self-defense for Asian allies. Following the withdrawal of 26,000 American troops, the South Korean government established a Weapons Exploitation Committee, which decided to pursue nuclear weapons. The withdrawal of the US from South Vietnam and Cambodia and the removal of military units from Taiwan increased South Korean fears concerning the strength of US support.

The announced intention of the Carter Administration to withdraw U.S. ground forces from the Peninsula reinforced that insecurity. Despite whatever security guarantees that may accompany it, such a withdrawal probably stimulated South Korea’s interest in acquiring nuclear weapons. In South Korea, it was assumed that withdrawal of US forces would be followed by a North Korean invasion of the South. Whether or not that assumption was well-founded, it was the premise upon which the ROK government operated and North Korean propaganda did little to counter it. Nuclear weapons were seen as a deterrent to invasion, as an important defensive weapon in the event of such an invasion, and as a means of deterring the Soviet Union or China from assisting North Korea.

By 1975 the US had pressured France into not delivering a reprocessing facility, effectiely ending attempts to develop nuclear weapons. Under pressure from the United States, Korea ratified the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) on 23 April 1975. Although President Park Chung-Hee said in 1977 that South Korea would not develop nuclear weapons, he continued a clandestine program that only ended with his assassination in October 1979.

South Korea may have had plans in the 1980s to develop nuclear weapons to deter an attack by the North. The plans were reported to have been dropped under US pressure. However, the reports seem to have emanated in the form of hearsay from a South Korean opposition legislator, with no confirmation from US or South Korean officials, or independent sources. The United States remained concerned, as indicated by the "special" inspections that the US conducts at the center of Seoul's nuclear research, the Korean Atomic Energy Research Institute (KAERI) located at Daeduk, near the city of Taejon. The United States maintains a ban on plutonium being supplied to South Korea.

Any hint that South Korea had set out to acquire nuclear weapons would bring forth condemnation from the US, Russia, China and many of South Korea’s Asian and European trading partners. Proliferation, or the hint of it, could be expected to strain the security guarantees by the United States and hasten the dissolution of that arrangement. This fact constitutes an inhibition against overt South Korean proliferation as long as there is some chance that the US security guarantee will be honored.

In 1991, President Roh Tae-woo announced ROK’s unwillingness to “manufacture, possess, store, deploy, or use nuclear weapons.” Similarly, in 1993 when President Kim Young-Sam was asked if he would categorically rule out development of South Korea’s own nuclear weapons, he responded, “Absolutely. That would disrupt peace in Northeast Asia and peace in the world at large.” Despite a North Korean threat to turn Seoul into a ‘sea of fire,’ there seemed to be little popular and governmental support for a South Korean nuclear deterrent.” North Korean nuclear programs were not seen as grave enough to merit South Korean nuclear weapons.

Korean President Park Geun-hye warned in May 2014 that another nuclear bomb test by North Korea (Democratic People’s Republic of Korea or DPRK) would be “crossing a Rubicon” and would make it “difficult for us to prevent a nuclear domino from occurring in this area.” Leaders of the South Korean ruling party said that the country should consider creating its own nuclear potential for self-defense. The news came a day after North Korea claimed it successfully tested its first hydrogen bomb. "It is time for us to peacefully arm ourselves with nukes from the perspective of self-defense to fight against North Korea's terror and destruction," Won Yoo-cheol, floor leader of the party, was quoted as saying by Yonhap 07 January 2016.

While the country's President Moon Jae In did not support the idea, by 2017 polls showed that a majority of the country favored it. Yoon Young-seok, a lawmaker from the Liberty Korea Party, said that the population wants to see a better balance of power between the South and the North.

Donald J. Trump, the Republican presidential candidate, discussed his views on foreign policy with the New York Times on 26 March 2016. "... right now we’re protecting, we’re basically protecting Japan, and we are, every time North Korea raises its head, you know, we get calls from Japan and we get calls from everybody else, and “Do something.” And there’ll be a point at which we’re just not going to be able to do it anymore. Now, does that mean nuclear? It could mean nuclear. It’s a very scary nuclear world. Biggest problem, to me, in the world, is nuclear, and proliferation. At the same time, you know, we’re a country that doesn’t have money. You know, when we did these deals, we were a rich country. We’re not a rich country. ... would I rather have North Korea have them with Japan sitting there having them also? You may very well be better off if that’s the case. In other words, where Japan is defending itself against North Korea... "

The President Park Geun-hye government, however, had rejected the need for nuclear weapons, relying instead on the protection of the US nuclear deterrent guaranteed under its security alliance with Washington. The South Korean English-language newspaper JoongAng Daily ran a strongly worded editorial criticizing Trump, calling his views "myopic" and "utterly short-sighted."

By 2016 advocates of nuclear deterrence said Seoul must pursue its own nuclear weapons programs to defend against North Korea’s growing nuclear and ballistic missile capabilities. Song Dae-sung, a political science professor at Kunkuk University in Seoul and author of the book Let’s Have Nuclear Power makes the case for a nuclear armed South Korea. “If North Korea becomes a nuclear-armed state and its adversary does not own nuclear power, then the non-nuclear state becomes a slave or hostage of the nuclear state. This is a basic principle of international politics,” said Song.

National Assembly Representative Won Yoo-chul, a leader within of the ruling Saenuri Party, has also been a strong nuclear advocate. Won has put together a study group in the parliamentary National Defense Committee to assess the risks and benefits of South Korea pursuing its own nuclear program. “The most efficient way to deter nuclear warfare is to have nukes for our self-defense,” Won has said.

Donald Trump, as the Republican candidate for president, cast doubt on the U.S. policy of providing extended nuclear deterrence in the region by questioning America’s commitment to protect South Korea. “If the U.S. elects a president who makes such an argument, then South Korea needs to own nuclear power all the more,” said Song.

North Korea’s withdrawal from the NPT in 2003 is a major justification for the current sanctions in place against it. However the South’s nuclear supporters say Seoul could invoke Article 10 of the NPT, which allows for a withdraw from the treaty when extraordinary events jeopardize national interests, by citing the North’s nuclear threat.

A group of security and nuclear experts launched a think tank to discuss ways to arm South Korea with nuclear weapons, while ruling party lawmakers on 11 September 2016 renewed calls for the redeployment of U.S. tactical nuclear weapons here and eventually South Korea's independent nuclear weapons development in response to North Korea's repeated nuclear tests. "The South Korean nuclear research group, composed of about 10 North Korea, security and nuclear specialists, was launched in early September," Cheong Seong-chang, a North Korea researcher at the Sejong Institute who represents the think tank, told Yonhap News Agency. "The members plan to have in-depth discussions on how South Korea could develop its own nuclear weapons and find common ground and share their knowledge on the issue." The group was the first known South Korean think tank on the nuclear armament issue whose launch comes amid North Korea's accelerating nuclear and missile threats.

Won Yoo-chul, a representative at the ruling Saenuri Party, argued in a statement issued after the test that "Only nuclear weapons could be an effective deterrence against nuclear weapons," urging the government to push for nuclear armament. Won's position has been supported by former Saenuri Chairman Kim Moo-sung and former Saenuri chief policymaker Kim Jung-hoon, among others. But a South Korean government official denied any move for nuclear armament, reconfirming its stance of denuclearization of the Korean Peninsula.

South Korean Foreign Minister Yun Byung-se told foreign officials on 02 October 2016 that the North’s nuclear test last month, its second of the year and most powerful yet, is being viewed by many in his country as “a kind of Sept. 11 attack”.

Gyeonggi Province Governor Nam Kyung-pil stressed that South Korea needed to prepare for nuclear armament amid rising uncertainties surrounding security on the Korean Peninsula. Nam, considered to be a potential presidential candidate, made the remark in an interview with Seoul-based Yonhap News Agency on 02 October 2016. He said South Korea needs to mull various options, including preparations for nuclear armament, citing concerns the United States may withdraw its nuclear umbrella from South Korea. Nam said such preparations must begin now, stressing that South Korea can start discussing the issue with the U.S. after preparing for it internally.

The governor said that the American people’s perception about the South Korea-U.S. military alliance is changing, adding that the U.S. policy on nuclear umbrellas could also change. Nam also called for the swift transfer of wartime operational control(OPCON) of the South Korean troops from Washington to Seoul. Under the current Seoul-Washington alliance, the top U.S. commander will have control over South Korean troops in the event of a war with North Korea. South Korea and the United States originally planned to transfer OPCON to Seoul in December 2015, but later postponed the move to an unspecified date in the mid-2020s.

Beginning in 2017, South Korean conservative and centrist political parties adopted election platforms calling on the United States to redeploy tactical nuclear weapons on the Korean Peninsula and for unspecified “nuclear sharing” arrangements similar to NATO. Hong Jun-pyo, the leader of the conservative opposition Liberty Korea Party who finished in second in the 2017 presidential election, was in Washington in October 2017. He called for a return of US nuclear weapons. The United States must swiftly redeploy tactical nuclear weapons in South Korea, Hong argued. should the US refuse to redeploy nuclear weapons, Hong warned South Korea should pursue its own nuclear weapons.

In early October 2016 Cho Tae-yong, the first deputy chief of the Blue House National Security Office, visited the United States. At the time, Daniel Crittenbrink was in charge of Asia for the US National Security Council (NSC). The South Korean official requested redeployment of tactical nuclear weapons to the South. However, the senior aide in the Obama administration at the time rejected the request.

US Secretary of State Rex Tillerson said on 20 March 2017 that the situation (surrounding the North Korean nuclear weapons) could evolve to a point where the U.S. could even consider allowing nuclear armament of (South Korea and Japan) to ensure the balance of mutual deterrence, in addition to considering of the redeployment of tactical nuclear weapons in South Korea.

South Korean Minister of National Defense Song Young-moo met with US Secretary of Defense James Mattis at the Pentagon on 30 August 2017 and broached the tactical nuclear weapon deployment issue. This was the first official discussion of the tactical nuclear weapon issue between top-level South Korean and US government figures. In a press briefing the same day, ministry spokesperson Cho Joon-hyeok dismissed the idea of redeployment, stating that the “administration’s basic position is for the denuclearization of the Korean Peninsula.”

Senate Armed Services Committee Chairman John McCain (Republican) announced on 10 September 2017 that the South Korea should consider relocating tactical nuclear weapons in response to North Korea's nuclear and missile provocations. McCain told CNN that the South Korean defense minister had called for the redeployment of nuclear weapons just a few days earlier. This refers to the remarks made by Defense Minister Song Young-moo on 04 September 2017. "It is different from government policy, but it should be considered as one of various measures to effectively deter and respond to the North Korean nuclear threat," Song said at the National Assembly Defense Committee.

Toby Dalton and Ain Hann note that "Longitudinal polling by SNU IPUS showed that between 2013 and 2016 a majority of respondents agreed that South Korea should possess nuclear weapons. Though that support dipped under 50 percent after 2016, the percentage of people opposed to possession of nuclear weapons has remained low, peaking at just over 27 percent in 2019... the only poll to pose questions about likely consequences suggested that there might be as much as a 15–30 percent drop in support."

On 16 February 2016, Jeong Seong-jang, head of the Unification Strategy Research Department at the Sejong Institute, said, “If the president makes a decision, South Korea can manufacture nuclear weapons for about 18 months and then mass-produce thousands of them.” Director Chung used the report as the basis for a report that was circulated privately to the Nonproliferation Expert Group in April 2015 by Charles Ferguson, president of the Federation of American Scientists (FAS). The report noted that South Korea could produce 2,500 kg of semi-weapon-grade plutonium from its four pressurized heavy water reactors annually, enough to make 416 nuclear bombs annually.

Jeong insisted that possessing nuclear weapons is not economically damaging. He said, "We have excellent nuclear technology and abundant nuclear materials, so we can develop nuclear weapons for about 1 trillion won." [about one billion dollars] He said, "We purchased about 7.8 billion dollars (about 9.13 trillion won) of weapons from abroad in 2014 alone. If we do this, we will be able to significantly reduce the cost of purchasing weapons,” he said.

Ferguson noted that "the four PHWRs at Wolsong would be the preferred production route for near-weapons-grade plutonium... [the] PyRoprocessing Integrated DEmonstration (PRIDE) facility ... could provide a smaller scale means to extract the first few bombs’ worth of fissile material while KAERI is building a bigger reprocessing facility... South Korea has a large plant that can produce about 400 tons per year of heavy water run by Korea Electric Power Corporation (KEPCO) Nuclear Fuel Limited in Daejon. Korea’s HANARO research reactor and four PHWRs at Wolsong routinely make tritium..."

According to the unpublished October 2014 calculations of Thomas Cochran and Matthew McKinzie, South Korea could make about 2,500 kg or 416 bombs’ worth of near-weapons-grade plutonium (with a Pu-240 content of about 10 percent) from the four PHWRs at the Wolsong Nuclear Power Plant assuming 6 kilograms of weapons-grade plutonium per bomb. Cochran and McKinzie point out the ROK could first make a “Simple, Quick Processing Plant,” which could only require four to six months to build.

The Moon administration proposed a program to acquire a nuclear-powered attack submarine. An atomic submarine can be a pathway to an atomic bomb. The Highly Enriched Uranium [HEU] needed for a bomb can also fuel a submarine. Higher levels of enrichment provide longer reactor core life and less frequent refueling. A naval reactor core might contain from 200 to 400 kilograms (kg) of U-235. The minimum mass of fissile material needed for a nuclear weapon is called a critical mass and depends on many factors. A bomb made with Urannium might need from 15 kig to 56 kg of U-235. The HEU required for a single nuclear submarine reactor would thus be the equivalent of at least 3 and possibly upwards of nearly 30 nuclear weapons.

Kim Chong In, the leader the People Power Party (PPP), South Korea’s main opposition party, stressed that the country needs to consider acquiring nuclear weapons if North Korea refuses to surrender its own nuclear arsenal. He made the statement speaking to the Seoul Foreign Correspondents’ Club at the Korea Press Center in Seoul on 24 November 2021, when asked about the argument of many on the South Korean right wing that the country should develop a nuclear arsenal. “It’s true that there are some conservatives who think that South Korea should proceed with nuclear armament if North Korea doesn’t denuclearize. If North Korea never gives up its nuclear weapons, South Korea may need to reconsider the option of nuclear armament,” Kim stated.

A 2023 study indicated that more than 76% of South Koreans believe the nation should develop and deploy its own nuclear weapons to serve as a deterrent, with China seen as the biggest threat to peace in the region but North Korea also a constant cause for concern. Announced on 30 January 2023, the study on attitudes towards a domestic nuclear deterrent was conducted by the Chey Institute for Advanced Studies, with 60.7% of the respondents to the think tank's questionnaire saying they believe South Korea is "somewhat in need" of developing its own nuclear weapons. An additional 15.9% said a nuclear deterrent is "very much in need." A mere 3.1% of those polled said the South has absolutely no need for its own nuclear weapons, while a further 20.3% responded that there is "little need” for a domestic nuclear deterrent. The Chey Institute study came on the heels of a series of similar polls that all point in a similar direction — increasing support for a domestic nuclear capability. In recent years, research by the Chicago Council on Global Affairs put the figure at 71% of the public, while another study by the Asian Institute for Policy Studies determined the support rate to be 70.2%. Perhaps surprisingly, support for an independent nuclear capability had support from across the political spectrum in South Korea. Conservatives insist an arsenal of nuclear weapons is necessary to fend off the threat posed by Beijing. China has in recent years been aggressively expanding its control of the South China Sea, is demanding control over Taiwan and has made increasingly bold territorial claims against many of its neighbors, including South Korea. The unpredictable Kim Jong Un-led regime in Pyongyang has also been investing heavily in its nuclear and long-range missile capabilities in recent years, with analysts predicting an eighth underground nuclear test at the North's Punggye-ri proving grounds in the coming months. Others in the South have been alarmed at the perceived fragility of the security alliance that has tied the US to Seoul since the outbreak of the Korean War in 1950. While in power, President Donald Trump strong-armed Seoul into sharply increasing the amount it paid to keep US troops in the South by threatening to withdraw US forces from the peninsula. Even some to the left of the political spectrum are throwing their support behind a homegrown nuclear capability. They say it would permit Seoul to rely less heavily on the defensive umbrella provided by the US, enable a drawdown of US military personnel and ensure that South Koreans made decisions for themselves on matters of national security.

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