North Korea

North Korea is the latest country to acquire nuclear weapons. In 2003, the country withdrew from the Non-Proliferation Treaty (NPT), and in 2006, the country tested its first nuclear weapon. Although the test explosion was considered a failed test, North Korea has since conducted additional nuclear weapons tests and tested several missiles. There is still great uncertainty surrounding North Korea’s nuclear weapons program, but the country is expanding its nuclear arsenal and, according to scientists, has about 20 nuclear weapons.

Between 1985 and 2003, North Korea was a member of the NPT, but then left the agreement. North Korea is not a party to the Comprehensive Test Ban Treaty (CTBT). North Korea is considered a de-facto nuclear weapon state because it developed its nuclear weapons after the NPT was negotiated in 1968. North Korea is not a member of the UN Treaty on the Prohibition of Nuclear Weapons (TPNW).

Currently, the tension between North Korea and the US, Japan and South Korea is palpable. After the country’s nuclear and missile tests, sanctions against the country have increased and the outside world has expressed strong criticism of the country’s nuclear weapons development. Between North Korea’s leader Kim Jong Un and former US President Donald Trump, there was a fierce exchange of words that further increased tensions and the threshold of using nuclear weapons has not been far away.

The North Korean leadership states that the motive for building nuclear weapons is to deter the United States from an attack. North Korea has pointed out that the leaders of Iraq and Libya were attacked when their nuclear weapons programs ended.


After the Korean War ended in 1953, the North Korean leadership began to explore the possibility of developing nuclear weapons. The construction of a reactor began in 1964 in Yongbyon and used the so-called “Magnox” technology where drawings and descriptions were publicly available.

Since 1986, the country has another operating reactor that produces so-called separated plutonium that can be used for nuclear weapons. Independent experts believe that the reactor has produced around 43 kilos (+/- 10 kilos) of separated plutonium. Scientists suggest that North Korea may have produced enough material to build 40-50 nuclear weapons, depending on the explosive power assigned to each nuclear weapon.


During the 1990s, the United States and South Korea negotiated with North Korea over the country’s nuclear weapons program. In the “Agreed Framework”, North Korea would suspend certain projects, especially plutonium production, that could lead to nuclear weapons production. In return, South Korea and the United States would, among other things, deliver oil and build two nuclear power reactors of the so-called light water type, which were not suitable for the production of weapons plutonium. The reactors were not built, partly because of opposition in the US Congress and North Korea not allowing some of the inspections required by the International Atomic Energy Agency (IAEA). This led to the resumption of the country’s nuclear weapons program in the late 1990s.

In 2000, a new agreement was negotiated to end North Korea’s nuclear weapons program. This agreement was later abandoned by then US President George W. Bush who notified the South Korean President that dialogue with North Korea would cease immediately.

Leaving the NPT

North Korea was a member of the Non-Proliferation Treaty (NPT) but withdrew from the agreement in early 2003. Just a month or so later, North Korean officials revealed at a US-North Korea roundtable that the country had developed nuclear weapons. Furthermore, North Korea has threatened that it has and is considering exporting reprocessed plutonium rods unless the United States agrees to bilateral talks. Negotiations with North Korea – which went on for many years with long periods of hiatus and reluctance to cooperate – were conducted in the so-called six-party talks between North Korea, the United States, Japan, South Korea, China and Russia.

North Korea’s first nuclear test was conducted on October 9, 2006. The explosive force was estimated at less than one kiloton, which can be compared to the bomb dropped on Hiroshima in 1945 which had an explosive force of 15 kilotons. The test did not reach the explosive power the country had expected.

By February 2007, the six-party talks had reached an agreement under which North Korea would freeze its nuclear weapons program within 60 days, provide a full inventory of its nuclear weapons material, close its plutonium-producing reactor at Yongbyon, and ultimately completely abolish its nuclear weapons program. In return, the country would receive financial support, energy aid and humanitarian assistance. In addition, North Korea would receive oil and previously frozen offshore assets would be released. The agreement also meant that North Korea and the US would hold bilateral talks between themselves.

North Korea left the six-party talks in April 2009 after the United States condemned a test of one of North Korea’s long-range ballistic missiles. In May 2009, North Korea conducted another test of a nuclear charge, this time estimated to be several kilotons. In total, the country has conducted six nuclear weapons tests (October 2022). North Korea has also tested several missiles capable of carrying nuclear weapons, something that continues to happen at regular intervals.

New negotiations

In June 2018, former US President Donald Trump and North Korean leader Kim Jong Un met in Singapore for a first-of-its-kind meeting to discuss North Korea’s nuclear weapons program and disarmament. The first meeting led to a joint statement which, among other things, addressed that “North Korea will work for the ‘complete denuclearization of the Korean Peninsula”. The second meeting was held in Hanoi in February 2019, but the talks broke down and no concrete progress was made.

Nuclear arsenal

Unlike the other nuclear weapons states that started their development of nuclear weapons with bombs from aircraft, North Korea develops its nuclear weapons only in the form of ballistic missiles.

North Korea does not make public information about its nuclear weapons capability or its stockpile of fissile material, making the country’s nuclear arsenal difficult to estimate. However, the country has the capacity to develop nuclear weapons and in 2017 something similar to a hydrogen bomb was tested. Scientists believe that North Korea, with its stockpile of material, can produce about 10-20 nuclear weapons. Today there are experts who believe that North Korea will increase its nuclear arsenal, but the sources are uncertain.

Nuclear weapon upgrade

North Korea has an active program to produce new missiles. Whether these missiles can carry nuclear weapons is still unclear. Despite North Korea’s development of several long-range missiles over the past decade, only the Nodong missile is sufficiently tested to carry a nuclear weapon. Scientists believe that the country does not have a functioning long-range missile at present.

In March 2022, new information came that there is ongoing activity at North Korea’s nuclear weapons facility. Old buildings are being repaired and new buildings are under construction. The country is said to have destroyed the buildings in connection with suspending its nuclear weapons program in 2018, but begun reconstruction of the buildings in early 2022.

The role of nuclear weapons in national security strategy

North Korea declared a “no-first-use” policy in 2016, meaning that it will not use nuclear weapons first in a conflict. However, this statement is diluted and questioned due to the country’s leader, Kim Jong Un’s statements about using nuclear weapons if the North Korean state’s existence, state security and its political leadership were in danger.

Sources and other information

Nuclear Notebook: North Korean Nuclear Weapons, 2021, Hans M. Kristensen and Matt Korda
Assessment of the Singapore Summit, Center for Strategic and International Studies, June 12 2018
The Six-Party Talks at a Glance, Arms Control Association, January 2022


Swedish Physicians Against Nuclear Weapons

Last updated
14 February, 2023