North Korea

There is considerable uncertainty surrounding the North Korean nuclear program and whether and if so how many nuclear weapons it may have produced. According to estimates, North Korea has around 10 warheads in its nuclear arsenal.

Developments in nuclear weapons


Yongbyon Magnox

After the destructive Korean war ended in 1953, the North Korean leadership began examining the possibilities of developing nuclear weapons. The construction of a small 20 Megawatt reactor (measured in thermal effect) was initiated in 1964 in Yongbyon, utilizing the so-called “Magnox”-technique where blueprints and descriptions were publicly available. This reactor utilizes natural Uranium as fuel (which does not need enrichment), using graphite as its neutron moderator and carbon dioxide as coolant.

North Korea has some indigenous deposits of Uranium, and the reactor itself was in use between 1986 and 1994, and again from 2003 to 2007. North Korea also began the construction of a larger reactor of the same type with a 200 Megawatt effect at the Yongbyon site, as well as a third 800 Megawatt reactor in Taechon, although the construction work was halted in 1994 after an agreement was reached with the US. This construction work has not been resumed.

In 2009 however, after the UN condemned North Korea’s latest rocket launch, North Korea announced through its state press agency KCNA that the country would begin operations to reprocess spent Uranium fuel in order to extract Plutonium. It is suspected that the extracted Plutonium has since been used for nuclear testing.

Despite some relaxations of tensions since then, North Korea signalled in 2013 that it would restart the operation of a 5 Megawatt experimental reactor at the Yongbyon site. Satellite imagery soon after then showed steam emanating from the site’s cooling towers suggested that North Korea has begun producing fuel rods for the restarted reactor. The restart of operations followed just a few days after North Korea publicly declared that it was in “a state of war” with South Korea.

A development plan using the conventional Purex-technique has also been constructed in order to extract Plutonium. Different estimates speculate that North Korea may have extracted between 6 to 24 kg of Plutonium, enough for a small amount of nuclear devices. Construction nuclear weapons that utilize Plutonium present however a far more demanding technical challenge than one utilizing enriched Uranium. Purifying Plutonium into pure metallic (weapons-grade) form is difficult, and additionally requires a complex trigger fuse using conventional explosives in order to create an implosion effect by triggering the fuse around the Plutonium charge at the exact same time.

All nuclear weapons were withdrawn from South Korea in 1991. North Korea and South Korea soon signed a mutual treaty of non-aggression, as well as a mutual declaration that the Korean peninsula would remain free of nuclear weapons. North Korea also became a member of the Non-Proliferation Treaty (NPT) in 1985, and additionally signed the “safeguards agreement” in 1992 that allowed for inspections by the IAEA, the International Atomic Energy Agency.


Kim Il Sung and Kim Jong Il

The inspections did however encounter difficulties as the IAEA found indications of preparations to create nuclear devices, and North Korea subsequently threatened to withdraw from the NPT. Then-US president Bill Clinton began preparing military action against North Korea, and former president Jimmy Carter flew to Pyongyang in order to negotiate. He succeeded in getting a promise from the former president Kim Jong-il on a halt on Plutonium production.

According to the negotiated framework, North Korea was to cease Plutonium production while the company ABB would in return build two light-water reactors in North Korea on the behalf of the US, a type of reactors that cannot be used for Plutonium production. The old North Korean reactors would subsequently be dismantled and the fuel rods were to be given up. 15 IAEA-inspectors then remained in Yongbyon in order to monitor the agreement. Further on it was agreed that relations between the two countries would improve and that North Korea would receive oil deliveries from the US. Meanwhile however, some US sources claimed that North Korea had enriched Uranium to weapons grade.

While there was not sufficient evidence for these claims, the chief of the Pakistani nuclear weapons programme, A. Q. Khan, reportedly visited Pyongyang on numerous occasions, possibly also selling gas centrifuges needed for Uranium enrichment. The level of technology in North Korea is however believed to be so low that it is unlikely that they have mastered the process sufficiently for large-scale production of highly enriched Uranium.

US suspicions against North Korea increased as former US president George W. Bush placed North Korea in the infamous “Axis of evil”. Oil deliveries were withheld, the light water reactor was never built, and diplomatic tries between the two countries withered. North Korea then signalled in 2003 that the country would withdraw from the NPT and that IAEA inspectors were barred from entry to North Korea and its sites. The reactor in Yongbyon was reopened in 2003, and in 2005 North Korea stated that it had produced nuclear weapons.

In October 2006, North Korea detonated a nuclear device with an explosive yield estimated to be only about one kiloton, based on estimates conducted by the CTBTO (Comprehensive Test Ban Treaty Organization). The low yield indicated that the nuclear test was a partial failure. The test nevertheless led to new negotiations within the Six Party Talk framework. The talks concluded with new agreements that North Korea would halt its nuclear activities and open up to international controls, and that the country in return would receive financial aid, energy supplies and security guarantees.

North Korea however left the Six Party Talks on a dismantling of its nuclear weapons programme in April 2009, after the US condemned the test of the country’s long-range ballistic missiles. In May 2009, North Korea conducted a test of an additional nuclear device, this time being estimated to yield several kilotons.

Following a dramatic escalation of North Korean rhetoric after a souring of international tensions dubbed the “2013 Korean crisis”, North Korea stated that it had conducted a third underground nuclear test in February 2013. The tensions had been triggered after North Korean had commenced two launches of “Kwangmyŏngsŏng” satellites using the Unha-3 rocket variant of its Taepodong-2 long-range ballistic missile in 2012.

While the rockets attempted to deliver an artificial satellite into orbit (the first launch was a failure, while the second was successful), the launches were controversial as they have generally been viewed as tests of the country’s long-range missile capability. This test was also estimated to also yield several kilotons according to multiple sources, similar to the 2009 test, and thereby marked a continued commitment of North Korea to its nuclear weapons programme.

North Korea has on several occasions attempted to establish direct bilateral negotiations between North Korea and the US, where the US has replied that such talks are only possible if the purpose of such talks are to re-establish the Six Party Talks.

Modes of delivery

North Korea has an active programme for producing short-, medium- and long-range ballistic missiles, often being based on Soviet (Scud-B and Scud-C in the case of the Nodong missile) and Russian design (R-27, in the case of the Musudan missile). Some of these have been sold to Iran and other countries (16). However, there is currently no public evidence of North Korea having developed a nuclear warhead that could be placed on its ballistic missiles.

  • Nodong: North Korea’s older medium-range and road-mobile “Nodong”-missile is believed to have a 1000-1250 km range. This enables it to strike the Japanese island of Okinawa which maintains a US military presence. The missile was most recently tested again on March 26th.
  • Musudan: North Korea is currently developing a medium-range ballistic missile (>3000 km range) dubbed the BM-25 “Musudan”. The Musudan was first being presented in a North Korean military parade in 2010, but has not yet been flight tested.
  • Taepodong-2: Believed to currently still be in development after a series of failed tests, North Korea’s Taepodong-2 missile is nevertheless believed to have the sufficient range to strike Alaska (>5500 km range) given a successful launch. The missile’s reliability is however disputed following the multiple failed tests and only one successful test, which on the other hand was for the purpose of delivering an artificial satellite into orbit and not re-entering the atmosphere, like a ballistic missile would need to do if it is to be used as a weapon.
  • Hwasong-13: North Korea is also developing another long-range ballistic missile (believed to have >5500 km similar to the Taepodong-2), dubbed the KN-08 “Hwasong-13”. While the Hwasong-13 was publicly displayed in a military parade in 2012, some analysts have argued that the missiles displayed were mock-ups due to design anomalies that caused doubt over whether these missiles were actually operative.

Despite North Korea’s developments of multiple longer-range missiles over the last decade, only the short-range Nodong-missile remains sufficiently tested to conclude its viability. Despite its short range, the missile continues to pose a regional security threat to North Korea’s neighbour states.

Nuclear weapons stockpile

North Korea does not publicly disclose information on its nuclear weapons capability and stockpile, which makes any assessment of North Korea’s capabilities based on guesstimates. Widely cited estimates have however estimated that the country per 2014 is likely to only have produced a maximum of 8 rudimentary nuclear weapons, assuming that the bombs use 5 kilogrammes each of North Korea’s limited Plutonium supply. The country’s conventional military capability thereby remains as a far greater security threat to neighbouring states today.

Fissile material inventory

Similar to North Korea’s nuclear weapons stockpile, very little is known about North Korea’s inventories of fissile material. Nevertheless, the fissile material used in North Korea’s three nuclear tests (per 2015) is believed to originate from indigenous fissile material production, more specifically the reactor at Yongbyon.

In late 2010, North Korea revealed that it had constructed a Uranium enrichment plant at the Yongbyon site with an estimated 2000 gas centrifuges bearing striking similarities to the Pakistani P-2 Uranium enrichment centrifuges. North Korea continues to claim that the enrichment plant is for producing low-enriched Uranium (LEU) for a civilian light-water reactor, but this is currently impossible to verify as the reactor is not under IAEA safeguards.

Nuclear threats

After the recent souring of international relations between North Korea and the US and its regional allies South Korea and Japan, the dispute has since 2013 been marked by a dramatic increase in rhetoric.

In March 2013, following a new round of UN-approved sanctions on North Korea, the country responded by publicly stating that it had the right to conduct a ”pre-emptive nuclear strike” on the US.


Kim Jong Un

Another recent nuclear threat came in late July 2014, in a speech delivered by top ranking North Korean vice marshal Hwang Pyong-so to the country’s General Political Bureau. In his speech, which was broadcasted on North Korean television, Hwang accused the United States of increasing military tensions on the Korean peninsula and stated that “If the US imperialists threaten our sovereignty and survival… our troops will fire our nuclear-armed rockets at the White House and the Pentagon – the sources of all evil”.

The Six Party talks

The Six Party talks was a framework aiming at ending North Korea’s nuclear weapons programme through negotiations involving North Korea, South Korea, China, Japan, Russia and the United States.

Beginning in 2003, the Six Party talks have experienced difficulties in containing North Korea’s nuclear ambitions, and finally broke down in 2009. Efforts have continuously been made by different countries in resuming the talks, most recently in 2013 as China attempted to resume talks after sending its nuclear weapons envoy to Pyongyang, with North Korea returning the favour by sending its nuclear weapons envoy to Beijing soon after. At the launch of a Chinese-initiated ten year anniversary of the Six Party talks, the talks were however boycotted by the US, South Korea and Japan due to the absence of North Korean commitments.

North Korea is generally believed to have benefitted from its coercive bargaining tactics and its threats of nuclear weapons production, often gaining much-needed oil and energy supplies in return for visible measures to discontinue its nuclear weapons programme. The country is however unlikely to be interested in discontinuing its nuclear weapons programme any time soon and thereby losing its strong source of bargaining power. However, there is also little reason to believe that the US and South Korea will worry over any immediate threat emanating from the north, as North Korea is unlikely to be able to produce a large number of nuclear weapons in the foreseeable future.

North Korea has claimed that there are still US nuclear weapons deployed in South Korea, an argument that a delegation from IPPNW (International Physicians for the Prevention of Nuclear War) was repeatedly told during its visit to Pyongyang in 2005. North Korea demands that the defence agreement that gives the US a right to intervene if South Korea is threatened is abolished. Additionally, North Korea desires a “non aggression” treaty with the US and ultimately a peace agreement, but talks on this subject have not yet begun as of 2015.

North Korea continues its policy of withdrawal from the NPT, and is not recognized as an official nuclear weapons state. North Korea is only partially believed to be a de facto nuclear weapons state as North Korea has demonstrated its capability to test nuclear fission devices, but not yet demonstrated a capability to develop these fission devices as weapons either on gravity bombs or as nuclear warheads for its ballistic missiles.

North Korea are testing both missiles and nuclear weapons frequently these days.

Last update: June 30, 2016