North Korea conducted an underground nuclear explosive test on October 16, 2006. The estimated yield of the test was less than one kiloton.
In a roundtable discussion with the United States and China in Beijing on April 24, 2003, North Korean officials admitted for the first time that they possessed nuclear weapons. Furthermore, North Korean officials claim to have reprocessed spent fuel rods and have threatened to begin exporting nuclear materials unless the United States agrees to one-on-one talks with North Korea.
Tensions between the United States and North Korea have been running especially high since, in early October of 2002, Assistant Secretary of State James Kelly informed North Korean officials that the United States was aware that North Korea had a program underway to enrich uranium for use in nuclear weapons. Initially North Korea denied this, but later confirmed the veracity of the US claim. In confirming that they had an active nuclear weapons program, they also declared the Agreed Framework nullified.
The Agreed Framework signed by the United States and North Korea on October 21, 1994 in Geneva agreed that:
Prior to the establishment of the Agreed Framework, intelligence sources believed that North Korea could have extracted plutonium from their reactors for use in nuclear weapons; perhaps enough for one or two nuclear weapons.
Nevertheless, it has remained unclear whether North Korea had actually produced nuclear weapons due to difficulties in developing detonation devices.
North Korea maintains uranium mines with an estimated four million tons of exploitable high-quality uranium ore. Information on the state and quality of their mines is lacking, but it is estimated that the ore contains approximately 0.8% extractable uranium. In the mid-1960s, it established a large-scale atomic energy research complex in Yongbyon and trained specialists from students who had studied in the Soviet Union. Under the cooperation agreement concluded between the USSR and the DPRK, a nuclear research center was constructed near the small town of Yongbyon. In 1965 a Soviet IRT-2M research reactor was assembled for this center. From 1965 through 1973 fuel (fuel elements) enriched to 10 percent was supplied to the DPRK for this reactor.
In the 1970s it focused study on the nuclear fuel cycle including refining, conversion and fabrication. In 1974 Korean specialists independently modernized Soviet IRT-2M research reactor in the same way that other reactors operating in the USSR and other countries had been modernized, bringing its capacity up to 8 megawatts and switching to fuel enriched to 80 percent. Subsequently, the degree of fuel enrichment was reduced. In the same period the DPRK began to build a 5 MWe research reactor, what is called the "second reactor." In 1977 the DPRK concluded an agreement with the International Atomic Energy Agency [IAEA], allowing the latter to inspect a research reactor which was built with the assistance of the USSR.
The North Korean nuclear weapons program dates back to the 1980s. In the 1980s, focusing on practical uses of nuclear energy and the completion of a nuclear weapon development system, North Korea began to operate facilities for uranium fabrication and conversion. It began construction of a 200 MWe nuclear reactor and nuclear reprocessing facilities in Taechon and Yongbyon, respectively, and conducted high-explosive detonation tests. In 1985 US officials announced for the first time that they had intelligence data proving that a secret nuclear reactor was being built 90 km north of Pyongyang near the small town of Yongbyon. The installation at Yongbyon had been known for eight years from official IAEA reports. In 1985, under international pressure, Pyongyang acceded to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). However, the DPRK refused to sign a safeguards agreement with the International Atomic Energy Agency (IAEA), an obligation it had as a party to the Nuclear Non-Proliferation Treaty.
In July 1990 The Washington Post reported that new satellite photographs showed the presence in Yongbyon of a structure which could possibly be used to separate plutonium from nuclear fuel.
In a major initiative in July 1988, South Korean President Roh Tae Woo called for new efforts to promote North-South exchanges, family reunification, inter-Korean trade, and contact in international forums. Roh followed up this initiative in a UN General Assembly speech in which South Korea offered for the first time to discuss security matters with the North. Initial meetings that grew out of Roh's proposals started in September 1989. In September 1990, the first of eight prime minister-level meetings between North Korean and South Korean officials took place in Seoul, beginning an especially fruitful period of dialogue. The prime ministerial talks resulted in two major agreements: the Agreement on Reconciliation, Nonaggression, Exchanges, and Cooperation (the "basic agreement") and the Declaration on the Denuclearization of the Korean Peninsula (the "joint declaration").
In late 1991 North and South Korea signed the Agreement on Reconciliation, Non-aggression, Exchanges and Cooperation and the Joint Declaration on the Denuclearization of the Korean Peninsula. The Joint Declaration called for a bilateral nuclear inspection regime to verify the denuclearization of the peninsula. The Declaration, which came into force on 19 February 1992, states that the two sides "shallnot test, manufacture, produce, receive, possess, store, deployor use nuclear weapons," and that they "shall not possess nuclear reprocessing and uranium enrichment facilities." A procedure for inter-Korean inspection was to be organized and a North-South Joint Nuclear Control Commission (JNCC) was mandated with verification of the denuclearization of the peninsula.
On 30 January 1992 the DPRK also signed a nuclear safeguards agreement with the IAEA, as it had pledged to do in 1985 when acceding to the Nuclear Non-Proliferation Treaty. This safeguards agreement allowed IAEA inspections to begin in June 1992. In March 1992, the JNCC was established in accordance with the joint declaration, but subsequent meetings failed to reach agreement on the main issue of establishing a bilateral inspection regime.
When North Korean Deputy Prime Minister Kim Tal-Hyon visited South Korea for economic talks in July 1992, President Roh Tae Woo announced that full North-South Economic Cooperation would not be possible without resolution of the North Korean nuclear issue. There was little progress toward the establishment of an inspection regime, and dialogue between the South and North stalled in the fall of 1992.
The North's agreement to accept IAEA safeguards initiated a series of IAEA inspections of North Korea's nuclear facilities. This promising development was halted by the North's refusal in January 1993 to allow special inspections of two unreported facilities suspected of holding nuclear waste. Ignoring the South-North Joint Declaration of the Denuclearization of the Korean Peninsula, North Korea refused IAEA inspections and operated nuclear reprocessing facilities, making the world suspicious of its nuclear intentions.
Lack of progress on implementation of the denuclearization accord triggered actions on both sides that led to North Korea's March 12, 1993, announcement of its withdrawal from the Nuclear Non-Proliferation Treaty (NPT). The North's threat to withdraw from the Nuclear Non-Proliferation Treaty (NPT) brought North-South progress to an abrupt halt. Tensions ran high on the Korean Peninsula as the confrontation between North Korea and the United States deepened.
The UN Security Council on 11 May 1993 passed a resolution urging the DPRK to cooperate with the International Atomic Energy Agency (IAEA) and to implement the 1991 North-South denuclearization accord. It also urged all member states to encourage the DPRK to respond positively to this resolution and to facilitate a solution.
The US responded by holding political-level talks with the DPRK in early June 1993 that led to a joint statement outlining the basic principles for continued US-DPRK dialogue and North Korea's "suspending" its withdrawal from the NPT. A second round of talks was held July 14-19, 1993, in Geneva. The talks set the guidelines for resolving the nuclear issue, improving U.S.-North Korean relations, and restarting inter-Korean talks, but further negotiations deadlocked.
Following the DPRK's spring 1994 unloading of fuel from its five-megawatt nuclear reactor and the resultant US push for UN sanctions, former President Carter's visit to Pyongyang in June 1994 helped to defuse tensions and resulted in renewed South-North talks. A third round of talks between the US and the DPRK opened in Geneva on July 8, 1994. However, the sudden death of North Korean leader Kim Il Sung on July 8, 1994 halted plans for a first ever South-North presidential summit and led to another period of inter-Korean animosity. The talks were recessed upon news of the death of North Korean President Kim Il Sung, then resumed in August. These talks concluded with the Agreed Framework.
Under the framework agreement, the North would freeze and eventually dismantle its existing suspect nuclear program, including the 50 MW and 200 MW graphite-moderated reactors under construction, as well as its existing 5 MW reactor and nuclear fuel reprocessing facility. In return, Pyongyang would be provided with alternative energy, initially in the form of heavy oil, and eventually two proliferation-resistant light water reactors (LWR). The two 1,000 MW light-water nuclear reactors would be safer and would produce much less plutonium, in order to help boost the supply of electricity in the North, which is now in a critical shortage. The agreement also included gradual improvement of relations between the US and the DPRK, and committed North Korea to engage in South-North dialogue.
A few weeks after the signing of the Agreed Framework, President Kim loosened restrictions on South Korean firms desiring to pursue business opportunities with the North. Although North Korea continued to refuse official overtures by the South, economic contacts appeared to be expanding gradually.
A close examination by the IAEA of the radioactive isotope content in the nuclear waste revealed that North Korea had extracted about 24 kilograms of Plutonium. North Korea was supposed to have produced 0.9 gram of Plutonium per megawatt every day over a 4-year period from 1987 to 1991. The 0.9 gram per day multiplied by 365 days by 4 years and by 30 megawatts equals to 39 kilograms. When the yearly operation ratio is presumed to be 60 percent, the actual amount was estimated at 60% of 39 kilograms, or some 23.4 kilograms. Since 20-kiloton standard nuclear warhead has 8 kilograms of critical mass, this amounts to mass of material of nuclear fission out of which about 3 nuclear warheads could be extracted.
Estimates vary of both the amount of plutonium in North Korea's possession and number of nuclear weapons that could be manufactured from the material. South Korean, Japanese, and Russian intelligence estimates of the amount of plutonium separated, for example, are reported to be higher -- 7 to 22 kilograms, 16 to 24 kilograms, and 20 kilograms, respectively -- than the reported US estimate of about 12 kilograms. At least two of the estimates are said to be based on the assumption that North Korea removed fuel rods from the 5-MW(e) reactor and subsequently reprocessed the fuel during slowdowns in the reactor's operations in 1990 and 1991. The variations in the estimates about the number of weapons that could be produced from the material depend on a variety of factors, including assumptions about North Korea's reprocessing capabilities -- advanced technology yields more material -- and the amount of plutonium it takes to make a nuclear weapon. Until January 1994, the Department of Energy (DOE) estimated that 8 kilograms would be needed to make a small nuclear weapon. Thus, the United States' estimate of 12 kilograms could result in one to two bombs. In January 1994, however, DOE reduced the estimate of the amount of plutonium needed to 4 kilograms--enough to make up to three bombs if the US estimate is used and up to six bombs if the other estimates are used.
On 22 April 1997, U.S. Defense Department spokesman Kenneth Bacon officially stated, "When the U.S.-North Korea nuclear agreement was signed in Geneva in 1994, the U.S. intelligence authorities already believed North Korea had produced plutonium enough for at least one nuclear weapon." This was the first time the United States confirmed North Korea's possession of plutonium.
In accordance with the terms of the 1994 framework, the US Government in January 1995 responded to North Korea's decision to freeze its nuclear program and cooperate with US and IAEA verification efforts by easing economic sanctions against North Korea in four areas through:Pyongyang is cooperating with Korean Peninsula Energy Development Organization, whose leading members are South Korea, the United States and Japan. KEDO has reached an agreement on the provision of the light-water nuclear reactors by 2003, and, in return, North Korea has frozen its nuclear program. South Korea, which has promised to bear the lion's share of the reactor project cost estimated at US$4.5 billion, is asking the United States to put up at least a symbolic amount. The US administration, however, has said it can make no contribution to the construction cost as Congress has not appropriated the necessary budget. An official in Seoul, however, said that South Korea cannot drop its demand simply because of domestic problems in the United States. The US Congress has been delaying approval of the cost for the reactor project. South Korean officials said the U.S. refusal to share the reactor cost would make it difficult for them to obtain approval from the National Assembly for the South Korean share.
Since the conclusion of the Supply Agreement in December 1995, six related protocols have come into effect and three rounds of expert-level negotiations have produced solid results. The ROK power company, Korea Electric Power Corporation (KEPCO), is the prime contractor for this project and has as its responsibility the design, manufacture, procurement, construction and management of the reactors. On 19 August 1997 KEDO and North Korea held a groundbreaking ceremony to begin construction of two light-water reactors.
In October 2002, North Korean officials acknowledged the existence of a clandestine program to enrich uranium for nuclear weapons that is in violation of the Agreed Framework and other agreements.
On October 9, 2006, North Korea announced it had conducted a nuclear test. The USGS reported a magnitude of 4.2 on the Richter Scale with a location at 41.29N 129.09E +/- 8.1 km. Initial speculations about the yield ranged from less than 1 kt up to 15 kt. On October 16, 2006, the Office of the Director of National Intelligence announced that analysis of air-samples conducted on October 11 had confirmed that the event had been an underground nuclear explosion near P'unggye on October 9, 2006. DNI concluded that the "explosion yield was less than a kiloton."