On 2 April 2013, the Democratic People's Republic of Korea announced that the March 2013 plenary meeting of the Central Committee of the Workers' Party of Korea had set forth "a new strategic line on carrying on the economic construction and the building of nuclear armed forces simultaneously under the prevailing situation to meet the legitimate requirement of the developing revolution." Subsequently a spokesman for the General Department of Atomic Energy of the DPRK said that as a result of the new strategic line "[t]he General Department of Atomic Energy of the DRPK decided to adjust and alter the uses of the existing nuclear facilities, to begin with, in accordance with the line. This will include the measure for readjusting and restarting all the nuclear facilities in Nyongbyon including uranium enrichment plant and 5MW graphite moderated reactor which had been mothballed and disabled under an agreement reached at the six-party talks in October, 2007."
The move followed a string of increasingly strong and threatening rhetoric from the DPRK following the decision by the United Nations Security Council to impose additional sanctions on the country following its third nuclear weapons test in February 2013. Both the Republic of Korea and the People's Republic of China expressed regret at the DPRK's decision, with China also calling on "the relevant parties to keep calm and exercise restraint." Secretary General of the United Nations Ban Ki-Moon said that the decision showed that the crisis on the Korean Peninsula "has already gone too far."
North Korea had several nuclear facilities that, collectively, had the potential to produce nuclear fuel for weapons. Most were located at Yongbyon, 60 miles north of Pyongyang, which had an estimated staff of some 2,000. The major installations included a 5-megawatt electric (MW(e)) research reactor, a larger a 50-MW(e) reactor that was under construction in Yongbyon, and a plutonium reprocessing facility. Yongbyon was also the site of the Radiochemical Laboratory of the Institute of Radiochemistry, the Nuclear Fuel Rod Fabrication Plant, and a storage facility for fuel rods.
Under the cooperation agreement concluded between the USSR and the DPRK, in 1965 a Soviet IRT-2M research reactor was assembled for this center. From 1965 through 1973 fuel elements enriched to 10 percent were supplied to the DPRK for this reactor. In 1974, Korean specialists independently modernized this reactor bringing its capacity up to 8 megawatts and switching to fuel enriched to 80 percent.
Since nuclear development began in earnest in the 1980s, the college of physics and technical college of physics were set up at Yongbyon to train specialists necessary for the operation of nuclear facilities like the atomic reactor at Yongbyon, the nuclear fuel re-processing plant and nuclear fuel manufacturing plant.
In March 1986, satellite imagery of Yongbyon depicted small craters in the sand near a river bank, apparently from experimental high-explosive detonations. At that time a study earlier imagery showed similar craters in the same area since 1983. In June 1988, satellite imagery reportedly indicated craters at a detonation test site used to develop high explosive implosion techniques for nuclear weapons located near the Kuryong-gang River [ie, Kuryong-gang 39°44'"N 125°49'"E]. By 1991, South Korean sources estimated that North Korea had conducted approximately 70 explosions at a test site located along the banks of the aka Yuryong river (south of Yongdong).
The Comprehensive Safeguards Agreement with the DPRK entered into force on 10 April 1992, permitting verification that all nuclear material and all nuclear facilities in the DPRK were used exclusively for peaceful purposes and assessment of whether the initial declaration of material and facilities was complete and correct.
On 4 May 1992, North Korea submitted its declaration of nuclear materials to IAEA, as required by IAEA's safeguards agreements. According to the declaration, North Korea had 7 sites and about 90 grams of plutonium in its possession that were subject to IAEA's inspections. According to North Korea, the nuclear material resulted from its reprocessing of 89 defective fuel rods in 1989.
In July 1992, an IAEA inspection team collected information that subsequently resulted in the disclosure of discrepancies in North Korea's declaration of nuclear materials. Instead of reprocessing spent fuel from 89 damaged fuel rods on just one occasion, IAEA concluded that North Korea had probably reprocessed spent fuel on 3-4 occasions since 1989. Additional inspections revealed further inconsistencies in North Korea's declaration.
These inconsistencies between the DPRK's declaration of nuclear material and International Atomic Energy Agency (IAEA) findings led the Agency to conclude that undeclared plutonium had to exist in the DPRK, whether in grams or kilograms. Three separate, but possibly interrelated elements were the object of the Agency's special interest: firstly, 2 sites that were apparently related to nuclear waste that could provide evidence of reprocessing activities in the DPRK; secondly, the core of the 5 MW(e) Experimental Nuclear Power Reactor, the history of which could shed light on the extent of any possible reprocessing; and thirdly the DPRK's reprocessing plant, called the Radiochemical Laboratory, and the use that had been made of it.
Late in 1992, the IAEA informally requested that it be given access to 2 additional sites, located in the Yongbyon nuclear complex, that it suspected of housing nuclear waste. North Korea allowed IAEA to visually inspect one of the sites, but denied any access to the other. On 9 February 1993, IAEA invoked the "special inspections clause" of its safeguards agreement with North Korea, indicating that it wanted to inspect 2 sites that North Korea had not declared and that IAEA suspected had a bearing on the history of North Korea's nuclear program. North Korea denied IAEA access to the 2 undeclared sites. North Korea said that the sites were military installations with no connection to its nuclear program.
At a 22 February 1993 meeting of the IAEA board, the members were shown US overhead surveillance photographs and a chemical analysis of data collected by IAEA inspectors. The evidence reportedly confirmed the existence of a nuclear waste dump, long denied by North Korea, and disclosed discrepancies in North Korea's declaration of the nuclear materials in its possession. On 12 March 1993, North Korea announced its intention to withdraw from the Non-Proliferation Treaty, effective 12 June 1993. The announcement elevated what was viewed as a serious proliferation threat into a major diplomatic confrontation between the United States and North Korea.
On 15 February 1994, after lengthy talks with the IAEA, a detailed understanding was reached with the IAEA about conducting inspections that the Agency requested, with the exception of the 2 non-declared, apparently waste related sites. IAEA resumed inspections between 3 and 14 March 1994. The inspectors proceeded without incident at several locations but encountered problems at the reprocessing plant, where they were precluded from entering certain portions of the plant and performing activities, such as taking samples from reprocessing equipment and conducting a gamma ray scan of the reprocessing facility, that North Korea had agreed to on 15 February 1994. On 15 March 1994, IAEA terminated inspections after North Korea barred the inspectors from taking samples at key locations in its plutonium reprocessing plant. The March 1994 inspection reportedly indicated that North Korea had resumed construction on the second reprocessing line in the facility, constructed new connections between the old and new reprocessing lines, and broken seals on previously tagged reprocessing equipment.
In early 1994, the American military prepared detailed plans for attacking the Yongbyon facility with precision-guided munitions. The US was confident that the reactor could be destroyed without causing a meltdown that would release radioactivity into the area. The nearby buildings designed to reprocess the reactor fuel into bomb material would also be leveled in the attack. The US demonstrated a willingness to use military force by positioning forces to strike Yongbyon and reinforcing military units that were deployed to defend South Korea.
After further talks between DPRK and other States, the DPRK accepted Agency inspection of the points earlier blocked. Following progress made during bilateral consultations between DPRK and United States representatives, the DPRK accepted enlarging the scope of inspections in early September 1994. The IAEA inspectors were given access to the Nuclear Fuel Rod Fabrication Plant and the Nuclear Fuel Rod Storage facility for periodic inspections, as required by the IAEA. The inspectors were also enabled, in addition to the other activities being carried out at the 5 MWe Reactor, to enter the reactor fuel storage to verify the fresh fuel rod inventory. However, at the Radiochemical Laboratory, the DPRK continued to refuse to allow the Agency inspectors to ascertain the state of completion of the new process line under construction there and declined examination of records and gamma-mapping activities.
On 21 October 1994, the United States and North Korea signed in Geneva a Framework Agreement to resolve the North Korean nuclear issue. Its main provisions were that 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 2 1,000 MW light-water nuclear reactors, which would be safer and would produce much less plutonium (the key material for atomic weapons), in order to help boost the supply of electricity in the North.
Under the "Agreed Framework" the DPRK agreed that there would be no operations at the facilities covered by the freeze and no construction work of any kind, either at existing facilities or new, related facilities; that the spent fuel from the 5 MWe reactor would be stored and disposed of in a manner that did not involve reprocessing in the DPRK; and that any movements of nuclear material or equipment within those facilities, any necessary maintenance work by the operator and any transfers of nuclear material out of the facilities would have to be carried out under the observation of IAEA inspectors or under other IAEA arrangements.
IAEA inspectors regularly monitored the 5-MW(e) reactor, the fuel fabrication plant, and the reprocessing plant. IAEA used all technical means available to monitor the freeze at these facilities, such as using seals that could indicate instances of tampering, using video cameras, and making short-notice inspections. The particular method(s) used depends on the circumstances at each of the 3 facilities. The primary monitoring method was the use and frequent verification of tamper-indicating seals on equipment and installations throughout the "frozen" nuclear facilities. Video cameras were also used for surveillance. Finally, short-notice inspections were used to monitor certain equipment and areas in the frozen facilities that have not been allowed to be sealed. IAEA inspectors also monitored activities related to the canning and storage of spent fuel from the 5-MW(e) reactor and had, through qualitative measurements of the fuel rods (spent fuel), verified whether the rods were, in fact, irradiated (spent) fuel rods.
As of late 1999, United States experts remained on-site in North Korea working to complete clean-up operations after largely finishing the canning of spent fuel from the North's 5-megawatt nuclear reactor.
Through late 2002, the DPRK continued to maintain a freeze on its nuclear facilities consistent with the 1994 US-DPRK Agreed Framework. North Korea had not allowed the IAEA to perform inspections sufficiently comprehensive at all sites to verify the operating history of the 5-megawatt (electric) reactor, the amount of reprocessing accomplished, and whether special nuclear materials had been diverted to develop nuclear weapons.
Under strict adherence to the Agreed Framework, North Korea was required to make its nuclear program completely transparent and had to allow the IAEA to perform special inspections prior to the delivery of Nuclear Suppliers' Group (NSG) controlled items to the Light Water Reactors. North Korea also had obligated itself beyond its NPT and IAEA requirements by agreeing to eliminate eventually all its existing or planned nuclear power and related facilities.
In early December 2002, North Korea received a shipment of 20 tons of the specialty chemical tributyl phosphate (TBP) from a Chinese company in Dalian, a Pacific coast port. The chemical shipment coincided with the announcement by Pyongyang that it would restart its nuclear reactors in Yongbyon, and the TBP could be used to extract material for nuclear bombs from North Korea's stockpile of spent nuclear-reactor fuel.
By the end of 2002, North Korea said it was lifting the freeze on facilities frozen under the agreed framework between the United States and North Korea, including a nuclear reactor at Yongbyon. Furthermore, North Korea asked the International Atomic Energy Agency to remove its cameras from the Yongbyon facility. North Korea defied world opinion on 21 December 2002 by removing United Nations seals and cameras at a nuclear power plant suspected of making weapons-grade plutonium. North Korea tampered with surveillance devices the UN nuclear watchdog installed at the Yongbyong complex. The agency said the North cut most of the seals on equipment and tampered with cameras at the 5-megawatt reactors. North Korea said the agency did not respond to Pyongyang's requests that it remove the equipment. The International Atomic Energy Agency said it was trying to keep communications open with Pyongyang. IAEA chief Mohamed ElBaradei said it was deplorable North Korea had ignored requests for talks.
US Senator Joe Biden said he believed North Korea's restarting of the Yongbyon nuclear reactor posed a greater threat than Iraq. He said within months Pyongyang could have enough material for 5 more nuclear weapons. The incoming chairman of the US Senate Foreign Relations Committee, Republican Senator Richard Lugar, said Washington had to actively engage its allies in the region.
During a visit to Yongbyon on 8 January 2004, North Korea showed an unofficial American delegation what it asserted was weapons-grade plutonium. The group spent about a day at Yongbyon, and was shown the empty cooling pond where the 8,000 fuel rods from the 5-megawatt nuclear reactor had been stored. During the visit, the reprocessing plant was operating.
The Six-Party plenary meeting held between 27 and 30 September 2007 resulted in the 3 October 2007 agreement on "Second-Phase Actions for the Implementation of the Joint Statement." Under the terms of the 3 October 2007 agreement, the DPRK agreed to disable all existing nuclear facilities subject to abandonment under the September 2005 Joint Statement and the 13 February 2007 agreement. The parties agreed to complete by 31 December 2007, a set of disablement actions for the 3 core facilities at Yongbyon, the 5-MW(e) Experimental Reactor, the Radiochemical Laboratory (Reprocessing Plant), and the Fresh Fuel Fabrication Plant, with oversight from a team of US experts. The DPRK also agreed to provide a complete and correct declaration of all its nuclear programs in accordance with the 13 February 2007 agreement by 31 December 2007 and reaffirmed its commitment not to transfer nuclear materials, technology, or know-how.
In November 2007, the DPRK began to disable the 3 core facilities at Yongbyon and completed most of the agreed disablement actions by the end of the year. Due to health and safety concerns, disablement activities at the 5-MW(e) reactor continued beyond 31 December 2007. Assistant Secretary of State Christopher Hill visited Pyongyang again in December 2007 as part of ongoing consultations on the implementation of Second-Phase actions and carried with him a letter from the President of the United States to Kim Jong-il. The DPRK missed the 31 December 2007 deadline to provide a complete and correct declaration, but efforts to secure a declaration continued into January 2008.
While the DPRK missed the 31 December 2007 deadline to provide a complete and correct declaration, it provided its declaration to the Chinese, chair of the Six-Party Talks, on 26 June 2008. The DPRK also imploded the cooling tower at the Yongbyon facility in late June 2008 before international media. Following the DPRK's progress on disablement and provision of a declaration, President Bush announced the lifting of the application of the Trading with the Enemy Act (TWEA) with respect to the DPRK and notified Congress of his intent to rescind North Korea's designation as a state sponsor of terrorism.
President Bush made clear that the United States needed to have a strong regime in place to verify the DPRK's declaration before it removes the DPRK from the list of state sponsors of terrorism. As of August 2008, the United States continued to work with its Six-Party partners to establish such a verification regime, and remained prepared to move forward with taking the DPRK off of the state sponsors of terrorism list once a verification regime was in place.