0.48 kilotons of TNT (2.0TJ) (Chinese academics)[1]
0.55–12 kilotons of TNT (2.3–50.2TJ) (Jane's Defence Weekly & South Korean estimates, but raised doubts on the lower end estimates because it does not correspond with the 4.2 Richter scale)[2]
On October 3, 2006, North Korea announced its intention to conduct a nuclear test.[7] The blast is generally estimated to have had an explosive force of less than one kiloton, and some radioactive output was detected.[8][9] United States officials suggested the device may have been a nuclear explosive that misfired.[8]
An anonymous official at the North Korean Embassy in Beijing told a South Korean newspaper that the explosive output was smaller than expected.[10] Because of the secretive nature of North Korea and small yield of the test, there remains some question as to whether it was a successful test of an unusually small device (which would have required sophisticated technology), or a partially failed "fizzle" or dud. A scientific paper later estimated the yield as 0.48 kilotons.[1]
North Korea had been suspected of maintaining a clandestine nuclear weapons development program since the early 1980s[13] when it constructed a plutonium-producing Magnoxnuclear reactor at Yongbyon, and various diplomatic means had been used by the international community to attempt to limit North Korea's nuclear work to peaceful and scientific means and encouraging North Korea to participate in international treaties. In 1994, the United States and North Korea signed the "Agreed Framework", whereby North Korea agreed to freeze its graphite moderated reactor program in exchange for fuel, moves toward normalization of political and economic relations, and the construction of two modern nuclear power plants powered by light-water reactors. Eventually, North Korea's existing nuclear facilities were to be dismantled, and the spent reactor fuel taken out of the country.
However, in 2002, rumors circulated that North Korea was pursuing both uranium enrichment technology and plutonium reprocessing technologies in defiance of the Agreed Framework. North Korea reportedly told American diplomats in private that they were in possession of nuclear weapons, citing American failures to uphold their own end of the "Agreed Framework" as a motivating force. North Korea later clarified that it did not possess weapons yet, but that it had a right to possess them. In late 2002 and early 2003, North Korea began to take steps to eject International Atomic Energy Agency inspectors while re-routing spent fuel rods for plutonium reprocessing for weapons purposes. Throughout the course of 2003, North Korean and American officials exchanged harsh words and staged military exercises which were interpreted by the other party to be aggressive. As late as the end of 2003, North Korea claimed that it would freeze its nuclear program in exchange for American concessions – in particular a non-aggression treaty – but a final agreement was not reached and talks continued to be cancelled or fall through. North Korea withdrew from the Nuclear Non-Proliferation Treaty in 2003 after not receiving light-water reactors promised by the United States which were going to be delivered in exchange for North Korea not developing their own power plants, as understood in the "Agreed Framework".
In early 2004 former Los Alamos National Laboratory director Siegfried S. Hecker, as part of an unofficial U.S. delegation, was allowed to inspect North Korea's plutonium production facilities. Hecker later testified before the United States Congress that while North Korea seems to have successfully extracted plutonium from the spent fuel rods, he saw no evidence at the time that they had actually produced a workable weapon.[14] In 2007, the former senior scientist of Pakistan, Dr. Abdul Qadeer Khan claimed that North Korea's nuclear program was well advanced before his visit in 1993 with Benazir Bhutto, former prime minister.[15][dubious–discuss]
In September 2004, though, North Korean officials announced they had successfully processed Yongbyon plutonium into a workable nuclear deterrent. Through 2005 more diplomatic talks were attempted between the United States, North Korea, South Korea, China, Japan, and Russia (the six-party talks) but little concrete change occurred.
Because North Korea had not conducted a successful test of a nuclear device, the extent of its nuclear weapons program remained ambiguous through 2005 and much of 2006. Though North Korea conducted numerous missile tests (some of which were branded failures by international experts[who?]), the question of whether they had actually mastered all aspects of nuclear weapons technology – ranging from material production to complex nuclear weapon design needed to produce the final detonation – remained unanswered. As of 2013[update] there was agreement in the U.S. intelligence community that North Korea could build a "modest" bomb with a yield of between 6 and 10 kilotons, but disagreement between Defense Intelligence Agency, CIA and the United States State Department over whether it could deploy a miniaturized warhead on a missile.[16]
North Korean statements
Rumours of an impending nuclear test circulated during 2005 and early 2006, though none came to immediate fruition. On October 3, 2006, however, North Korea claimed that it would soon conduct a nuclear test, and on October 9, 2006, the state claimed to have successfully conducted a test. The Korean Central News Agency, the state's news agency, issued the following statement:[17]
The field of scientific research in the DPRK successfully conducted an underground nuclear test under secure conditions on October 9, Juche 95 (2006), at a stirring time when all the people of the country are making a great leap forward in the building of a great, prosperous, powerful socialist nation.
It has been confirmed that there was no such danger as radioactive emission in the course of the nuclear test as it was carried out under scientific consideration and careful calculation.
The nuclear test was conducted with indigenous wisdom and technology 100 percent. It marks an historic event as it greatly encouraged and pleased the KPA and people that have wished to have powerful self-reliant defence capability.
It will contribute to defending the peace and stability on the Korean Peninsula and in the area around it.
Later, the North Korean envoy to the U.N. said it would be better for the Security Council to offer its congratulations rather than pass "useless" resolutions.[18]
Threats of war
On October 10, 2006, an unnamed North Korean official was quoted as saying that North Korea could launch a nuclear missile unless the United States would sit down for face-to-face talks.[19] However, few, if any, military and defense experts believed that the North Koreans possessed the technology to mount a nuclear warhead to a ballistic missile.[20]
On October 11, the Associated Press reported that North Korea had threatened war if attempts would be made to penalize them through further sanctions.[21] This statement occurred even as Japan moved to tighten sanctions on the country.[21] South Korea said they were ensuring their troops were prepared for nuclear war.[21] A U.S. Army major, stationed along the border between North and South Korea, said that the overall situation was "calm" but that "Communist troops were more boldly trying to provoke their southern counterparts: spitting across the demarcation line, making throat-slashing hand gestures, flashing their middle fingers and trying to talk to the troops."[21]
On the day of the test, the North Korean Foreign Ministry stated that "if the U.S. keeps pestering us and increases pressure, we will regard it as a declaration of war and will take a series of physical corresponding measures".[22]
On October 17, North Korea denounced UN sanctions over its nuclear test as a declaration of war and the United States and other nations suspected that North Korea was seeking to conduct a second nuclear test despite international pressure.[23]
Kim Jong-il's alleged apology
On October 20, 2006, Kim Jong-il allegedly said that he was "sorry" over his country's nuclear test, and wished to return to talk with the United Nations. According to a Chinese envoy, Kim Jong-il said:
If the U.S. makes a concession to some degree, we will also make a concession to some degree, whether it be bilateral talks or six-party talks
Kim Jong-Il also stated that he had no future plans to test another nuclear device; the U.S. State Department discounted this report.[24]
Return to six-party talks
On October 31, 2006, North Korea agreed to rejoin six-nation disarmament talks. The agreement was struck in a day of unpublicized discussions between the senior envoys from the United States, China and North Korea at a government guesthouse in Beijing.[25] The talks resumed on December 18, 2006.
Yield estimates and authenticity
The site vs. 50-year predictions, according to USGS, indicating the probability of the detected blast being due to natural causes.
The low yield of the test initially raised questions as to whether it was a nuclear explosion but detection of airborne radioactive isotopes by a United States military aircraft confirmed that it was a nuclear explosion.[9][26] Radioactive isotopes of the element xenon are produced by the atom splitting that takes place in nuclear explosions and readily seeps out even from underground tests.[27] The advance warning of the test sent to the Chinese government reportedly said that the planned test yield was to be equivalent to approximately four kilotons in strength, but most outside estimates, based largely on seismic readings, put the yield at much less.[28]
At a meeting with PresidentVladimir Putin, Russian Defense MinisterSergei Ivanov stated that "the power of the tests carried out was 5 to 15 kilotons",[3] though this early estimate is much higher than any other international estimate. An early report by the Institute of Geoscience and Mineral Resources of South Korea said the blast was equivalent to an earthquake registering 3.58 on the Richter scale,[29] which corresponds to the explosion of 100 tons of TNT. This was later revised to at least 800 tons,[30] corresponding to a blast wave of 4.2. The U.S. Geological Survey also estimates the blast wave at 4.2.[31] (Note that 4.2 is considerably more powerful than 3.58 because the Richter scale is a logarithmic scale.)
According to Jane's Defence Weekly, "initial and unconfirmed South Korean reports indicate that the test was a fission device with a yield of 0.55 kT ... The figure of 0.55 kT, however, seems too low given the 4.2 register on the Richter scale. This could suggest – depending upon the geological make-up of the test site – a yield of 2–12 kT".[2]
An official in France's Atomic Energy Commission reported that they estimated the blast was "about or less than a kiloton" and expressed uncertainty about whether or not the blast was actually nuclear.[32][33] There have been various large planned and unplanned non-nuclear explosions comparable in yield to small nuclear detonations, such as the U.S. "Minor Scale" explosion from 1985, which used conventional explosives to simulate a 4 kiloton detonation. According to the Washington Times anonymous U.S. intelligence sources speculated there "was a seismic event that registered about 4 on the Richter scale, but it still isn't clear if it was a nuclear test. You can get that kind of seismic reading from high explosives".[34]The Wall Street Journal explains that this blast was equivalent to the explosive force of about US$100,000 worth of ammonium nitrate.[35] International experts have said that it will take some time to confirm whether it was a successful nuclear test, as North Korea claimed, or an unsuccessful one ("fizzle"), or perhaps not even a nuclear test at all.[36]
However 7 years later, after the 2013 nuclear test, the Federal Institute for Geosciences and Natural Resources, a state-run geology research institute in Germany, estimated the yield ranging at minimum of 700 tons to the max of 2 kilotons and the 2009 test ranges from minimum of 5 kilotons to the max of 12 kilotons instead with relevant statistics.[4][37]
By comparison, the first plutonium corenuclear device tested by the United States (Trinity test) had a yield of 20 kilotons of TNT, and the first nuclear device detonated by India in 1974, though of primitive design, had a yield in the region of 8 kilotons of TNT. If the North Korean nuclear test is less than even a kiloton in yield, it would be a historically small inaugural nuclear test. Even if it were as many as the reported intentional yield of 4 kt it would be the smallest nuclear test ever conducted by a state as a first test. Some advanced nuclear powers have produced very small tactical nuclear weapons in the low-kiloton range, but their development is far more technologically challenging than that of weapons in the 15–20 kiloton range, requiring advanced weapons materials and core geometries.[38]
If the North Korean device was significantly short of its predicted yield, it could be classified as a "fizzle" indicating that some aspect of the nuclear weapon design or material production did not function correctly. In a fizzle the warhead blows itself apart too fast for the nuclear reactions to generate a large amount of energy, or fails to form a supercritical mass for some other reason. A fizzle can result from predetonation, insufficient precision in the explosive lenses used to compress the plutonium core, or impurities in the plutonium itself, among other factors.[38] A fizzle can also result from the use of reactor grade plutonium rather than weapons-grade material.[39]
On October 13, 2006, CNN reported that two U.S. government officials with access to classified information stated that the initial air sampling over North Korea shows no indication of radioactive debris from the event that North Korea says was an underground nuclear test. Some hours later, the report was reversed and stated there was evidence of radiation, though not enough data has been collected yet to be conclusive. The newspaper Hankyoreh reported an unnamed North Korean diplomat had acknowledged that the actual yield was smaller than expected.[28]
On October 16, 2006, the United States government reported that a test had found radioactive gas compatible with a nuclear explosion.[8]
The explosion was also recorded worldwide by the global monitoring system operated by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). Two weeks after the detonation, a CTBTO radionuclide monitoring station in northern Canada detected traces of the radioactive noble gas xenon in the air. Backtracking calculations by analysts at the CTBTO indicated that the xenon particles originated from North Korea and that the explosion had been nuclear in nature.[41]
Test site location
A map of the Korean peninsula. The estimated location of the test (41.311°N, 129.114°E) is marked in red.NASA Blue Marble Image of estimated location of the test (41.2943° N 129.1342° E)
According to initial reports from South Korean government sources, the test was carried out at a mountain in Musadan-ri in Hwadae-kun, near the city of Kilchu, in North Hamgyŏng province on the northeast coast.[42] However, later reports from the state National Intelligence Service identified the site as being a place in Sangpyong-ri, about 15km from the coastal city of Kimchaek and about 50km west of Musadan-ri.[43]
International condemnation of the tests by governments has been nearly unanimous, including from North Korea's close ally and benefactor, the People's Republic of China.[45] All five veto-wielding permanent members of the United Nations Security Council condemned the nuclear test. On October 10, however, South Korean Prime Minister Han Myeong-sook told Parliament that South Korea will not support any United Nations resolution containing military measures against North Korea in retaliation for its nuclear test.[46]
Economic impact
Negative economic effects were seen throughout the region after the test. South Korea's KOSPI index fell 2.4% to 1319.4,[47] forcing the Korea Exchange to suspend trading for five minutes upon receiving the news.[48] The Japanese and Taiwanese stock exchanges were closed for a market holiday on the day of the test.[49] The Japanese yen also fell to a seven-month low against the United States dollar while oil on the world market rose above US$60 a barrel.[50]Gold prices rose 1% as a safe haven investment.[51] Several stock markets in Asia from the Singapore Exchange to the Philippine Stock Exchange have traded lower, possibly due to the tests.[52] American stock markets were mixed, with the Dow Jones Industrial Average down at its open the next day; however, at 10:30am EDT, the Dow rebounded and concluded the day with an increase of 7.60 points (+0.06%).[53]NSE and BSE of India, however, showed some strength.
On October 14, 2006, the UN Security Council unanimously approved limited military and economic sanctions against North Korea. All five permanent members stated that the sanctions, set out in UNSC Resolution 1718, were intended to penalize the country's regime, not inhabitants. They also stated that if North Korea were willing to cooperate and complied with all the measures contained in the resolution, the sanctions would be lifted. The United States compromised on its initial desire to block all imports of military equipment, and to have an unlimited reference to Chapter VII of the United Nations Charter so providing a legal justification for future military action, in order to gain full support for the resolution.[54]
The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is a multilateral treaty to ban nuclear weapons test explosions and any other nuclear explosions, for both civilian and military purposes, in all environments. It was adopted by the United Nations General Assembly on 10 September 1996, but has not entered into force, as eight specific nations have not ratified the treaty.
North Korea has a military nuclear weapons program and, as of early 2020, is estimated to have an arsenal of approximately 30 to 40 nuclear weapons and sufficient production of fissile material for six to seven nuclear weapons per year. North Korea has also stockpiled a significant quantity of chemical and biological weapons. In 2003, North Korea withdrew from the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). Since 2006, the country has conducted six nuclear tests at increasing levels of expertise, prompting the imposition of sanctions.
Nuclear weapons tests are experiments carried out to determine the performance, yield, and effects of nuclear weapons. Testing nuclear weapons offers practical information about how the weapons function, how detonations are affected by different conditions, and how personnel, structures, and equipment are affected when subjected to nuclear explosions. However, nuclear testing has often been used as an indicator of scientific and military strength. Many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status through a nuclear test.
Amchitka is a volcanic, tectonically unstable and uninhabited island in the Rat Islands group of the Aleutian Islands in southwest Alaska. It is part of the Alaska Maritime National Wildlife Refuge. The island, with a land area of roughly 116 square miles (300 km2), is about 42 miles (68 km) long and 1 to 4 miles wide. The area has a maritime climate, with many storms, and mostly overcast skies.
The Ryanggang explosion was a large explosion that took place in North Korea on 9 September 2004 in the northern province of Ryanggang. The nature and cause of the suspected explosion is the subject of speculation. No neighboring nations have claimed any detection of radioactive isotopes characteristic of a nuclear explosion.
A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lower mass, or a combination of these benefits. Characteristics of nuclear fusion reactions make possible the use of non-fissile depleted uranium as the weapon's main fuel, thus allowing more efficient use of scarce fissile material such as uranium-235 or plutonium-239. The first full-scale thermonuclear test was carried out by the United States in 1952 and the concept has since been employed by most of the world's nuclear powers in the design of their weapons.
A nuclear explosion is an explosion that occurs as a result of the rapid release of energy from a high-speed nuclear reaction. The driving reaction may be nuclear fission or nuclear fusion or a multi-stage cascading combination of the two, though to date all fusion-based weapons have used a fission device to initiate fusion, and a pure fusion weapon remains a hypothetical device. Nuclear explosions are used in nuclear weapons and nuclear testing.
Underground nuclear testing is the test detonation of nuclear weapons that is performed underground. When the device being tested is buried at sufficient depth, the nuclear explosion may be contained, with no release of radioactive materials to the atmosphere.
Reactor-grade plutonium (RGPu) is the isotopic grade of plutonium that is found in spent nuclear fuel after the uranium-235 primary fuel that a nuclear power reactor uses has burnt up. The uranium-238 from which most of the plutonium isotopes derive by neutron capture is found along with the U-235 in the low enriched uranium fuel of civilian reactors.
National technical means of verification (NTM) are monitoring techniques, such as satellite photography, used to verify adherence to international treaties. The phrase first appeared, but was not detailed, in the Strategic Arms Limitation Treaty (SALT) between the US and USSR. At first, the phrase reflected a concern that the "Soviet Union could be particularly disturbed by public recognition of this capability [satellite photography]...which it has veiled.". In modern usage, the term covers a variety of monitoring technologies, including others used at the time of SALT I.
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The 2009 North Korean nuclear test was the underground detonation of a nuclear device conducted on Monday, 25 May 2009 by the Democratic People's Republic of Korea. This was its second nuclear test, the first test having taken place in October 2006. Following the nuclear test, Pyongyang also conducted several missile tests. A scientific paper later estimated the yield as 2.35 kilotons.
The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, or CTBTO Preparatory Commission, is an international organization based in Vienna, Austria, that is tasked with building up the verification regime of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). The organization was established by the States Signatories to the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in 1996.
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North Korea conducted its fourth nuclear detonation on 6 January 2016 at 10:00:01 UTC+08:30. At the Punggye-ri Nuclear Test Site, approximately 50 kilometres northwest of Kilju City in Kilju County, an underground nuclear test was carried out. The United States Geological Survey reported a 5.1 magnitude earthquake from the location; the China Earthquake Networks Center reported the magnitude as 4.9.
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A nuclear detonation detection system (NDDS) is a device or a series of devices that are able to indicate, and pinpoint a nuclear explosion has occurred as well as the direction of the explosion. The main purpose of these devices or systems was to verify compliance of countries that signed nuclear treaties such as the Partial Test Ban treaty of 1963 (PTBT) and the Treaty of Tlatelolco.
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