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Last Updated: November, 2014

Upon the breakup of the Soviet Union, Ukraine inherited the third largest nuclear weapons stockpile in the world after the Russian Federation and the United States.

However, in the January 1994 Trilateral Statement, Ukraine committed to full disarmament. Kiev joined the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) as a non-nuclear weapon state in 1994, acceded to the Strategic Arms Reduction Treaty (START I), and having transferred all of its nuclear warheads to Russia for elimination, became nuclear-weapon-free in 1996.

Ukraine retains significant nuclear expertise, fuel cycle capabilities, and a large nuclear power program. [1] Ukraine's first nuclear power plant was commissioned in 1977, and another 15 plants have come online since then, generating approximately half of the country's electricity supply. However, the 1986 Chernobyl disaster, the world's worst nuclear accident to-date, occurred in what is now Ukraine. In the shadow of Chernobyl, Kiev placed a moratorium on nuclear energy projects in 1990. The inability to meet its energy needs after the Soviet collapse led Ukraine to lift the moratorium three years later in 1993. As outlined in its 2006 energy plan, nuclear power will continue to play a significant role in Ukraine's energy portfolio for the foreseeable future. [2]


Soviet Nuclear Power Program and the Chernobyl Legacy

Ukraine's nuclear power program developed as a component of the Soviet program in the 1970s. As a part of this larger system, Ukraine possessed piecemeal fuel cycle capabilities. While Ukrainian territory contained extensive uranium mining and milling operations and heavy water production capabilities, it lacked uranium enrichment and plutonium reprocessing capabilities. [3] Fifteen power reactors were built on Ukrainian territory during the Soviet era, giving the country the largest civilian nuclear power program in the former Soviet Union outside of Russia. [4] The first of these reactors were the infamous Soviet-designed RBMK-1000 light-water cooled, graphite moderated reactors built at Chernobyl in the 1970s, which had severe design flaws. [5]

On 26 April 1986, reactor 4 at the Chernobyl nuclear power plant (Chernobyl-4) suffered a criticality accident and a core meltdown. Ironically, the accident occurred during a safety test to determine how long cooling of the reactor core could continue in the event of a loss of electricity to the plant. A series of operator errors, exacerbated by serious RBMK-1000 design flaws, resulted in an uncontrolled surge in the reactor's criticality, followed by fuel melting and steam explosions. Because the RBMK-1000 design did not include a containment structure, the explosions in the reactor released much of the reactor's highly radioactive core directly into the environment, heavily contaminating large areas of the Soviet Union and Europe with isotopes such as iodine-131 and cesium-137 via a radioactive plume. [6] By October 1986, a concrete structure known as the sarcophagus had been built to encase the remnants of Chernobyl-4's core. The other three RBMK reactors at the Chernobyl power station were restarted shortly after the accident in order to meet Ukraine's power demands. [7]

Concerns stemming from the disaster led Ukraine, in August 1990, to place a five-year moratorium on the construction of new nuclear reactors and increases to the power capacities of existing nuclear power plants. [8] When the USSR collapsed in 1991, it became clear that the history of dependence on Moscow for energy commodities had created severe problems for Ukraine's energy sector, suddenly faced with restructuring, privatization, consumer debt, market liberalization, and numerous power outages. Prior to 1991, Ukraine imported from Russia 10% of the coal, 50% of the gas, 92% of the oil, and 100% of the nuclear fuel that it consumed. [9] Ukraine's nuclear sector remained dependent on Russia for nuclear fuel and essential equipment, since its Soviet-type RBMK and VVER reactors only operated on Russian-made fuel assemblies.

Also in 1991, Ukraine's nuclear power industry suffered when a serious fire at Chernobyl-2 disabled the unit and prevented its further operation. Together with the infamous disaster at Chernobyl-4 in 1986, the incident sparked fresh international debate about the safety of the RBMK reactors. In Kiev, the Verkhovna Rada (Ukraine's parliament) responded to the accident by passing legislation which called for the closure of the Chernobyl Nuclear Power Plant by the end of 1993. [10] In 1993, however, the Rada repealed the moratorium and decided to keep Chernobyl open in order to address projected power shortages for the winter of that year. [11] Nevertheless, the fire at Chernobyl-2 focused renewed international attention on Ukraine's nuclear power sector, and particularly the Chernobyl Nuclear Power Plant.

Beginning in July 1994, the Group of Seven (G-7) spearheaded a movement aimed at shutting down Chernobyl. Thus, in the period from mid-1994 through 1995, Ukrainian and Western experts proposed a myriad of options for replacing Chernobyl's contributions to the grid. The first energy replacement options considered included building a gas-fired power plant, modernizing coal and oil plants, or constructing two new nuclear reactors in the town of Slavutych, located near Chernobyl. [12] In December 1995 Ukraine and the G-7 signed a Memorandum of Understanding (MoU) which provided for closing Chernobyl in exchange for Western funding for the completion of Khmelnytskyy-2 and Rivne-4. [13] The MoU shortened the lifetime of the Chernobyl reactors, which were originally projected to operate through 2011, and permitted their operation only until the year 2000.

In November 1996, Chernobyl-1 shut down in accordance with a pledge made by Ukrainian President Kuchma at a Nuclear Safety Summit in Moscow in April of that year. [14] The last reactor online at the plant, Chernobyl-3, continued operating until December 2000, when it went offline as scheduled in the 1995 MoU. The Khmelnitsky-2 and Rivne-4 reactors became operational in 2004.

Inherited Nuclear Arsenal and Denuclearization Negotiations

Upon independence in 1991, Ukraine inherited the world's third largest nuclear arsenal, consisting of approximately 1,900 strategic nuclear warheads and 2,500 tactical nuclear weapons. The arsenal also included 130 SS-19 and 46 SS-24 intercontinental ballistic missiles (ICBMs), and 25 Tu-95 and 19 Tu-160 strategic bombers with air-launched cruise missiles (ALCMs). [15]

Prior to the Soviet collapse and around the time of the nuclear energy moratorium, the Rada adopted the Declaration of Sovereignty in July 1990, which proclaimed Ukraine's wish to adhere to three non-nuclear principles: not to maintain, produce or acquire nuclear weapons. [16] However, once Ukraine gained independence, support for denuclearization within the Rada and elsewhere began to vacillate. While Ukraine chose to sign the Lisbon Protocol of the START I treaty in May 1992, Kiev asserted administrative control over the nuclear weapons on its territory around the same time. [17] Little movement toward denuclearization occurred over the next year. The Rada delayed START ratification, and 162 deputies signed a statement which set preconditions for ratification. In May 1993, a U.S. envoy suggested that in exchange for START ratification, the U.S. would provide financial assistance (in addition to the $175 million already promised in 1992), and act as a mediator between Russia and Ukraine on nuclear issues. [18]

In the summer of 1993, the concept of a trilateral deal between the United States, Ukraine and Russia arose during discussions among the three countries. From these discussions U.S. negotiators began to believe Ukraine would ratify START and accede to the NPT as a non-nuclear weapon state in exchange for the right amount of financial assistance. In November 1993, the Rada voted to ratify START but attached 13 preconditions. These stipulations included security guarantees, financial assistance for dismantlement, compensation for tactical nuclear weapons already returned to Russia, and acknowledgement that only 36% of the launchers and 42% of the warheads on Ukrainian territory were subject to elimination. The Rada resolution received sharp criticism from the United States and provoked retaliatory threats from Russia. [19]

Negotiations on the trilateral deal envisioned during the previous summer began in December 1993, and an agreement was reached in mid-January 1994. Under the Trilateral Agreement, Ukraine agreed to denuclearization in exchange for security assurances, financial assistance, and a denuclearization implementation timetable. [20] While the agreement did not meet all the preconditions set forth by the Rada, the parliament agreed to START ratification in February 1994 and approved Ukraine's accession to the NPT in November 1994.

Ukraine had transferred all of its nuclear warheads to Russia by 21 May 1996. By January 2002, all strategic bombers on Ukrainian territory had been dismantled, transferred to Russia, or converted to non-military use; all ICBMs had been eliminated or disassembled pending elimination; and all ICBM silos had been destroyed. In total, Ukraine received over $500 million in U.S. financial assistance for nuclear dismantlement through the Nunn-Lugar Cooperative Threat Reduction program. [21]

Recent Developments and Current Status

Ukraine's Enerhoatom ('Energoatom' in Russian), operates 15 reactors at four nuclear power plants (Khmelnitskyy, Rivne, South Ukraine, and Zaporizhzhya). Nuclear energy currently generates nearly half of Ukraine's electricity needs, and the "Energy Strategy of Ukraine for the Period until 2030," released in 2006, foresees construction of 11 new nuclear units in order to maintain nuclear's share in electricity generation at the present level. [22]

Although Ukraine possesses modest deposits of natural uranium, it still depends on Russia for fuel fabrication and other fuel cycle services. These bilateral ties were reinforced in June 2010 when Ukraine signed a long-term fuel supply contract with Russia's TVEL. This contract was followed in September 2010 by a contract between TVEL and Ukraine's Nuclear Fuel to establish a joint venture to manufacture VVER-1000 fuel assemblies. [23] In order to diversify its nuclear fuel supply, Kiev has also partnered with the United States via the Ukraine Nuclear Fuel Qualification Program, allowing it to purchase Westinghouse-produced nuclear fuel in addition to that provided by Russia. [24]

Decommissioning of the four RMBK power reactors at Chernobyl remains an ongoing project. In January 2010, a law on the progressive decommissioning of Chernobyl went into effect. [25] Final dismantlement of the site is scheduled to occur by 2065. [26] Efforts are currently underway to build a new containment structure for Chernobyl-4, which is scheduled to be completed by 2014. Projected to cost over €1 billion, the structure will cover both the reactor and the sarcophagus erected in 1986. [27]

Ukraine converted its research reactor at the Institute for Nuclear Research in Kiev to LEU-based fuel in 2008 under the auspices of the U.S. Global Threat Reduction Initiative (GTRI). [28] President Yanukovych announced at the Washington Nuclear Security Summit in April 2010 that Ukraine give up all of this material by the time of the 2012 Seoul Nuclear Security Summit. In September 2011, Ukraine signed a Memorandum of Understanding (MOU) with the United States which built upon commitments made at the 2010 Nuclear Security Summit. According to the MOU, in exchange for Ukraine's agreement to repatriate the HEU, the United States will build a state-of-the-art neutron source in Kharkiv for the production of medical isotopes which runs on LEU. [29] In March 2012, Ukraine announced that it had fulfilled this commitment with the removal of the last batch of highly enriched uranium to Russia. [30]

[1] Mykola Riabchuk, "Ukraine's Nuclear Nostalgia," World Policy Journal (Winter 2009/2010), 95.
[2] "Energy Strategy of Ukraine for the Period until 2030," Cabinet of Ministers of Ukraine, March 15, 2006,
[3] "Ukraine," Country Nuclear Fuel Cycle Profiles (Vienna: IAEA, 2002).
[4] "Nuclear Power in Ukraine," World Nuclear Association, accessed March 21, 2012,; "Nuclear Power in Russia," World Nuclear Association, accessed March 21, 2012,
[5] Richard Rhodes, Nuclear Renewal (New York: Whittle Books, 1993), pp. 84-86.
[6] "Chernobyl Accident 1986," World Nuclear Association, updated September 2011,
[7] "Chernobyl Nuclear Power Plant Accident," U.S. Nuclear Regulatory Commission, April 2009,
[8] "Ukraine moratorium on nuclear power construction," BBC Summary of World Broadcasts, September 7, 1990.
[9] Judith Perera, The Nuclear Industry in the Former Soviet Union (London: Financial Times Energy Publishing, 1997), pp. 70-74.
[10] "Parliament Chairman Denies Decision to Stop Chornobyl NPP," Upresa Daily Report, November 30, 1995.
[11] Ann MacLachlan, "Ukrainian Regulator Resigns to Protest Chernobyl Decision," Nucleonics Week, December 9, 1993; Ron Popeski, "Ukraine Votes to Keep Chernobyl Open," Reuters, October 21, 1993.
[12] Peter Coryn and Ann MacLachlan, "Ukrainians have Mixed Reactions to Chernobyl Gas Proposal," Nucleonics Week, June 15, 1995; "Ukrainian Government Negotiating Chernobyl's Future with a Divided Team," Post-Soviet Nuclear & Defense Monitor, June 12, 1995.
[13] Memorandum of Understanding Between the Governments of the G-7 Countries and the Commission of the European Communities and the Government of Ukraine on the Closure of the Chernobyl Nuclear Power Plant, Signed at Ottawa on December 20, 1995.
[14] Chernobyl Reactor No. 1 to Close this Year," Reuters, April 22, 1996.
[15] Steven Pifer, "The Trilateral Process: The United States, Ukraine, Russia and Nuclear Weapons," Arms Control Series Paper 6, Foreign Policy at Brookings, May 2011,
[16] Mykola Riabchuk, "Ukraine's Nuclear Nostalgia," World Policy Journal (Winter 2009/2010), p. 98.
[17] William C. Potter, The Politics of Nuclear Renunciation: The Cases of Belarus, Kazakhstan, and Ukraine (Washington, DC: The Henry L. Stimson Center, 1995), pp. 20-23.
[18] William C. Potter, The Politics of Nuclear Renunciation: The Cases of Belarus, Kazakhstan, and Ukraine (Washington, DC: The Henry L. Stimson Center, 1995), pp. 20-23.
[19] William C. Potter, The Politics of Nuclear Renunciation: The Cases of Belarus, Kazakhstan, and Ukraine (Washington, DC: The Henry L. Stimson Center, 1995), pp. 20-23.
[20] "Trilateral Statement by the Presidents of the U.S., Russia, and Ukraine," January 14, 1994.
[21] "Ukraine: Cooperative Threat Reduction Program," Nuclear Threat Initiative, July 16, 2002,
[22] "Energy Strategy of Ukraine for the Period until 2030," Cabinet of Ministers of Ukraine, March 15, 2006,
[23] "Nuclear Power in Ukraine," World Nuclear Association, accessed March 21, 2012,
[24] "Ukraine hopes to improve nuclear fuel quality due to Russian-U.S. competition," BBC Worldwide Monitoring, June 22, 2011,
[25] "Chornobyl nuclear power plant site to be cleared by 2065," KyivPost, January 4, 2010,
[26] "Chernobyl Nuclear Power Plant – Decommissioning," Chernobyl NPP, updated October 2010,
[27] Chernobyl Accident 1986," World Nuclear Association, updated September 2011,
[28] "NNSA aids in reactor conversions," Platts Inside Energy, October 20, 2008,
[29] "Memorandum of Understanding with Ukraine on Nuclear Security Cooperation," Press Release, U.S. Department of State, September 26, 2011,; "Ukraine Completely Removes Highly Enriched Uranium," Worldwide News Ukraine, March 22, 2012,
[30] "Ukraine Completely Removes Highly Enriched Uranium," Worldwide News Ukraine,, March 22, 2012,

Get the Facts on Ukraine
  • Transferred the third largest nuclear arsenal in the world back to Russia after the Soviet collapse
  • Member of the Nuclear Suppliers Group and Missile Technology Control Regime
  • No engagement in biological or chemical weapons activities since independence in 1991

This material is produced independently for NTI by the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies and does not necessarily reflect the opinions of and has not been independently verified by NTI or its directors, officers, employees, or agents. Copyright 2016.