Nuclear Deterrence

Atoms for Peace

A U.S. program announced by President Dwight D. Eisenhower at the United Nations on 8 December 1953 to share nuclear materials and technology for peaceful purposes with other countries. This program required countries receiving nuclear materials to agree to inspections of the transferred technology to ensure it was not used for military purposes. The program was formally established in 1954, following the passage of the Atomic Energy Act, and ended abruptly in 1974 following India's first nuclear test.

Intercontinental ballistic missile (ICBM)

A ballistic missile with a range greater than 5,500 km

Extended Deterrence

A country protected from potential adversaries by the nuclear weapons' backed security guarantee of an ally is said to be under an (extended deterrence) nuclear umbrella. See entry for Deterrence.

Gun-type (nuclear) weapon:

A device in which two or more pieces of fissionable material, each smaller than a critical mass, are brought together very rapidly so as to form a supercritical mass which can explode as the result of a rapidly expanding fission chain reaction

Nuclear-Weapon-Free Zone (NWFZ)

A geographical area in which nuclear weapons may not legally be built, possessed, transferred, deployed, or tested.

Zangger Committee (ZC)

A group of 35 nuclear exporting states established in 1971 under the chairmanship of Claude Zangger of Switzerland. The purpose of the committee is to maintain a "trigger list" of: (1) source or special fissionable materials, and (2) equipment or materials especially designed or prepared for the processing, use, or production of special fissionable materials. Additionally, the committee has identified certain dual-use technologies as requiring safeguarding when they are supplied to non-nuclear weapon states. These include explosives, centrifuge components, and special materials. The Zangger Committee is an informal arrangement, and its decisions are not legally binding upon its members

Positive security assurances

A guarantee given by a nuclear weapon state to a non-nuclear weapon state for assistance if the latter is targeted or threatened with nuclear weapons.

Strategic nuclear warhead

A high-yield nuclear warhead placed on a longrange delivery system, such as a land-based intercontinental ballistic missile (ICBMs), a submarine-launched ballistic missile (SLBMs), or a strategic bomber

Strategic Bomber:

A long-range aircraft designed to drop large amounts of explosive power—either conventional or nuclear—on enemy territory

Global Strike Mission

A mission assigned to U.S. STRATCOM in January 2003 aimed at providing the President of the United States with the option to order preemptive military strikes against highvalue and mobile WMD targets with conventional or nuclear weapons

Fission

A nuclear bomb based on the concept of releasing energy through the fission (splitting) of heavy isotopes, such as Uranium-235 or Plutonium-239

Thermonuclear weapon

A nuclear weapon in which the fusion of light nuclei, such as deuterium and tritium, leads to a significantly higher explosive yield than in a regular fission weapon. Thermonuclear weapons are sometimes referred to as staged weapons, because the initial fission reaction (the first stage) creates the condition under which the thermonuclear reaction can occur (the second stage). Also archaically referred to as a hydrogen bomb.

Negative security assurances

A pledge by a nuclear weapon state that it will not use nuclear weapons against a non-nuclear weapon state. Some states have policies that allow for the use of nuclear weapons if attacked with other WMD by a non-nuclear weapon state.

No-First-Use

A pledge on the part of a nuclear weapon state not to be the first party to use nuclear weapons in a conflict or crisis.

Global Threat Reduction Initiative (GTRI)

A program established by the U.S. National Nuclear Security Administration in May 2004 to identify, secure, remove, and/or facilitate the removal of vulnerable nuclear and radiological materials around the world.

Space Launch Vehicle (SLV)

A rocket used to carry a payload, such as a satellite, from Earth into outer space. SLVs are of proliferation concern because their development requires a sophisticated understanding of the same technologies used in the development of long-range ballistic missiles. Some states (e.g., Iran), may have developed space launch vehicle programs in order to augment their ballistic missile capabilities.

Strategic Arms Limitations Talks (SALT I & II)

A series of discussions between the Soviet Union and the United States aimed at limiting missile systems and other strategic armaments. The first round of talks (SALT I) was held from 1969 to 1972, and concluded with the 20 May 1971 signing of the Anti-Ballistic Missile (ABM) Treaty and the Interim Agreement limiting strategic offensive arms. • SALT II was held from 1972 to 1979. The SALT II Treaty was signed on 18 June 1979, but was not ratified by either country, although both committed to abiding by its limits. For additional information, see the entries for SALT I and SALT II.

Nuclear Security Summits

A series of international summits that emerged out of U.S. President Barack Obama's call in April 2009 to "secure all vulnerable nuclear material around the world within four years." The summit process focuses on strengthening international cooperation to prevent nuclear terrorism, thwarting nuclear materials trafficking, and enhancing nuclear materials security

Electromagnetic Pulse (EMP)

A sharp pulse of radio-frequency (long wavelength) radiation produced when an explosion occurs in an asymmetrical environment, especially at or near the earth's surface or at high altitudes. The intense electric and magnetic fields can damage unprotected electrical and electronic equipment over a large area

Safeguards

A system of accounting, containment, surveillance, and inspections aimed at verifying that states are in compliance with their treaty obligations concerning the supply, manufacture, and use of civil nuclear materials. • The term frequently refers to the safeguards systems maintained by the International Atomic Energy Agency (IAEA) in all nuclear facilities in nonnuclear weapon state parties to the NPT. IAEA safeguards aim to detect the diversion of a significant quantity of nuclear material in a timely manner. However, the term can also refer to, for example, a bilateral agreement between a supplier state and an importer state on the use of a certain nuclear technology.

Theater missile defense (TMD)

A system of missile interceptors designed to intercept ballistic missiles launched from a certain region or area.

Fuel Cycle

A term for the full spectrum of processes associated with utilizing nuclear fission reactions for peaceful or military purposes.

Light-water reactor

A term used to describe reactors using ordinary water, where the hydrogen is hydrogen-1, as a coolant and moderator, including boiling water reactors (BWRs) and pressurized water reactors (PWRs), the most common types used in the United States.

Kiloton

A term used to quantify the energy of a nuclear explosion that is equivalent to the explosion of 1,000 tons of trinitrotoluene (TNT) conventional explosive.

New START

A treaty between the United States and Russia on further limitations and reductions of strategic offensive weapons, signed on 8 April 2010, which entered into force on 5 February 2011. • Under the New START provisions, the two sides have to reduce the number of deployed strategic warheads and the number of deployed strategic delivery vehicles within seven years of the treaty's entry into force. • The treaty's verification measures are based on the earlier verification system created under START I. • New START supersedes the Moscow Treaty, and its duration is 10 years, with an option of extension for up to five years.

Mixed Oxide (MOX) fuel

A type of nuclear fuel used in light water reactors that consists of plutonium blended with uranium (natural, depleted or reprocessed). The MOX process also enables disposition of military plutonium, with the resulting fuel usable for energy generation.

United Nations Special Commission on Iraq (UNSCOM)

An inspection and weapons destruction program established pursuant to paragraph 9(b)(l) of UN Security Council Resolution 687 (1991) following the 1990 to 1991 Gulf War. Section C of the resolution called for the elimination, under international supervision, of Iraq's WMD and ballistic missiles with a range greater than 150 kilometers, together with related items and production facilities. It also called for measures to ensure that Iraq did not resume the acquisition and production of prohibited items. UNSCOM was set up to implement the non-nuclear provisions of the resolution, and to assist the International Atomic Energy Agency in the nuclear areas. It was replaced by UNMOVIC in 1999

Multiple Independently-targetable Reentry Vehicle (MIRV)

An offensive ballistic missile system with multiple warheads, each of which can strike a separate target and can be launched by a single booster rocket.

Layered BMD system

An approach to ballistic missile defense that consists of several "layers" of weapons intended to intercept an incoming ballistic missile at different phases of its flight. A layered approach would include a first layer (e.g., boost phase) of defense, with remaining targets passed on to succeeding layers (e.g., midcourse and terminal).

Preemptive military action

An attack launched to preempt expected aggression by an enemy. In the context of WMD issues, this would involve striking WMD arsenals or facilities to eliminate them before broader hostilities ensue.

Dirty Bomb

An informal term for a radiological dispersal device (RDD), a device pairing conventional explosives with radiological materials. Once detonated, the conventional explosives disperse the radioactive material, radioactively contaminating the target area.

International Atomic Energy Agency (IAEA)

Founded in 1957 and based in Vienna, Austria, the IAEA is an autonomous international organization in the United Nations system. • The Agency's mandate is the promotion of peaceful uses of nuclear energy, technical assistance in this area, and verification that nuclear materials and technology stay in peaceful use. • Article III of the Nuclear Non-Proliferation Treaty (NPT) requires non-nuclear weapon states party to the NPT to accept safeguards administered by the IAEA. The IAEA consists of three principal organs: the General Conference (of member states); the Board of Governors; and the Secretariat.

UNSC Resolution 1887

In September 2009, the UN Security Council committed to working toward the reduction of nuclear weapons and global nuclear dangers by adopting UNSCR 1887. In addition to calling for nuclear arms reductions, a strengthened NPT, greater support for the IAEA, and more robust export controls, the resolution also encouraged states to share best practices for improving nuclear safety and security standards, in order to reduce the risk of nuclear terrorism and to secure vulnerable nuclear materials within four years. The resolution also called on states to "minimize to the greatest extent that is technically and economically feasible the use of highly enriched uranium for civilian purposes, including by working to convert research reactors and radioisotope production processes to the use of low enriched uranium fuels and targets." UNSCR 1887 also reaffirmed the need for full implementation of UNSCR 1540.

Anti-Ballistic Missile (ABM) Treaty

It was signed by the United States and the Soviet Union on May 26, 1972, and entered into force on October 3, 1972, constrained strategic missile defenses to a total of 200 launchers and interceptors per country, which were divided between two widely separated deployment areas These restrictions were intended to prevent the establishment of a nationwide defense, and the creation of a base for deploying such a defense The US withdrew from the AMB in 2002

Strategic Defense Initiative (SDI)

Launched by U.S. President Ronald Reagan in March 1983, the SDI was aimed at studying the feasibility of research and development of defensive measures against ballistic missiles, with the ultimate goal of establishing a national missile defense system that would protect the United States from ballistic missile attacks. See entries for Anti-Ballistic Missile Treaty, Ballistic Missile.

Transparency measures

Measures designed to increase confidence in a state's compliance with treaty obligations, or to provide warnings of noncompliance through access to information or the exchange of information, access to facilities, and other cooperative measures. See entries for Confidence and Security Building Measures, National Technical Means, and Verification.

Nonproliferation

Measures to prevent the spread of biological, chemical, and/or nuclear weapons and their delivery systems. See entry for Proliferation.

Comprehensive Nuclear-Test-Ban Treaty (CTBT)

Opened for signature in 1996 at the UN General Assembly, the CTBT prohibits all nuclear testing if it enters into force. • CTBT entry into force is contingent on ratification by 44 Annex II states (https://www.ctbto.org/the-treaty/status-of-signature-andratification) • Five of the 44 Annex 2 States have signed but not ratified the CTBT; they are China, Egypt, Iran, Israel, and the United States.

Peaceful Nuclear Explosion (PNE)

PNEs are nuclear explosions carried out for non-military purposes, such as the construction of harbors or canals.

Passive defenses

Passive defenses are measures intended to reduce the consequences of a (WMD) attack (e.g., the use of shelters during a nuclear attack, the use of protective clothing to reduce the impact of a chemical weapons attack, or the use of inoculations to reduce the impact of a biological weapons attack).

Strategic Arms Reduction Treaty (START I, II, & III)

Refers to negotiations between the United States and the Soviet Union/Russian Federation, held between 1982 and 1993 to limit and reduce the numbers of strategic offensive nuclear weapons in each country's nuclear arsenal. • The talks culminated in the 1991 START I Treaty, which entered into force in December 1994, and the 1993 START II Treaty. Although START II was ratified by the two countries, it never entered into force. • In 1997, U.S. President Bill Clinton and Russian President Boris Yeltsin discussed the possibility of a START III treaty to make further weapons reductions, but negotiations resulted in a stalemate. Following the U.S. withdrawal from the Anti-Ballistic Missile Treaty (ABM) in 2002, Russia declared START II void. • START I expired on 5 December 2009, and was followed by the New START treaty. See entries for New START and the Trilateral Statement. For additional information, see the entries for START I, START II, and New START.

Fuel Bank

Refers to programs to set aside a guaranteed stockpile of LEU fuel, with its release typically under IAEA control, to mitigate the effects of possible disruptions in a country's LEU fuel supplies. Fuel bank concepts are typically envisioned as diminishing the incentive for countries to develop indigenous uranium enrichment capabiliti

Weapons-grade material

Refers to the nuclear materials that are most suitable for the manufacture of nuclear weapons, e.g., uranium (U) enriched to 90 percent U-235 or plutonium (Pu) that is primarily composed of Pu-239 and contains less than 7% Pu-240. Crude nuclear weapons (i.e., improvised nuclear devices), could be fabricated from lower-grade materials

Nuclear Forensics

Refers to the process of investigating the origin of nuclear material, for example in nuclear materials trafficking cases.

Lisbon Protocol (START I Protocol)

Refers to the protocol of the 1991 START I Treaty, which entered in force in December 1994 as the result of negotiations between the United States and the Soviet Union/Russian Federation, held between 1982 and 1993 to limit and reduce the numbers of strategic offensive nuclear weapons in each country's nuclear arsenal.

Medium-enriched uranium (MEU) fuel

Refers to uranium fuel with a concentration of the isotope U-235 between 20 and 35%. MEU is sometimes used to fuel research reactors.

Highly enriched uranium (HEU)

Refers to uranium with a concentration of more than 20% of the isotope U-235. Achieved via the process of enrichment.

Low enriched uranium (LEU)

Refers to uranium with a concentration of the isotope U-235 that is higher than that found in natural uranium but lower than 20% LEU (usually 3 to 5%). LEU is used as fuel for many nuclear reactor designs.

Wassenaar Arrangement (WA)

Representatives of 33 states met in Vienna, Austria in July 1996, and established this arrangement intended to contribute to regional and international security by promoting transparency and greater responsibility with regard to transfers of conventional arms and dualuse goods and technologies. This organization was the successor to the Coordinating Committee for Multilateral Export Controls (COCOM).

UNSC Resolution 1540

Resolution 1540 was passed by the UN Security Council in April 2004, calling on all states to refrain from supporting, by any means, non-state actors who attempt to acquire, use, or transfer chemical, biological or nuclear weapons or their delivery systems. The resolution also called for a Committee to report on the progress of the resolution, asking states to submit reports on steps taken towards conforming to the resolution. In April 2011, the Security Council voted to extend the mandate of the 1540 Committee for an additional 10 years

Strategic Offensive Reductions Treaty (SORT)

Russian President Vladimir Putin and U.S. President George W. Bush signed the Strategic Offensive Reductions Treaty, also called the Treaty of Moscow on 24 May 2002. The treaty stated that both the United States and Russia would reduce the numbers of their deployed nuclear warheads to between 1700 and 2200 within the next ten years. It established a Bilateral Implementation Commission, scheduled to meet at least twice a year, to establish procedures to verify and assist reductions. The treaty was rendered obsolete by the signing of the New START treaty in 2010.

SSBN

Ship, Submersible, Ballistic, Nuclear: A hull classification for a submarine capable of launching a ballistic missile. The "N", or nuclear, refers to the ship's propulsion system. SSBN's are generally reserved for strategic vessels, as most submarine launched ballistic missiles carry nuclear payloads. A non-strategic vessel carries the designation SSN, or attack submarine.

SSGN

Ship, Submersible, Guided, Nuclear: A hull classification for a submarine that carries guided cruise missiles. The "N", or nuclear, refers to the ship's propulsion system. Also known as attack submarines, SSGNs serve a conventional military support role and are often used for special forces transportation

Theater ballistic missile

Short- or medium-range ballistic missiles with a range between 300km and 3,500 km.

Tactical nuclear weapons

Short-range nuclear weapons, such as artillery shells, bombs, and short-range missiles, deployed for use in battlefield operations.

Trilateral Statement

Signed by U.S. President Bill Clinton, Russian President Boris Yeltsin, and Ukrainian President Leonid Kravchuk in January 1994, the Trilateral Statement on the Non-Proliferation of Weapons of Mass Destruction and the Means of Their Delivery committed Ukraine to rid itself of nuclear weapons and to transfer 200 SS-19 and SS-24 warheads to Russia over a ten-month period. The Trilateral Statement also specified that Ukraine was to deactivate its SS-24s within the same ten-month period. The United States and Russia agreed to guarantee Ukraine's borders and grant Ukraine security guarantees provided that Ukraine joined the NPT as a non-nuclear weapon state. Ukraine finished transferring its nuclear weapons to Russia in 1996 and acceded to the NPT as a non-nuclear weapon state in 1994.

Treaty on the Non-Proliferation of Nuclear Weapons (NPT)

Signed in 1968, the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) is the most widely adhered-to international security agreement. The "three pillars" of the NPT are nuclear disarmament, nonproliferation, and peaceful uses of nuclear energy. Article VI of the NPT commits states possessing nuclear weapons to negotiate in good faith toward halting the arms race and the complete elimination of nuclear weapons. The Treaty stipulates that nonnuclear-weapon states will not seek to acquire nuclear weapons, and will accept International Atomic Energy Agency safeguards on their nuclear activities, while nuclear weapon states commit not to transfer nuclear weapons to other states. All states have a right to the peaceful use of nuclear energy, and should assist one another in its development. The NPT provides for conferences of member states to review treaty implementation at five-year intervals. Initially of a 25-year duration, the NPT was extended indefinitely in 1995

Research reactor

Small fission reactors designed to produce neutrons for a variety of purposes, including scientific research, training, and medical isotope production. Unlike commercial power reactors, they are not designed to generate power

Additional Protocol

The Additional Protocol is a legal document granting the International Atomic Energy Agency (IAEA) complementary inspection authority to that provided in underlying safeguards agreements. The principal aim is to enable the IAEA inspectorate to provide assurance about both declared and possible undeclared activities. Under the Protocol, the IAEA is granted expanded rights of access to information and sites, as well as additional authority to use the most advanced technologies during the verification process.

Quadrennial Defense Review (QDR)

The QDR outlines the U.S. Defense Department's strategy for defending the United States and the resources needed to do so.

Outer Space Treaty

The Treaty on Principles Governing the Activities of States in the Exploration and use of Outer Space, Including the Moon and other Celestial Bodies prohibits the placement of Weapons of Mass Destruction in orbit around the earth, on the moon or any other celestial body, or otherwise in outer space. • The treaty also stipulates that the exploration and use of outer space be carried out for the benefit and in the interest of all countries, and that the moon and other celestial bodies are to be used exclusively for peaceful purposes. It was opened for signature on 27 January 1967, and entered into force on 10 October 1967.

Treaty of Pelindaba

The Treaty on the African Nuclear-Weapon-Free-Zone was opened for signature in Cairo in April 1996. The treaty prohibits the research, development, manufacturing, stockpiling, acquisition, testing, possession, control, and stationing of nuclear explosive devices on any member's territory. The treaty also prohibits the dumping of radioactive waste originating from outside the continent within the region. In addition, the treaty requires parties to apply International Atomic Energy Agency safeguards to all their peaceful nuclear activities. The treaty also provides for the establishment of the African Commission on Nuclear Energy (AFCONE), which supervises treaty implementation and ensures compliance with its provisions. For additional information, see the ANWFZ

Seabed Treaty

The Treaty on the Prohibition of the Emplacement of Nuclear Weapons and other Weapons of Mass Destruction on the Seabed and the Ocean Floor and in the Subsoil Thereof prohibits the placement of nuclear weapons or any other weapons of mass destruction on the seabed, the ocean floor, and in the subsoil of the ocean floor beyond a signatory's 12-miles coastal zone. Opened for signature on 11 February 1971, it entered into force on 18 May 1972.

Treaty of Rarotonga

The Treaty on the South Pacific NuclearWeapon-Free Zone (SPNWFZ) prohibits the testing, manufacturing, acquiring, and stationing of nuclear explosive devices on any member's territory. The treaty also prohibits the dumping of radioactive wastes into the sea. In addition, the treaty required all parties to apply International Atomic Energy Agency safeguards to all their peaceful nuclear activities.

Theater High Altitude Air Defense (THAAD)

The U.S. Army's air defense program designed to provide extended defense, and to engage an incoming missile at ranges of up to several hundred kilometers. THAAD deploys a hit-to-kill interceptor equipped with an infrared seeker. The interception is intended to occur outside the earth's atmosphere, or high in the atmosphere.

United Nations Disarmament Commission (UNDC)

The UNDC was established in 1952 as a deliberative body. The purpose of the UNDC is to examine and make recommendations on disarmament issues, and to follow-up and evaluate decisions made within special sessions

United Nations Convention on the Law of the Sea

The United Nations Convention on the Law of the Sea (UNCLOS) was opened for signature at Montego Bay, Jamaica, on 10 December 1982. It entered into force 12 year later on 16 November 1994. The Law of the Sea establishes a comprehensive legal framework to regulate all ocean space, its uses and resources. It contains, among other things, provisions relating to the territorial sea, the contiguous zone, the continental shelf, the exclusive economic zone, and the high seas. It also provides for the protection and preservation of the marine environment, for marine scientific research, and for the development and transfer of marine technology. For the purposes of nuclear weapon-free-zones, the most important provision of the UNCLOS is the right of innocent passage and freedom of the high seas.

Reprocessing

The chemical treatment of spent nuclear fuel to separate the remaining usable plutonium and uranium for refabrication into fuel, or alternatively, to extract the plutonium for use in nuclear weapons

Triad

The concept of the triad integrates three forms of nuclear weapons deployment: intercontinental ballistic missiles (ICBMs); sealaunched ballistic missiles (SLBMs); and strategic bombers

Force Structure

The configuration of a country's nuclear or conventional forces. For example, in the United States and Russia, nuclear forces are structured in a triad, with nuclear warheads deployed on bombers, land-based missiles, and sea-based missiles

Lethal dose (radiation)

The dose of radiation expected to cause death to an exposed population within 30 days to 50 percent of those exposed.

Megaton (MT)

The energy equivalent released by 1,000 kilotons (1,000,000 tons) of trinitrotoluene (TNT) explosive. Typically used as the unit of measurement to express the amount of energy released by a nuclear bomb

Nuclear (use) doctrine

The fundamental principles by which a country's political or military leaders guide their decision-making regarding the conditions for the use of nuclear weapons.

First Use

The introduction of nuclear weapons, or other weapons of mass destruction, into a conflict. In agreeing to a "no-first-use" policy, a country states that it will not use nuclear weapons first, but only under retaliatory circumstances

Critical Mass

The minimum amount of concentrated fissionable material required to sustain a chain reaction. See entry for Chain reaction.

Single Integrated Operational Plan (SIOP)

The nuclear war plan for an integrated response to a nuclear attack on the United States. In 1960, the U.S. Joint Strategic Target Planning Staff completed the SIOP 62. Since then, a version of the SIOP war plan has dictated how U.S. nuclear forces would be used in a conflict. With guidance from the President, the Secretary of Defense, and the Joint Chiefs of Staff, the Staff of the U.S. Strategic Command (STRATCOM) works out the details of the SIOP. STRATCOM designs and maintains the list of targets for nuclear attacks. The Pentagon formally changed the name of the SIOP in 2003, to OPLAN 8044 Revision

Fallout

The process of the descent to the earth's surface of particles contaminated with radioactive material from a radioactive cloud. The term is also applied in a collective sense to the contaminated particulate matter itself

Proliferation (of weapons of mass destruction)

The spread of biological, chemical, and/or nuclear weapons, and their delivery systems.

United Nations Monitoring, Verification and Inspection Commission (UNMOVIC)

The successor to the United Nations Special Commission on Iraq established by UN Security Council Resolution 1284 (1999), UNMOVIC was mandated to establish a reinforced, ongoing monitoring and verification system to check Iraq's compliance with its obligations not to reacquire WMD. UNMOVIC was terminated in June 2007. See entry for United Nations Special Commission on Iraq

Half-life

The time in which one half of the atoms of a particular radioactive substance decay. Measured half-lives vary from millionths of a second to billions of years, depending on the isotope. Also called physical or radiological half-life.

Yield

The total amount of energy released by a nuclear explosion, generally measured in equivalent tons of trinitrotoluene (TNT). A kiloton is equivalent to 1,000 tons of TNT; a megaton is equivalent to one million tons of TNT

Treaty of Tlatelolco

This treaty, opened for signature in February 1967, created a nuclear-weapon-free zone in Latin America and the Caribbean. The Treaty of Tlatelolco was the first international agreement that aimed to exclude nuclear weapons from an inhabited region of the globe. The member states accept the application of International Atomic Energy Agency safeguards on all their nuclear activities. The treaty also establishes a regional organization, the Agency for the Prohibition of Nuclear Weapons in Latin America (OPANAL), to supervise treaty implementation and ensure compliance with its provisions.

Throw-weight

Throw-weight refers to the weight of the payload that a missile is capable of delivering, and is a measure of the destructive potential of a ballistic missile.

UF6

UF6 (Uraniumhexafluoride or "hex") is the chemical form of uranium used to enrich uranium in a centrifuge

Nuclear Posture Review

Under a mandate from the U.S. Congress, the Department of Defense regularly conducts a comprehensive Nuclear Posture Review to set forth the direction of U.S. nuclear weapons policies. To date, the United States has completed three Nuclear Posture Reviews (in 1994, 2001, and 2010).

Delayed (worldwide) Fallout

consists of the smaller particles which ascend into the upper troposphere and stratosphere, to be carried by winds to all parts of the earth. The delayed fallout is brought to earth, mainly by rain and snow, over extended periods ranging from months to years, and can contaminate the animal food-chain

Early (local) Fallout

is defined, somewhat arbitrarily, as those particles which reach the earth within 24 hours after a nuclear explosion

The "front-end"

of the uranium-plutonium nuclear fuel cycle includes uranium mining and milling, conversion, enrichment, and fuel fabrication

RDD

radiological dispersal device

Vertical proliferation

refers to an increase in the quantity or capabilities of existing WMD arsenals within a state

The "back-end" of the nuclear fuel cycle

refers to spent fuel being stored in spent fuel pools, possible reprocessing of the spent fuel, and ultimately longterm storage in a geological or other repository

Horizontal proliferation

refers to the spread of WMD to states that have not previously possessed them