Mexico is one of the few countries which has technical capabilities to manufacture nuclear weapons. However it has renounced them and pledged to only use its nuclear technology for peaceful purposes following the Treaty of Tlatelolco in 1968. In the 1970s Mexico's national institute for nuclear research successfully achieved the creation of highly enriched uranium which is used in nuclear power plants and in the construction of nuclear weapons. However the country agreed in 2012 to downgrade the high enriched uranium used on its nuclear power plants to low enriched uranium, the process was realised with the assistance of the International Atomic Energy Agency. It is unknown if Mexico ever created or possessed nuclear or any other kind of mass destruction weapons.
The use of nuclear energy in Mexico isn't something new. The country has been using technologies such as X-rays since late 19th century, evidence of the use of various radiations and radioisotopes for medical activities since the 1920s exist, practice that strengthen during the next decades alongside the use of industrial scintigraphies. Given its huge importance, the investigation of nuclear sciences formally began in the late 40s with two fields of interest: energetic and non-energetic applications and the study of nuclear sciences.
The CNEN (Mexico's Nuclear Energy National Committee) started nine programs: nuclear physics, education and training, seminaries, reactors, radioisotopes, industrial applications for nuclear energy, agronomy, genetics and radiologic protection.
During the sixties, the most relevant scientific project on the country was the construction of the Salazar Nuclear Center in the state of Mexico, started in 1964. Two years later, the center already possessed a Tandem Van de Graaff particle accelerator and in 1968 a TRIGA Mark III. In 1972, the CNEN changed its name to ININ (National Institute for Nuclear Research). However, regardless of the new name, its objective remains the same until today.
In 1961 the Mexican government argued that use of nuclear weapons could not be justified under the right to self-defence in the UN charter. Six years later the country would sign the Treaty of Tlatelolco in which Mexico and several other Latin American countries agreed not to manufacture nuclear weapons and to limit its nuclear technology for peaceful purposes only.
In 2000, Mexico was one of 7 nations launching a declaration "Towards a Nuclear Weapon Free World: The Need for a New Agenda" calling for further action to implement the provisions of the Treaty on the Non-Proliferation of Nuclear Weapons.
In April 2010, the Mexican government reportedly reached an agreement to turn over its highly enriched uranium to the United States. The US would help convert highly enriched uranium stored at Mexican research facilities into a less enriched form unsuitable for weapons, thus eliminating all highly enriched uranium in Mexico. Later in March 2012 Rachel Maddow reported that all highly enriched uranium had been removed from Mexico.
In October 2010 Mexico signed a contract with the Russian uranium supplier Rosatom, which will supply low enriched uranium (3%, a level of enrichment unsuitable for weapons) for the Mexican nuclear power plant Laguna Verde.
In 2012 Mexico was admitted into the Nuclear Suppliers Group (NSG) as an observer state, which the US claimed as an achievement in preventing nuclear proliferation.