France is a nuclear weapon state member of the Nuclear Non-proliferation Treaty. It has officially declared that it has fewer than 300 nuclear warheads in its arsenal. This number includes operationally deployed warheads as well as warheads in reserve.
France's stock of fissile materials is estimated to be 6±1 tonnes of military plutonium and 31±6 tonnes of weapon-grade-equivalent HEU (this includes 4.850 tonnes of civilian HEU). Large-scale production of plutonium for military purposes ceased in 1992. France announced the definitive halt of fissile material production for weapons purposes on 22 February 1996 and stopped producing highly enriched uranium by the end of June 1996. In its declaration to IAEA, France reported having a stock of 57.5 tonnes of separated unirradiated civilian plutonium as of December 2011.
France produced highly enriched uranium (HEU) at a dedicated enrichment complex near Pierrelatte at the Tricastin site. The Pierrelatte facility included four units that provided different levels of enrichment. The first unit to come online was the low-enrichment plant in 1964, and production of highly enriched uranium using all four units started in early 1967. Beginning in 1979, the Pierrelatte plant also used product from the Eurodif plant, located nearby. HEU production at Pierrelatte ended in late June 1996. The plant was shut down and is being dismantled.
The amount of weapon-grade HEU produced by the Pierrelatte plant is estimated to be 35±5 tonnes. (This does not include HEU consumed in naval fuel.)
The main removals from this HEU stockpile were due to the operation of the two HEU fueled Célestin tritium-production reactors, which were also used for plutonium and special-isotope production. These reactors, which were shut down in December 2009, consumed about 5-7 tonnes of HEU. About 2-4 tonnes of HEU were consumed in nuclear tests.
The current stock of military-related weapon-grade HEU is therefore estimated to be 26±6 tonnes. France also has declared a stock of 4.638 tonnes of civilian HEU, including 3.176 tonnes of fresh HEU, as of December 2011. Some of this material may have been produced domestically, but a significant fraction is probably of U.S. and Russian origin for use in research-reactor fuel. With this uranium taken into account, the total HEU stock is 31±6 tonnes.
France is operating two commercial uranium enrichment facilities - the Georges Besse I gaseous diffusion plant, operated by Eurodif, and the centrifuge plant Georges Besse II, operated by SET (Société d'enrichissement du Tricastin). Both companies are subsidiaries of Areva.
Large-scale plutonium production for military purposes in France started in 1956 and ceased in 1992. France built a series of dedicated production reactors at its Marcoule site, but also used several civilian reactors owned and operated by Electricité de France (EDF) to produce additional weapon-grade plutonium (and tritium).
The dedicated plutonium production reactors, graphite-moderated gas-cooled G1, G2, and G3, were located at Marcoule. They became operational in 1956, 1958, and 1959 respectively. The reactors have been shut down. In total, G1, G2, and G3 produced about 4 tons of weapons plutonium with an average plutonium-239 content of about 94.9 %.
The fast-neutron reactor Phénix, which went critical in mid-1973 and operated at significant power level until the late 1990s, produced about 340 kg of plutonium for the weapon program. France also operated two dedicated tritium-production Célestin reactors at Marcoule. These reactors, which became operational in 1967 and 1968 and were shut down in December 2009, produced about 700-800 kg of weapon grade plutonium in addition to their main product - tritium.
In addition to its dedicated military reactors, France has also used its fleet of gas-graphite power reactors to produce plutonium for military purposes. These reactors could have produced up to 1.7 tonnes of weapon-grade plutonium.
The total amount of weapon-grade plutonium produced in France is estimated to be 7±1 tonnes.
Nuclear tests conducted by France consumed about one ton of plutonium. The estimate for the current stockpile is therefore about 6±1 tonnes.
France operates two large commercial reprocessing plants - UP2 and UP3 at La Hague. It uses separated plutonium to fabricate MOX fuel that is used in light water reactors. In its most recent declaration submitted to IAEA, France reported owning 57.5 tonnes of separated unirradiated plutonium as od December 31, 2011.