Hans M Kristensen & Matt Korda. Bulletin of the Atomic Scientists. Volume 75, Issue 1, 2019.
France’s nuclear arsenal contains approximately 300 warheads, a number that has remained stable over the past decade. Nearly all of these warheads are deployed or operationally available for deployment on short notice. A small number of additional warheads are in maintenance.
Other than the United States, France is the most transparent of the nuclear-armed states, having disclosed details about its nuclear forces and operations for many years. The current force level is the result of adjustments made to France’s nuclear posture following former President Nicolas Sarkozy’s announcement on March 21, 2008 that the arsenal would be reduced to fewer than 300 warheads (Sarkozy 2008). Former President François Hollande reaffirmed this posture on February 19, 2015, when he declared that France had a stockpile of 300 warheads for “three sets of 16 submarine-based missiles and 54 ASMPA [air-launched] delivery systems,” which together provide France with both strategic and tactical nuclear capabilities (Hollande 2015).
As Sarkozy said in 2008, the 300-warhead stockpile is “half the maximum number of warheads we had during the Cold War” (Sarkozy 2008). By our estimate, the French warhead inventory peaked in 1991-1992 at around 540 warheads, and the size of today’s stockpile is about the same as it was in 1984, although the composition is significantly different.
Successive heads of state, including Presidents Sarkozy, Hollande, and now Macron, have consistently reiterated France’s nuclear weapons doctrine. The Defense Ministry’s 2013 White Paper on Defense and National Security says the nuclear doctrine is “strictly defensive,” and that using nuclear weapons “would only be conceivable in extreme circumstances of legitimate self-defense,” involving France’s vital interests. France does not have a no-first-use policy, though, and reserves the right to conduct a “final warning” limited nuclear strike, in an effort to signal to an adversary that they have crossed a line—or to signal the French resolve to conduct further nuclear strikes if necessary—in an attempt to restore deterrence (Tertrais 2019). Although France is a member of NATO, its nuclear forces are not part of the Alliance’s integrated military command structure. And the White Paper says the French nuclear deterrent “ensures, permanently, our independence of decision-making and our freedom of action within the framework of our international responsibilities, including in the event of any threat of blackmail that might be directed against us in the event of a crisis” (French Ministry of Defense 2013). For a more in-depth examination on the evolution of France’s nuclear doctrine, see Bruno Tertrais’ authoritative report, “French Nuclear Deterrence Policy, Forces and Doctrine” (Tertrais 2019).
The French government says it will spend €25 billion on its nuclear forces between 2019 and 2023 (Parly 2018).
Submarine-launched ballistic missiles
The French force of submarine-launched ballistic missiles (SLBMs) constitutes the backbone of the French nuclear deterrent. Under the command of the Strategic Ocean Force (Force Océanique Stratégique, or FOST), the French Navy operates four Triomphant-class nuclear-powered ballistic missile submarines (SSBNs) equipped with nuclear-armed long-range ballistic missiles—Le Triomphant (hull number S616), Le Téméraire (S617), Le Vigilant (S618), and Le Terrible (S619). Like the other Western nuclear powers, the French Navy maintains a continuous at-sea deterrent posture with at least one boat on patrol, one preparing for patrol, one returning to port, and one in maintenance. Each patrol lasts an average of approximately 70 days, and FOST completed its 500th deterrent patrol in July 2018 when Le Téméraire returned to Île Longue, marking 46 years of continuous SSBN patrols since the first one in 1972 (French Ministry of Defense 2018d). Each submarine can carry a set of sixteen M51 SLBMs, but since one boat is always undergoing routine maintenance, France has only produced enough missiles for three boats.
The SSBN force is based at the Île Longue naval base near Brest in Brittany, which includes two drydocks, nuclear warhead storage, and a unique facility with what appear to be 24 vertical silos for storing missiles that are not loaded on submarines. The missiles are assembled about four kilometers south of the base at the Guenvénez Missile Storage and Maintenance. Long-term submarine repairs and refueling take place at the Brest naval base across the bay, which has three large drydocks (Naval Technology n.d.). The SSBNs are built and dismantled at the shipyard in Cherbourg.
France relocated its SSBN command center from Houilles, Yvelines to the Île Longue base in 2000, while submarine communication facilities continue to operate using France’s HWU transmitter at Rosnay and possibly other locations. French SSBNs are protected during their operations by nuclear attack submarines, maritime patrol aircraft (such as Atlantique 2s), anti-submarine frigates, and minesweepers.
All French SSBNs now carry the M51 SLBM, which was deployed starting in 2010 to replace the M45 SLBM (Tran 2018). The last M45 was offloaded in late 2016. The M51.1, which has greater range and better accuracy than the M45, can carry up to six 100-kiloton TN75 MIRV warheads, but probably only carries an average of five warheads each. Some missiles are thought to have been downloaded to carry fewer warheads, in order to increase targeting flexibility in limited scenarios. An upgraded version of the M51.1, known as M51.2, was flight tested on July 1, 2016 from Le Triomphant and declared operational by the French Defense Minister in December 2017 (Parly 2017). The M51.2, which carries a new warhead—the tête nucléaire océanique, or TNO—has since been added to Le Téméraire (Willett 2018). The TNO is reportedly stealthier than the TN75 and is housed within a new reentry vehicle, with the entire package weighing approximately 500 kilograms (Kile and Kristensen 2017). The remaining boats will be upgraded to the M51.2 by 2020 (Willett 2018). A third iteration of the missile—the M51.3—is in development and scheduled for completion by 2025 and will incorporate a new third stage for extended range and further improvement in accuracy (Parly 2017).
The M51 has reportedly been developed in close conjunction with the Ariane 5 space-launch vehicle, and the two share a number of technological commonalities, including solid-fueled heavy boosters, electronics, wiring, and guidance systems. The three-stage M51 reportedly has a range in excess of 9,000 kilometers and carries a liquid-propellant post-boost vehicle, allowing for the deployment of MIRVs and penetration aids (Willett 2018; Tertrais 2019).
Given that the Triomphant-class SSBNs are expected to reach the end of their operational lives in the 2030s, development on a third generation of ballistic missile submarine is expected to begin as part of the 2019-2025 military planning period. The new submarine class, which is known as SNLE-3G, will begin entering operational service around 2035 and incorporates a longer hull and advanced stealth features (Vavasseur 2018).
Air-launched cruise missiles
The second leg of France’s nuclear arsenal consists of nuclear ASMPA (air-sol moyenne portée-améliorée) air-launched cruise missiles for delivery by fighter-bombers operated by the Strategic Air Forces and the Naval Nuclear Aviation Force. The bombers assigned to the nuclear mission also serve conventional missions.
The Strategic Air Forces (Forces Aériennes Stratégiques or FAS) operate two squadrons of approximately 40 nuclear-capable Rafale BF3 aircraft organized into two squadrons, the EC 1/4 “Gascogne” and EC 2/4 “La Fayette” at Saint-Dizier Air Base (Air Base 113) about 190 kilometers east of Paris (Pintat and Lorgeoux 2017). EC 2/4 operated nuclear-capable Mirage 2000Ns at Istres Air Base until June 21, 2018, when the aircraft was officially retired from the French Air Force. After the Mirage 2000N’s retirement, EC 2/4 moved from Istres to Saint-Dizier. Now both squadrons operate Rafale BF3 twin-seat strike fighters, leaving the Rafale the sole aircraft responsible for France’s nuclear strike mission (French Ministry of Defense 2018a; Jennings 2018b).
The Naval Nuclear Aviation Force (Force Aéronavale Nucléaire or FANu) operates at least one, possibly two, nuclear squadrons (11F and possibly 12F) of Rafale MF3 aircraft for nuclear strike missions onboard France’s sole aircraft carrier, the Charles de Gaulle. The FANu and its ASMPA missiles are not permanently deployed onboard the carrier but can be rapidly deployed by the president in support of nuclear operations (Kristensen 2009, Pintat and Lorgeoux 2017). While the Charles de Gaulle’s home port is Toulon on the Mediterranean coast, the aircraft are based at the Landivisiau Naval Aviation Base in northern France. The nuclear ASMPA missiles earmarked for deployment on the carrier are thought to be co-located with ASMPAs belonging to the Strategic Air Forces at either Avord Air Base or Istres Air Base—or possibly at both. The 11F squadron conducted a four-day exercise in March 2018 to ensure it was ready to carry out its nuclear mission on the Charles de Gaulle (French Ministry of Defense 2018b) after it completed a nuclear reactor refueling overhaul in September 2018 (French Ministry of Defense 2018c). The French carrier is the only surface ship in NATO equipped to carry nuclear weapons.
At the October 2018 Euronaval defense exposition, the Minister of the Armed Forces announced that in 2020, France will make a decision on replacing the Charles de Gaulle. The final decision on a carrier must take into consideration the type of aircraft that will eventually replace the Rafales between 2035 and 2040 (Irish 2018); France and Germany announced in April they would jointly develop a sixth-generation combat aircraft that could potentially be nuclear-capable (Sprenger 2018).
The ASMPA missile is equipped with a nuclear warhead known as the tête nucléaire aéroportée, or TNA. Its maximum yield is rumored to be up to 300 kilotons, although the yields demonstrated in the 1995-1996 nuclear testing series indicate that lower yield options for the TNA may be available (Kristensen 2015). The ASMPA, which has a range of up to 500 kilometers, first entered service in 2009 and has now completely replaced the earlier ASMP. France produced a total of 54 ASMPAs, including those needed for flight testing. A mid-life refurbishment program is scheduled to begin in 2022.
Until 2009, management and storage of France’s air-launched nuclear weapons was conducted by Dépôts-Ateliers de Munitions Spéciales (DAMS) located at Saint-Dizier, Istres, and Avord Air Bases. In 2009, these three bases were adapted for ASMPA storage and renamed to “K Buildings.” (Tertrais 2019). Although nuclear-capable Rafales operated by the Strategic Air Forces are all located at Saint-Dizier, all three bases serve as dispersal and storage sites. Moreover, Avord, Istres, or both serve as storage sites for the ASMPAs assigned to the Charles de Gaulle for the Naval Nuclear Aviation Force strike mission.
France has begun design development of a stealthier, extended-range replacement for the ASMPA, which will be called the ASN4G (air-sol nucléaire 4ème génération) and enter into service around 2035. Hypersonic technologies are among the potential ASN4G propulsion options, although this might increase the length of the missile beyond what the current Rafale aircraft can carry (Pintat and Lorgeoux 2017). If so, decisions regarding the ASN4G would have to be paired with decisions regarding France’s next generation of nuclear-capable aircraft.
Given the Rafales’ relatively short range, France’s air-launched nuclear weapons capability depends on a support fleet of refueling aircraft. France currently operates a mixed fleet of Boeing C-135FR and KC-135R tanker aircraft. Replacing this aging fleet has been a strategic priority for nearly a decade, but was delayed significantly due to budget issues. Delivery of the new tankers—a fleet of 15 Airbus A330-200 “Phénix” Multi-Role Tanker Transport (MRTT) aircraft—has now been scheduled for completion by 2023, and the first Phénix arrived at Istres, its future home base, on September 27, 2018 (Jennings 2018a).
The nuclear weapons complex
France’s nuclear weapons complex is managed by the Direction des Applications Militaires, or DAM, a department within the Nuclear Energy Commission (Commissariat à l’énergie atomique et aux énergies renouvelables, or CEA). DAM is responsible for research, design, manufacture, operational maintenance, and dismantlement of nuclear warheads.
Warhead design and simulation takes place at the DAM center in Bruyères-le-Châtel, about 30 kilometers south of Paris. The center houses the Tera 1000—the most powerful European supercomputer with a 25 petaflop capacity—and employs about half the people affiliated with the military section of the Nuclear Energy Commission (CEA 2016).
The Commission’s Valduc Center, about 30 kilometers northwest of Dijon, is responsible for nuclear warhead production, maintenance, and dismantlement. It has recently expanded as a result of the 2010 French-British Teutates Treaty, an agreement to collaborate on technology associated with the two countries’ respective nuclear weapons stockpiles. The Epure facility at Valduc will ultimately include three high-power radiographic axes, including the AIRIX x-ray generator, which will “make it possible to characterise, to the highest level of precision, the state and hydrodynamic behaviour of materials, under the conditions encountered in the pre-nuclear phase of weapon functioning,” as the Nuclear Energy Commission said in its 2016 annual report. (CEA 2016). This function is critical to maintaining and developing France’s nuclear weapons in the absence of live nuclear test explosions.
Finally, the Nuclear Energy Commission’s CESTA (Centre d’Études Scientifiques et Techniques d’Aquitaine) near Le Barp is responsible for designing equipment for nuclear weapons and reentry vehicles, as well as for coordinating the development of nuclear warheads. The Megajoule laser, France’s equivalent to the US National Ignition Facility, is located at the same site. Construction on the Megajoule began in 2005 and it was first used to conduct experiments in 2014 (CEA 2016). It is designed to validate theoretical models of nuclear weapons detonations, and therefore plays an important role in France’s nuclear simulation program.