Action 3

The UK has eliminated its arsenal of WE177 gravity bombs that were deployed on Royal Air Force and Royal Navy aircraft and helicopters. All the weapons were dismantled by August 1998 and fissile material recovered from dismantled WE177 warheads was retained for defence purposes. The UK also dismantled its final Chevaline (Polaris) warheads in April 2002 leaving Trident as the UK’s sole nuclear weapons system.

The UK has also embarked on a wide-ranging modernisation of its nuclear weapons complex and submarine-based strategic nuclear weapons system since 2005. This has involved:

• Construction of a new ‘Dreadnought’ class of ballistic missile submarines to deploy the Trident II (D5) SLBM following a parliamentary vote in 2007.
• Participation in a US life extension programme to modernise the Trident SLBM fleet
• Started work on a new A21/Mk7 ‘Astrea’ warhead to replace the current Holbrook warhead.
• Investment in a suite of facilities at AWE Aldermaston and AWE Burghfield under the Nuclear Weapons Capability Sustainment Programme since 2005, including radiographic, hydrodynamics, and high-energy laser facilities, a new warhead assembly and disassembly plant, and a Future Materials Campus for the manufacture and storage of nuclear materials, improved science and analysis capabilities and processes to recover used materials.
• Investment in the Technology Development Centre supporting the UK-France Teutates programme at the Atomic Weapons Establishment (AWE) Aldermaston (in operation since 2014) and the French Atomic Energy Commission’s Epure facility at Valduc, France, for future UK hydrodynamic and radiographic experiments.Significant investment in the Rolls Royce Raynesway site that produces submarine reactor cores for UK SSBNs and SSNs.
• Significant investment in BAE Systems Barrow shipyard at Barrow-in-Furness that builds UK SSBNs and SSNs.
• Significant investment in His Majesty’s Naval Base (HMNB) Clyde where the UK’s SSBN and SSN fleets are based including the Royal Naval Armaments Depot (RNAD) Coulport where nuclear warheads are stored and loaded onto submarines.

In the latter stages of the Cold War and immediately following its ending, the United States––both of its own volition and in concert with other countries––led the world in reducing the role and number of nuclear weapons in its stockpile. This led to an approximately 85 percent reduction from its Cold War peak. In particular, the United States also reduced its non-strategic nuclear arsenal by more than 90% since the end of the Cold War.

The United States’ 2010 Nuclear Posture Review included notable adjustments to US nuclear policy, including a strengthened negative security assurance to “not use or threaten to use nuclear weapons against non-nuclear weapons states that are party to the NPT and in compliance with their nuclear non-proliferation obligations,” as well as commitments to fulfilling its deterrence objectives at significantly lower nuclear force levels and reduced reliance on nuclear weapons and establishing conditions where a “sole purpose” policy could be safely adopted.

These policy shifts guided much of US nuclear policy throughout the first half of the period between the 2010 and 2020 NPT Review Conferences. In February 2011 and January 2012, the Department of Defense released a new National Military Strategy and a corresponding new defense strategy, both of which reaffirmed plans to achieve US deterrence objectives with a smaller nuclear force that would reduce both the number of warheads in the US stockpile and their role in US national security strategy.

In 2013, the Obama administration announced the first revision of its nuclear weapons employment guidance since 2002, which directed the Department of Defense to align US nuclear missions with the guidance of the 2010 Nuclear Posture Review. This narrowed the scope of missions through which nuclear weapons could be employed, reduced the role of nuclear weapons in deterring non-nuclear attacks, and directed the Department of Defense to examine and reduce the role of launch under attack in nuclear planning. The employment guidance also referenced a 2013 inter-agency review—which included the participation of the State Department, the Defense Department, the National Security Council, the intelligence community, the Joint Chiefs of Staff, US Strategic Command, and the Office of the Vice President, which concluded that US deterrence requirements could be met by reducing US nuclear forces by up to one-third. Despite these actions, however, the Obama administration also initiated a large-scale nuclear modernization campaign and introduced a new gravity bomb to the arsenal––the B61-12.

The New START Treaty, to which the United States is a party, placed limits on deployments of strategic nuclear warheads and launchers. The United States met the treaty’s central limits by the deadline of February 2018. As part of the posture changes associated with New START, the United States de-MIRVed its intercontinental ballistic missile force such that each ICBM now carries only a single warhead, converted a portion of its nuclear-capable bomber force to conventional roles, and reduced the number of launch tubes on each ballistic missile submarine by four per boat.

The 2018 Nuclear Posture Review continued the nuclear modernization campaign that had been initiated under the Obama administration, but also added two supplementary capabilities: the low-yield W76-2 warhead for the ballistic missile submarine force, and a nuclear sea-launched cruise missile (SLCM-N). The deployment of the W76-2 did not result in an increase in the number of nuclear weapons in the U.S. arsenal, as its development involved modifying a small number of existing weapons.

Between fiscal years 1994 and 2020, the United States reduced its nuclear stockpile from 10,979 to 3,750, and dismantled approximately 9,100 warheads. However, the overwhelming majority of these reductions took place prior to 2010, and the pace of dismantlement dropped by approximately 53 percent after 2010, from an average of 547 warheads per year to 258 warheads per year after 2010. [1] During this period, entire classes of warhead where dismantled, including the dismantlement of all W62 warheads by August 2010, all B53 gravity bombs and all components associated with the W70 warhead by October 2011, and the W80-0 by the end of Fiscal Year 2012.

France retired its ground-based nuclear missiles Pluton in 1991 and dismantled the Hades weapon system in 1997. The ground-based component was fully dismantled in 1998.

In 1998, France reduced the number of ballistic missile submarines from 6 to 4.

In 2008, it reduced the number of squadrons affected to the nuclear mission from three to two (Strategic Air Forces), which was effective in 2013.