Dreadnought-class submarine

The Dreadnought-class submarine is the UK's next-generation nuclear-powered ballistic missile submarine (SSBN) program, designed to replace the current Vanguard-class submarines that have carried the UK's nuclear deterrent since the 1990s. The program, formerly known as the Successor program, was approved by the UK Parliament in 2016 with an estimated cost of £31 billion (plus £10 billion contingency).

Key aspects of the Dreadnought-class program:

1. Vessels: Four submarines will be built: Dreadnought, Valiant, Warspite, and King George VI. The four-boat fleet ensures that at least one submarine is always on deterrent patrol, maintaining continuous at-sea deterrence (CASD).

2. Builder: BAE Systems Submarines at Barrow-in-Furness, Cumbria. BAE Systems is the prime contractor for the submarine design and construction.

3. Nuclear reactor: The PWR3 (Pressurised Water Reactor 3) is a new generation nuclear reactor designed by Rolls-Royce for the Dreadnought-class. The PWR3 represents a significant advancement over the PWR2 used in the Vanguard and Astute classes, with improved efficiency, safety, and lifespan.

4. Missiles: The Dreadnought-class will carry the US Trident D5LE2 (Life Extension 2) ballistic missile, providing the UK's nuclear warhead delivery capability. The UK participates in the US Trident missile program through the Polaris Sales Agreement and subsequent arrangements.

5. Common Missile Compartment (CMC): The Dreadnought-class shares a Common Missile Compartment design with the US Columbia-class SSBN, developed jointly by the US and UK to reduce costs and ensure compatibility.

6. Characteristics: The Dreadnought-class will be approximately 153 meters long and displace about 17,200 tons submerged, making them the largest submarines ever built for the Royal Navy.

The Dreadnought-class program is one of the largest defense procurement programs in UK history. The construction timeline envisions:

• Dreadnought (S101): Laid down 2016, launch ~2028, service ~early 2030s
• Valiant (S102): Under construction
• Warspite (S103): Under construction
• King George VI (S104): Planned

The program connects to the UK's broader nuclear enterprise, including:

• The Atomic Weapons Establishment (AWE) at Aldermaston, which designs and maintains the UK's nuclear warheads
• The Épure/Teutates joint nuclear weapons simulation program with France
• The US-UK Mutual Defense Agreement for nuclear cooperation
• Rolls-Royce for the PWR3 reactor and naval nuclear propulsion

The Dreadnought-class also connects to the AUKUS framework through the sharing of submarine technology and expertise. The UK's experience in nuclear submarine design and construction (Astute and Dreadnought classes) is directly relevant to the SSN-AUKUS program, which will use UK design expertise for the trilateral submarine.

The UK's continuous at-sea deterrence (CASD) has been maintained since 1969, and the Dreadnought-class will ensure this continues into the 2060s. The program represents the UK's long-term commitment to an independent nuclear deterrent as a cornerstone of national security and NATO deterrence.