Rolls-Royce PWR

The Rolls-Royce pressurised water reactor (PWR) series has powered the Royal Navy's nuclear submarines since the Valiant class, commissioned in 1966.[1]

For the Rolls-Royce small modular reactor design, see Rolls-Royce SMR.

Background

Nuclear reactor designs, operating methods and performance standards are highly classified.[2]

The United Kingdom's first nuclear-powered submarine HMS Dreadnought was commissioned in 1963 powered by a Westinghouse S5W reactor, provided to Britain under the 1958 US-UK Mutual Defence Agreement.[3][4]

PWR1
HMS Valiant, the first British nuclear submarine to be powered by a British built reactor

The first British naval reactor was the PWR1. It was based on a core and reactor assembly of purely British design. The reactor first went critical in 1965, four years later than planned.[5] Technology transfers under the US-UK Mutual Defence Agreement eventually made Rolls-Royce entirely self-sufficient in reactor design in exchange for a "considerable amount" of information regarding submarine design and quietening techniques being passed on to the United States.[6][7][8][9]

The reactor fuel was highly enriched uranium (HEU) enriched to between 93% and 97%. Each nuclear core had a life of about 10 years, so had to be refueled about twice during the lifetime of a submarine.[10][11]

Rolls-Royce Marine Power Operations at Derby was the centre for design and manufacture of the UK's submarine reactors, and remains so today. The Ministry of Defence's Vulcan Nuclear Reactor Testing Establishment (NRTE), at Dounreay, tested each reactor core design prior to its installation in nuclear submarines.

Submarines

PWR2

The PWR2 was developed for the Vanguard-class Trident missile submarines and is a development of the PWR1. The first PWR2 reactor was completed in 1985 with testing beginning in August 1987 at the Vulcan Naval Reactor Test Establishment.

The reactor fuel is highly enriched uranium (HEU) enriched to between 93% and 97%. The latest PWR2 reactor core design is "Core H", which has a life of about 30 years removing the need for refueling, allowing a submarine to avoid two reactor refits in its service life.[10][11] HMS Vanguard was fitted with the new core during its refit, followed by her three sister boats. The Astute-class submarines have this full-life core installed. As they were developed for SSBNs, the reactors are considerably larger than those of then-current British fleet submarines. The diameter of then-forthcoming Astute-class hulls was therefore increased to accommodate the PWR2.

A safety assessment of the PWR2 design by the Defence Nuclear Safety Regulator in November 2009 was released under a Freedom of Information request in March 2011.[12][13] The regulator identified two major areas where UK practice fell significantly short of comparable good practice: loss-of-coolant accident and control of submarine depth following emergency reactor shutdown.[14][13] The regulator concluded that PWR2 was "potentially vulnerable to a structural failure of the primary circuit", which was a failure mode with significant safety hazards to crew and the public.[13][15]

In January 2012 radiation was detected in the PWR2 test reactor's coolant water, caused by a microscopic breach in fuel cladding. This discovery led to HMS Vanguard being refueled early and contingency measures being applied to other Vanguard and Astute-class submarines, at a cost of £270 million. This was not revealed to the public until 2014.[16][17]

In February 2013, the Ministry of Defence (MoD) awarded Rolls-Royce a £800 million ten year "foundation" contract to "deliver and maintain" the reactors of the Astute-class and the Vanguard-class replacement the Successor.[18][19] In February 2019, the MoD awarded Rolls-Royce a £235 million three year contract for Nuclear Propulsion Lifetime Management for the Trafalgar, Vanguard and Astute classes.[20]

Submarines

PWR3

Three propulsion options were considered for the replacement of the Vanguard-class, the Successor: PWR2, PWR2b (derivative with improved performance) and PWR3.[21] PWR3 was a new system "based on a US design but using UK reactor technology".[22][23] The Royal Institution of Naval Architects reported that it was likely that the UK was given access to the US Navy S9G reactor design used in their Virginia-class submarines.[24] The PWR3 was a simpler and safer design with a longer life and lower maintenance requirements than the PWR2 variants and cost roughly the same as the PWR2b.[21] The PWR3 has 30% fewer parts compared to the PWR2.[25]

In March 2011, Defence Secretary Liam Fox said the PWR3 was the preferred option "because those reactors give us a better safety outlook".[26][27] In May 2011, the Ministry of Defence announced that PWR3 had been selected for the Successor (later named the Dreadnought-class in 2016).[21][15] The PWR3 cost about £50 million more per boat to purchase and operate compared to PWR2 designs. This is offset by the PWR3's longer life over the 25-year life PWR2 designs.[21] The PWR3 does not require reactor core prototype tests; instead computational modelling is used.[28][29] Consequently, the Vulcan Nuclear Reactor Testing Establishment operated by Rolls-Royce closed in 2015.[30]

In June 2012, the MoD awarded Rolls-Royce a £600 million contract to produce reactors for the Dreadnought-class and also for the final boat of the Astute-class HMS Agincourt.[31] The MoD also awarded Rolls-Royce a further £500 million to refurbish their Rolls-Royce Marine Power Operations reactor core manufacturing plant at Derby to manufacture the PWR3 and to extend the plant's operational life to 2056.[31][32] In January 2020, the National Audit Office reported that the construction of the plant was five years behind schedule and was now forecast to be in service in 2026.[32][33]

Submarines
  • Dreadnought-class SSBN[31]
    • HMS Dreadnought (under construction)
    • HMS Valiant (under construction)
    • HMS Warspite (under construction)
    • HMS King George VI (on order)

Future

Rolls Royce is building the reactor for SSN-AUKUS,[34] which may be the PWR3, or a derivative.[35][36]

See also

References
  1. Asst Chief Engineer - Astute Christopher Palmer. "Management of Key Technologies in the UK Naval Nuclear Propulsion Programme" (PDF). Rolls-Royce Submarines. Retrieved 29 September 2021.
  2. Ritchie 2015, p. 3.
  3. Ritchie, Nick (February 2015). The UK Naval Nuclear Propulsion Programme and Highly Enriched Uranium (PDF) (Report). Federation of American Scientists, Washington, D.C.: University of York, UK. p. 3. Retrieved 19 September 2021.
  4. Vanguard to Trident; British Naval Policy since World War II, Eric J. Grove, The Bodley Head, 1987, ISBN 0-370-31021-7
  5. Daniels, R.J (2004). The End Of An Era: The Memoirs Of a Naval Constructor. Periscope Publishing. pp. 135–136, 153. ISBN 1-904381-18-9. Retrieved 25 April 2017.
  6. Gardiner, Robert; Chumbley, Stephen; Budzbon, Przemysław (1995). Conway's All the World's Fighting Ships 1947-1995. Annapolis, Md: Naval Institute Press. p. 529. ISBN 1557501327.
  7. Daniels, R.J (2004). The End Of An Era: The Memoirs Of a Naval Constructor. Periscope Publishing. p. 134. ISBN 1-904381-18-9. Retrieved 25 April 2017.
  8. James Jinks; Peter Hennessy (29 October 2015). The Silent Deep: The Royal Navy Submarine Service Since 1945. Penguin UK. p. 195. ISBN 978-0-14-197370-8.
  9. "Nuclear-Powered Submarines". US Naval Institute. November 2021. the British made important contributions to U.S. submarine design, such as the concept of rafting for silencing and initial types of pump-jets
  10. Ritchie 2015, pp. 3–6.
  11. King, S J; Putte, D Vande (July 2003). Identification and Description of UK Radioactive Wastes and Materials Potentially Requiring Long-term Management. Nirex Report N/085. UK Nirex Ltd: Didcot. pp. 17–19. ISBN 1840293306. Retrieved 21 September 2021.
  12. Rob Edwards (10 March 2011). "Flaws in nuclear submarine reactors could be fatal, secret report warns". The Guardian. Retrieved 28 March 2011.
  13. McFarlane, Head of the Defence Nuclear Safety Regulator Cdre Andrew (2009). "Annex B: Successor SSBN - Safety Regulator's advice on the selection of the propulsion plant in support of the future deterrent (4 November 2009) DNSR/22/11/2". Successor Submarine Project (Note by the Assistant Secretary) (PDF). (09)62. Defence Board. Released under FOI. Retrieved 29 September 2021.
  14. Joseph Watts (11 March 2011). "Expert warned MoD on safety of Rolls-Royce nuclear sub reactors". Derby Telegraph. Archived from the original on 18 September 2012. Retrieved 28 March 2011.
  15. "PWR3 Reactor chosen for Trident". defencemanagement.com. 18 May 2011. Archived from the original on 22 July 2011.
  16. "Nuclear submarine to get new core after test reactor problem". BBC. 6 March 2014. Retrieved 8 March 2014.
  17. David Maddox (8 March 2014). "MoD accused of Dounreay radiation leak cover-up". The Scotsman. Retrieved 8 March 2014.
  18. "MOD awards £800 million submarine propulsion contract". Ministry of Defence (Press release). 13 February 2013. Archived from the original on 10 September 2015. Retrieved 30 September 2021.
  19. Parliamentary Under-Secretary of State for Defence Philip Dunne (13 February 2013). "Rolls-Royce Submarines (Foundation Contract)". UK Parliament. House of Commons. Retrieved 30 September 2021.
  20. "Defence Secretary Announces £235 Million Submarine Nuclear Propulsion Deal". Ministry of Defence (Press release). 25 February 2019. Retrieved 30 September 2021.
  21. The United Kingdom's Future Nuclear Deterrent: The Submarine Initial Gate Parliamentary Report (PDF) (Report). Ministry of Defence. May 2011. p. 5. Retrieved 12 October 2013.
  22. Hollinshead, Dr P; MacKinder, A P (2009). "Annex A: Successor Submarine Project Review Note (24 November 2009)". Successor Submarine Project (Note by the Assistant Secretary) (PDF). (09)62. Defence Board. Released under FOI. Retrieved 29 September 2021.
  23. "Safety paramount for RN nuclear submarine reactors" (PDF). Defence Codex: The Magazine for Defence Engineering and Science. Ministry of Defence (9): 15. Autumn 2011. Archived from the original (PDF) on 13 October 2011.
  24. Turner, Julian (29 July 2013). "Deep impact: inside the UK's new Successor-Class nuclear submarine". Naval Technology. Retrieved 29 September 2021.
  25. "Nuclear – Engineering Excellence" (PDF). Rolls-Royce. 2016. Retrieved 1 October 2021.
  26. Severin Carrell (23 March 2011). "Navy to axe 'Fukushima type' nuclear reactors from submarines". The Guardian. Retrieved 28 March 2011.
  27. "Trident Replacement Programme". UK Parliament. House of Commons. 14 March 2011. Retrieved 29 September 2021.
  28. Grimes, Professor Robin; Ion, Professor Dame Sue; Sherry, Professor Andrew (28 October 2014). Royal Navy Nuclear Reactor Test Facility Review (PDF) (Report). Released under FOI. Retrieved 29 September 2021.
  29. "Submarine reactor testing to end at Vulcan" (PDF). Desider: The Magazine for Defence Equipment and Support. Ministry of Defence (43): 10. December 2011. Archived from the original (PDF) on 6 December 2011.
  30. Ministry of Defence (22 July 2015). "Shutdown of shore test facility reactor" (Press release). Retrieved 29 September 2021.
  31. "Royal Navy submarine contract awarded". Ministry of Defence (Press release). 18 June 2012. Archived from the original on 19 June 2012.
  32. National Audit Office. (10 January 2020). Ministry of Defence : Managing infrastructure projects on nuclear-regulated sites (PDF). House of Commons papers, session 2019/20, HC 19. pp. 4, 36, 53–54. ISBN 9781786042934. Retrieved 1 October 2021.
  33. Chuter, Andrew (13 May 2020). "Three British nuclear programs are $1.67 billion over budget". DefenseNews. Retrieved 1 October 2021.
  34. Allison, George (14 June 2023). "Rolls-Royce Expands for Aussie submarine reactor needs". Retrieved 23 October 2023.
  35. Thomas, Richard (14 March 2023). "The evolution of the UK's SSNR into the SSN-AUKUS". Naval Technology. Retrieved 24 October 2023.
  36. "AUKUS plan details: a triumph of hope over experience". Nuclear Information Service. Retrieved 24 October 2023.

Further reading
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