Russia built 248 nuclear submarines and five naval surface vessels (plus nine icebreakers) powered by 468 reactors between 19, and was then operating about 60 nuclear naval vessels. In 2021 the World Associationof Nuclear Operators (WANO) extended its peer-level pre-startup reviews – a normal procedure for power plants – to Russian icebreakers. More than 14,000 reactor years of nuclear marine operation have been accumulated, Russia claims 7000 of these, and the US Navy has 6200 rector-years to 2021, with 526 reactors. Lloyd's Register shows about 200 nuclear reactors at sea, and that some 700 have been used at sea since the 1950s. Other sources quote 108 reactors in US naval vessels in mid-2019. Over 200 PBq of fission products was released causing high radiation exposure of about 50 others, including ten with ARS. In 1985 the K-431 was being refuelled in Vladivostok when a criticality occurred causing a major steam explosion which killed ten workers. The K-27 accident at sea in 1968 also involved coolant failure, this time in an experimental lead-bismuth cooled reactor, and nine deaths from ARS as well as high exposure by other crew. * The K-19 accident at sea in 1961 due to cooling failure in an early PWR resulted in eight deaths from acute radiation syndrome (ARS) in repairing it (doses 7.5 to 54 Sv) and possibly more later as well as many high doses. (Apart from reactor accidents, fires and accidents have resulted in the loss of two US and about four Soviet submarines, another four of which had fires resulting in loss of life.) In the US, UK and French navies there has never been a nuclear plant accident. There were more than 20 radiation fatalities.* Nevertheless, by Russia’s third generation of marine PWRs in the late 1970s safety and reliability had become a high priority. However, early Soviet endeavours resulted in a number of serious accidents – five where the reactor was irreparably damaged, and more resulting in radiation leaks. The safety record of the US nuclear navy is excellent, this being attributed to a high level of standardisation in naval power plants and their maintenance, and the high quality of the Navy's training program. The largest submarines are the 26,500 tonne (34,000 t submerged) Russian Typhoon class, powered by twin 190 MWt PWR reactors, though these were superseded by the 24,000 t Oscar-II class (eg Kursk) with the same power plant. Eventually four generations* of submarine PWRs were utilised, the last entering service in 1995 in the Severodvinsk class. Russia developed both PWR and lead-bismuth cooled reactor designs, the latter not persisting. Rolls-Royce built Westinghouse-derived units for the UK Royal Navy submarines and then developed the design further to the PWR2. The technology was shared with Britain, while French, Russian and Chinese developments proceeded separately.Īfter the Skate-class vessels, reactor development proceeded and in the USA a single series of standardized designs was built by both Westinghouse and GE, one reactor powering each vessel. Nuclear power had revolutionised the Navy. Remarkably, the Enterprise remained in service to the end of 2012.īy 1962 the US Navy had 26 nuclear submarines operational and 30 under construction. A cruiser, USS Long Beach, followed in 1961 and was powered by two of these early units. Nautilus led to the parallel development of further ( Skate-class) submarines, powered by single pressurised water reactors, and an aircraft carrier, USS Enterprise, powered by eight Westinghouse reactor units in 1960. This marked the transition of submarines from slow underwater vessels to warships capable of sustaining 20-25 knots submerged for long periods, independent of needing air for diesel engines to charge batteries. The first nuclear-powered submarine, USS Nautilus, put to sea in 1955. Work on nuclear marine propulsion started in the 1940s, and the first test reactor started up in USA in 1953. So far, exaggerated fears about safety have caused political restriction on port access.
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