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Is there room these days for nuclear propelled surface ships? Times have moved on from the Cold War and the mind-set of the 1950s when nuclear was ‘in’ – when even nuclear powered family cars were proposed.
Atomic cars never eventuated, but nuclear-propelled ships and submarines did. The main motive was range: naval tacticians didn’t have to wonder where the next top-up might come from. A warship that didn’t need to devote displacement and space to bunkerage could also use the weight for something else. That was a particular benefit for aircraft carriers, where one of the limiting factors was the fuel that could be carried for air operations – which, in a conventional ship, had to compete for space with the fuel needed to run the ship. A nuclear carrier, by contrast, could carry more aviation fuel.
Another up-side was power-to-speed ratios. In conventional warships, the hull is designed to produce least drag at a modest speed where the engines work most efficiently. That means that relatively higher horsepower is needed to drive the hull at top speed. A nuclear ship, by contrast, can be optimised for hydrodynamic efficiency at top speed, and can run at high speed almost without limit. Most conventional warships have restricted range at speed – some of the French ‘super-destroyers’ of the 1930s had endurance measured in hours when flat out.
All these advantages prompted the US Navy to look into nuclear surface warships during the late 1950s, leading to the cruiser Long Beach and super-carrier Enterprise, followed by the frigate Bainbridge. Seven nuclear-propelled escorts followed between then and 1980, variously classified as frigates or cruisers. They were joined from 1975 by the nuclear-powered Nimitz supercarrier class.
In practise, the power output of early reactor designs was limited, meaning nuclear escorts operated on less power than conventionally driven equivalents. USS Truxtun, for instance, had just 60,000 hp (sometimes quoted as 70,000) compared to the 85,000 hp of the conventional Belknap class.
Nuclear power also came with a massive down side. Fission reactors were inherently dangerous, producing toxic by-products. They demanded larger crews than a conventional plant. And accidents were possible. The fact that the US Navy – at least – never suffered a nuclear accident did not reduce the potential. In New Zealand, opposition to all things nuclear was such that nuclear weapons and power were made illegal, by statute, in 1985, stopping all visits by nuclear armed or propelled warships.
Just to cap it off, nuclear warships were expensive. Special facilities were required to deal with waste, and refuelling was tricky. Even during the Cold War, US naval budgets didn’t allow for many nuclear surface vessels, and other nations couldn’t afford them at all. Worse, over time the radioactivity affected the metals of the reactor and containment shell itself, limiting reactor life – after which the dangerously ‘hot’ reactor had to be removed and stored for a time span of some thousands of years.
These down-sides – and especially the costs – outweighed the advantages of atomic power; and all the US Navy’s nuclear surface escorts were taken out of service soon after the end of the Cold War. The last, USS South Carolina, was decommissioned at the end of July 1999. Just to underscore the difficulty of scrapping such ships, it was 2010 before her reactor and associated structures were finally in long-term storage at the Hanford Nuclear Reservation. The Soviets were late to the party, not taking the step until 1974 with Project 1144 Orlan, large missile cruisers with nuclear reactors boosted by oil-fired super-heaters. Five were planned but only four completed, dubbed ‘Kirov’ class. One remains in service today. A command ship, SSV-33 Ural, was built using a derived hull and the same base reactor system, but was decommissioned in 2002 and is being scrapped.
So is there room for nuclear propelled surface ships? The system is still in use for US aircraft carriers – along with one French carrier – but not for other surface ships; and even the carrier and submarine fleets are shrinking. The Russians might build their second class of nuclear-driven cruisers, Project 23560, although indications by May 2017 were that these had been suspended.
All of which suggests that nuclear surface-ship propulsion, in general, has had its day. It will be around a while to a small extent – the US Navy’s Ford class class has an expected lifespan well into the century and up to ten are planned. But construction of the class – with typical intervals of five years between each new hull – is a multi-decade process and given the way politics can change over such time-spans, there is no guarantee that all will be funded.
If you enjoyed this article and want to read more on naval engineering, check out my book Dreadnoughts Unleashed, available on Kindle. Click to buy.
Copyright © Matthew Wright 2017