Nuclear merchant ships could open up Arctic routes for real
British shipping biz poised to make a killing?
Nuclear - particularly good for icebreaking. And yes, you do still need to do that in the North East Passage, actually
Nuclear power is also excellent for aircraft carriers, which need high speed to generate wind across their decks and make flight operations easier. This can be achieved using conventional propulsion, but it involves a lot of fuel-guzzling running at full throttle and thus the need for frequent inconvenient refuelling. Furthermore the exhaust funnels and air intakes up and down from engine rooms to superstructure take up a lot of deck plan which could otherwise be holding more planes.
The US Navy, the only one in the world with a large fleet of nuclear carriers, used to have nuclear cruisers as well, but has since retired these in favour of gas-turbine ships. Russia, though it has no nuclear carriers, does still operate nuclear surface warships - most notably the monster Kirov-class missile battlecruisers.
Russia is also the only present-day operator of civilian nuclear-powered ships. The main advantage of nuclear propulsion from the Russians' viewpoint is that a nuclear ship can easily develop a lot more thrust than a conventional one. This doesn't offer a proportional increase in speed - normally a given ship's hull has a limit, related to the waterline length, after which you can add huge amounts more poke and achieve very little in terms of greater speed*. This is why nuclear tech's much greater power-to-weight ratio compared to conventional doesn't generally offer more than a knot or so more of top speed.
Vast extra thrust beyond what's needed to get top or nearly-top speed is very handy in one application, however: that of ramming the ship through floating ice. Russia operates a small fleet of nuclear icebreakers used for operations off its northern coasts, icebound for much of the time. Normally these are used to break a path for regular cargo vessels and so on, but the Russians also built a nuclear-powered cargo vessel intended to break her own way through ice, NS (Nuclear Ship**) Sevmorput.
Much of the world has come to the erroneous conclusion that ships can now sail off the northern coast of Russia without any need for icebreaking, but this isn't actually true. A German firm sent two of its ships on a journey from Korea to Rotterdam last summer, which a lot of the Western press took as evidence that the North East Passage/Northern Sea Route had finally opened up due to climate-driven retreat of the Arctic ice cap. In fact the trip was only made possible by the presence of Russian icebreaker NS 50 Let Pobedy for the northern parts of the route. What is true, however, is that the Northeast Passage route from the Far East to Europe is a lot shorter than the usual journey via the Suez Canal.
Apart from Russian icebreakers, a few other nuclear-powered merchant ships were built and run back in the 1960s and 1970s as demonstration projects, but they couldn't compete with conventional merchantmen on running cost in the era of cheap fuel oil, and nobody back then considered emissions to be much of an issue.
Nowadays, with oil prices high and emissions becoming a potential major entry on shipping firms' balance sheets, some analysts consider that nuclear container ships could be worth building. Modern container ships go fast, and sustained high speed is where nuclear looks best compared to conventional. The UK government's Maritime and Coastguard Agency (MCGA) has confirmed to the Reg that major Chinese container line COSCO is discussing the requirements that British authorities might impose on visiting nuclear container vessels. The British shipping industry is also interested (Blighty no longer has much of a merchant marine as such, but a large proportion of the world's shipping deals are still struck in the City of London).