Last month marked the 50th anniversary of the launch of Britain’s first nuclear submarine – HMS Dreadnought. Nuclear power in defence has a long history, but interest is now growing in using the technology for merchant shipping, in response to environmental concerns and the rising price of fossil fuels. It is thought that bulk carriers, oil tankers and even cruise ships could benefit from uranium fuel and also having zerocarbon emissions. 

Lloyd’s Register estimates that there are 200 nuclear reactors at sea. These are primarily in naval surface ships and submarines, but also in some vessels in the merchant sector. Since the time of the first nuclear-powered submarine, some 700 nuclear power plants have seen service at sea. 

The development of nuclear propulsion for civilian shipping has largely focused on icebreakers. But David Dobson, commercial projects director at Babcock’s marine division for integrated technology, says: “As fossil fuels become scarcer there will be a compelling argument for utilising alternative fuels for ship propulsion.

“Nuclear propulsion for large ocean-going vessels becomes more economic as fossil-fuel costs rise. The other advantage is that nuclearpowered vessels can trade for up to 10 years without refuelling. 

“The emissions levels are zero, making the adoption of nuclear-powered vessels a real alternative in highly sensitive environments.”

A new nuclear dawn in shipping would pose real challenges, however. While nuclear technology is well-established in submarines and electricity generation, nuclear-powered merchant ships would require high levels of engineering expertise in terms of design, manufacturing, operation and decommissioning. Large numbers of reactors would need to be built to make start-up costs economical. “Costs would of course significantly decrease for multiple reactor production,” Dobson says.

John Carlton, professor of marine engineering at City University London, says different methods of ship design would need to be employed to ensure the reactor’s integrity would be maintained in the event of an accident or collision. The possibility of terrorist strikes on shipping would also have to be considered. International regulatory frameworks would need to cope with an increasing number of nuclear-powered ships on the high seas. And special ports, with appropriate safety strictures and technology, would have to be designated for refuelling. Radioactive waste from the ship’s engine would also have to be safely handled and stored.

Dobson also highlights some of the barriers to a new nuclear dawn for shipping: “There are significant safety challenges that must be met both in design and operation of these vessels. Compliance with both international and national regulatory frameworks would be a prerequisite.”

Organisations such as the International Atomic Energy Agency and the International Maritime Organisation would need to work more closely together, Carlton believes. 

Having said all that, he argues that a bulk carrier could run with a reactor “about the size of a dustbin,” probably only needing to be refuelled every five to seven years. Ships would probably be able to travel at greater speeds. Nuclear propulsion would probably be suitable for larger ships, while smaller ships could one day rely on fuel cells, he said. 

Carlton said it was impossible to say for certain that nuclear power would one day be employed far more widely in merchant shipping. “My suspicion, however, is that it probably will.”