Last Updated: Jun 2011
The Second International Maritime Organization (IMO) Greenhouse Gas (GHG) Study in 2009 stated that installing nuclear reactors on board "is not foreseen to be an interesting option for international shipping, for environmental, political, security and commercial reasons."
However, since the 1960s there has been a steady, slow development of merchant ship nuclear propulsion, principally with ice breakers.
Currently around 150 ships are powered by more than 220 small nuclear reactors and more than 12,000 reactor years of marine operation has been accumulated, the World Nuclear Association told SustainableShipping.
The biggest driver has been the increasing pressure on the industry to lessen its impact on the environment.
Nuclear power is said to produce no notable carbon dioxide (CO2) sulphur oxides (SOx), nitrogen oxides (NOx), or particulates.
Nuclear also offers high speeds at a time when many vessels are having to reduce their speeds to cut fuel consumption and emissions. A nuclear powered ship does not have any speed-radius limitation
Nuclear reactors can be built with fuel supplies that last for 10 to 20 years, which means that a vessel can go years without having to stop and refuel.
During the Sustainable Shipping conference in Miami in 2010, however, delegates heard from a panel of experts that nuclear would not be a feasible alternative to bunker fuel. The main reasons given were the cost of the capital for equipment, training, the number of people required and the issue of ship insurance.
There is also a large initial cost of purchasing a nuclear reactor. Nuclear reactors are very expensive to design, build and install. Nuclear reactors require individuals with specialised experience in the nuclear field for maintenance and operation.
The additional capital cost of nuclear compared to fossil fuels is a significant obstacle despite the fact that savings on fuel and potential emissions charges would make nuclear economic in the long run.
The reactors and turbines also require more person-hours over their operational life which greatly increases the direct maintenance costs.
The propulsion plants of nuclear-powered ships remain a source of radiation even after the vessels are shut down and the nuclear fuel is removed.
The biggest obstacle, however, is believed to be public perception.
Nuclear power has been the most controversial of all energy sources due to public concerns about reactor safety following the 1979 accident at Three Mile Island in Pennsylvania and the 1986 incident at Chernobyl in Ukraine.
The US nuclear Navy, however, has an excellent safety record, 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.
In 2010, environmental group Greenpeace slammed attempts by the nuclear industry to rebrand nuclear power as clean and emission free as greenwashing.
Michael Grey from BIMCO said that attitudes are changing. However, following the 2011 Tōhoku earthquake in March 2011, that resulted in the meltdown at the Fukushima Daiichi nuclear reactor, interest in nuclear has waned.