|Fig. 1: U.S. Navy Aircraft Carrier (Courtesy of Wikimedia Commons).|
While a gas-powered engine has traditionally driven cargo ships, engineers have also strived to create nuclear powered ships. These ships are built with nuclear power plants on board that are able to power the ship and eliminate the need for gas. Since the 1950s, the military has used nuclear powered aircraft carrier ships, but there has been less of a nuclear emergence amongst civil ships. In 1953, President Dwight Eisenhower delivered his famous Atoms for Peace speech in which he made it clear to the world his desire for greater use of nuclear energy. The launching of the N.S. Savannah in 1964 as the first nuclear powered merchant ship was a realization of Eisenhower's goal; however, as seen with the N.S Savannah, there are many advantages and disadvantages of nuclear powered ships. 
Nuclear energy has been used to drive a variety of different types of cargo ships including military, merchant, and icebreaker ships. All of these ships have a nuclear power plant onboard that heats water to produce steam, which then powers turbines and turbo generators that power the ship. The first military nuclear ship was an aircraft carrier named the USS Enterprise that was commissioned in 1961. These ships were widely successful, and by 1990 there were more nuclear reactors being used on ships that on land based power plants. 
Merchant nuclear ships were far less successful than aircraft carriers, as they suffered from the costs of infrastructure. As will be mentioned further in the advantages and disadvantages section, building these nuclear-based ships is extremely expensive. The first merchant nuclear ship was the N.S. Savannah that was commissioned in 1964 and largely viewed as a failure. This ship was destined to prove the capabilities of nuclear power and move the world away from gas engines. Unfortunately, many viewed it as an inefficient compromise between a freighter and passenger line ship. Only a few other merchant nuclear cargo ships were developed after the N.S. Savannah including the Mutsu, Otto Hahn, and Sevmorput. None of these ships were able to gain their intended success, and the Otto Hahn was eventually re-powered with a diesel engine.
There has been much more success with nuclear powered icebreaker ships, particularly in the Soviet Arctic. These nuclear ships have powerful engines well suited for propelling through large sheets of ice, and they rarely need to be refueled.
One of the biggest advantages of using nuclear powered cargo ships is the reduced need for fuel. Nuclear engines can run for several months without need for resupplying fuel tanks, which has proven to be significantly impactful in remote areas like the Russian arctic. Further, reducing fuel demand has also allowed for a cut in fuel costs that helps make up for the significant amount of capital needed to purchase such ships. On top of their fuel efficiency, nuclear ships are more powerful and have less of an environmental impact on society. Nuclear fission emits no greenhouse gases, unlike its gas powered counterpart, and avoidance of nuclear leakage has been exceptional. Lastly, the process of decommissioning and recycling nuclear ships has been thoroughly thought out. Once ships are ready to be decommissioned, their reactors are de-fueled and removed for land disposal, after which the rest of the vessel is recycled. 
Unfortunately, there are significant disadvantages to nuclear powered ships, the most significant being the price. The cost of purchasing a nuclear versus gas-powered vessel is drastically higher. Further, since most of these trips are prepped for lengthy voyages, there is increased stress on the need for all equipment to remain technically sound. Keeping this expensive equipment in good standing is also increasing difficult due to the high levels of exposure to salt water corrosion.
However, all in all nuclear technology not only in cargo ships, but also in airplanes, submarines, and cars may prove to be important in the near future with our constantly diminishing levels of fossil fuels. Though currently this technology has not captured a significant share of the market, it could be the way of the future.
© Jay Fuster. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 T. Thueringer and J. Parkinson, "The Ship that Totally Failed to Change the World," BBC News, 25 Jul 14.
 R. Fieldhouse, "Nuclear Weapons at Sea", B. Atom. Sci. 43, 19 (1987).
 J. Forsythe, 3 R's of Nuclear Power: Reading, Recycling, and Reprocessing (AuthorHouse, 2009).