Using nuclear propulsion on a liquid-natural gas (LNG) carrier vessel could lead to faster transit times with zero emissions, according to a report from the American Bureau of Shipping (ABS). 

The study from the ABS — which was funded by the U.S. Department of Energy — looked into the possibility of installing high temperature, gas-cooled nuclear reactors (HTGR) on a standard LNG carrier, while taking into account factors such as heat management, safety shielding and weight distribution. The proposed carrier would have a pair of reactors situated in the stern of the vessel, supplemented by batteries at the opposite end inside a reinforced hull. If the reactors ever failed, the ship would be able to use backup diesel generators to make its way to the nearest port. 

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“While this technology is well understood on land, adapting it for marine application is in its infancy," ABS senior vice president and chief technology officer Patrick Ryan said in an October 29 news release. "However, this study and the other research we have carried out clearly highlight its significant potential to address not only shipping’s emissions challenge but to deliver a range of other operational advantages to the industry."

In addition to the potential advantages the technology offers in terms of speed and emissions, nuclear-powered vessels — which have been used by the U.S. Navy since 1955 — don't need to refuel, although the HTGR reactor would need to be replaced every six years at a specialized shipyard capable of handling radioactive materials. HTGR technology would also only work with larger LNG carriers due to various "design constraints," the ABS said.

Commercial nuclear-powered ships are not a new idea. According to the Bulletin of the Nuclear Scientists, in 1959, the U.S. launched the nuclear-powered NS Savannah, a passenger/cargo vessel that became known as the “Peace Ship.” Germany followed with the nuclear ship Otto Hahn, launched in 1964, which was primarily a research vessel and bulk cargo carrier. But the cost of operations, public resistance, and other technical challenges saw the idea falter.

Now, the attractions of alternatives to diesel fuel, in light of climate change and growing regulation on carbon emissions, has brought renewed interest. China recently announced plans for a massive nuclear-powered container ship. And in May 2024, Rafael Grossi, director general of the International Atomic Energy Agency, encouraged a study of nuclear power applied to commercial shipping to aid the environment.

But George M. Moore, formerly senior analyst in the Office of Nuclear Security at the International Atomic Energy Agency (IAEA) in Vienna, Austria, said in an article published September 4, 2024, in the Bulletin that, "the development of nuclear-powered commercial ships a particularly bad idea in an era of international terrorism and piracy. And that’s not even to mention the cost of insuring them."