A nuclear-powered LNG carrier would cost roughly 2.5 times as much to build as a conventional vessel, according to a new study supported by the American Bureau of Shipping — but lower fuel costs over decades of operation could offset that premium.

Presented at Gastech 2026, the study examined a 174,000-cubic-meter LNG carrier fitted with a 20-25 MWe high-temperature gas-cooled reactor (HTGR) under development by Japan's Blossom Energy. ABS, Blossom Energy and an unnamed global shipping company benchmarked the nuclear design against a conventional LNG-fueled newbuild, comparing vessel arrangement, propulsion systems and operating conditions across a range of potential regulatory penalty scenarios.

The upfront capital cost is the biggest hurdle. Initial investment for the nuclear vessel would run approximately 2.5 times that of a conventional LNG carrier. Over the longer term, however, the reactor would substantially reduce fuel costs, potentially improving the economics across the ship's service life.

The study also modeled a structurally different ownership approach: treating the reactor as a long-term energy asset rather than equipment permanently tied to one hull. Under that model, operators could remove the reactor when the first vessel reaches the end of its operating life and reinstall it aboard a second vessel — increasing the reactor's residual value and spreading the capital burden across two ship lifecycles.

"Nuclear energy has the potential to fundamentally change the economics of commercial shipping, from vessel design to long-term operating costs," said Patrick Ryan, ABS Senior Vice President and Chief Technology Officer.

"This study provides a quantitative basis for discussing nuclear propulsion in commercial shipping," said Blossom Energy CEO Shimpei Hamamoto.

Building on earlier work

The Gastech 2026 paper extends several years of nuclear shipping research focused specifically on LNG carriers. In 2024, ABS and Herbert Engineering Corporation studied the integration of an HTGR into a 145,000-cubic-meter LNG carrier, examining heat and energy management, shielding, weight distribution and other design challenges.

That earlier study found an HTGR-powered vessel could operate without conventional fuel combustion while potentially allowing higher transit speeds. The reactor design evaluated at the time would require fuel replacement roughly every six years. The concept also demanded significant changes to the ship itself: locating the reactor toward the stern, placing batteries in areas normally occupied by fuel tanks, and reinforcing portions of the hull.

A year later, the Korea Atomic Energy Research Institute (KAERI) and Samsung Heavy Industries secured Approval in Principle for an LNG carrier powered by a small modular molten salt reactor. The 100 MWth concept was designed to operate for the vessel's full service life without fuel replacement, with ABS and the Liberian flag state issuing the approval at Gastech 2025.

ABS has since widened its nuclear work beyond gas carriers. In July, it awarded Approval in Principle for a nuclear-powered 15,000 TEU containership concept developed with the Korea Research Institute of Ships and Ocean Engineering and KAERI, also using advanced reactor technology intended for marine propulsion.

The commercial question

For shipowners and charterers, the study reframes the nuclear debate. The growing volume of concept approvals and technical studies reflects rising industry interest as shipping weighs alternatives to conventional bunker fuels and faces tighter emissions requirements. But commercial deployment still confronts significant regulatory, safety, port access, crewing and public acceptance hurdles — any of which could stall orders regardless of the math.

The latest work moves the discussion beyond whether nuclear propulsion can technically be installed aboard an LNG carrier, and toward the more practical question for owners weighing newbuild programs: whether a construction premium of 2.5 times can be recovered through decades of lower fuel expenses. With fuel cost savings and reactor reuse now quantified, expect class societies and reactor developers to pressure regulators and port authorities next to define the approval pathway that would make those economics bankable.