Three Nuclear Ship Designs Win Approval in 60 Days, but Port Entry and Liability Rules Remain Decades Behind

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Three separate approvals in principle for nuclear-powered commercial vessels have been granted since June 2026, yet none of the designs is close to obtaining a construction contract, a flag-state license, or permission to enter a commercial port.

The American Bureau of Shipping granted the most recent approval on 16 July 2026 for a 15,000 TEU container ship concept developed by Samsung Heavy Industries, the Korea Atomic Energy Research Institute, and the Korea Research Institute of Ships and Ocean Engineering. The vessel would carry two molten salt reactors using the MARINA design under South Korea’s K-Moonshot programme.

A month earlier, Lloyd’s Register approved a pure car and truck carrier based on a Hyundai Glovis 7,000 CEU design adapted for a molten salt reactor, following a joint study with HD Hyundai Heavy Industries, HD Korea Shipbuilding & Offshore Engineering, and G-Marine Service. On 12 June 2026, ABS also approved a reactor design from the MIT Maritime Consortium that uses a synthetic heat-transfer fluid at near-atmospheric pressure, a project involving Capital Maritime Group and HD Korea Shipbuilding & Offshore Engineering.

An Approval in Principle, or AiP, is a classification society’s statement that a concept appears technically feasible against known safety standards at an early design stage. It is not a certificate to build and it is not a permit to operate. Lloyd’s Register states plainly that an AiP does not guarantee regulatory approval or assure compliance with every applicable code.

That distinction matters more for nuclear propulsion than for almost any other marine technology because the codes an AiP checks a design against are, in the case of nuclear ships, decades out of date.

The core international rule is Chapter VIII of the SOLAS Convention, which requires bilateral agreement between the flag state and any foreign state a nuclear vessel visits. The International Maritime Organization adopted Resolution A.491(XII), the Code of Safety for Nuclear Merchant Ships, in 1981. It was written around pressurised water reactor technology and draws on radiation-dose guidance that predates current international recommendations. The World Nuclear Transport Institute concluded in a gap assessment that the code offers no real guidance for newer reactor types including molten salt and small modular designs. The IMO is now revising the code under a workplan endorsed at MSC 111 in May 2026, with a target adoption date of 2030.

On 22 July 2026, the U.S. Maritime Administration and the Port of Long Beach signed a Memorandum of Cooperation to explore small modular reactor technology for commercial shipping and port operations. The agreement brings together MARAD, the Port, the U.S. Coast Guard, Department of Energy, and Nuclear Regulatory Commission to examine safety and regulatory issues, but it does not authorize nuclear-powered ships. On 23 June 2026, the U.S. Coast Guard and Nuclear Regulatory Commission signed a memorandum of understanding to coordinate licensing of civilian maritime nuclear projects.

Only one country outside Russia has passed a dedicated national statute for nuclear shipping. The United Kingdom’s Merchant Shipping (Nuclear Ships) Regulations 2022 require a safety assessment to be lodged twelve months before a nuclear ship arrives in UK waters.

There is still no international treaty in force that governs liability for damage caused by a nuclear-powered ship. The 1962 Brussels Convention on the Liability of Operators of Nuclear Ships has never entered into force. A related treaty, the 1971 Convention on Civil Liability in the Field of Maritime Carriage of Nuclear Material, governs nuclear cargo on ordinary ships, not propulsion reactors. Without a functioning international liability regime, insurers and P&I clubs must work out coverage on a bespoke basis, a significant commercial barrier before any newbuild contract can be signed.

Commercial nuclear shipping has been tried before with consistent results. The U.S.-built NS Savannah entered service in 1962 and operated for roughly a decade, but it was not a commercial success. West Germany’s NS Otto Hahn ran from 1964 to 1979 but required port entry negotiations on a bilateral, country-by-country basis. Japan’s NS Mutsu suffered a shielding failure in 1974 that triggered public backlash and blockades by local fishermen. Russia’s Sevmorput, launched in 1988, is the sole commercial nuclear-powered cargo ship still operating today.

None of the three 2026 concepts has a construction contract, a keel-laying date, or a flag state prepared to license it. The approvals are best read as evidence that classification societies believe the underlying engineering questions can, in principle, be answered safely. They are not evidence that the political, legal, and insurance questions are close to resolution. On the historical record, those questions have consistently taken longer to resolve than the engineering ones, and there is no verified indication that this pattern has changed in 2026.