ABS Certifies Korean 15,000-TEU Container Ship Powered By Two Molten Salt SMRs

South Korea's push to put small modular reactors on the open ocean crossed another checkpoint on Friday. The Korea Research Institute of Ships & Ocean Engineering (KRISO) said the American Bureau of Shipping (ABS) has granted Approval in Principle to the conceptual design of a 15,000-TEU container ship propelled by two molten salt small modular reactors, in a project run jointly with Samsung Heavy Industries and the Korea Atomic Energy Research Institute (KAERI).

Two SMRs, one 25-knot box boat

The design pairs a redundant two-reactor layout with an energy-storage buffer that soaks up surplus reactor output and dispatches it back into the propulsion train when the ship accelerates or maneuvers. KRISO handled the hull, reactor layout and power-operation software; KAERI is developing the marine-grade molten salt reactor itself. The hull is optimized for 25 knots, sits inside the expanded-Panama-Canal envelope, and centralizes the reactor amidships to reduce collision and wave-slam risk. Removing conventional fuel tanks and funnels also lifts container-loading efficiency across the deck.

Why the ABS stamp matters

ABS's Approval in Principle sits at the front end of its Novel Concept Class Approval process. It doesn't authorize construction — it confirms the concept complies with the intent of applicable ABS rules and industry codes, subject to a list of follow-on conditions. That's a workable checkpoint for a design partner shopping the concept to shipowners, port authorities and finance houses. It follows a similar approval from Lloyd's Register a month earlier, giving the Korean team two of the world's top marine classification societies on record backing the underlying architecture.

Nuclear at sea, revisited

The commercial pitch is straightforward: global shipping burns about 350 million tonnes of fossil fuel a year and accounts for roughly 3% of worldwide CO2 emissions, and the International Maritime Organization is chasing net-zero by around 2050. Reactor-powered ships don't refuel like conventional vessels and don't emit at the stack. The engineering gap is not just the reactor — it is verifying that reactor, hull motion and marine environment behave together, which is why KRISO says it ran scaled-model tests in its deep-sea engineering tank to feed the layout back into safety analysis.

The project builds on a 2023 memorandum in which nine South Korean organisations agreed to jointly develop marine-grade molten salt reactors and the regulatory pathway around them. It also arrives against a busier maritime-nuclear backdrop that already includes first-of-a-kind microreactor demonstrations onshore, and separate next-generation nuclear industrial bets in the United States.

What comes next

KRISO says the next phase is basic and detailed design, including the ship-reactor interface work that has to happen before any yard cuts steel. Samsung Heavy Industries will bring the shipbuilding side; KAERI will keep advancing the marine MSR. If the follow-on class work holds up, the trio will have set out a credible base design for the first generation of nuclear-propelled deep-sea box ships — a potentially large second act for South Korean shipbuilding, which is already coming off a run of state-backed advanced manufacturing bets.

Reporting based on coverage from World Nuclear News, Seoul Economic Daily and The Korea Times.