SMR-powered car carrier wins global classification society approval

South Korea is moving ahead with the development of a large cargo vessel powered by a small modular reactor.

The Korea Atomic Energy Research Institute announced Monday that it has received Approval in Principle, or AiP, from global classification society Lloyd's Register for a concept design of a car carrier equipped with a molten salt reactor. The design was developed through a joint project with HD Hyundai Heavy, HD Korea Shipbuilding, Hyundai Glovis and Z-Marine Services.

AiP is a formal process in which a classification society reviews a new vessel design or technology and certifies that it meets international regulations and safety standards. It is considered the first step toward actual ship development.

A molten salt reactor, a type of SMR, is a next-generation reactor that uses salt rather than water as a coolant. It is designed so that the liquid nuclear fuel — molten salt — solidifies if an abnormal signal is detected inside the reactor, preventing serious accidents at the source. This approach maximizes safety, making it widely regarded as ideal for maritime nuclear power generation. Its fuel cycle of more than 20 years matches the operational lifespan of a vessel, meaning the reactor need not be replaced once installed. Its relatively compact size also makes it easier to integrate into ships. The reactor can produce both high-efficiency electricity and hydrogen simultaneously, opening potential use as a next-generation green hydrogen production platform.

HD Hyundai Heavy and HD Korea Shipbuilding carried out the concept design and reviewed key technologies, while Hyundai Glovis drew on its experience operating large car carriers to identify environmental factors in real-world maritime operations and propose ways to ensure operational flexibility.

Z-Marine Services examined practical requirements from a ship management perspective — including onboard safety, maintainability, crew support and long-term operational reliability — while the research institute handled the MSR technology review in its role as a nuclear technology development organization.

The AiP marks a significant milestone, as it represents formal confirmation from a global classification society of the technical feasibility of an MSR-powered car carrier, including its safety and operability.

The participating organizations plan to continue reviewing next-generation ship propulsion technologies and jointly explore ways to secure the safety, operability and regulatory compliance of nuclear-powered vessels.

The project is set to gain further momentum after "development of an MSR-based SMR vessel" was selected as one of 12 missions under K-Moonshot, the government's AI-driven science and technology innovation initiative.

"This achievement confirms the applicability of MSR technology in the maritime sector, taking into account actual vessel operating conditions," said Cho Jin-young, director of the Advanced Reactor Research Division at the Korea Atomic Energy Research Institute. "We will continue our research and cooperation to verify and demonstrate the safety of nuclear technology for maritime use."