American Bureau of Shipping (ABS) has issued an approval in principle (AIP) for the integration of a nuclear reactor into a cargo vessel propulsion system developed in collaboration with the Massachusetts Institute of Technology (MIT), HD Korea Shipbuilding & Offshore Engineering (HD KSOE) and Capital Maritime Group.

The AIP — described as the first to be granted through the MIT Maritime Consortium — covers a reactor design that uses a special synthetic fluid to carry heat from the reactor core. ABS notes that current designs in the sector typically focus on micro-scale thermal outputs of 10 to 20 megawatts. It adds that the MIT design operates at near-atmospheric pressure, which can allow for thinner, lighter reactor vessels, supporting modular construction and easier transport.

ABS, HD KSOE and Capital Maritime Group are founding members of the MIT Maritime Consortium, which brings together academia and industry to advance technologies with the potential to reshape the maritime sector, including alternative fuels, new nuclear technologies, data-driven operational strategies, autonomy, cybersecurity and onboard manufacturing. ABS reviewed the reactor-to-machinery interface based on class requirements as part of its new technology qualification (NTQ) service, which provides a structured framework for the early adoption and implementation of innovative solutions.

Patrick Ryan, ABS senior vice president and chief technology officer, commented: "As the industry evaluates new pathways for the future, this approval in principle highlights the value of collaboration with key stakeholders in advancing promising commercial nuclear technologies. The MIT reactor design is an interesting piece of technology. With characteristics that can support modular fabrication and vessel integration, these emerging technologies represent one possible pathway toward the safe, practical development of next-generation commercial shipping solutions."

Sangmin Park, senior vice president at HD KSOE and head of the Green Energy Research Laboratory, stated: "As global environmental regulations tighten, the maritime sector requires paradigm-shifting solutions. Nuclear energy represents one of the most promising alternatives to traditional fossil fuels. Through this successful collaboration with ABS, MIT and Capital Maritime Group, we are proud to demonstrate our readiness to lead the eco-friendly vessel market by presenting a safe and innovative nuclear-powered shipping solution."

Stergios Stergiou, chief sustainability officer of Capital Clean Energy Carriers Corp, remarked: "It is our responsibility as an industry to explore every potential solution, including those that challenge conventional thinking. Nuclear propulsion is one such frontier. Through our membership in the MIT Maritime Consortium alongside ABS and HD KSOE, we are committed to ensuring that any pathway to net zero is grounded in the non-negotiable highest standards of crew safety, vessel integrity and environmental protection. This AIP is the first step in that process."

Themis Sapsis, Koch Professor of Marine Technology at MIT and co-director of the Maritime Consortium, said: "The MIT Maritime Consortium is a unique collaboration between academia and key industry stakeholders aiming to address critical gaps in the modernisation of the commercial fleet through the development of bold technological solutions, industry standards and policies. Our reactor design is one of the first concrete outcomes of this synergy, providing a realistic pathway towards nuclear propulsion for commercial vessels."