The American Bureau of Shipping (ABS) has granted an Approval in Principle (AIP) for a next-generation commercial cargo ship propulsion system. This project integrates a nuclear microreactor core into a cargo vessel. It was collaboratively designed by a consortium consisting of the Massachusetts Institute of Technology (MIT), HD Korea Shipbuilding & Offshore Engineering (HD KSOE), and the Capital Maritime Group.
“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,” said Themis Sapsis, Koch Professor of Marine Technology at MIT and Co-director of the Maritime Consortium. “Our reactor design is one of the first concrete outcomes of this synergy, providing a realistic pathway towards nuclear propulsion for commercial vessels.”
The system replaces high-pressure water systems with a specialised synthetic fluid to safely transport heat out of the reactor core. The design targets low-power operational configurations optimised explicitly for maritime shipping, generating a thermal output of 10-20 MW. Lower internal pressures mean the reactor requires much thinner and lighter structural containment walls. This drop in overall weight drastically simplifies modular fabrication and transport logistics.
This is the first AIP awarded via the MIT Maritime Consortium. ABS, HD KSOE, and Capital Maritime serve as founding members of this alliance, which actively merges academic research with real-world industry applications to engineer decarbonised shipping solutions. The formal safety review focused heavily on the vital physical interface connecting the reactor machinery to the ship’s primary mechanical components.
“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,” said Patrick Ryan, ABS Senior Vice President and Chief Technology Officer. “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.”
The commercial shipping sector generates approximately 3% of global carbon emissions annually by burning roughly 350m tonnes of heavy fossil fuel. As the International Maritime Organisation (IMO) enforces strict targets to reach net-zero greenhouse gas emissions by or around 2050, this microreactor design aims to map out a realistic and practical alternative pathway toward clean commercial ship propulsion. The technical clearance was granted under the structured ABS New Technology Qualification (NTQ) service, ensuring that early adoption maps cleanly to uncompromising safety, environmental, and crew protection standards.
“As global environmental regulations tighten, the maritime sector requires paradigm-shifting solutions,” said Sangmin Park, Senior Vice President at HD KSOE and Head of Green Energy Research Laboratory. “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 at Capital Clean Energy Carriers Corp noted: “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.”
