Allseas aims to finalise initial design studies and develop prototype
Marine construction specialist Allseas has launched an ambitious five-year plan to design, develop and deploy a small modular reactor (SMR) tailored for integration into offshore vessels and for onshore use.
The company, founded in 1985 with offices in Switzerland and the Netherlands, said it had chosen high-temperature gas-cooled reactors (HTGRs) in the 25 MW range, due to their inherently safe characteristics.
Generation IV HTGRs are powered by tri-structural isotropic (Triso) particle fuel, known for its high safety performance. Each Triso fuel particle is a small, uranium-based kernel coated with multiple layers of ceramic materials, effectively creating a tiny, self-contained “pressure vessel” that can retain fission products under all reactor conditions.
Allseas said the technology results in passive safety: the reactor self-regulates and remains stable, keeping temperatures well below critical thresholds. In the unlikely event of malfunction, the system automatically cools down and shuts off without the need for active intervention or external cooling.
The company said its move into nuclear marks a bold step, aiming to deliver clean, high-performance energy systems to sea and shore.
It said the maritime sector contributes 3% to global CO2 emissions. The industry has been looking at ways to reduce emissions, with nuclear reactors being considered both for vessels and for onshore facilities.
Alternative fuels like hydrogen, methanol and ammonia currently face limitations in availability, scalability and cost – particularly for remote, energy-intensive operations.
According to Allseas, nuclear offers unmatched energy density, combining zero emissions with stable, scalable power supply.
Onshore, industrial clusters face high energy costs, grid congestion and volatile renewable supply. SMRs can ease grid pressure while providing consistent, carbon-free power and heat – accelerating decarbonisation and boosting industrial resilience and long-term competitiveness.
Allseas said responsible waste management is central to its long-term plan and it has been is exploring approaches, such as the reuse of graphite and reprocessing of spent Triso fuel to further reduce environmental impact
Initial Deployment Likely To Begin On Land
Allseas said it has set out a clear five-year roadmap. In the first year, it will finalise initial design studies for offshore and onshore use. This will be followed by prototype development and pre-licensing discussions in consultation with organisations such as the Dutch Authority for Nuclear Safety and Radiation Protection, the International Maritime Organisation and International Atomic Energy Agency and Lloyd’s Register.
Research partners include NRG Pallas, the Netherlands-based research group that has been demonstrating the safety of Triso fuel, and Delft University of Technology, which has been working on a microreactor based on HTR technology for more than 10 years.
Allseas said initial deployment will likely begin on land while offshore regulations are finalised, followed by application on its own vessels and broader industry adoption.
Earlier this year the head of the American Bureau of Shipping said nuclear can be a transformational technology for the industry, but challenges remain including the need for a new commercial model and for public/private partnerships in a bid to finance development and deployment.
A December 2024 European study said additional regulatory work will be needed before nuclear power can be widely adopted on merchant vessels, with the potential risks requiring more detailed studies to better understand additional safeguards that will be required to address major hazards.
