Allseas turns to nuclear power for offshore fleet

Marine construction specialist Allseas has launched a five-year plan to design, develop, and deploy a small modular reactor tailored for both offshore vessels and onshore use. 

Both uses have their benefits, as nuclear offers energy density with zero emissions and a stable, scalable power supply. Onshore, SMRs can ease grid pressure while providing consistent, carbon-free power and heat. 

Allseas has selected high-temperature gas-cooled reactors (HTGRs) in the 25MWe range, due to their inherently safe characteristics. This fourth-generation reactor technology generates energy without combustion or emissions.

HTGRs are powered by tri-structural isotropic (TRISO) fuel particles, each containing a uranium oxide core, coated with several advanced protective ceramic layers that securely contain fission products, even under extreme conditions.

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 active intervention or external cooling.

Allseas is also exploring circular approaches to waste management, such as the reuse of graphite and the reprocessing of spent TRISO fuel.

In the first year, the company will finalise initial design studies for offshore and onshore use. This will be followed by prototype development and pre-licensing discussions.

“Our goal is to start production at a dedicated facility by 2030. Initial deployment will likely begin on land while offshore regulations are finalised, followed by application on our vessels and broader industry adoption. This aligns with our sustainability targets – 30% emissions reduction by 2030, and net-zero operations by 2050,” said Stephanie Heerema, project manager for nuclear development at Allseas.