The cruise industry is making significant strides towards credible pathways to net zero. Driven by regulation and more environmentally conscious clientele, attention increasingly turns to technologies that until recently sat outside the commercial maritime mainstream.
Advanced nuclear power joins methanol and hydrogen, along with now well-established LNG, as a feasible solution to power the industry long into the future.
Passenger vessels are among the most energy-demanding ships in the global fleet. In addition to propulsion, modern cruise ships must support extensive ‘hotel’ loads to power accommodation, entertainment venues, pools, galleys and climate control systems around the clock. As regulatory pressure mounts and expectations around environmental performance rise, cruise operators are evaluating a wide range of emerging energy sources, each with distinct benefits and constraints.
Small modular reactors (SMRs) could reshape how cruise ships operate, where they sail, and how they deliver energy-intensive guest experiences.
Not a near-term solution, industry conversations have moved from whether nuclear power should be discussed at all to how it might one day be applied safely, credibly and acceptably to the cruise industry.
LR held exploratory discussions with most of the major cruise operators, to help them understand what nuclear propulsion could entail in practice from a technical, operational and economic perspective.
What cruise operators want
“There is real interest from cruise lines in exploring nuclear, not because it offers an easy solution but because the potential benefits are significant,” says Jez Sims, LR’s Director Nuclear Technologies. “They want clarity on what nuclear could enable, what it would demand, and where the trade-offs sit.”
Nuclear power offers extremely high energy density and the ability to generate continuous power for years without refuelling. These features could remove many operational constraints imposed by conventional fuels, including a dependence on bunkering infrastructure and limits on range or deployment duration.
“For cruise, the long deployment horizon is one of the strongest attractions, offering continuity of service that conventional options struggle to match,” Sims explains. “A nuclear-powered vessel delivers zero emissions at the point of use and wouldn’t need to call at a port for bunkering purposes. That opens up new conversations about where ships can go and how long they can stay there.”
One of the most frequently cited potential benefits of nuclear propulsion is operational flexibility. Cruise ships face growing restrictions on emissions in sensitive environments and ports, alongside increasing demands to shut engines down and connect to onshore power while berthed.
“With nuclear, a ship effectively becomes its own self-contained microgrid,” says Sims. “You can remain alongside with zero emissions, keep hotel services running without interruption, and access ports or regions that are currently constrained by local power availability or environmental limits.”
This has applications for polar or remote regions, where shore power is unavailable and conventional emissions limit access.
Long term potential
While the deployment of nuclear in the cruise industry remains a long way off, Francesco Ruisi, LR’s VP Global Passenger Ship Segment Director, acknowledges its long-term potential. “It is not a silver bullet, nor a substitute for near term decarbonisation measures already underway. But as the industry confronts the scale of the energy transition ahead, many believe it would be short sighted not to examine every credible option.”
Ruisi says removing large fuel tanks could also reshape internal layouts. “If you take fuel storage out of the equation, you potentially free up space. From a passenger perspective, the ship would feel largely the same, but there may be opportunities for more efficient use of machinery space,” he says.”
Despite these theoretical advantages, nuclear power’s greatest challenge is not from technology but perception. Public attitudes toward nuclear energy have been shaped by high-profile accidents and military programmes, often without distinction between military and civilian applications.
“People often ask whether the hardest part is the technology or the regulation,” says Sims. “Both are challenging, but they are solvable. Public perception is different. It is deep-seated and takes time to shift.” Any future adoption of nuclear propulsion would require not only technical and regulatory assurance, but also transparent, fact-based engagement with passengers and the wider public, says Sims.
Safety, regulation and the global framework
Commercial nuclear-powered ships would need a comprehensive, internationally accepted regulatory framework including integrated safety cases, agreements with flag, port and coastal states, and clear approaches to fuel supply, waste management and eventual decommissioning.
“Nuclear will only work if regulators are aligned,” says Meg Dowling, LR Senior Engineer for Nuclear and Alternative Fuels. “You need shipping and nuclear regulators to share responsibilities in oversight, so as not to re-invent the wheel of either regulatory program. We think existing practices can be used in new ways to be inclusive of advanced nuclear technologies.”
Dowling draws parallels with LNG’s introduction into shipping. “LNG showed how frameworks like the IGF Code can evolve, how competency standards can be developed, and how collaboration between regulators, classification societies and industry underpins safe adoption. Nuclear would require the same approach, just at a higher level of complexity.”
New skills and competencies
A critical part of that complexity lies in people. As shipping transitions to new energy sources, workforce capability is emerging as a defining challenge. Hundreds of thousands of seafarers will require new skills across alternative fuels, including nuclear.
“This area brings together maritime and civil nuclear expertise,” Dowling explains. “That means competencies in radiation protection, emergency planning and specialised engineering, alongside traditional marine skills.”
However, she notes that advanced reactor designs may also reduce onboard requirements. “With inherent safety features, automation and refuelling restricted to specialist facilities, there is potential for optimisation. You may only need a small number of nuclear specialists onboard, supported by robust systems and shore-based expertise.”
This situation, she argues, reinforces the need for early engagement. “Training frameworks, certification pathways and regulatory approval must be developed well in advance. Regulators play a central role in framing this possibility, including approving any training regime.”
Most experts view nuclear as a long-term option, with first-of-a-kind commercial vessels more likely to emerge in other shipping segments first.
“I would expect to see early demonstrators emerging towards the end of this decade,” says Sims. “From there, their performance will determine the pace, but you could see scaling over the following ten to twenty years.”
In that context, cruise is seen as both a challenging and a compelling use case. Ships operate close to populations, carry thousands of people, and are highly visible. They are however, “effectively floating hotels,” notes Sims and “not unlike nuclear-powered aircraft carriers that have operated safely for decades”.
For now, nuclear power sits firmly in the exploratory phase for cruise.
“As with all emerging fuels, the question isn’t whether nuclear is perfect,” Dowling concludes. “It’s whether the industry can demonstrate that it is safe, reliable and acceptable within regulatory frameworks. If that can be achieved, nuclear may well become part of the future energy mix for cruise.”
