The rise of small modular reactors points to a step change for nuclear applications in shipping if regulatory hurdles can be overcome, according to Lloyd’s Register’s (LR’s) new report, Fuel for Thought: Nuclear.

Nuclear power could transform the maritime industry with emissions-free shipping, whilst extending the life cycle of vessels and removing the uncertainty of fuel and refuelling infrastructure development, but regulation and safety considerations must be addressed for its widespread commercial adoption, the report says.

It assesses the opportunity presented by nuclear for commercial maritime given its proven track record in naval applications, with the study pointing to the role of new small modular reactors (SMRs) in bringing to market suitable low-maintenance reactors to meet the propulsion and energy requirements of commercial ships.

Commercial relationships between shipowners and energy producers will be altered as power is likely to be leased from reactor owners, separating the shipowner from the complexities of licensing and operating nuclear technology, the report notes. SMRs represent a leap forward in reactor design, emphasising safety, efficiency, and modularity for streamlined production. As SMR technology matures and regulatory clarity increases, ship designs optimised for nuclear propulsion will emerge, ushering in a new era of efficient and environmentally friendly vessels.

The report outlines the vital importance of adopting stringent safety protocols to prioritise the protection of seafarers and the environment. It suggests that for novel designs and nuclear technology in the short-term, LR’s Risk Based Certification could provide an approach for first movers to certify their projects by demonstrating a level of safety equivalent to that of conventional oil-fuelled systems.

Mark Tipping, LR’s Power to X Director said the new report Nuclear “represents one of the first easily accessible overviews on the use of nuclear power in shipping, combining information from a wide range of sources into one report tailored for commercial shipping and the wider maritime value chain. Whilst its use in commercial shipping has been limited, by overcoming negative perceptions and a lack of investment levels, nuclear propulsion could provide immense value for the maritime sector in its decarbonisation journey, allowing for emissions free vessels with longer life cycles.

The LR report notes that “six main technologies are recognised by the Generation IV International Forum (GIF), a group with the goal of coordinating international cooperation on the development of advanced reactor technologies, representing 13 countries and the EU.” For shipping, “the most promising technologies include refinements of existing pressurised water reactor (PWR) designs and certain of the less proven Generation IV technologies which are in various stages of development”. However, “For all the technologies, the main challenges are the setting of standards for their use in shipping, and proving the operational safety of reactor designs.”

For maritime applications, the most promising reactors with the shortest time to market are: PWRs, heat pipe micro reactors (HPMRs), molten salt reactors (MSRs), lead cooled fast reactors (LFRs), and high temperature gas reactors (HTGRs).

 The report says “PWRs are unique among the reactor technologies in that there is experience of operating such reactors in a marine environment through multiple militaries, and a few historic examples of government-backed merchant vessels. For production of a small modular PWR – the type necessary for broader adoption in the maritime sector – development is at a similar level to other technologies where validation of an integrated prototype is underway in a test environment.”

Technology demonstration projects of HPMRs “are ongoing, including at BWXT and Westinghouse, for both defence and civil applications”.

As to MSRs, “Experimental test facilities exist, both full scale and separate effect test facilities for various MSR technologies. The technology is undergoing validation and will require marinisation.” The report notes that MSR fuel “exists at an experimental level, but there is no large scale demonstration of fuel production”. It notes the “multiple inherent passive safety features” of MSRs.

 LFRs also have passive safety features that reduce the core temperature when it rises above normal operating levels without operator intervention. “The fuel and technology exist and has been tested in maritime through defence applications, including through reactor maintenance and refuelling in defence applications”. LR omits to mention that this is primarily in Russia and that it involves lead-bismuth rather than lead.

The report says: “TRISO reactor fuel for HTGRs exists in demonstration quantities but no large scale production is available. The reactor technology is operational on land, but is not proven in maritime application.”

The report makes reference to LR’s Zero Carbon Fuel Monitor – an insights-based assessment of the readiness of zero carbon fuels for maritime applications and industry wide comparisons of alternative solutions across the entire fuel supply chain. The fuels are assessed according to technology readiness level (TRL), investment readiness level (IRL) and community readiness level (CRL), which relates to public perception. TRL is assessed on a scale of one to nine, IRL and CRL are on a scale of one to six. TRL for all nuclear fuels are currently still on 9, and both IRL and CRL on six.

The report concludes that nuclear power can be seen as a transformational technology rather than an incremental or even step change improvement. “It will not be a direct replacement for oil-fired systems like some alternative fuels, but rather a primary catalyst to fundamentally reshape the shipping industry.” Part of the transformation would be safer, more reliable, emissions free, longer-lived, and more productive ships. “Another part of the transformation will be in the ship operator’s structure, including technical management, procurement, approach to quality, and an elevated safety culture.”

The primary challenges for the early adoption of SMRs and their application in the maritime industry is “the social licence to operate and regulatory ambiguity”. National regulations and approvals on a case-by-case basis are expected in the near term until global standards are agreed at the IMO and IAEA.

“As SMR technology matures and regulatory clarity increases, ship designs optimised for nuclear propulsion will emerge, ushering in a new era of efficient and environmentally friendly vessels,” the report says. “The collective efforts to take advantage of these opportunities and advance nuclear-powered commercial shipping underscore the immense value of this technology. With its potential to provide a safe, zero-emission fuel source that eliminates the need for frequent refuelling, nuclear power promises to transform the shipping industry, contributing to a cleaner and more sustainable future for global trade and transportation.”

Meanwhile, the UK-based Nuclear Energy Maritime Organisation (NEMO), which was launched in March has recently welcomed some new members. These include full members engineering company OEGS Technology, developing advanced nuclear technology to produce clean energy; Global Nuclear Security Partners, a leading management consultancy specialising in nuclear security; international law firm Pillsbury Winthrop Shaw Pittman; and service-oriented solutions provider Assurance Reliability Compliance Pty Ltd (ARC-Assure). Borealis Maritime Limited, a privately owned investment and asset management company, joined as an associate member.