Having established the market landscape and emerging opportunities for maritime nuclear during Session #1, the focus in Session #2 shifted towards the technologies, fuels and operational frameworks that could enable deployment in practice.
The session was structured around a central premise that reactor technology, fuel strategy and operational design cannot be considered independently. Together, they form a system-level architecture that influences licensing, economics, supply chains, operations, maintenance, safeguards and ultimately commercial viability.
The discussion also continued to reinforce a key distinction first introduced during Session #1. Maritime nuclear should not be viewed as a single market. Floating Nuclear Power Plants (FNPPs) and nuclear propulsion may share common technological foundations, but they optimise for different outcomes, face different constraints and are likely to evolve through different deployment pathways.
Reactor Technologies and Fuel Considerations
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Oscar Hamilton began with a concise “Nuclear Reactors 101” overview designed to establish a common baseline for both technical and non-technical participants.
The presentation explained the fundamentals of nuclear fission, how reactors generate heat, and how that heat is converted into useful power. Particular emphasis was placed on understanding the role of fuel and how fuel behaviour influences operational planning throughout the lifecycle of a nuclear asset.
Oscar’s section then explored the main reactor technologies currently under discussion for maritime applications.
Pressurised Water Reactors (PWRs) emerged as the strongest near-term reference case. Their advantages include extensive operational experience, mature fuel supply chains, regulatory familiarity and significant precedent from both civilian and naval nuclear programmes. However, participants also heard about some of the associated challenges associated with high-pressure systems, shielding requirements, containment structures and planned refuelling outages.
Other reactor technologies were examined considering maritime suitability rather than theoretical performance. These included:
High Temperature Gas Reactors (HTGRs), offering high-temperature operation and robust TRISO fuel forms. • Fast spectrum reactors, including sodium, lead and molten salt variants, which may offer higher power density and longer operating cycles. • Microreactors, which could support smaller-scale applications such as ports, islands and modular floating power systems. • Generation IV concepts more broadly, which may offer attractive long-term characteristics but currently face greater licensing, supply chain and commercial uncertainty.
A consistent message throughout was that reactor generation should be viewed as a maturity indicator rather than a ranking system. More advanced technologies are not necessarily ‘better’ technologies. Instead, they represent different balances between performance, complexity, risk and readiness.
The Importance of Fuel Strategy
One of the strongest themes of the presentation was the importance of fuel.
While much discussion often focuses on individual reactor designs, participants were reminded that in many ways fuel choices shape the entire operating model.
This element of the session examined conventional Low Enriched Uranium (LEU), Higher Assay Low Enriched Uranium (HALEU), TRISO fuel forms, liquid fuels and metallic fuels.
Fuel selection was shown to influence:
Refuelling frequency and outage strategy. • Reactor compactness and power density. • Safeguards and security requirements. • Fuel fabrication and transportation pathways. • Waste management and end-of-life planning. • Commercial and contractual structures.
Particular attention was given to HALEU. Higher enrichment levels can support longer operating cycles and more compact reactor designs, both attractive features for maritime deployment. However, participants also heard that global HALEU supply chains remain immature and may become a significant strategic consideration for future projects.
The overall conclusion was that reactor and fuel decisions must be taken together. A change in fuel strategy can fundamentally alter the operating, regulatory and commercial characteristics of a maritime nuclear asset.
Maritime Design Constraints
The presentation also highlighted several challenges unique to maritime deployment.
Unlike land-based facilities, maritime nuclear assets must operate in environments characterised by continuous motion, vibration and changing orientation. Designers must account for ship motion, flooding scenarios, allision / collision risks, grounding events and a range of marine-specific accident conditions.
Examples were presented showing how marine accident sequences differ from those typically considered in terrestrial nuclear design.
Participants heard how factors such as decay heat removal, natural circulation, shielding, containment and safety system performance must be validated specifically for maritime environments rather than being transposed across from land-based designs.
This reinforced another important theme: successful maritime nuclear deployment requires adaptation of proven nuclear principles to a fundamentally different operating environment.
From Technology to Deployment
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The second half of the session shifted from technology selection towards implementation.
Rob Chaplin explored how developers move from reactor concepts and fuel strategies into deployable products through the use of Concept of Operations (CONOPS), systems engineering and integrated design processes.
A central message was that technology does not deploy itself.
Before engineering decisions can be made, developers must understand the operational need. Is the objective to provide grid-scale electricity from an FNPP? Industrial energy supply to a remote location? Power to a port? Or commercial ship propulsion?
Each use case creates different requirements, constraints and success criteria.
Participants were introduced to the relationship between:
Operational Architecture, defining why the asset exists and how it will be used.
Functional Architecture, defining what functions the system must perform.
Physical Architecture, defining how those functions are implemented.
This framework provides a structured pathway from business need to engineering design.
The Importance of Integration
A recurring message throughout Rob’s presentation was that maritime nuclear is fundamentally an integration challenge.
The final design must satisfy customers, regulators, classification societies, operators, insurers and infrastructure providers simultaneously.
Examples demonstrated how engineering decisions are influenced by many and varied inputs such as shipyard capabilities, port infrastructure, grid interfaces, maintenance strategies, security requirements, emergency planning, classification society requirements, and national nuclear regulatory guidelines.
The presentation also highlighted the growing role of maritime classification societies. Recent work by ABS, alongside activities within organisations such as Lloyd’s Register and DNV, was presented as evidence that regulatory and class frameworks continue to mature.
The implication was that successful deployment will depend not only on reactor technology but also on the industry’s ability to develop integrated operating models that satisfy a wide range of stakeholders.
Panel Discussion
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The live panel discussion brought together Oscar Hamilton, Rob Chaplin and (during the morning session) Ioannis Kourasis to explore several cross-cutting themes.
Discussion focused on the tension between near-term deployment and long-term technological ambition. Panellists generally agreed that mature PWR-based systems currently offer the strongest pathway towards early deployment, particularly for FNPP applications. However, they also acknowledged that advanced reactor technologies may ultimately prove better suited to certain propulsion and compact marine applications.
The panel repeatedly returned to the distinction between technical feasibility and commercial readiness. Reactor technology alone was rarely identified as the principal barrier. Instead, participants heard about the importance of licensing pathways, fuel supply chains, insurance markets, shipyard capabilities and regulatory confidence.
Fuel strategy was also discussed extensively, particularly the implications of HALEU availability, safeguards requirements and refuelling infrastructure.
The final section of the discussion focused on what the industry still needs to demonstrate. Topics included first commercial deployments, licensing precedents, fuel-cycle infrastructure, regulatory coordination and stakeholder confidence.
Key Takeaways
Several themes emerged consistently throughout the session:
There is no universally correct maritime reactor technology.
FNPPs and propulsion systems optimise for different outcomes and may require different technical solutions.
Reactor selection and fuel strategy are inseparable.
Maritime deployment is an integration challenge as much as a technology challenge.
Commercial readiness extends beyond reactor physics to include regulation, operations, infrastructure and finance.
Near-term deployments are likely to prioritise maturity and deployability over theoretical optimisation.
Long-term success will depend on the credibility of the entire operating ecosystem, not simply the reactor itself.
Session #2 therefore provided the technical and operational foundation for many of the discussions that will follow throughout the remainder of the CONVOY programme. Future sessions will continue to build on these themes as the focus shifts increasingly towards applications, deployment pathways, regulation, finance and commercial implementation.
Full Webinar Recording
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