Interview with Professor Jan Emblemsvag, Norwegian University of Science and Technology (NTNU)

By Longyu Xue, China Ship Survey

Amid the global shipping industry’s accelerating decarbonisation transition, nuclear propulsion technology is returning to the centre of discussions in the commercial shipping sector. For ocean-going transportation, offshore vessels and other vessel types with high energy demand, how to significantly reduce greenhouse gas emissions while maintaining range, cargo capacity and operational reliability has become an unavoidable challenge. Alternative fuel pathways such as methanol, ammonia, hydrogen, biofuels and synthetic fuels are being developed, but they still face uncertainties in terms of availability, lifecycle emissions, storage and transport safety, infrastructure development and cost competitiveness. Against this backdrop, nuclear propulsion, with its high energy density, long operational cycles and low operational carbon emissions, is once again emerging as an important option as the shipping industry explores deep decarbonisation pathways.

In recent years, with the development of Generation IV reactors, small modular reactors (SMRs) and marine electric propulsion systems, the technical foundations for nuclear-powered merchant vessels are evolving. Unlike conventional large light water reactors (LWRs), new-generation reactors place greater emphasis on features such as modularity, low-pressure operation, passive safety and accident-tolerant fuels. These developments have renewed the research value of nuclear propulsion for commercial vessels, and have shifted the industry debate towards more concrete issues such as vessel-type matching, system integration, safety design, regulatory frameworks and business models.

Funded by the Research Council of Norway and led by the Norwegian University of Science and Technology (NTNU) with participation from industrial partners including VARD, the NuProShip project is one of the representative initiatives in current European research on nuclear-powered merchant vessels. NuProShip stands for “Nuclear Propulsion in merchant Shipping”. The project focuses on the potential applications of Generation IV small nuclear reactors in merchant and specialised vessels, with research covering reactor type selection, vessel concept design, power system integration, safety analysis, economic assessment and regulatory adaptation.

Starting from actual vessel operational requirements, the NuProShip project analysed how different reactor pathways match different vessel types. The research suggests that future nuclear-powered vessels are unlikely to adopt a single technology solution to cover all markets; rather, differentiated applications are more likely to emerge based on vessel size, power demand, load variation characteristics and operational scenarios. The project team systematically assessed technologies from 99 advanced nuclear reactor developers worldwide, ultimately identifying three reactor types with the greatest potential for maritime applications: Molten Salt Reactors (MSR), High-temperature Gas-cooled Reactors (HTGR), and Liquid Metal Fast Reactors (LFR).

In Phase II of the NuProShip project, the work progressed to concrete vessel concept design. A case study led by Vard Design on a nuclear-powered offshore construction vessel examined the feasibility of using a helium gas-cooled reactor as the primary power source, and analysed its implications for vessel layout, safety systems, power redundancy and system performance under dynamic positioning (DP) conditions. Published findings show that the nuclear power system can fully meet DP2 power architecture requirements and has the potential to be upgraded to DP3 standards.

However, technical maturity is only the first step towards commercial operation of nuclear-powered merchant vessels; issues such as licensing, regulation, liability insurance, port access and public acceptance still need to be addressed. Against this background, China Ship Survey recently interviewed Professor Jan Emblemsvag of the Department of Ocean Operations and Civil Engineering at NTNU. As a core lead of the NuProShip project, Professor Emblemsvag has been following the application prospects of nuclear propulsion technology in commercial shipping since 2015 and is one of the most influential experts in this field globally. In this exclusive interview, he further elaborated his assessment of the development prospects of nuclear-powered merchant vessels, covering topics including the role of nuclear propulsion in shipping decarbonisation, the suitability of the three reactor technology pathways for different vessel types, inherent safety design of nuclear-powered merchant vessels, practical challenges for shipowners considering investment, as well as regulation, classification society collaboration, crew training and future research directions.

Professor Jan Emblemsvag of the Department of Ocean Operations and Civil Engineering at Norwegian University of Science and Technology (NTNU)

Photo Credit: NTNU

Q: The shipping industry is facing urgent pressure to reduce emissions. Where do you see nuclear propulsion fitting into shipping’s decarbonisation pathways? Is it a supplementary solution for specific market segments, or could it become the mainstream choice for ocean-going vessels in the future?

A: I think that it will eventually become the mainstream choice. With the smallest reactor being 5 MWe, the market is massive – around 60,000 ships globally.

Q: The NuProShip projects have identified three reactor types with potential for maritime use: Molten Salt Reactors (MSR), High-temperature Gas-cooled Reactors (HTGR), and Liquid Metal Fast Reactors (LFR). Could you please compare in detail how these three technology pathways suit different vessel types?

A: The MSR and the HTGR fit different vessel categories depending on size and ramping requirements. The HTGRs will fit really well for ships that use electric drives (ships with a lot of station keeping) whereas the MSRs will fit those using steam turbines with not too much ramping up and down.

The LFRs do not like ramping and also, they require high minimum loads, which implies that they are best for base-load operations. This is most likely found on floating nuclear power plants (FNPPs) of various sorts and highly specific vessel types.

Q: Safety concerns over nuclear-powered merchant ships still prevail among the industry and the public. You have stressed that “safety must be built into the reactor itself for commercial use”. Can current nuclear technologies truly deliver this, and how?

A: Yes, the key is 1) Generation IV technologies with 2) low pressure and 3) accident tolerant fuel such as TRISO fuel. This combination is truly strong and can without any problems overcome the relatively ‘bad’ reputation that Lightwater reactors (LWR) have gained due to accidents in the past.

The public do not understand the difference between Generation II LWRs and Generation III LWRs, so going down that lane trying to educate a large amount of people on those distinctions is relatively futile. People, however, understand that Generation IV is something new and different. The same can be said about the fuels. When people see TRISO fuel they are amazed whereas the traditional nuclear fuel struggles with acceptance.

Q: For shipowners, what are the key practical difficulties they should focus on when considering an investment in nuclear-powered merchant vessels?

A: In the beginning, the ship will have limited operational area due to adoption rate of rules and regulations. Also, with nuclear licensing processes, there will be no possibilities of selling these ships in the open market – only to other shipowners with nuclear operating license. Changing flag etc will most likely be difficult. Hence, there are a number of strings attached, but the benefits are large – faster ships, much, much longer range and after the first few ships, we also expect lower costs.

Q: In your view, what practical steps should industry stakeholders take to overcome the regulatory, commercial and other challenges and risks that stand in the way of large-scale adoption of nuclear-powered merchant vessels? When do you expect a major breakthrough in the application of nuclear propulsion in commercial shipping?

A: We hope to put the first few vessels on the water within 10 years. To speed up tot process (not overcome), the shipping industry could partly finance the licensing work that is ongoing to speed it up. The new rules that the US NRC have issued are very helpful in that they now provide more adopted regulations for small reactors instead of using the one that applies to large reactors. We use the US NRC as baseline for our work.

The class societies of the world should also collaborate on developing a common framework. All such developments are very welcome because it will help a lot since such frameworks will be needed to help land-based nuclear regulatory bodies provide assistance to the maritime industry.

Q: What new professional competency requirements will the operation of nuclear-powered merchant vessels place on seafarers? Does the shipping industry need to build dedicated supporting training and qualification certification systems accordingly?

A: This is a very good question for which I do not have any definitive answer, yet. What is sure, is that we cannot use today’s naval training due to the difference in reactor technologies and also the performance requirement differences.

Q: What suggestions would you offer to supply chain stakeholders who are still taking a wait-and-see approach to nuclear power technology? What preparations should they be making now for a possible nuclear-powered shipping era?

A: Wait and see is a good approach for the majority, but for those that want to be early and influence the adoption and technologies, it is important to engage. I think that for those that want to wait and see, the critical thing is to hedge their risks when building new vessels. The best way of doing that is probably to spend time orienting themselves on the development.

Once the first few ships are out, it will still go some years before the numbers rise fast due to supply chain constraints, but when these first few ships are out it is definitively time to act (strategies etc must be ready) – or else they will be too late.

Q: With Phase II of the NuProShip project successfully concluded, what research directions will you be focusing on next?

A: NuProShip II is finished in a few months, but we have already secured funding for a center on nuclear propulsion, so the work goes on with even greater intensities. There are no new directions, as such. We continue the ongoing work along the different paths that NuProShip projects have taken us because there are still a lot of details to figure out.