Radical thinking needed on nuclear ship regulation

Authors:
Markus Virtasalo, Solution Manager, Electric Solutions, ABB Marine & Ports
Samuli Hänninen, Segment Manager, Icebreaking ships, ABB Marine & Ports

Historical differences of opinion over whether zero-emission nuclear power can overcome safety and environmental concerns to take a role in commercial shipping are quickly being revised in response to developments in 4^th generation reactor technology.

Fascinating in terms of innovation, perseverance and in some cases longevity, earlier generation reactors had little impact on global shipping as a whole, with the naval, coastguard, icebreaking and other publicly funded ships concerned often known by name.

In fact, the pressurized water reactors (PWR) or light water reactors (LWR) used in such instances were not suitable for civil use because they required large emergency planning zones (EPZs) that effectively made them uninsurable for commercial operators.

4th generation small modular reactor (SMR) nuclear technology is very different from its ancestors. Under development in ranges of 5MW-200MW, many SMRs are designed to operate at or near atmospheric pressure and have intrinsic passive safety characteristics. A molten salt reactor (MSR) type, for example, exploits a chemically inert and non-flammable substance, whose stability and high boiling point enables rapid adjustment to load changes and facilitates large temperature design margins of up to 700°C.

MSRs also shut down passively once external power is cut, meaning there is no chain reaction that could remain or accelerate on its own in the absence of control. In the case of the 4^th generation reactor, the EPZ should fit comfortably into a ship’s hull.

A cluster of ship studies, new guidance from classification societies, firm interest from marine insurers and inclusion in the latest IMO work on decarbonization demonstrate that the nuclear option is now being widely re-evaluated. 

In 2024, ABB signed an MoU with Blykalla, a company specialized in lead-cooled reactor technology, to explore how its automation, electrification and digitalization solutions can support SMRs for land-based use in Sweden¹. For ABB Marine & Ports, information on Blykalla’s 28MW test reactor adds significantly to knowledge to support shipboard nuclear power, especially where special alloys are concerned.

In summary, many of the past negative arguments made against nuclear power in the maritime context seem no longer to apply, whether they relate to past failures on land, risk of catastrophe, proliferation or vulnerability to use by terrorists.

In April 2025, the 83rd meeting of the IMO's Marine Environment Protection Committee (MEPC) will decide on amendments to MARPOL which include a proposal from 47 Member States and NGOs to adopt a tax or levy on fossil fuels consumed by ships, with rules coming into effect from 2027. As 4th generation nuclear technology does not require the use of fossil fuels, such proposals would not apply to it.

But a global maritime industry, which IMO wants to achieve net zero emissions by around 2050 is also still heavily relying on fossil fuels. At last count fossil fuels contributed almost 99 percent to energy consumption². In 2021, IMO MEPC 77/6/1 put the 2020 HFO consumption figure for ships of over 5,000GT at 101 million tons. Given the lower energy density of e-fuels, the same combustion capability would require 218 million tons of e-ammonia.

Overall progress on 4th generation nuclear reactors has been sufficient for IMO to begin working towards the legislative framework necessary for future systems to be acceptable on ships and by ports. 

According to observations of the Norwegian University of Science and Technology, the extra electricity needed to produce that quantity of e-ammonia ashore would amount to 2616TWh/year, where the net electricity generation of all 27 EU-countries was 2785TWh in 2021 (all sources)³.

American Bureau of Shipping (ABS) recently estimated that oil- and LNG-based fuels would still contribute over half of all ship fuels in 2040⁴.

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This is one context for considering the shipboard application of the reactor outputs specified above, which would be suitable for powering ships ranging from high-end yachts up to the largest containerships. They would also generate sustainable energy efficiently and cause zero emissions, independent of any external decarbonization device or green fuel supply chain issue, while also needing little or no refueling at all.

Taking account of initial capital, fuel and running costs, and dismantling, ABB estimates based on levelized energy lifecycle cost assumption suggest that a shipboard 4^th generation nuclear reactor working with steam-electric plant could deliver electricity for $35-90 per MWh.

Nuclear momentum

A cluster of ship studies, new guidance from classification societies, firm interest from marine insurers and inclusion in the latest IMO work on decarbonization demonstrate that the nuclear option is now being widely re-evaluated.

In August 2024, A.P. Moller–Maersk A/S joined a nuclear-powered container ship feasibility study, working with Lloyd’s Register (LR) and Core Power. In July 2024, LR also published a Fuel for Thought: Nuclear report⁵. In October 2024, ABS published new guidance on nuclear power systems for marine and offshore applications⁶. Other projects include a study analyzing the use of civil nuclear reactor technology to power a Newcastlemax bulk carrier from ULC-Energy and C-Job Naval Architects.

In January 2025, Norwegian shipyard Vard presented NuProShip – a Research Council of Norway-funded project including the Norwegian University of Science and Technology, the Norwegian Maritime Administration, class society DNV, Knutsen Tankers and Spanish nuclear consultancy IDOM. The Blykalla lead-cooled reactor concept was one of the three shortlisted for the NuProShip project.

In publicizing its work to match a concept for a seagoing reactor with a concept ship design, for example, Vard’s focus on three specific reactors came after the evaluation of technologies from 99 companies.

IAEA’s Atomic Technology Licensed for Applications at Sea (ATLAS) initiative is due to launch in 2025 to establish a framework to enable safe and secure deployment of peaceful civil nuclear applications at sea. 

The inclusion of nuclear power in the EU taxonomy rules in 2022 marked a significant milestone, bringing clarity to nuclear as a sustainable investment under specified criteria. In March 2023, the EU Commission adopted the European Net Zero Industry Act (NZIA), classifying SMR technologies as net-zero technologies allowing the NZIA platform to help accelerate SMR development in Europe. However, nuclear was not included then as a "strategic technology", which would have further supported projects in permitting and public procurement. In early 2024, the Commission announced the launch of the European Industrial Alliance on SMRs, which aims to facilitate and accelerate the development, demonstration, and deployment of SMRs in Europe by the early 2030s.

Unfortunately, where nuclear is concerned, owners face an overwhelming mass of ongoing research in numerous different designs, promising intelligence and forward-looking claims. Furthermore, some projects driving SMR development are the preserve of private investors seeking power for AI & data centers, while others are publicly funded projects where information is dispersed between many stakeholders.

Focusing on the lucrative goal of a ship power option promising cheaper electricity, zero emissions and a GHG-free energy source that could feed back into the grid in port, one certainty is that a new regulatory framework is needed to support seagoing operation.

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Formally, the IMO adopted the Convention on the Liability of Operators of Nuclear Ships in 1962, but the instrument was never ratified. Despite the Code of Safety for Nuclear Merchant Ships, adopted by IMO Resolution A.491.XII in 1981 into the Safety of Life at Sea Convention (SOLAS), therefore, there is currently no marine liability convention applicable to vessels using nuclear power for propulsion.

In plain terms, due to the lack of an IMO convention that provides an accepted liability framework for nuclear powered vessels, reinsurance is not currently forthcoming in the case of liabilities caused by a nuclear fuel or nuclear waste.

Onboard with NEMO

In 2024, maritime interests including nuclear technology providers, classification societies and P&I Clubs coalesced around NEMO (the Nuclear Energy Maritime Organization), a grouping whose aims include securing NGO status at the IMO. ABB’s NEMO membership is pending final approval.

Initially, NEMO’s workload includes a review of IMO regulations, a project to adapt International Atomic Energy Agency (IAEA) safety, security and other standards for Floating Nuclear Power Plant, and consideration of insurability. Its work will draw on the IAEA’s Atomic Technology Licensed for Applications at Sea (ATLAS) initiative, which is due to launch in 2025 to establish a framework to enable safe and secure deployment of peaceful civil nuclear applications at sea. The work within ATLAS is seen as an important piece of the bridge between two global regulators.

In 2024, maritime interests including nuclear technology providers, classification societies and P&I Clubs coalesced around NEMO (the Nuclear Energy Maritime Organization). 

Already, overall progress on 4th generation nuclear reactors has been sufficient for IMO to begin working towards the legislative framework necessary for future systems to be acceptable on ships and by ports.

At the 109^th Maritime Safety Committee meeting, nuclear was included in the Development of a Safety Regulatory Framework to Support the Reduction of GHG Emissions from Ships Using New Technologies and Alternative Fuels Correspondence Group.

Some of this work will involve ‘gap analysis’ of the 1981 Code of Safety for Nuclear Merchant Ships. However, as this was developed with PWR and LWR reactors in mind, any such review must take account of 4^th generation technologies and their new safety case, but also IAEA safety standards and IMO’s switch from prescriptive to goal-based rules. Due to report back to MSC in June 2025, the group’s work could result in the first formal move by IMO Member States to update the Code in 44 years.

As a company positioned at the forefront of driving sustainable shipping through electrical propulsion and integrated solutions for ship and shore, one area of ABB’s nuclear focus is to evaluate the safety case for new technology in greater detail.

A ship power option offering cheaper electricity, zero emissions and a GHG-free energy source that could feed back into the grid in port? A new regulatory framework is needed to support seagoing operation. 

Today, the ‘knowns’ include the engineering behind converting nuclear power to thermal energy, and a full understanding of the machinery lifecycle costs that guide estimates for the unit price of electricity generation on board. From the shipboard plant perspective, work to interface a reactor with versatile ‘steam-electric’ plant and integrate it with Azipod® propulsion involves familiar thought processes, and practical knowledge of the flexibility of steam-electric power across diverse vessel types. Already, it is possible to work on system optimization that is ‘reactor-agnostic’, leaving interface work until later.

ABB Marine & Ports is committed to driving decarbonization in maritime. To reach the net-zero target, renewable energy sources play a key role. 4th generation nuclear offers abundant potential to become a true market disrupting technology for shipping. To facilitate this development, clear focus must be given also to offering input and insights to regulatory considerations.

References:

[1] ABB and Blykalla collaborate on small modular nuclear reactor technology in Sweden

[2] MEPC 82/6/38 – IMO fuel oil consumption data for 2023.

[3] Making the Case for Nuclear Power in Shipping, Gard Summer Seminar 2023, Jan Emblemsvåg, Norwegian University of Science and Technology

[4] ABS: Beyond the Horizon, Carbon Neutral Fuel Pathways and Transformational Technologies, page 39, © 2024 American Bureau of Shipping 

[5] Lloyd’s Register: Fuel for thought: Nuclear report

[6] ABS: Nuclear Power Systems for Marine and Offshore Applications