Splitting The Atom


Nuclear energy is increasingly being considered as an important component to achieve net zero. This leads to the question of whether nuclear energy could help decarbonise shipping, and does it have any future in the design of large superyachts?

The potential of nuclear energy is clear, Russia operates a fleet of nuclear icebreakers and the navies of the world have safely operated nuclear powered aircraft carriers and submarines for decades. The first commercial nuclear powered ship, NS Savannah, was launched in 1959. This pioneering project, and several similar ships, fell by the wayside due to public perceptions and high operating costs. But does the latest nuclear technology now allow us to overcome these challenges?

Since the early 2000’s, the nuclear industry has expended considerable effort to develop smaller cheaper reactors, which can be built in a modular design to lower the cost of land based nuclear power. This includes the recent development of heat pipe micro reactors, some of which are designed to fit within shipping containers whilst producing up to 10MW of electrical energy.  Modular and micro reactor designs seek to provide intrinsically safe solutions and many also address the issues of high-level nuclear waste by using alternative nuclear fuels.

Lateral is a subsidiary company of the BMT group. Within BMT and Lateral, there has been considerable work undertaken to study the use of new nuclear reactors in commercial ships, naval ships and submarines. This work has included a multi-year joint industry project, aimed at examining the ship design impact and feasibility of modular reactors. 

Through these studies the consistent result is that the application of nuclear power to conventional ship design is a difficult challenge, requiring careful consideration of radiological shielding and redundancy. It often requires considerable unexpected space and weight, but in nearly all cases feasible designs have been developed. It could therefore be concluded that using nuclear energy on a large yacht is indeed technically possible. 

The main challenge of applying this technology lies outside the confines of ship design. To date the international regulatory framework for nuclear powered ships is complicated and immature. Whilst many codes and agreements exist these are not primarily focused on privately owned ships operating modular or micro reactors. The potential for nuclear energy to cause long lasting personal and environmental harm means that the level of tolerable safety risk is much lower than we are used to in conventional ship design. This approach of probabilistic safety combined with regulatory uncertainty will require a huge engineering effort to prove the safety of the ship to passengers, operators and external parties. 

Even when approved by a flag state, under current regulations a nuclear ship may not be legally allowed into other countries. The solution for this problem is to establish a bilateral agreement between the approving flag state and the country to be visited. However, It is hard to imagine wide ranging agreements being made across all possible yacht destinations to allow a pleasure yacht to operate on a worldwide footprint.

For a nuclear ship to be approved to start construction a detailed plan must be developed that covers all aspects of building, commissioning, and operation of the ship. Some of the micro reactor designs will need to be refuelled or replaced within the ship’s lifespan. This will require nuclear approved shipyard facilities; this is likely to be a considerable investment especially for single ships or even small fleets. 

The liability for the yacht must be considered for decommissioning, in operation and in the event of a nuclear accident. Obtaining insurance against these long-term liabilities could prove practically impossible due to the scope of risk involved and it is unlikely that any nation state would accept responsibility for the liabilities arising from a pleasure yacht. 

Micro and modular reactors typically do not use nuclear fuel that could be used to make nuclear weapons. The security threat is however still high with the risk that a terrorist could use the reactor to make a “dirty bomb.” Whilst solutions to this problem can be developed, they add a further layer of complexity to commercial ship operations and design.

History has demonstrated that despite the best engineering efforts and safety precautions nuclear will still be judged primarily through public perception. The effects of nuclear accidents at Fukushima and Chernobyl remain a key part of the public’s perception of nuclear energy. A nuclear-powered pleasure yacht is likely to invoke strong public feelings causing political and practical problems during port stays.

For all the above reasons, it’s not possible to make a good case for building nuclear yachts. The drive to net zero is likely to result in continued development of small reactors. If this development is successful for land-based applications, and regulatory issues are resolved for commercial shipping, then this position may need to be reconsidered.

In the case that a reinvigorated nuclear industry using new technology creates a revolution in reactor design perhaps a more sensible goal for this revolution would be to use land based nuclear reactors to create clean, abundant, and cheap zero carbon energy. This clean energy could be utilised for transport via electrification and synthetic fuel production.

Written by Simon Brealey, Chief Mechanical Engineer.

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