Operational considerations for commercial nuclear propulsion

Known to most as a senior London arbitrator, Michael Allen’s first career before becoming a lawyer was as an engineer officer on British nuclear submarines. Below, he poses plenty of questions about crew onboard the next generation of nuclear-powered ships.

There is increasing activity towards the advent of commercial nuclear propulsion, focussing on the molten salt reactor (MSR) instead of the pressurised water reactor (PWR).

Seagoing experience for the past 70 years or so, commencing with USS Nautilus, has been with PWRs. As a result of the close co-operation between Lord Mountbatten and Admiral Rickover, the Royal Navy’s first nuclear submarine, HMS Dreadnought, was launched on Trafalgar day, October 21 1960. Dreadnought was in fact an American Skipjack class design with a British front end and a US reactor and machinery configuration. Going aft, there was a sign “Checkpoint Charlie, you are now entering the American sector”.

The design and build of full size MSRs may prove to be easier than providing fully trained operators

Thereafter, the Royal Navy built nuclear submarines to a national design but RN/USN exchanges, not only technical but also operational, had been an essential part of gaining PWR experience.

At its very simplest, the reactor is the heat source which boils the water which generates the steam which propels the turbines which drive the vessel and the generators which provide electrical power. Of course, it is very much more complex than that and, for commercial shipping, revolutionary, not evolutionary. It is therefore essential that the watchkeepers fully understand the plant they are looking after but they will have no previous experience to draw on.

There are advantages of MSRs over PWRs, lower pressure, higher temperature, primary pump flow rate control, less risk of meltdown but the training of PWR operators gives some insight into what may be required for MSRs. This has been broadly divided between the theoretical and the practical.

The theoretical has generally taken place by way of post graduate academic study of nuclear physics for officers and similar courses for senior ratings. Whilst the MSR differs from the PWR, presumably such theoretical nuclear physics education will have to be provided. For example, will operators need a thorough understanding of molten salt treatment similar to that required for reactor water chemistry in a PWR?

The practical training may be a more difficult issue to address.

There are numerous operating issues which simply cannot be rehearsed and practiced at sea. Accordingly, simulator training plays a major role in, as far as possible, ensuring safety, very much in the same way as it does in the aircraft industry. It is important for effective simulator training that the participants feel that they are sitting in the real thing, such as a cockpit or a submarine manoeuvring room, even though they are firmly on the ground.

Whilst the theoretical study will most likely be a one off, simulator training should continue ashore for as long as the watchkeepers are employed. This is particularly important given the potential monotony of watchkeeping when the vessel is on passage at a steady speed with very little happening. The unexpected will occur and watchkeepers have to react instantly and correctly. Emergency operating procedures have to be second nature.

Nuclear propulsion training and operation is a different matter for armed services than for commercial operators but safety is fundamental for both. Not only would shipowners be entering a new era, so would their insurers, both H&M and P&I, as well as classification societies and flag states. Every party needs to be confident that crews have been trained as thoroughly as possible. This raises more issues; where will the first crews be recruited from and who will have the necessary operational experience to train them? Will they seek a higher rate of pay than currently on offer? Will the operational training have to take place on the first vessel built and how long will that take? Will commercial operators invest in simulator training? Will it be required by their insurers as a condition precedent for cover? Will there be a requirement for regular third party (flag, class) inspection of watchkeepers to ensure that they are and remain fully trained? Will it be necessary to have a modified form of training for the Master and bridge watchkeepers to fully understand what is going on below?

The design and build of full size MSRs may prove to be easier than providing fully trained operators.


  1. Education and training of highly qualified personnel to operate advanced modular reactor technologies like the MSR onboard large ships is quite rightly going to be one of the most important aspects of deployment, right from the start.

    One of the main reasons the MSR is being proposed instead of conventional reactors like the PWR is that the MSR has some distinct design advantages and should require much less operator interaction.

    A good example is the exchange of cooling water. On a conventional PWR powered system, the exchange of cooling water is a complex and highly intensive task for the operators.

    In an MSR the fuel and coolant is the same, and no exchange of coolant is required. The fuelsalt is liquid and contained in the core between maintenance cycles.

    In a conventional PWR the very high pressure of the systems must be managed very carefully by the operators. This is not trivial and requires extensive training in the safe operation of the system. It also requires quite a large cohort working shifts onboard.

    In an MSR there is only ambient pressure and we anticipate a much simpler routine for managing the flow of heat to the turbo machinery. It should ideally be confined to control room operations.

    Today, no MSR-trained crews exist. However, over the next years in parallel with the the completion of the first MSRs we will build a simulator system for the entire reactor and power conversion system. The aim is to create a ‘live’ scenario where we can train operators and officers on the new systems, before being deployed to the first floating power units.

    Working with specialist technology companies, Regulators, Class, Flag, IMO and the IAEA we expect to be able to create a dynamic learning environment in which a new generation of seafarers will be educated.

    Graduates of science and engineering looking for an exciting career where they can travel the world and meet interesting people, should with some luck start considering heading out to sea.

    All those with existing knowledge and experience from reactor management at sea are encouraged to get in touch and get engaged.

  2. This is an important task but should not be considered an exceptionally challenging hurdle. Far more significant than salary is the need to get young people fired up and interested. Society should appreciate them and give them the social status previously occupied by airline pilots, for example.

  3. Good article. What are the security considerations? The Iranians, Gulf of Guniea pirates, Yemeni terrorists to name but a few. The potential for a dirty bomb will make insurers think twice I am sure!

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