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Small Modular Reactors
Small Modular Reactors, or SMRs, are new innovations in the world of nuclear. They are the hottest topic in the nuclear industry right now because they will be cheaper and built much faster than traditional power plants. They will also be more accessible to developing countries who currently do not use any nuclear power because large plants are too expensive. They will be a massive help in the fight against climate change!
The IAEA definition of an SMR is that they have a power capacity of up to 300 MW, about one third of a traditional power plant. Breaking down the name, an SMR is defined as:
Small
Small
Modular
Modular
Reactor
Reactor
Advantages of SMRs
They are smaller so they can be sited at many locations where large reactors can’t be built.
They do not have to be on the coast with access to sea water because they do not need as much emergency cooling as large reactors.
Parts and systems of the reactor can be mass produced in a factory, then shipped to be assembled on site.
This allows more control in manufacturing, this means that construction will be much cheaper and faster than large reactors.
By being smaller and cheaper, SMRs will be more accessible to developing economies that cannot afford large nuclear power plants.
This will enable countries in Africa, Asia and South America to start generating more electricity that is carbon neutral.
They are versatile as they can be used to generate electricity, provide steam for heating, or be used to generate hydrogen.
They can be installed near industrial plants to provide heat for activities such as steel making. They can contribute to the green hydrogen economy by generating it carbon free.
Compared to existing reactors they are simpler and rely more on passive safety systems and operate at lower power and pressure.
In some designs, no people will be needed on site as the reactor will be remotely controlled!
SMRs can go longer without being refuelled. Existing plants need to be refuelled every 1-2 years.
Most SMR designs can go much longer without needing to be shut down for refuelling, for most it ranges from 3-7 years. Some will be able to run for 30 years on the first fuel load!
Disadvantages of SMRs
Uncertainty – Since they are new and no SMRs have been built yet, their construction and performance is still unknown. However, once a few have been constructed and are operating and the designs are proven, this will no longer be an issue.
Race against time – Another consequence of SMRs being new innovations is that it takes many years to go from designing one to switching one on. Beyond it taking time to design, the reactors have to go through licensing to ensure they are safe to build. This places SMRs at a disadvantage to wind turbines and solar panels as they can be constructed much faster.
Global Status
There are many companies around the world designing their own SMRs. There are 78 registered designs on the IAEA public database.
This graph shows the different reactors being designed across the world and where they are being developed. All these companies are racing to be the first to successfully design and build an SMR.
UK Status
The first one in the UK is expected to be built for power on in the early 2030s. It will take time to build the first one because the designs have to be licensed by the Office for Nuclear Regulation, then the factories have to be built to put the parts together before the power plant is assembled on site. After the first one is built the following power plants will be constructed much faster as the supply chain is established, and lessons will be learned to make it more efficient.
There is currently a competition being run by Great British Nuclear to determine which companies and SMR designs that the UK government should support going forward. In October 2023 this was shortlisted to 6 companies that have been invited to bid for UK government contracts as part of the next stage of the competition. This will result in a final investment decision in 2029.
Matthew Young
