SMR - How do small nuclear reactors work?

Emmanuel Macron's recent announcements about small modular reactors (PRM), in English SMR (Small Modular Reactors) have made it possible to bring this technology back to light. These small modular reactors make it possible to provide a nuclear energy, with a much more modest power compared to current nuclear power plants (from 50 to 500 MW instead of the usual 900 MW).

This technology is not new abroad since China and the US are developing this type of projects and an SMR is already in operation in Russia. The French President announced that he wanted to” Catch up ” accumulated by 2030. The France 2030 project will devote 1 billion euros from its budget to it as part of the energy transition.

What is an SMR (Small Modular Reactor)?

A latest-generation reactor: easy to manufacture, assemble and operate

Small modular reactors offer better solutions in terms of maintenance and operation due to their small sizes. An important industrial site can become difficult to manage due to its size; on the other hand, nuclear safety can be provided without difficulty on a small power plant.

As an ongoing project, we can cite, The Nuward launched in 2019 and developed by EDF, TechnicAtome, Naval Group And the CEA.

The capacity of such installations varies between 150 and 170 MW for the reactors developed in the Nuward project, i.e. the equivalent of a coal-fired power plant.

The chimney varies from a height of 25 to 30 meters high for 4 meters in diameter. These are installations more modest and modular. The result is that these power plants produce energy in smaller quantities and for mainly local needs.

Source: the republic energy news sfen

The reactors of the future in the French nuclear industry?

These reactors are announced as part of the France 2030 recovery plan and will be present in The reactor park of the future of French nuclear power. This is what the current public authorities and the regulatory framework affirmed in 2022.

It must be admitted that these models bring innovation and pragmatism in the face of the usual criticisms about nuclear power. These smaller modular reactors can be aggregated to allow for greater power generation capacity.

This flexibility of operation, operated by cutting-edge technology, makes it possible to improve maintenance but also to reduce network costs and, in the end, reduce bills for businesses and individuals. Waste management is also facilitated because the lifetime of the installation is equal to that of the turbine, there is no handling or recharging of fuel. The life cycle is thus improved.

In addition, there is a real complementarity relationship with the development of renewables and green energies in The French energy mix.

What are the differences between EPR and SMR?

The EPR reactor (European Pressurised Reactor) is a pressurized water reactor (PWR) in the 1600 MWe class. Strongly similar to current reactors in France, SMRs are however, as their name suggests, much smaller.

“To give an idea, an EPR produces between 4,500 and 5,000 thermal megawatts, while an SMR is more like around 500 thermal megawatts”, explains J.-M. Ruggieri of The IAEA (International Atomic Energy Agency).

Do you want to go further? Consult our dedicated article: What are the differences between an EPR and an SMR?

How do SMRs work?

A heat transfer or heat transfer fluid to transport heat from one point to another

Like any nuclear device, the power plant uses a heat transfer fluid to Transforming and transporting heat released by the energy of the reaction to the electric turbine. In the vast majority of cases, it is water recovered from a local water point (river, sea water, etc.). Some power plants use another heat transfer fluid such as metal, molten salts or even gas.

Source: WikiWand

Thermal and electrical production

Thermal production is conventional in the case of SMRs. It's about two closed and independent water circuits. The nuclear fission reaction In the fuel chain, energy is released which brings the water contained in the primary circuit to a high temperature.

This water indirectly heats the water contained in the secondary circuit; this water transformed into steam feeds a turbine which, itself, will power an electricity generator. Thermal energy produced by power plants can also be used directly for production Of hydrogen or seawater desalination.

Load tracking

In general, a nuclear power plant is built in order to meet a need for an electricity base. It is supposed to work a significant number of hours per year. If the demand is not sufficient, it is possible to keep the same charge level and to recover this energy in another form, mainly in the form of heat.

As mentioned above, seawater desalination or hydrogen production also remain viable solutions for supplying an auxiliary circuit, which is essential for the proper functioning of the power plant.

Are small modular reactors (SMRs) safer?

The size of this type of installations reinforces the effectiveness of controls of safety ofASN (Nuclear Safety Authority). Smaller reactors that are easier to modernize and require less permanent labor, allow for easier and simplified quality controls. All security processes are thus strengthened.

Source: Franceinfo

Are SMRs capable of meeting current energy challenges?

Waste reduction

The entire fabrication of an SMR nuclear power plant core is carried out in a single global manufacturing plant and a limited number of people have access to the fuel before and after irradiation. Unlike the EPR model, waste presents a reduced risk of non-proliferation.

Safety devices

Power plant cooling systems can use The convection effect, which makes it possible to do without pumps in case of urgent problems. In case of overheating, the core can be quickly cooled and thus avoid any risk of overheating or even melting.

Another device that recalls waste management instructions is that there are underground pools for storing spent fuel.

SMRs for adaptable and affordable electricity production

The SMR concept is oriented to local energy and needs, while being able to also meet demands for flexibility at the request of the network and RTE.

Nuclear production is partly controlled in France, the associated costs are known and make it possible to generate a sufficient margin while offering electricity at a reasonable cost, even more so in a period of sustainable increase in electricity prices.

What SMR projects for France?

In France, there are still no projects on an industrial scale. It is planned, in the France 2030 project, A first prototype in working condition developed by EDF and the CEA by 2030.

Around the world, around fifty projects are being developed and tested.

What is the future of nuclear power in France?

La energy transition is an urgent challenge that needs to be addressed quickly. Nuclear power is the most pragmatic choice to guarantee a reduction of greenhouse gases As well as a security of supply.

Nuclear technologies have two major advantages, namely: its “clean” nature (from a CO2 perspective) and waste management. A genuine response to historical criticisms on the subject.

It is very likely to see this sector develop in the coming decade. France's ambition is to regain its place on an international level. The reason why research on the subject was initially oriented towards export.

France is between 5 and 10 years behind the most advanced countries in the world. The French government's energy policy is favorable to the maintenance and development of the nuclear industry.

To go further, do not hesitate to consult our article: Is nuclear fusion the energy of the future?