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What is a nuclear plant?

A nuclear plant is an industrial facility for the production of electricity using nuclear fission.

What is the difference between a nuclear plant and other electricity plants?

The main difference between conventional power plants and a nuclear plant is that in the first the thermal energy that activates the electricity production circuit is usually sourced from fossil fuels (or other sources), so the initial reaction is chemical. In nuclear plants, however, everything begins in the nuclear reactor.

The nuclear reactor is where a nuclear chain reaction is produced in a controlled manner. It is this reaction that produces the thermal energy from which electrical energy is generated. The rest of the energy production process is identical to that of conventional power plants.

The power of a nuclear reactor can range from watts (kW) to gigawatts (GW). Reactors must be constantly refrigerated. For this reason, nuclear power plants, like conventional thermal power plants, are usually located near large bodies of water (rivers or seas) in order to ensure a constant supply of cold water. The reactors do not generate greenhouse gases, but they do generate radioactive waste.

How does a nuclear reactor work?

Reactors are composed of the following elements:

Fuel: elements whose nuclei can be easily altered to produce thermal energy. The fuel used is usually uranium-235 and plutonium-239.

Moderator: this slows down the neutrons produced in fission, controlling the chain reaction.

Coolant: this prevents the core from overheating and displaces heat to more useful areas of the reaction (e.g., to water to produce steam).

Control bars: these can be placed in the reactor core to regulate the amount of fuel undergoing fission.

What happens with the radioactive waste?

The radioactive fuel used to activate nuclear reactors, once used, becomes radioactive waste. Radioactive waste is also produced in other sectors (such as hospitals) and can be of different levels, depending on its degree of radioactivity. According to the level, they are treated in different ways. The waste produced by nuclear power plants is High Level Waste (HLW).

After use, the fuel is stored in cooling pools within the facility, which cool residual reactions to a standstill, reducing radioactivity to levels that can be isolated by concrete. They are then placed in dry nuclear storage containers, where the waste is held in an atmosphere of inert gas (helium), refrigerated, and insulated with various materials to protect personnel from radiation.

The waste then goes to Temporary Storage Sites (TSS), which are located underground, but close to the surface in areas with geologically stability. Their lifespan is 50 years, and they must be constantly monitored to ensure that no earthquakes have damaged their structure. TSSs are used as long as Deep Geological Storage is available. In countries with advanced nuclear technology, such as France and the UK, ATCs are located next to reprocessing plants.

Spent fuel can be reprocessed to separate uranium and plutonium; at this time, however, it is more expensive to reprocess the fuel than to extract and enrich uranium. Work is currently underway on the development of molten salt reactors, which would allow nuclear waste to be reused as an energy source until its level of radioactivity is considerably lower, thus facilitating waste management.

Finally, the high-level or semi-periodic waste goes into Deep Geological Storage (DGS) for thousands of years. Today, the DGS of reference is the Onkalo reservoir in Finland.

How have nuclear plants evolved over history?

Early scientists working with nuclear energy, including Albert Einstein, did not believe that atomic energy could have practical applications – or at least not in the near future. However, about a decade later, research on the subject had grown quite advanced, and the first military applications took place.

In the 1950s, the specter of nuclear bombs began to give way to a much more positive view of this type of energy, which was theoretically cleaner, cheaper and more efficient. As early as 1951, a U.S. nuclear reactor powered 4 electric light bulbs for the first time. It was not until 1954 that the nuclear power plant at Obninsk in the Soviet Union was able to feed the first electricity grid. This was followed by Calder Hall in the UK, which commercialized nuclear power for the first time in 1956. Calder Hall also produced plutonium, making the Shippingport Atomic Power Station in Pennsylvania, USA, the first all-electric nuclear power station in 1957.

Thanks to the concealment of early accidents, a boom in nuclear power plants began. Since the 1960s, and for almost 30 years, an average of 15 nuclear power plants per year were opened around the world. The 1970s also saw a proliferation of anti-nuclear movements, which eventually came together under the anti-nuclear emblem showing a smiling sun and the text Nuclear power? No thanks.

Since the tragic accident in Chernobyl of 1986, confidence in nuclear power plants was lost both at the state level and among the populace at large. Over the next 30 years, an average of one nuclear power plant was opened each year, and many of the existing ones were decommissioned. Today, nuclear energy accounts for only 11% of world energy production, with the largest suppliers being the United States and France.

The 21st century has brought nuclear energy back into the limelight thanks to a better understanding of the processes, the ability to develop more effective safety measures and, above all, because of the urgent need to find sustainable sources of energy. That is why in 2008 a group of physicists, developers and environmental activists reinterpreted the old smiling sun emblem and, replacing it with an atom, changed the text to: Nuclear power? Yes, please.

What is the future of nuclear power plants?

Today, the leading countries in sustainable energy are concentrating on the development of nuclear energy. However, implementation models are changing with respect to conventional nuclear plants to make electricity production and distribution more efficient.

On the other hand, the generation capacity of nuclear plants is more than double that of conventional plants, and the carbon footprint is almost non-existent. Everything points to nuclear energy gaining more and more ground. In Europe there are currently 106 nuclear reactors distributed among 13 member states, producing about 26% of the electricity used in the European Union.

In the United States, currently the largest producer of nuclear energy, there are 92 nuclear reactors located in 53 nuclear power plants in 28 states. This produces 771,638 GW per hour (according to 2021 statistics), which represents 18.9% of the energy used in the country. This represents practically half of the energy not derived from fossil fuels.

As part of the plan to reduce carbon emissions to zero by 2050, the UK is focused on replacing fossil fuel with renewables, nuclear power and hydrogen. Currently, 16% of the energy produced in the country is nuclear energy, while 40% is still fossil energy, mainly gas. By 2026, a new nuclear power plant, the first in 30 years, currently under construction in Somerset, is expected to produce 4% of the country’s power.

Nuclear plants require a higher initial capital investment than conventional plants, and also require the implementation of higher safety measures. However, the energy density produced (i.e. the ratio of the amount of energy produced to the amount of fuel) and the slightly lower fuel costs make it a competitive option. The most ambitious nuclear energy project to date is the International Thermonuclear Experimental Reactor, better known as ITER.

What is ITER and what is Ferrovial’s role in it?

ITER is a mega-project, the result of a joint effort by 39 countries around the world, led by China and the European Union. The International Thermonuclear Experimental Reactor (ITER) mimics solar processes through nuclear fusion, and promises to become the most sustainable and cleanest source of energy on the planet. Iter, in Latin, means road.

Located in Cadarache in the south of France, the ITER facility covers 42 hectares and consists of a total of 39 buildings. Ferrovial Agroman has participated in the project by constructing seven of the buildings and collaborating in the design of the structures in general.

The major planning, design and implementation challenges faced include the following:

  • Careful study of the soils to detect and prevent any imperfections that could affect the behavior of the foundations and alter plant processes.
  • The installation and assembly of machinery, which can reach enormous dimensions, with the relative difficulties of moving, positioning and assembly. This includes the cryostat, the largest single component of the complex, which requires the simultaneous work of two cranes with a load capacity of 1500 tons for its assembly.
  • The anticipation of accidents such as seismic events, fires, explosions, aircraft impacts, etc.

In conjunction with the International Space Station, ITER is one of the most expensive international projects in history. In the experimental phase, the reactor has been able to produce 10 times the amount of energy needed to carry out the processes, and this without CO2 emissions. The first results from ITER are expected in 2025.

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