Tech UPTechnologyThe role of nuclear energy in the energy transition

The role of nuclear energy in the energy transition

We are warned. Before 2050, it is urgent to prevent the planet’s temperature from rising by 1.5 ° C or the consequences will be very difficult to manage : climate refugees, rising sea levels … Greenhouse gases are the main accelerators of this process. In addition, the pollution in the atmosphere of these gases (mainly carbon dioxide and methane), coming from the use of fossil fuels, cause 7 million deaths a year globally, according to UN estimates.

Carbon, oil and gas continue to be the foundation of our global energy supply, and the urgent need for an energy transition is not easily tackled. To put aside fossil fuels, the most logical solution seems to turn to renewable energies (wind, solar, hydraulic …) but before making any approach we must start to consider several issues: efficiency, sustainability, economic profitability, security, democratic mechanisms …

What role does nuclear energy play in the energy transition? Is it a mistake to believe that nuclear energy is not compatible with a sustainable and ecological future? Willing to generate educated and realistic conclusions in the population, Muy Interesante has spoken with several experts who have contributed points of view for and against this highly controversial source of energy.



Let’s start with efficiency. Currently, the electricity generated in nuclear power plants in Spain represents approximately 20% of the total (and 10% globally). For some experts, it seems unlikely to stop depending on this 20% to move towards a transition solely and exclusively towards renewables. In fact, it is likely that to completely stop relying on fossil fuels, this percentage will need to increase further. Is an energy transition without nuclear power realistic?

The first thing to understand is that we cannot totally stop relying on fossil fuels overnight. For this reason, the concept of energy transition refers to a progressive dependence on other types of energy sources, and the intention of both the pronuclear and anti-nuclear sectors is that this transition is dominated mainly by renewables. Today the percentage is approximately 40% fossils, 40% renewable and 20% nuclear , and the objective is to share the cake so that fossils are replaced by renewables. The question is, by what percentage is this realistic? If all nuclear power plants were shut down, how can the antinuclear power plants be sure that this 20% of nuclear power could be replaced by renewable energy?

For Pablo García García, nuclear engineer and president of Jóvenes Nucleares, ceasing to have nuclear energy would have even worse consequences: “If nuclear power plants were closed today, the alternative would not be renewables. The alternative for that 20% in Spain would be natural gas , which has high CO2 emissions, and makes the price of electricity more expensive ”.


In the opinion of the disseminator Operador Nuclear, an engineer with a Nuclear Power Plant Supervision License, the only realistic option for an energy transition is the hydro-nuclear combination , as is the case, for example, in Sweden, where today they already obtain 90% of its energy supply through this combination: “At present, these two technologies are the only ones low in emissions and with the capacity to supply electricity without depending on inclement weather or day and night cycles,” he explains.

Hydroelectric plants are viable for countries with large water reserves and relatively low consumption, such as Norway. In contrast, it seems likely that countries with the highest consumption and least water would need nuclear energy to meet their energy needs.

But the assumption that we cannot give up nuclear power in the energy transition is perhaps resigned to the funding decisions of governments. Many experts believe that we do not see feasible depending exclusively on renewables, simply because not enough is invested for it.

Luis Sánchez Vázquez, doctor in Peace, Conflicts and Democracy with a specialty in Environmental Conflicts, and professor in the Department of Regional Geographic Analysis and Physical Geography of the University of Granada, acknowledged in an interview with Muy Interesante that, for him, it could be realistic that they would come to replace that 20% that nuclear energy represents , if firm bets were made by state and supra-state governments: “Nuclear energy, due to its very high construction costs and investments necessary for safety, cannot be carried out carried out by private initiatives, as has been demonstrated in recent decades, where the construction of any reactor has not been completed with a 100% private initiative. The nuclear option is only viable with a majority component of state investment, and therefore, if this enormous state investment were destined to research, development and innovation of diversified renewable energies, I think that it could replace that 20% of nuclear production ” .


Is nuclear energy sustainable? As Antonio García-Olivares, from the CSIC reminds us: “The IAEA (International Atomic Energy Agency) maintains in some reports that we have uranium reserves so that the current reactors continue to operate for up to 200 years. However, for this calculation, he estimates that uranium will come out in a third of current reserves and in two-thirds of undiscovered deposits, and calls for increased investments to extract and discover more reserves. I am much more confident in the Energy Watch Group estimates that uranium production can be sustained until 2035, if the number of plants remains roughly the same as there are today, and will decline thereafter. If on top of that we increased the number of plants to produce everything we need (5 times more), the uranium would not last even 4 years ”.

However, and no matter how idealistic a 100% renewable situation may seem to us, it is difficult to imagine a realistic energy transition without the great production capacity that nuclear power plants possess; at least, not as long as humans do not reduce their level of consumption. Nuclear power has the ability to generate large amounts of energy very efficiently. According to the Intergovernmental Panel on Climate Change (IPCC), to produce the same amount of energy as in a nuclear power plant, 450 times more land is needed in a solar plantation; in turn, 17 times more cement, glass, metals and mineral are also required.

For the American anthropologist and ecologist Michael Shellenberg, co-founder of the Breakthrough Institute and founder of Environmental Progress , nuclear power is nothing less than the “true environmental dream.” These were the words chosen during a videoconference with Muy Interesante: “They want us to believe that we have no resources, that it is inefficient, but we should learn to use nuclear energy waste, because it solves all problems: there is no food limit, no there is a water limit … The argument that we would need 2 or 3 Earths to supply our energy needs is ridiculous, because we do not need biomass ”. And he adds: “The reason is that nuclear energy requires few resources compared to the waste generated.”

And here comes the first argument against nuclear energy, which is quite logical and straightforward: waste management.

Waste management

Taking into account that both nuclear and renewable energy do not emit greenhouse gases into the atmosphere (what is expelled in the large chimneys of nuclear power plants is water vapor), we could consider that both can be considered, a priori, energy clean. Nuclear Operator explains: “Renewable and nuclear energies do not emit into the atmosphere during their electricity generation , although it is true that both generate waste, especially in their dismantling phase. If these wastes are treated safely in such a way that they do not affect people and the environment, as occurs in both energies, we can consider them comparatively clean ”, he explained in a conversation with Muy Interesante.

But when we talk about nuclear energy, these are not the waste that are of concern: the result of nuclear fission emits ionizing radiation, which can harm both the environment and humans, and high-level waste can remain active for hundreds or more. even thousands of years. Therefore, it is worth asking whether the planet has the sufficient capacity to host nuclear waste indefinitely. In addition, nuclear fuels can also pose a pollution problem in nearby waters or land. As Antonio García-Olivares, senior scientist at the Institute of Marine Sciences (CSIC) points out: “The environmental problems derived from uranium mining (very environmentally impactful) and the occupational risks derived from working with fissile material are very relevant, not only in the power plants if not in all the phases of the nuclear cycle ”.

Nuclear operator provides us with some data on the efficiency-waste ratio: “A 1 GW nuclear power plant produces approximately 9 m3 of high-level waste each year. It is a very small amount compared to the enormous amount of energy generated. On the other hand, it states: “Nuclear power plants make periodic gas and liquid discharges, but always after having allowed them to decay, be filtered and released in compliance with national and international regulations, with the aim of not harming people and the environment. ”.

The fuels used in nuclear power are mainly uranium and plutonium, but deuterium and tritium are also used. The latter, for example, has a biological half-life of about 12 days.

Antonio García-Olivares is very critical of the problem of nuclear waste: “The problem of high-level waste has no solution; none of the types of deep definitive repository for high-level waste can ensure its safety beyond a few centuries “, he explains, based on his experience in a 15-year work at Ciemat (Center for Energy, Environmental and Technological Research ).

But we cannot ignore the fact that high radiation waste goes through a storage and preservation process with a very strict security control , or it is desirable that it be so, and there are technological solutions for its treatment. Furthermore, Pablo García García, from Jóvenes Nucleares, adds: “Nuclear energy is not only committed to preserving nuclear waste, but it also has the capacity to do so.”

It is clear that, in the nuclear issue, the storage of waste is one of the most conflictive points. But over the decades, technological innovations have made this process increasingly strict and efficient , and nuclear power plants are currently very committed to waste management, aware that they are their great weak point. “We have a lot to thank anti-nuclear associations like Greenpeace, which for decades fought to prevent nuclear waste from being dumped into the sea, ” exemplifies Pablo.

Assuming that the waste can remain isolated and safely preserved for hundreds or thousands of years on Earth, there are other issues that concern the population in reference to this energy source: security.


Where does the fear of nuclear energy come from? The beginnings of this technology were not very favorable, since the military use of the atomic bomb was one of the greatest tragedies of the human being. Despite this, scientists saw nuclear energy as the great energy promise in the middle of the 20th century, and its commercial uses began in the 60s with the opening of the first nuclear power plants.

Since the first plants were opened, there have been two or three accidents serious enough to once again cloud the enormous potential of this technology as an unlimited source of energy. But, as we mentioned, technological progress has perfected security measures to unsuspected limits.

Is the risk of a nuclear accident negligible? How should we, as a society, take this risk in favor of such a powerful energy source? Undoubtedly, this is one of the questions that human societies must ask themselves to move towards a just, sustainable and democratic energy transition , as one of our interviewees, Luis Sánchez Vázquez, points out.

Let’s start with nuclear power plant safety. Pablo García García gave us many details about how to work in a nuclear power plant, and about the level of radiation to which workers in a power plant are exposed.

To establish the level of ionizing radiation that can be dangerous to health, there is an energy unit used for its measurement: the sievert. International organizations establish that 1 sievert per year is already considered a potentially dangerous level for health.

As well; Nuclear power plant regulations establish that their workers cannot be exposed to more than 20 millisieverts per year. Finally, in the practice of a worker, the exposure is even lower, since it does not reach 0.5 millisieverts per year.

“The Chernobyl accident cannot be taken as an example to criticize the safety of nuclear power plants. Nowadays, a power station like that would never have been approved in Spain, ”says Pablo.

So, does the population have an irrational fear of nuclear energy, or is its rejection justified due to the apocalyptic consequences that a serious nuclear disaster would entail on our planet?

We cannot ignore the fact that, no matter how few, 3 accidents have marked the trajectory of nuclear energy in the world in black: Chernobyl, Three Mile Island and Fukushima (although in reality it was a natural catastrophe and there was no direct deaths from a radioactivity leak).

Pablo García García establishes an analogy that is very useful for us to understand the fear of societies to a nuclear accident: traffic accidents vs. plane accidents: “The mathematical risk of a nuclear accident today is very low, but the perception of the real risk is much higher. Something similar happens with traffic and air accidents; the latter are much more unlikely, although their consequences are much more catastrophic ”.

To get an idea of the mathematical risk that Pablo talks about, we are going to give a figure. According to him, the probability of a nuclear accident occurring is [1×10 (-6)] one in ten to the negative six, which is the same as a single accident in a million years of operation.

Regarding the military risks of nuclear energy, anthropologist Michael Shellenberg has a surprising and provocative perspective: “With the use of the atomic bomb the entire intellectual sphere predicted a nuclear war that never happened. What happened, on the contrary, is that we use nuclear energy in a much more cautious way. It is a peace bomb, because nobody wants to use it ”.

A radioactive world

Assuming nuclear power plant safety is under control today, and nuclear power plant radiation is negligible, do we have any idea how much radiation the average human receives? Obviously, it depends on where you live. We can assume that if you live near a nuclear waste dump, you may be exposed to higher levels of radiation. But the reality is surprising; no more than anyone who lives in a big city.

Of all the ionizing radiation that any human being receives throughout his life, around 88% is there for the fact of being alive, they come from nature itself. As Miguel Ángel Sabadell, astrophysicist and collaborator of Muy Interesante describes in his article ‘The Earth, that great radioactive bathtub’: “Every hour, some 30,000 nuclei of radioactive isotopes present in the air we breathe disappear in our lungs. Due to the food we eat, about 15 million nuclei of potassium-40 and about 7,000 of natural uranium disintegrate in our stomach and intestines ”.

Around 10-15% of the radiation that a human being receives will come from artificial sources, such as medical instruments (X-rays); and only 0.1% comes from nuclear energy.

A note here from Nuclear Operator: “It is important to differentiate between ionizing radiation (alpha, beta, X, gamma and cosmic rays) and all electromagnetic radiation, such as radio frequency, which are non-ionizing and therefore radiologically harmless” .

Outlook for the future

After reading this information, you will be more or less convinced that nuclear fission is necessary for a realistic energy transition. But you should know that it is not the only possible nuclear source, and perhaps not the most efficient and clean. What if there was an energy source that did not carry the problem (more or less controlled) of waste, and was in turn as effective or more than fission? In fact, it exists, but we have not yet found the human way to carry it out. We are talking about nuclear energy by fusion.

As its name suggests, fission (which is what power plants use today) consists of dividing complex nuclei into simpler ones to release energy. But the opposite process, fusion, consists of unifying these nuclei, a process that occurs naturally in stars like our Sun, but which requires temperature conditions that are very difficult to achieve on Earth.

Nuclear fusion has already been achieved, but we still do not know how to translate it into energy efficiently.

Right now there are two research projects on Earth aimed at achieving commercial uses for fusion. ITER, in Europe; and the NIF, in the United States. ITER is an international consortium in which Spain participates, which works with an experimental fusion reactor located in France. Scientists are convinced that they will achieve an efficient fusion process by 2035, and that they will be able to bring the first commercial nuclear fusion power plant into operation by 2050.


But many experts are cautious about these perspectives, such as the anthropologist Michael Shellenberger: “We know what is going to happen in the future, but we don’t know when; maybe in the year 2400, nobody knows. You have to be cautious. Engineers always promise the dream of perfect technology and that they are going to be heroes for it. ” In addition, he adds: “Science has its share of faith. Promising that we will invent this technology by 2050 is a religious phrase.”

There is also a very interesting project called MYRRHA, which uses nuclear waste itself as fuel. This process is complicated because its reuse requires very specific treatment and materials. Spain is involved in the IFMIF-DONES project, which will be dedicated to the production of materials for the use of waste as fuel, and which will be installed in Granada in 2015. ” This initiative will place Spain as a leading country in innovation” , as stated Pablo Garcia.

Although investment in renewables increases, an energy transition based 100% on these types of sources may not be viable. One of the major criticisms of the traditional environmentalism that is positioned against nuclear energy is a certain lack of constructive attitude regarding the visibility of alternatives. For this reason, we may have to adopt as a society a more scientific perspective and with a view to progress in everything related to nuclear energy, see its ‘green’ side; without ceasing to be critical of its problems, but trusting in the solutions that technological advance can provide.


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