Nuclear power is one of the most controversial sources of generation in the modern energy landscape. Since its emergence in the 20th century, it has been seen both as a promising solution to the climate crisis and as a latent threat to the environment and human health. Its low direct carbon dioxide emissions position it as a viable alternative to fossil fuels, but questions about its cleanliness, safety, and sustainability continue to generate intense global debate.
Analyzing the environmental impact of nuclear energy goes far beyond measuring the CO2 emitted per kilowatt-hour. It involves studying the entire life cycle, from uranium extraction to radioactive waste management, including the construction, operation, and eventual decommissioning of nuclear power plants. Below, we provide a detailed and comprehensive overview of whether nuclear energy can be considered clean or polluting, based on all the relevant factors involved in its development and use.
CO2 emissions: Is it really clean energy?
One of the main arguments in favor of nuclear energy is its ability to produce electricity without emitting CO2 during the generation phase. Unlike coal, natural gas, or oil, nuclear reactors do not burn fossil fuels to generate heat, which avoids the direct release of greenhouse gases.
However, When analyzing the complete cycle, indirect CO2 emissions are significant.These occur during uranium mining and processing, power plant construction, fuel enrichment, transportation, infrastructure maintenance, and, ultimately, its decommissioning.
Studies such as those conducted by the Polytechnic University of Catalonia estimate that nuclear energy emits around 66 grams of CO2 per kilowatt-hour., a much lower amount than coal (up to 1000 gCO2/kWh) or diesel (778 gCO2/kWh), but significantly higher than renewable sources such as wind power (9 gCO2/kWh) or solar photovoltaic (30 gCO2/kWh). Therefore, It cannot be considered a completely clean technology, especially compared to renewables.
Radioactive waste: an unsolved problem
One of the biggest environmental challenges of nuclear energy is the management of radioactive waste.These highly hazardous materials can remain active for thousands or even hundreds of thousands of years, requiring extremely secure, long-term storage solutions.
Currently, There is no definitive or universally accepted technical solution for the final treatment of this waste. Much of it is temporarily stored at the nuclear power plants themselves, which increases the risks in the event of an accident, leak, or attack.
Over the years, alternatives such as deep geological storage have been proposed, but technical feasibility, high costs, and a lack of social and institutional consensus have prevented these proposals from being widely implemented.
In addition, the nuclear industry generates various types of waste – liquid, gaseous and solid –, which can affect water, air, and soil if not managed with extreme care. Even under normal operating conditions, power plants emit low-level radiation, which, although difficult to detect with the naked eye, can have dangerous cumulative effects on health and the environment.
Health risks and nuclear accidents
Long-term exposure to radiation, even at low levels, has been linked to an increased risk of certain types of cancer., especially among populations living near nuclear power plants. Scientific research indicates that low levels of radiation can alter human DNA and increase the incidence of degenerative diseases.
The cases of Chernobyl (1986) and Fukushima (2011) have demonstrated the real dangers of nuclear accidents.Both events caused massive environmental disasters, forcing the evacuation of large regions, leaving areas uninhabitable for centuries and causing devastating effects on flora, fauna, and public health.
Despite advances in security, There is no absolute guarantee that an accident will not happen again.Human error, technical failures, or natural disasters can trigger critical situations. Furthermore, in contexts of geopolitical instability, nuclear power plants can be targets of attack or terrorism.
Water, cooling and aquatic ecosystems
Nuclear power plants require huge amounts of water for their cooling systems., which generates collateral impacts on nearby bodies of water, whether rivers, lakes or oceans.
The cooling system has two specific impactsOn the one hand, the influx of water from natural sources can trap and kill fish and other aquatic species; on the other, the water returned to the environment is at a significantly higher temperature, which disrupts the thermal balance of the affected ecosystem, causing the disappearance of heat-sensitive species.
Furthermore, if radioactive leaks or spills are recordedThe problem is getting worse. In Argentina, for example, various measurements identified tritium levels in water that far exceeded the internationally recommended thresholds for human consumption, even without a nuclear accident.
Uranium availability: a non-renewable resource
Unlike renewable sources such as wind or solar, nuclear energy depends on minerals such as uranium., whose availability is limited and whose extraction and processing entail strong environmental and energy impacts.
Experts estimate that, at current consumption rates, exploitable uranium reserves could be depleted within a few decades, even without expanding the global nuclear fleet. Furthermore, a significant portion of the available uranium is found in low-concentration ores, further increasing the carbon footprint and emissions associated with its extraction.
Therefore, Nuclear energy cannot be considered a renewable source, since its raw materials are not regenerated at a rate equal to or greater than global consumption.
Economic costs and competitiveness compared to renewables
One of the most common myths is that nuclear energy is cheap.While operating and generation costs per kilowatt may be relatively low once the plant is built, the initial investment in infrastructure is extraordinarily high.
The levelized cost of electricity (LCOE) for nuclear power currently exceeds that of renewables, such as onshore wind or large-scale solar photovoltaic. Furthermore, many nuclear projects suffer decades-long delays, massive cost overruns, and resulting financial problems.
Recent studies show that with the same investment required for one megawatt of nuclear power, up to four megawatts of renewable energy could be installed, not including additional aspects such as waste management or decommissioning.
The geopolitical and military dimension of nuclear energy
One cannot talk about nuclear energy without considering its link to military technology.Enriched uranium and plutonium generated in reactors can be used, directly or indirectly, to manufacture nuclear weapons.
Throughout history, several countries have developed their military programs using research or civilian reactors, establishing a close relationship between the peaceful and military uses of this technology.
Even in countries without declared military programs, The mere possession of nuclear technology can generate international tensions and increase the risks of nuclear proliferation. Therefore, organizations like the IAEA maintain strict control over facilities, materials, and processes related to this energy source.
What role does nuclear energy play in the energy transition?
In the midst of the climate crisis, Some experts argue that nuclear energy may be a necessary evil. to reduce emissions while consolidating renewables. However, there are many nuances to consider.
The Intergovernmental Panel on Climate Change (IPCC) It has noted that while nuclear power is low in operational emissions, it has other negative environmental impacts, such as uranium mining, the risk of accidents, thermal inefficiency at high global temperatures, and long-term radioactivity.
The IPCC also classified nuclear energy as the technology with the lowest net contribution to the UN Sustainable Development Goals and the only one with a negative rating in terms of sustainability.
Meanwhile nuclear fusion projects Fusion projects such as ITER (Europe) or NIF (USA) are seeking to develop a much safer, cleaner, and long-lasting alternative. However, fusion still presents technological challenges and will not be commercially available in the short term.
Nuclear energy cannot be considered a definitive solution, but rather a declining technology with high costs, risks, and side effects. Prioritizing renewable energy, improving energy efficiency, advancing smart grids, and developing storage systems must be the path forward for a real and safe transition.
The debate on nuclear energy is not only technical, but also ethical and political.It involves deciding whether we are willing to mortgage future generations with radioactive waste, assume potential accidents that could ruin entire ecosystems, or rely on a source historically associated with military purposes. Faced with this dilemma, renewable energies continue to show a much more favorable overall balance for the health of the planet and humanity.