Decoding Nuclear Energy
To understand the safety dynamics of nuclear power, it is essential to delve into the atomic process of energy production. This can be accomplished through either nuclear fission or fusion. The current reactors utilize the more established process of fission. The atom's nucleus comprises protons and neutrons which are similar in mass but differ electrically. Neutrons, being uncharged, can move freely, enabling them to collide with and split other nuclei, resulting in fission. This process is repeated continuously in a nuclear reactor, triggering a chain reaction that generates energy. Fusion, in contrast, involves the collision of two light nuclei within plasma to form heavier nuclei.
Understanding Nuclear Power and Radioactivity
A significant concern associated with nuclear power is the radiation emission, which poses harm to humans and the environment. The fuel core of a fission reactor contains uranium, encased within rods immersed in a fluid, typically water. The heat energy produced by the reaction is transferred to this fluid, which is then converted into electricity. During reactions, the participating nuclei tend to generate not just energy but also 'nuclear ash', which are radioactive chemical elements emitting alpha, beta, and gamma radiation. The waste produced can remain active for thousands of years, which, along with safety concerns, forms the crux of the anti-nuclear power campaign.
Managing Nuclear Waste
It is essential to note that radioactive waste is not exclusive to nuclear power plants; it also results from other industrial activities. A nuclear power plant typically generates approximately 3 cubic meters of waste annually. This waste is either stored in controlled repositories or recycled for energy production. The volume of waste produced is minute compared to chemical waste from industries. Thus, radioactive waste management is a less daunting task. For the same energy yield, no other energy source produces less waste. Furthermore, there have been no reported incidents of death or illness due to exposure to nuclear waste to date.
The Safety Quotient of Nuclear Energy
The risk of a nuclear accident is virtually negligible. With the current safety protocols in place, even extreme events potentially damaging the core hardly result in radiation leakage. When evaluating the harm caused by nuclear power in terms of death toll, it pales in comparison to fossil fuels, which contribute to pollution and global warming. Interestingly, even renewable sources, touted as clean and safe, pose more risks than nuclear power. For instance, dam collapse at a hydroelectric power plant is likelier to result in casualties than a nuclear disaster. Nuclear accidents have been there, it is true, and their media reach has been emphasized and continues to be. But they are rare events that have in fact caused a negligible number of deaths. There were no fatalities in Fukushima, while those in Chernobyl in the first weeks numbered 54. If, on the other hand, we consider the effects of radiation over time we are talking about a few hundred, according to the latest estimates.
The mistakes of Chernobyl
The Chernobyl accident was due to a set of human errors that were avoidable both in the design phase and in the famous test that triggered the tragedy. In fact, that reactor was missing a key element, which is the core containment shell. In addition, the control rods also contained graphite, an element that increases the power of the core, while the rods allow it to be reduced. When the test was performed on the night of April 26, 1986, the personnel present were not adequately informed about the reactor configuration. Therefore, faced with the instability of the core, it was decided to increase the power by deactivating almost all the control rods. At that point, the shutdown test of the cooling system was carried out. The resulting increase in temperature prompted the bars to be reinserted, the graphite tips of which became stuck and caused the reactor lid to explode with the release of radiation outside. Today, nuclear power plants are built with the containment system and have automatic safety systems that minimize the risk of such a catastrophe.
The Fukushima accident
Even in the case of Fukushima in 2011, there is an explanation that has no connection with the operation of the reactor. In that case it was the earthquake and subsequent tsunami that triggered the reactor crisis. During an earthquake, power plants are designed to shut down and the core cooling system is activated. In that case, the earthquake deactivated the cooling activation system. There was a second diesel-powered emergency cooling system, but the floor where their control system was located flooded because of the tsunami. The high temperatures in the reactor then generated hydrogen that leaked from the containment system, triggering the explosion. The radiation produced, due to the presence of the containment structure, was one-tenth that of Chernobyl. Thanks to the low radiation exposure in the case of Fukushima, there were no fatalities.
Why is nuclear power the energy of the future?
The safety of nuclear reactors has made huge strides. First-generation reactors were abandoned because of the risk of corrosion during operation, and second-generation reactors because they did not guarantee cooling safety in case of accidents. Already the third-generation reactors were designed to reduce the number of waste and were equipped with automatic shutdown systems. Today we are talking about fourth-generation nuclear power, which will produce electricity, thermal energy and hydrogen with such a low amount of waste that it will be possible to store it within the plants themselves. The future then features nuclear fusion, which is still being studied today because of the problem of the very high temperatures the reactors must withstand. In fact, nuclear fusion is the reaction that takes place in the Sun and produces no waste. The energy that can be produced by fusion can be up to ten times that produced by fission.
The benefits of nuclear power
Having made it clear that nuclear power is a clean source in exactly the same way that renewables are, because its environmental impact in terms of emissions is not comparable to that of traditional fuels, it is also a source to focus on in order to free ourselves from the problems of fossil fuels. We have enough uranium to think about exploitation over the long term, until fusion is a sufficiently mature technology. The nuclear source then lacks two limitations that plague renewables instead. First, nuclear is not an intermittent source: sun and wind, on the other hand, are not always available, while hydro and geothermal sources are not exploitable by all countries. Second, renewables have a low energy density: to meet the world's energy needs with renewables alone, we would need much more land than is actually available. So renewables are crucial, but they are not the solution to the problem of growing energy demand. Also from an economic point of view, the exploitation of nuclear power justifies the high investment required, because it compensates for it with a much higher energy output than a wind or solar plant.
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