How Dangerous Nuclear Reactors Are - Essay Example

How Dangerous Nuclear Reactors Are Nuclear reactors have been in the news for many reasons lately. Firstly, in a world that is more and more concerned with energy that does not produce carbon emissions, nuclear generators seem like a better and better option. Unfortunately, there is also the dark side of nuclear power, as recently shown by the meltdowns at the Fukushima Daiichi nuclear disaster of March 2011. Nuclear energy is a highly powerful resource, and as with anything that is so powerful, it has both good and bad sides, and must be treated with care. When properly used, however, nuclear energy can be a powerful tool for the good of mankind – if used improperly it can be very dangerous. The most important thing is to have a thorough understanding of exactly what happens inside of a nuclear reactor. The kind of physical process that occurs within a nuclear reactor is called nuclear fission, and it is one of two common forms of nuclear reaction. The other is called nuclear fusion, and that is what is used in most modern atomic bombs, and won’t be discussed extensively here. Each kind of reaction revolves around changing a single atom – fission is the splitting of one atom into two, whereas fusion is the combining of two atoms into a new one. Every atom is made of three parts: neutrons, protons and electrons. Each of these has a charge – protons are positively charged, and attract negatively charged electrons. Neutrons have no charge. Neutrons are naturally occurring parts of atoms that exist in every element – usually there are just as many neutrons as there are protons in any given element. They are very heavy, and give most elements about half of their total weight. If you look at your body in terms of atomic weight, about half of it would be made of neutrons. The three parts of atoms, protons, electrons and neutrons, exist in a balance in atoms that make up the things that we see around us. They exist in a balance because whenever they become unbalanced, they break down or recombine in a more balanced form. Think of a coin standing on its edge – in small change will cause it to fall so that one of the two sides is flat against the ground, but once it falls it won’t move or change as easily as it originally did. Atoms are like this – they are in a stable situation because if they weren’t, they couldn’t last very long. Changing one of the elements, either protons, neutrons or electrons, however, creates an unbalanced atom that wants to change to become balanced again. To create a fission reaction, a neutron is fired at very heavy element, such as uranium-235 (the number “235” is essentially the total combined number of protons and neutrons in the atom). This new neutron is then added to the atom, creating uranium-236 (since an additional neutron was added). Uranium-236, unlike uranium-235, is not stable. Unstable atoms ‘want’ to become stable again, and usually shift themselves in order to do so. In nuclear fission, uranium-236 breaks into two smaller, stable elements. This act of breaking releases a great deal of energy, along with three new neutrons. In early atomic bombs, these three neutrons would then go on to hit three other uranium-235 atoms, which would then break up, release three new neutrons, and so forth, until this spreading chain reaction completely broke down all of the uranium. This is called an “uncontrolled fission reaction,” and results in the massive, devastating explosions that occurred in Hiroshima and Nagasaki. This is very different than what happens in a nuclear reactor, however. In a nuclear reactor, the reacting compound is surrounded by other compounds that can absorb extra neutrons as they are released, so those do not create further reactions. This is called a “controlled fission reaction,” and this cannot possibly lead to an explosion. To repeat, a controlled fission reaction cannot result in the kind of nuclear explosion that atomic bombs do – their structure means that that is not possible. That is not to say, however, that explosions or other issues cannot happen at a nuclear plant. The popular term “meltdown” is usually used to describe a situation in which something has gone very, very wrong in a nuclear power plant, and the reaction has begun to happen at a rate faster than is safe. This raises temperatures significantly, and can cause systems that were made to contain the nuclear energy to fail. One of the biggest issues with temperature rising is that that materials begin to boil. Water is one of the main ways that nuclear reactors are cooled. In fact, the only point of a nuclear reactor is to create heat to boil water that then powers steam turbines. But as temperatures rise, the boiling becomes uncontrolled, and other things begin to boil as well. This can lead to huge build up of pressure, which can cause steam explosions, if the pressure of steam becomes too high. Furthermore, Hydrogen, a very volatile gas, can sometimes be released as part of the creation of nuclear power, and this gas is highly prone explosion when mixed with normal air or any source of ignition. This means that if there is a problem at a nuclear plant, small, mechanical explosions are possible – just like they are at other steam-powered plants. In a nuclear plant, however, any released gases will be tainted with nuclear radiation, and could be more harmful to people than the normal explosion would be. Nuclear reactors are certainly powerful devices that must be treated with a great deal of respect and caution. They are not, however, as dangerous as they are sometimes made out to be by the media. Nuclear reactors cannot explode in the same way that an atomic bomb can, though smaller explosions are possible, as they are at any kind of power plant. If properly regulated, nuclear power can make up a safe and important part of the nation’s power supply. Read More