Gone Fission: The Power of Nuclear Energy

It may be best known as the energy that powers the fictional town of Springfield, but nuclear power supplies over sixteen percent of the world’s electricity, with over four hundred nuclear power plants around the world (Morgan 42). Nuclear technology uses energy released by splitting the atoms of certain elements, usually uranium (“Today”). This is different from the energy of other atomic events such as ordinary chemical reactions, which involve only the orbital electrons of atoms (Britannica). It used for producing electricity for lighting, heating, and cooling our homes and buildings. It is also used to produce nuclear weapons, some of the most powerful and dangerous weapons ever created (Tesar 359). Generation of nuclear power is clean, but safety and cost is a major problem (Morgan 42). However nuclear energy could be one of the needed alternative energy sources as fossil fuels run low.

Nuclear power is obtained from the energy stored inside the nucleus of an atom (Graham 4). The atom contains a positively-charged nucleus, surrounded by negatively-charged neutrons. The nucleus, which contains most of the mass of the atom, is composed of protons and neutrons bound together by strong nuclear forces. These forces are much greater than the electrical forces that bind electrons to the nucleus (Encarta II). When the nucleus of the atom is split by the collision of a neutron, it releases this “binding energy” force, a process called nuclear fission (Nuclear Science 50; Graham 4). Heavy fission products are formed by the fissioning of a nucleus. The combined mass of the fission products is slightly less than that of the original material, and the lost mass is converted into energy (Americana 511i).

With most elements, nuclear fission would be impossible because the nuclei are too tightly bound. However radioactive elements, such as uranium, contain big, unstable nuclei that are easy to break apart. Uranium is the heaviest natural elements and contains ninety-two protons (Graham 4). Uranium-238, in which fission occurs spontaneously, has an extremely long half-life of 4.5 billion years; therefore, it is still present in large quantities (Americana 511i; Brian). Uranium-235 is one of the few materials that can undergo induced fission. If a free neutron runs into a U-235 nucleus, the nucleus will absorb the neutron without hesitation, become unstable, and splits immediately into two lighter atoms. An incredible amount of energy is released, in the form of heat and gamma radiation (Brian). Each fission also releases extra neutrons which can be used to split other nuclei. In December 1942, Encrico Fermi stacked blocks of graphite containing uranium in the first atomic “pile.” Control rods of cadmium were pulled away so that neutrons could hit the uranium. The neutrons from one fission were causing more fissions, causing a chain reaction (Nuclear Science 55).

A nuclear fission reactor, surrounded by a thick layer of concrete or steel, releases energy by means of a controlled fission chain reaction (Morgan 42). There are two types of nuclear reactors. The majority of nuclear power plants have thermal reactors (Graham 29). One of the more advanced designs of the thermal reactors is the gas-cooled reactor. Uranium is spread out in thin fuel control rods. By lowering and raising the control rods, the chain reaction can be controlled. When the rods are lowered, more neutrons are absorbed and the reaction slows down. A substance which is not affected during the reaction, such as graphite, helps to slow the neutrons. Carbon dioxide gas is pumped around the reactor to take up heat from the reaction. The hot carbon dioxide is used to heat water to produce steam (Morgan 42). The steam then drives a steam turbine, which spins a generator to produce power (Brian).

The other type is the fast reactor. While thermal reactors convert about one-third of the heat energy from the fuel into electricity, fast reactors convert about half. Also fast reactors produce more fuel than they use (Graham 32).

Small nuclear reactors can power all sorts of vehicles. Unfortunately, because of the cost of developing nuclear technology, the difficulties of operating it, and the hazards from radiation, the majority nuclear-powered vehicles can only be found in the military. Nuclear-powered submarines can stay underwater for several months at time, hidden and able to roam the ocean. Most spacecraft instruments are powered by electricity from sunlight by solar panels. However, beyond thee orbit of Mars, there is not enough sunlight to use solar panels. Space probes sent to study the solar system’s outer planets are powered by tiny nuclear reactors (Graham 38-39).

There are other advantages to nuclear energy aside from being able to power vehicles. Because of uranium’s long half-life, nuclear power plants can still produce electricity long after coal and oil become scarce (ThinkQuest). Most experts agree that oil will probably only last between thirty and fifty years, while coal may last only two hundred (Morgan 4). Another advantage is that nuclear power plants need less fuel than ones which burn fossil fuels. Five hundred grams of uranium produce the same quantity of heat as one thousand four hundred tons of coal (Morgan 42). Although costly, electricity production costs from nuclear energy is cheaper than gas or oil. Also, unlike coal and oil burning plants, nuclear power plants do not cause air pollution (ThinkQuest).

Sadly there are several disadvantages to nuclear energy. Nuclear fuel produces its own waste. There are three types of waste. Low-level waste includes workers’ clothing and old equipment that have been contaminated very little by radioactivity. Intermediate-level waste includes used fuel cans and chemicals from waste-treatment processes. High-level waste consists mostly of liquid chemicals. In the past, nuclear waste was simply dumped in the sea or buried underground. Some parts of the former Soviet Union are so contaminated that a visitor could receive a lethal dose of radiation just by standing near a lake where waste was dumped. Nuclear leaks and dumped waste can still affect us today. High doses of radiation destroy life because radiation can break the DNA molecule inside the cell’s nucleus, damaging or killing living cells. While high doses can cause ulcers and burns on the skin, even a low dose of radiation can make people sick. Nuclear fuel must be carefully transported and must not leak or escape into the environment. Currently nuclear waste is buried at special sites on land, but an alternative option would be to bury the waste deep underneath the seabed (Graham 15, 18-25).

When a fission reaction gets out of control, a meltdown occurs, leading to a nuclear explosion and the emission of huge amounts of radiation. In 1979, the cooling system at the Three Mile Island nuclear reactor failed. Radiation leaked, and several thousands of people were forced to flee. Fortunately there were no deaths, and the problem was solved minutes before a total meltdown would have occurred. Nine years later, large amounts of radiation escaped from the reactor in Russia’s Chernobyl nuclear power plant. Hundreds of thousands of people were exposed to radiation, and several dozen died within a few days. Thousands more may still die of cancers obtained by the radiation (ThinkQuest).

Another annoying disadvantage is that a nuclear reactor has a life of only up to fifty years. After that, it can no longer be used and will need to be replaced (Morgan 43). A political disadvantage is that several nations of the world now have more than enough bombs to kill every person on the planet. Russia and the United States alone have about fifty thousand nuclear weapons between them (ThinkQuest). Atomic bombs contain uranium or plutonium, which is split to release vast amounts of energy and radioactive particles. The atomic bombs that fell on Hiroshima and Nagasaki in 1945 were based on fission reaction (Morgan 45).

Scientists hope that the next generation of nuclear energy will be provided by fusion. Nuclear fusion is the opposite of fission, in which two small nuclei collide to form one heavier nucleus and then release energy. This process is what powers the sun and the many stars. The main problem is that the fuel must be heated up to very high temperatures (Morgan 44; Encarta VI).

Nuclear energy is safer and will last longer than fossil fuels, but there are still too many safety hazards that make it an unreliable alternative energy source for future generations. In the future, scientists may find a way to achieve nuclear fusion, but for now we must work with what is available. In my opinion, the disadvantages outweigh the advantages. Therefore, it is not the most efficient of the alternative energy sources. As Mr. Burns of the Springfield Nuclear Power Plant would say, “Oh, meltdown. It's one of those annoying buzzwords. We prefer to call it an unrequested fission surplus.”

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