While atoms are tiny particles that make up every object in the universe, the bonds that hold atoms together can yield enormous energy. Releasing energy from the nucleus of an atom is achieved in two ways: nuclear fusion and nuclear fission. Historically, the advantages of nuclear power generation both precede and outnumber the disadvantages when presenting recommendations to prevent or at least mitigate further global warming. Consequently, the following summary of arguments for and against nuclear power can both initiate and substantiate those assessments, reviving reconsideration by the public, or at least by politicians. Advantages of nuclear power generation: a)Nuclear power generation does emit relatively low amounts of carbon dioxide (CO2). The emissions of green house gases and therefore the contribution of nuclear power plants to global warming is therefore relatively little; b}This technology is readily available, it does not require development time; and c) Vast amounts of electrical energy can be generated at one single plant.
The disadvantages of nuclear power generation however, appear overwhelming: a)The radioactive waste from nuclear energy is extremely dangerous and requires caretaking for several thousand years (10,000 years according to United States Environmental Protection Agency standards); b)High risks: Despite high security standards, the possibility of accidents prevails. While it is technically impossible to build a plant with 100% security, a small probability of failure will always remain. The consequences of an accident could be absolutely devastating both for humans and for the rest of nature. As the number of nuclear power plants and nuclear waste storage shelters increase, so does the probability of catastrophic failures increase; c)Nuclear power plants as well as nuclear waste could be preferred targets for terrorist attacks because no atomic energy plant engineering can endure an attack similar to the 9/11 attack of New York City. Such an act of terrorism would initiate cataclysmic events affecting our entire planet; d)The radioactive waste that is produced during the operation of nuclear power plants can be used for the production of nuclear weapons despite the global goals of decommissioning Weapons of Mass Destruction. Similarly, the same abilities and knowledge used to design nuclear power plants can be applied to building nuclear weapons and encourage nuclear proliferation; e)The resource and energy source for nuclear energy is Uranium however, Uranium is a scarce resource, estimated to last for only the next 30 to 60 years depending on the actual demand; and f)The time frame needed for formalities, planning and building of a new nuclear power generation plant is in the range of 20 to 30 years in the western democracies, making it impossible to build new nuclear power plants in a short time.
Clearly, nuclear power is neither "green" nor sustainable: both nuclear waste and retired nuclear plants are far-from-green, life-threatening legacies for future generations. Subsequently, the spirit of sustainability is flagrantly contradicted if future generations are destined to manage hazardous radioactive waste inherited from preceding generations. Uranium, the source of energy for nuclear power, is neither abundant on Earth nor a non-renewable resource expended or converted during the nuclear reactions at nuclear power plants. While predictions vary, the supply of Uranium is expected to last for the next 30 to 60 years, respective of the actual demand.
1. Low Pollution
As our demand for electricity soars, the pollution produced from fossil fuel-burning plants approaches dangerous levels to supply our demand. Coal, gas and oil burning power plants are already responsible for half of America's air pollution. Burning coal produces carbon dioxide, which depletes the protection of the ozone. Many power plants burn soft coal that also contains sulfur, which becomes sulfuric acid precipitation when the gaseous byproducts are absorbed in clouds. Surprisingly, coal also contains radioactive material; a coal-fired power plant emitsmore radiation into the air than a nuclear power plant. The world's reserves of fossil fuels are headed for depletion. The sulfurous coal which many plants use is more polluting than the coal that was previously used. As the use of soft coal increases, the pollution increases. Most of the anthracite, which plants also burn, has been depleted. According to estimates, fossil fuels will be burned up within fifty years. Conversely, there are large reserves of Uranium and new breeder reactors that can produce more fuel than they use. Unfortunately this doesn't mean we can have an endless supply of fuel Breeder reactors need a feedstock of Uranium and Thorium, so when we run out of these two fuels, in about 1000 years, breeder reactors will cease to be functional. This solution has more longevity than burning coal, gas, or oil.
Nuclear power plants need little fuel, so they are less vulnerable to shortages because of strikes or natural disasters. Global markets and international relations will have little effect on the supply of fuel to the reactors because Uranium is evenly deposited around the globe. One disadvantage of Uranium mining is that it leaves the residues from chemically processing the ore, which leads to radon exposures for the public. These effects do not outweigh the benefits by the fact that mining Uranium out of the ground reduces future radon exposures. Coal burning leaves ashes that will increase future radon exposures. The estimates of radon show that it is safer to use nuclear fuel than burn coal. Mining of the fuel required to operate a nuclear plant for one year will avert a few hundred deaths, while the ashes from a coal-burning plant will cause 30 deaths.
Safety is both a pro and con, depending on which way you see it. The results of a compromised reactor core can be disastrous, but the precautions have prevented meltdowns in all but a few cases in history. Nuclear power is one the safest methods of producing energy. Each year, 10,000 to 50,000 Americans die from respiratory diseases due to the burning of coal, and 300 are killed in mining and transportation accidents. In contrast, no Americans have died or been seriously injured because of a reactor accident or radiation exposure from American nuclear power plants. There are a number of safety mechanisms that make the chances of reactor accidents very low. A series of barriers separates the radiation and heat of the reactor core from the outside. The reactor core is contained within a 9-inch thick steel pressure vessel. The pressure vessel is surrounded by a thick concrete wall. This is inside a sealed steel containment structure, which itself is inside a steel-reinforced concrete dome four feet thick. The dome is designed to withstand extremes such as earthquakes or a direct hit by a crashing airliner. Many sensors are in place to pick up increases in radiation or humidity. An increase in radiation or humidity could mean there is a leak. There are systems that control, manage, and even stop the chain reaction as required, such as the Emergency Core Cooling System, which ensures that cooling water is abundantly available to cool the reactor in the event of an accident.
If there is a loss of coolant water in a fission reactor, the rods would overheat. The rods that contain the Uranium fuel pellets would dissolve, leaving the fuel exposed. The temperature would increase with the lack of a cooling source. When the fuel rods heat to 2800°C, the fuel would melt, and a white-hot molten mass would melt its way through the containment vessels to the ground below it. This is a worst-case scenario, and there are many precautions in place to minimize this possibility. Emergency water reservoirs are designed to immediately flood the core in the case of sudden loss of coolant. There are normally multiple sources of water to draw from, as the low pressure injection pumps, containment spray system, and refueling pumps are all potentially available, and all draw water from different sources. The disaster at Three Mile Island was classified as a partial meltdown, caused by the failure to supply coolant to the core. Although the core was completely destroyed, the radioactive mass never penetrated the steel outlining the containment structure. Several feet of special concrete, a standard precaution, was capable of preventing leakage for several hours, giving operators enough time to fix the flooding system of the reactor core. The worst case of a nuclear disaster was in 1986 at the Chernobyl facility in the Ukraine. A fire ripped apart the casing of the core, releasing radioactive isotopes into the atmosphere. Thirty-one people died as an immediate result. And estimated 15,000 more died in the surrounding area after exposure to the radiation. Three Mile Island and Chernobyl are just examples of the serious problems that meltdowns can create.
Radiation doses of about 200 rems cause radiation sickness, but only if this large amount of radiation is received all at once. The average person receives about 200 millirems a year from everyday objects and outer space. This is referred to as background radiation. If all our power came from nuclear plants we would receive an extra 2/10 of a millirem a year. The three major effects of radiation(cancer, radiation sickness and genetic mutation) are nearly untraceable at levels below about 50 rems. In a study of 100,000 survivors of the atomic bombs dropped on Hiroshima and Nagasaki, there have been 400 more cancer deaths than normal, and there is not an above average rate of genetic disease in their children. During the accident at Three Mile Island in America, people living within a 50 mile radius only received an extra 3/10 of one percent of their average annual radiation. This was because of the containment structures, the majority of which were not breached. The containment building and primary pressure vessel remained undamaged, fulfilling their function.
6. Waste Disposal
The byproducts of the fissioning of Uranium-235 remain radioactive for thousands of years, requiring safe disposal away from populated areas until they lose their significant radiation values. Many underground sites have been constructed, only to be filled within months. Storage facilities are not sufficient to store the world's nuclear waste, which limits the amount of nuclear fuel that can be used per year. Transportation of the waste is risky because many unknown variables affect the containment vessels and the potential for compromised vessels, the results of which would be lethal. Instead, the highly radioactive depleted fuel assemblies are initially stored in pools resembling large swimming pools specially designed to cool the fuel and act as a radiation shield. An increasing number of reactor operators now store their depleted fuel assemblies in dry storage facilities using outdoor-rated concrete or steel containers with air cooling systems. The United States Department of Energy's long range plan is for permanent storage of depleted fuel assemblies beneath the earth's surface in a geologic repository, at Yucca Mountain, Nevada.
Yucca Mountain: site of the nation's first long-term geological repository for nuclear waste.