Nuclear energy has often been proposed as the ideal alternative to fossil fuels. It does not produce harmful air pollutants or greenhouse gases, and many energy security issues (described in the next section) would be resolved with the introduction of more nuclear power sources. However, despite the positive attributes of the technology, there are other environmental and health issues associated with nuclear energy. This section examines these issues, which include the harmful effects of radiation, the dangers of a nuclear power plant explosion, and the problems that arise with disposal of nuclear waste.
Radioactivity and radiation are words that many people have heard before but have little understanding of their meaning. Chapter 1 describes how a nuclear reaction is able to take place because of the radioactive properties of certain elements like uranium and plutonium. These elements spontaneously emit energy in the form of particles, or rays. In other words, the reaction happens without any stimulus. Although the term radiation is used to describe all types of energy (e.g., light energy or microwave energy), it is ionizing radiation that is of concern with nuclear fuel and weapons. Radiation emitted from radioactive elements can be dangerous for humans if they are exposed to high levels of radiation. Such exposure is known to drastically increase a person's risk for developing cancer. Some types of radiation also have adverse effects on human and animal cells. They cause mutations to occur in the structure of DNA (deoxyribonucleic acid, the basic building block of all life), which may result in genetic effects that can be passed on to future generations. If humans are exposed to extremely high levels of radiation, they may develop radiation sickness. This illness results in the loss of function from major bodily organs. If too many cells in an organ are exposed to too much radiation at one period of time, the organ will die. It is important to note that a person's risk of being exposed to this much ionizing radiation in their lifetime is extremely low. These effects are mentioned here so that the reader understands why high levels of radiation exposure are dangerous and why there are public concerns over radiation levels in the environment.
Accidents at nuclear power plants are an extreme illustration of the problem with nuclear power generation. Accidents are dangerous because they could release high levels of radiation into the environment. Because of their severity, the development of nuclear power has been discouraged in many countries, including the United States. The most common way that a nuclear accident occurs is from overheating problems. If the coolant through a nuclear reactor is not operating properly, then the reactor will overheat. When this happens, the reactor can potentially be damaged, resulting in a number of possible catastrophic events, including explosions that could release large amounts of radioactive material to the environment. The impacts from a nuclear meltdown are widespread. (A meltdown occurs when the core of a nuclear reactor overheats and melts.) If radiation from such an accident becomes airborne, not only will a large number of people be exposed to toxic levels of radiation, but it will contaminate crops and livestock, creating a public health crisis impacting entire populations.
There are only a few instances of nuclear meltdowns in global history. A significant scare occurred in March 1979 at Three Mile Island in Pennsylvania. A faulty valve resulted in a loss of coolant to a reactor. The coolant loss was not discovered for several hours. By the time the malfunction in the reactor was discovered, the core of the reactor had reached 5,000 degrees Fahrenheit and the top of the reactor had melted (Rothman 1998, 146). Plant operators flooded the reactor with water, which immediately turned to steam and destroyed the remainder of the reactor. Radioactive steam was released into the atmosphere, but most of the radioactive material was contained within the reactor. While nobody was killed in the accident, the incident fueled public fear of nuclear power. It was not until 1993 that cleanup crews finished evaporating the radioactive coolant and the reactor was sealed (Manahan 2000, 575).
A far worse accident occurred in 1986 at Chernobyl in the Russian Ukraine when a nuclear reactor exploded, releasing a plume of radioactivity all over Europe. The explosion, caused by excessive heat and pressure that had built up in the reactor, created a large fire that threatened other reactors at the plant. Emergency workers who rushed to the accident to put out the fire were exposed to deadly levels of radiation. Thirty-one people died as a result of the accident (Cohen 1990, 111). The indirect damage to human health was never quantified, but radiation spread throughout Europe, contaminating crops in regions as far north as Scandinavia (Manahan 2000, 576).
In addition to the threats to public health that can occur from a reactor meltdown, radioactive waste produced from nuclear fuel reactions poses a problem for waste managers. Because spent fuel rods can release lethal amounts of radiation for an extremely long period of time, the waste from these operations needs to be stored in a safe enclosure. Waste that is produced from nuclear reactors can be handled in two ways. It can be sent to a reprocessing plant where fuel can be recycled, or it can be sealed in solid containers, usually made of glass, and stored in underground vaults (Cohen 1990, 177). A number of issues need to be considered in choosing the process for radioactive waste management, including transportation concerns and location of waste repositories. Since waste is often stored underground, the latter concern involves selecting sites that are geologically sound and where there will be minimal risk of groundwater contamination. Controversy over one such site in the United States, Yucca Mountain, is discussed in chapter 3.
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