Nuclear energy may offer a partial alternative to fossil fuels. Nuclear power generates no GHGs, but adequate measures to dispose of nuclear waste have yet to be developed, and the long lead time required to construct a nuclear power plant precludes using nuclear energy as a global replacement for GHG-emitting energy sources in the short term.

Since the 1950's, countries such as the United States, the Soviet Union (now Russia), and France have relied on nuclear power as an energy source. Electric power is generated in nuclear power plants by fission reactors that heat water to turn turbines. Nuclear fission produces no greenhouse gases (GHGs). Mining uranium to power the reactors causes some environmental degradation, but the most significant drawbacks of nuclear energy are the high cost of reactor construction, the long lag time required to build reactors, and the difficulty of safely disposing of the nuclear waste generated by the reactors.

When several countries began to build nuclear reactors to generate electric power in the 1950's, nuclear energy was haled as the energy of the future. Uranium was and still is in plentiful supply, and supporters of nuclear power indicated it would provide inexhaustible electric power in the future.

A few countries, most notably France, engaged in extensive reactor construction, and approximately 80 percent of France's electric power now comes from nuclear power. Other countries, such as the United States, initially built several reactors. Support for nuclear power declined in the United States, however. No new power reactors were ordered after 1978. Approximately 20 percent of the electric power produced in the United States in the first decade of the twenty-first century came from nuclear energy.

Worldwide, approximately 16 percent of all electric power is generated by nuclear energy. In the first decade of the twenty-first century, some 440 nuclear power reactors were in operation in thirty countries. Six different types of power reactor were in operation, with research underway to expand this number. The most common reactor was the pressurized water reactor (268 reactors), followed by the boiling water reactor (94 reactors).

In spite of its initial problems, nuclear power may offer some advantages in dealing with climate change generated by burning fossil fuels. The operation of fission reactors does not generate any GHGs. Uranium is in plentiful supply, both from mines throughout the world and as material reprocessed from old nuclear weapons (Caldicott, 2006). Nuclear reactors can be constructed to fit existing needs, with electric power capacities ranging from nearly 2 gigawatts per reactor to much smaller capacities to serve small communities.

Once in operation, a power reactor may be expected to operate for forty to sixty years. Although challenging, it may be possible to generate as much as 1 terawatt of electric power per year with nuclear energy by 2050. If this goal is accomplished, it will be possible to achieve a substantial reduction in carbon emissions by mid-century. The technology to build nuclear reactors already exists and does not have to be invented; new advances, however, can lead to increased reactor efficiency. The construction of nuclear power reactors is a feasible alternative to fossil fuel power plants.

One criticism that has sometimes been levied against nuclear power is that it is not safe. Some critics indicate that reactors may leak radioactive matter. Power reactors in Western countries such as the United States, the United Kingdom, and France have had minimal leakages with no health risks. Other critics indicate that power reactors may have major accidents, including core meltdowns, pointing to accidents at the Three Mile Island Nuclear Power Plant in the United States in 1979 and the Soviet reactor at Chernobyl in 1986. The Three Mile Island accident led to a radiation leak of less than 50 curies of radiation, and no health issues have been traced to this incident. The Chernobyl accident was far more severe, with a release of 100 million curies of radiation, numerous deaths, and continuing health problems resulting from the accident, as well as lingering health problems in the region. Western countries do not use reactors of the Soviet design, which had limited containment around the reactors. The safety claims regarding most Western power reactors are generally overstated. In many ways, nuclear power produces fewer health problems than do coal-fired power plants.

All existing nuclear power reactors are fission reactors (Caldicott, 2006). The potential exists, however, eventually to construct fusion reactors. Such reactors would produce much less radioactive waste and operate more efficiently than fission reactors. Although advocates over the last thirty years have repeatedly indicated that fusion would become the energy source of the future, the technology remains relegated to the laboratory for the near term. No means of sustaining the temperatures required for fusion (about 100 millionœ Celsius) has yet been found. In addition, questions involving the high costs of construction and the production of the tritium gas necessary for a fusion reaction must be addressed.

Several environmentalists and other advocates of nuclear energy argue that the United States and other Western countries should reconsider its use. They point to the negative impacts of coal and oil plants, such as acid rain and GHG emissions. In addition, some economists predict that oil will become increasingly expensive, making nuclear energy more cost-effective.

Most of the twentieth century problems with nuclear energy remain, and some new issues have been raised as well. As fears of terrorism and so-called suitcase devices have increased, the need to control even relatively small amounts of nuclear material has become more urgent, and even well-protected nuclear power plants pose security risks. Although terrorists might prefer more high profile targets than reactors and upgrading nuclear fuel is difficult, the security threat may sway public opinion against expanding nuclear energy.

Moreover, there are no ideal methods of nuclear waste disposal. Wastes with low levels of radioactivity are currently being stored underground in the United States and elsewhere. The greatest source of concern is high-level radioactive waste, such as spent fuel rods, piping, and the like. France has long followed a policy of reprocessing and reusing spent fuel rods. This is an attractive solution, but the process produces weapons-grade plutonium as a by-product. The United States and most other countries have not adopted this practice, in part out of fear that some plutonium might fall into the wrong hands.

The United States and most other countries that use nuclear energy have not solved the problem of spent nuclear fuel as yet. The United States is developing an underground storage facility at Yucca Mountain in Nevada, but it is controversial and is unlikely to be operational until 2015 at best. Until the Yucca Mountain site becomes operational, American nuclear power facilities are storing spent fuel on site. This approach is also being followed by most of the other countries that operate nuclear power reactors. The Russian Federation stores spent fuel on site but also engages in a limited amount of reprocessing at Chelyabinsk-65, and another facility at Krasnoyarsk is scheduled to start operation in 2015. The former Soviet government also engaged in extensive injection into the ground of a good deal of its lower-level waste such as cesium 137 and strontium 90. This injection occurred at three Soviet sites, producing several environmental problems.

Nuclear waste storage on site remains an option for nuclear power facilities, but the waste issue will need to be resolved if extensive use is to be made of nuclear energy in the future. The French and possibly the Russians seem to be comfortable with reprocessing. France and the United Kingdom are engaged in a joint project to develop a means to recycle spent nuclear fuel without producing weapons- grade plutonium. Most other countries are trying to develop underground sites, as Finland is doing at Olkiluoto, or shipping their nuclear waste to countries such as the United States for storage. Because of the long period of radioactive decay of some of this waste (several million years in some cases), developing safe, permanent storage facilities remains a challenging issue.

Nuclear energy may provide some help in mitigating global warming, but its impact is unlikely to be felt in the short run. In the United States, for example, the time required to obtain a permit to build a power reactor had increased to three and one-half years by the time the last reactor was permitted in 1978 (Caldicott, 2006). Once a permit was issued, construction required around ten additional years. Although reactors have been constructed in other countries such as France or Russia in much shorter periods of time, they are complex facilities that cannot be constructed in short order. In some nations--such as Germany or the Scandinavian countries, where power reactors have been shut down--the largely antinuclear public will have to be convinced to allow new nuclear facilities to be constructed before any such project can be considered.

A large-scale expansion of nuclear energy is not likely until the 2020's, if then. In the United States, sixteen utilities had announced plans for potential reactor construction by 2007, but it would be several years before any of these facilities could go online. Elsewhere, the situation was much the same.

Nuclear energy has much to offer as an alternative to fossil fuels. Utilization of nuclear energy can help to provide a middle-term solution to the need for clean energy until ways can be found to enable cleaner, renewable sources such as solar energy to satisfy humanity's energy needs. In addition to environmental factors, the increasing cost of oil will help make nuclear energy more attractive. Fears of terrorism, radiation leaks, and the difficulties surrounding nuclear waste disposal are obstacles to a resurgence of nuclear energy. The length of time required to build an operational reactor negates any advantages of nuclear energy as a short-term solution to energy-related GHG emissions. Public opinion appears to be becoming more favorably inclined toward nuclear energy, but a good deal of opposition remains. As with many issues concerning global warming, the longer the wait before construction of power reactors begins, the more costly the process will be, and the less help the reactors will provide in combating the increasing emission of GHGs.

Reference

Caldicott, Helen. Nuclear Power Is Not the Answer. New York: New Press, 2006.

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