Nuclear Energy - A Smart Energy Alternative

Chernobyl. Three Mile Island. When people think of nuclear energy, these incidents and others often come to mind. In light of recent energy shortages, discussions about alternative power sources have taken on a renewed sense of urgency. Nuclear energy is a viable option that is often brought under consideration, but frequently drowned out by members of a vocal, militant opposition. Proponents of nuclear energy find themselves fighting the ghosts of the past, and while public sentiment towards nuclear power is growing more favorable, the prevailing attitude remains, "Not in my back yard."

A basic diagram of the nuclear energy generation process used in power plants.

In reality, nuclear power is an extremely safe, environmentally friendly form of energy. Accounting for seventeen percent of the world's total electrical production, nuclear power is utilized safely and effectively in many countries, especially throughout Europe. In France, nuclear reactors provide about seventy-five percent of the country's electricity. The United States, housing over one hundred of the world's more than four hundred nuclear plants, uses nuclear power to generate approximately fifteen percent of its total annual energy consumption.

Energy From Nuclear Reactions

Operation of a Nuclear Reactor

Control rods, often composed of boron or cadmium, are interspersed among the uranium rods. These control rods remove free neutrons from the system, and can be raised or lowered to control the rate of nuclear reaction. The control rods, along with the coolant, protect against overheating, and have the ability to stop the reaction if there are any problems.

Coolant is used to protect the uranium rods from adverse effects of the heat released during to nuclear fission. The coolant medium is usually water, but may also be a liquid metal such as sodium. The heat produced from uranium fission is used to produce steam. This steam propels a turbine, which in turn runs a power generator.

After eighteen months of use, uranium rods must be replaced as fission begins to slow. Nuclear power plants have large containers of water in which spent rods can be placed while they lose their radioactivity. Recently, many plant containers have become full, and the problem of long-term storage for radioactive uranium has arisen. The debate of what to do with the nuclear waste is far from being decided. If buried underground, uranium takes millions of years to decay. The United States government currently plans to store radioactive waste at Yucca Mountain, Nevada. Other ideas for long-term waste storage involve sinking sealed containers to the ocean floor, and shooting nuclear waste into the sun.

The large containment structure of a nuclear power plant holds the core reactor, where uranium atoms are split.

Safety: Perception vs. Reality

The most infamous of meltdowns occurred in April of 1986 at Chernobyl, a disaster that killed thirty-one people, made twenty square miles of land uninhabitable, and dispersed radioactive dust particles into the atmosphere. The bitter legacy of Chernobyl continues to this day for the people of the Ukraine and surrounding countries, with confirmed of cases of thyroid cancer, and elevated rates of birth defects.

Due to a design flaw, the Chernobyl reactor was unstable at low power settings. Poorly trained operators disabled crucial safety mechanisms during a low-power reactor test. A power surge caused fuel elements to rupture, leading to a pressure explosion. A second explosion spewed burning fuel fragments, allowing air to enter the core. The moderating medium in the reactor was graphite, which burst into flames in the presence of air, sending radioactive fission products into the atmosphere.

Anti-nuclear activists cite the possibility of another Chernobyl as the most compelling reason to avoid nuclear energy. In reality, a repeat of the Chernobyl disaster in the United States is simply not possible. To begin with, the unstable reactor design at Chernobyl was a product of communist isolationism. Although modern reactors and safety systems existed in the United States and western Europe, Soviet authorities insisted on Soviet technology, even if that technology was vastly inferior. Secondly, the plant operators at Chernobyl were severely undertrained, unprepared to deal with an inherently unstable system.

To perform the low-power testing, the Chernobyl operating crew disabled the reactor automatic shutoff features. Such disregard for safety features is simply impossible for commercial nuclear plants operated in the United States. Finally, the main cause of radioactive emissions at Chernobyl was the graphite moderating medium, which burned for nine days. Such an immense radioactive emission is impossible in the United States, as we have no graphite moderated power reactors.

Cooling Towers are used to remove the heat from the reactor core.

Another well-known nuclear incident occurred at Three Mile Island. While it dealt a staggering blow to the American nuclear industry, the partial meltdown at Three Mile Island was actually a success story for safety controls. The difference between the two incidents was that the plant at Three Mile Island was properly constructed and operated, and adequate safety features allowed the meltdown to be controlled. The presence of standard secondary containment structures made this possible. Under careful supervision, nuclear power plants in the United States all must have adequate safety systems.

Clean and Cost Effective

In addition to being environmentally friendly, nuclear power is cost effective. Plants run at only fifty to eighty percent of the cost of fossil fuel plants producing the same amount of power. Reliability is another important benefit. Nuclear power's capacity factor, the amount of energy it produces in a certain amount of time, is seventy-five percent, and while it is nearly equivalent to fossil fuel, it is significantly higher than wind or solar energy.

Epilogue

Nuclear power truly is one of the world's finest sources of energy. Clean, reliable, and safe, it clearly offers a multitude of advantages. As the world's supply of fossil fuels becomes depleted, nuclear energy is one option that will have to be pursued aggressively. Al Gore said it best, "Nuclear power, designed well, regulated properly, and cared for meticulously, has a place in the world's energy supply." The question now is what place will it hold in the future.


Sources:
http://www.howstuffworks.com/nuclear-power.htm?printable=1
http://library.thinkquest.org/2763/Electricity/Generating/Nuclear.html?tqskip=1
http://pw1.netcom.com/~res95/energy/nuclear.html
http://www.nucleartourist.com/
http://www.world-nuclear.org/info/chernobyl/inf07.htm