By CHARLES CHAVES/ecoRI News contributor
Renewable energy and nuclear power increasingly factor into the evolving American energy equation to replace polluting coal. Even some environmentalists acknowledge that nuclear is a viable emissions-free option to dirty coal while renewable-energy technologies continue to advance.
Nuclear fission reactors generate electrical power by splitting the atomic nuclei of uranium. This process creates a massive amount of heat — thermal energy — and radiation. The resultant heat is in turn utilized to make steam from water that then moves turbine blades to drive generators to produce electricity.
The steam is continually recycled back into usable water, as conservation is becoming an increasingly imperative concern at power plants and other businesses. In other words, decreasing power plant water consumption and wastewater discharge are important environmental issues.
Instead of burning some material, nuclear power plants split uranium nuclei, as noted, without producing any air pollution in the process. In short, the heat that the fission of atoms produces is the reactor’s only fuel. In contrast, coal- and oil-burning power plants have been releasing air pollution for decades. Mercury, for example, harms the nervous system and the kidneys; particulates cause bronchitis and lung cancer; vanadium damages our respiratory system; and nickel causes convulsions.
Coal-burning power plants moreover emit arsenic, cyanide and dioxin that can severely impair the lungs and the human heart. Coal quite notably contains sulfur. Its combustion consequently generates sulfur dioxide that mixes with water in the air to make sulfuric acid, which is the main culprit of acid rain.
There are 104 nuclear reactors operating at 65 sites in 31 states, providing about 20 percent of the total U.S. electrical output, according to the Nuclear Energy Agency (NEA), and 70 percent of it is emissions-free energy. On average, one nuclear plant produces the energy equivalent of 20 square miles of solar panels. That’s because no renewable-energy source is as efficient as nuclear power.
Nuclear reactors don’t spew any emissions that contribute to global warming, acid rain or smog. Advocates of nuclear energy consequently argue that nuclear power must be part of the U.S. energy mix to reduce air pollution and greenhouse gases. They also emphasize that nuclear plants are at present safer and note that no further accidents have occurred since the 1979 Three Mile Island one in Pennsylvania.
The March 2011 earthquake and tsunami in Japan and the ensuing accident at the Fukushima Daiichi nuclear power station raised legitimate questions about the ability of U.S. nuclear plant facilities to withstand natural disasters. Nevertheless, supporters of such energy stress that the industry is conducting thorough inspections of seismic and flooding readiness at every U.S. nuclear power facility. Opponents, however, note that some emissions are released during the mining and uranium enrichment stages of preparation.
In addition, nuclear power production generates highly radioactive byproducts such as spent fuel rods. Critics of nuclear plants also highlight that there is still no national program to store such dangerous radioactive waste material and, as a result, each nuclear plant handles its own byproducts. Nevada’s Yucca Mountain site has long been proposed as a final resting place or repository for radioactive nuclear waste, but it hasn’t secured official approval partly due to shipping concerns and political resistance in Nevada.
Some in the industry argue that pebble-bed technology could some day become one of the main models for safer and less expensive nuclear reactors. Because of its intrinsic safer design, a pebble-fuel nuclear reactor wouldn’t melt or overheat, according to researchers.
This type of reactor was first developed in Germany in 1960. It’s currently under development at MIT, University of California at Berkeley and Idaho National Laboratory, among others.
Demand for electricity in the United States is expected to increase 40 percent by 2030, according to the U.S. Department of Energy. Nuclear power currently provides about 20 percent. In this context, it wouldn’t be wise to decommission or phase out U.S. nuclear reactors at this time — as some opponents have suggested.
This scenario would probably lead to increased utilization of coal-fired power plants, which generate roughly 50 percent of all U.S. electricity. This potential replacement of power sources would result in higher emissions that contribute to air pollution, acid rain, greenhouse gases and smog, in addition to more health problems and their consequential costs.
Renewable-energy sources such as solar, wind, geothermal, waves, tides and hydrogen, among others, can generate large amounts of clean electricity. Not being mainstreamed, however, such resources are not yet producing enough electrical power to the point of being capable of substituting nuclear power.
Granted, nuclear energy is not a holistic power generation solution, but nonetheless it is pragmatic to continue to use nuclear electricity as a transitional, carbon-free energy bridge to a cleaner and more sustainable future. Moreover, nuclear electricity could be a viable option to power electric vehicles, thereby reducing air pollution and greenhouse-gas emissions in the process.
Nuclear electricity also could be employed for electrolysis of seawater into hydrogen gas for future fuel-cell powered vehicles.
Nonetheless, the United States still needs an environmentally responsible national policy to grapple with radioactive nuclear waste issues. Specifically, it’s imperative to find a long-term solution to deal with nuclear waste, which presently is stored in steel and concrete cylinders near reactor plants.