Nuclear power is clean, efficient, and cheap. It works by splitting uranium atoms to create heat. The resultant steam turns generators to create electricity. But there are disadvantages. If something goes wrong, it can create a nuclear meltdown. The resultant radioactivity is catastrophic. The spent fuel is also radioactive, making it difficult to discard.
As a result, only 4.4% of the world's energy is produced by nuclear power. But for many countries, nuclear power's benefits outweigh its risks.
- The United States ranks highest in production of nuclear energy.
- Nuclear power plants don’t emit greenhouse gases and are not easily destroyed by natural calamities. These generate many jobs and have low operating costs.
- Accidents can be catastrophic and waste disposal is costly.
Top 10 Nuclear Producers
The United States is the world's largest producer of nuclear power. In 2017, it generated 805 billion kilowatt-hours of electricity. That's 32% of the 2.5 trillion kWh of nuclear power produced worldwide. The United States’ leadership came from its historic role as a pioneer of nuclear power development. The first commercial pressurized water reactor, Yankee Rowe, started up in 1960 and operated until 1992.
In 2017, the top 10 producers were:
|Country||Billion kWh produced|
How Nuclear Power Works
All power plants heat water to produce steam, which turns a generator to create electricity. In nuclear power stations, that steam is made by the heat generated from nuclear fission. It’s when an atom is split, releasing enormous amounts of energy in the form of heat.
Uranium 235 is used as fuel because it breaks apart easily when it collides with a neutron. Once that happens, the neutrons from the uranium itself start colliding with its other atoms. This starts a chain reaction. That's why nuclear bombs are so powerful.
In a nuclear generator, special rods that absorb excess neutrons control the chain reaction.
These control rods are placed next to the fuel rods, which contain uranium fuel pellets. Over 200 of these rods are grouped into what is known as a fuel assembly. When the engineers want to slow down the process, they lower more control rods into the assembly. When they want more heat, they raise the rods.
The United States has two types of nuclear power plants. There are 65 pressurized water reactors and 34 boiling water reactors. They differ in how the heat is transferred from the reactor to the generator.
- Pressurized water reactors use high pressure to keep the water in the reactor from boiling. This allows it to heat to super-high levels. The heat is then transferred through pipes to a separate container of water in the generator. It creates the steam that drives the electricity turbine. The water from the reactor then returns to be reheated. The steam from the turbine is cooled in a condenser. The resulting water is sent back to the steam generator. Here's an animated version of a pressurized water reactor.
- Boiling water reactors, on the other hand, use boiling water directly to create the steam to drive the generator. Here's an animated version of the boiling water reactor.
What is most important is that the entire process takes place in a contained environment in order to protect the outside world from any contamination. The power plants can be cooled down and even stopped quickly.
Don't emit greenhouse gases
Resilient during extreme weather
Low operating costs
Accidents could emit radioactive materials
No good solution to disposal of nuclear waste
Not a renewable fuel source
Nuclear power plants don't emit any greenhouse gases, unlike coal and natural gas. As a result, they don't contribute to climate change. This benefit is becoming more attractive as the world seeks to reduce global warming.
Nuclear power plants are also more resilient than other forms of energy production during natural disasters. For example, hurricanes can destroy solar and wind farms. They are less likely to damage the reinforced buildings that house nuclear plants.
Nuclear plants create more jobs than other forms of energy. They create 0.5 jobs for every megawatt hour of electricity produced. This is in comparison to 0.19 jobs in coal, 0.05 jobs in gas-fired plants, and 0.05 in wind power. The only other power source that creates more jobs/mWh is solar photovoltaic. This source generates 1.06 jobs/mWh.
For decades, nuclear power generation had the cheapest operating costs.
According to the 2008 figures, the cost ran at 1.87 cents per kilowatt hour(kWh). This was only 68% of the cost of coal. Until recently, it was just 25% of the cost of natural gas.
But fears about global warming inhibited new construction of coal-fired power plants. As a result, new gas-fired power plants were built from 1992 to 2005. These supplied about 270,000 megawatts of energy. At the time, those plants seemed to have the lowest investment risk. As a result, only 14,000 MWe of new nuclear and coal-fired capacity came online. It helped drive up natural gas prices. This forced large industrial users offshore and pushed gas-fired electricity costs toward 10 cents/kWh, according to the Nuclear Energy Institute’s report.
Nuclear fuel is efficient. About 28 grams of uranium release as much energy as 100 metric tons of coal. As a result, transportation is less expensive.
Because of the radioactive nature of its fuel source, nuclear power has two huge disadvantages. They are the possibility of accidents and the disposal of nuclear waste.
An accident at the plant could release radioactive material into the environment as a plume or cloud-like formation of radioactive gases and particles. These particles may be inhaled or ingested by people and animals or deposited on the ground. The particles are composed of unstable atoms that give off excess energy, called radiation, until they become stable. In low doses, radiation is harmless. After a nuclear meltdown though, the large doses destroy living cells and cause mutations, illness, and death.
Although the chances of a nuclear meltdown are rare, the potential impact can be catastrophic.
The only U.S. nuclear disaster was at Three Mile Island in 1979 when the radioactive fuel rods partially melted. Only a small amount of radioactive gas was released. There were no measurable health effects. Still, no new nuclear power plants were built for 30 years.
Almost 3 million Americans live within 10 miles of an operating plant. They risk direct radiation exposure in case of an accident. If you are one of those people, the Department of Homeland Security tells you how to prepare for such an accident.
Disposal of nuclear waste is a huge disadvantage. Low-level waste comes from contact with the nuclear fuel in day-to-day operations. It is disposed of on-site or it is sent to a low-level waste facility in one of 37 states.
High-level waste consists of spent fuel. It takes hundreds of thousands of years to deactivate. There are 80 sites around the country where this waste is stored. Most of the sites are near current or former nuclear reactors. Many are located near rivers, lakes, and oceans.
In the Nuclear Waste Policy Act of 1982, Congress told the U.S. Nuclear Regulatory Commission to design, construct, and operate a permanent geologic repository for the disposal of high-level waste in Yucca Mountain, Nevada. It would cost $100 billion. It would require 300 miles of railroad tracks, and titanium shields to keep the waste intact.
Local officials don't want the hazard of nuclear wastes in their state.
They delayed its development until 2013 when the NRC won its case in the U.S. Court of Appeals. In 2015, the NRC completed a safety assessment. In 2016, it completed an Environmental Impact Statement.
Nuclear power is not a renewable resource. There are 80 years worth of fuel in known reserves if used at current rates.
U.S. Nuclear Power Stations
There are 95 operating nuclear reactors in 29 states. Most are located east of the Mississippi River. They generate around $40 billion to $50 billion each in electricity sales. They directly create over 100,000 jobs. Every dollar spent by the average reactor generates $1.87 in the U.S. economy. That created another 375,000 jobs.
U.S. nuclear power plants generated 849.6 terawatt-hours in 2017. That's 19% of the total 4,460.8 terawatt-hours of total U.S. electricity production in 2017. It was second to coal, which generated 28%, and natural gas at 25%. It's greater than hydroelectricity, which contributed only 6.5%, and other alternative sources including wind power at 20.3%.
There are also 31 test reactors at research universities. They are used to create small amounts of radiation for experiments. This is where scientists study neutrons and other subatomic particles, examine automotive and medical components, and learn how to improve cancer treatment.
The Future of U.S. Nuclear Power
Annual U.S. electricity demand is projected to rise 47% by 2050. With rising oil and gas prices and concern about global warming, nuclear power has started to look attractive again. In the late 1990s, nuclear power was seen as a way to reduce dependency on imported oil and gas. This policy change paved the way for significant growth in nuclear capacity.
The Energy Policy Act of 2005 provided financial incentives for the construction of advanced nuclear power plants. The newest plant began operation in October 2016. Two new reactors are under construction in Georgia.
On the other hand, fracking of domestic shale oil and natural gas has made gas an affordable alternative to modernizing old nuclear power plants. Building new gas-fired plants costs less than keeping old nuclear power plants running. Refurbishing old coal-fired power plants to run on natural gas costs less as well.
It seems the future of expanding nuclear power in America depends on natural gas prices. If they rise again and stay high, expect attention to return to nuclear power generation.