As the world looks to shift away from fossil fuels, nuclear energy is a popular option. However, as nuclear energy is under scrutiny, having been called a safety risk, there are a lot of factors to understand about this energy source. Firstly, nuclear energy is not a renewable energy, but a nonrenewable alternative to fossil fuels in generating energy around the world. Nuclear energy is not a specific geological formation like its energy counterparts, but rather it is a reaction that creates fuel. It is generally originated from uranium, which is an element formed deep within the ground, similar to natural gas, coal, and oil.
Nuclear energy is the splitting of uranium atoms. This process is known as fission, which produces steam that, in turn, forms electricity through a turbine generator. In the United States, 98 industrial reactors account for 30 percent of global nuclear generation in 2018.
Uranium is the most used product in nuclear plants for fission. However, plutonium and other elements with an atomic number of greater than 94. (Plutonium has an atomic number of 94, uranium has an atomic number of 92). U-235 is a specific type of uranium with atoms that are easier to split; this is most common in nuclear power plants.
Despite having no emissions and being commonly found around the world, uranium is not considered a renewable energy resource. However, U-234 is rare. Uranium ore is mined, and then U-235 is extracted and sent to processing.
Nuclear Up Until the Manhattan Project
In December 1942, a professor at the University of Chicago named Dr. Enrico Fermi conducted the first controlled nuclear chain reaction under the bleachers of the football stadium. It was part of a World War II atomic bomb program, which led to the construction of the first commercial nuclear power plant in Shippingport, Pennsylvania.
Eight years prior, Fermi had begun his experimentation in Rome. He found that neutrons are able to split atoms of many different kinds. Fermi also found through his experiments with neutrons that some targets produced heavier elements, while others (such as uranium) produced lighter elements. This was at the cusp of discovering fission, as in 1938, German scientists Otto Hahn and Fritz Strassman showed that the lighter elements were about half the mass of the original uranium. This was the first demonstration of atomic fission. In Denmark, Lise Meitner and her nephew Otto Frisch were able to break down how and why that had happened: the nucleus of the element’s atoms captured neutrons, which causes strong vibrations that split the nucleus (not equally).
Between Fermi, Hahn and Strassman, as well as Meitner and Frisch, proved the concept of a self-sustaining chain reaction based on Albert Einstein’s theory that lost mass is transformed into energy.
December 2, 1942, the day of Fermi’s experiment, was the beginning of the nuclear age.
In June, any and all federal programs on nuclear energy were taken over by the United States Army, which closed doors to international swapping of research material. About a year later, under an effort charged by Winston Churchill, it was discovered that the army’s program would cost millions of dollars — “all for a bomb as no work was being done on other applications of nuclear energy,” reported the World Nuclear Association. These are the early days of the Manhattan Project.
The first atomic device was tested in Alamagordo, New Mexico in 1945. It was made from plutonium. One month later, in August 1945, two atomic bombs were dropped in Japan within days of each other.
The Nuclear Age
The United States began using commercial nuclear power plants in 1960 for electrical generation. Westinghouse designed the Yankee Rowe pressurized water reactor, a commercial plant able to produce 250 megawatts. Yankee Rowe operated until 1992. Also in 1962, Argonne National Laboratory in Illinois developed the boiling water reactor, which was put into a prototype, which was from 1957 to 1963,
It has since had ebbs and flows leading up to its current status as a power source in the country. In 2018, there were 98 nuclear reactors in 60 power plants in 30 states. But this is not the most the country has had online. In 2003, the U.S. was operating 104 nuclear reactors. However, due to technological advancements, the current fleet is able to generate the same capacity as the 2003 reactors.
Down to the details
Nuclear energy is a powerful resource. There are about 90 in the United States that account for 20 percent of domestic electricity.
Tiny molecules that make up all gases, liquids, and solids are called atoms. An atom’s core is filled with protons and neutrons surrounded by electrons. There is a high level of energy in the bonds that hold the nucleus together. Nuclear energy is released when these bonds are broken. Nuclear fission is used to break these bonds in order to produce electricity.
Nuclear power plants use nuclear fission to release energy. Though other elements can be split to generate nuclear energy, most use uranium atoms. During the fission process, a neutron is introduced with a uranium atom. The collision splits the atom, releasing heat and radiation — also more uranium atoms, causing the process to repeat itself. This is the nuclear chain reaction. Nuclear power plants are able to control this reaction to produce heat.
The production of electricity from nuclear reactions is often called the nuclear fuel cycle. The progression of nuclear fuel — i.e. the activities in the nuclear cycle — is done in two ways. There are front-end and back-end processes of this fuel cycle. On the front end, the preparation of the fuels begins, whereas steps in the back end ensure the safe management and containment of the fuel. This measure is also where energy can be reprocessed or disposed of. If spent nuclear fuel, i.e. elements that have been used in nuclear reactors but are no longer viable, is not reprocessed it is then called an open fuel cycle. If spent fuel is reprocessed, this is called a closed fuel cycle. The nuclear fuel cycle begins at the uranium mines and ends with nuclear waste.
The front end of the nuclear cycle is where uranium is prepped for the nuclear reactor. These steps are mining for triuranium octoxide, which is converted into uranium. It undergoes enrichment and fuel fabrication before entering the reactor. The reactor, after using the fuel, then sends it to storage. From there, the energy source is either: reprocessed for reconversion; reprocessed to become vitrified and then disposed of; or stored and immediately disposed of underground.
The back end of the nuclear cycle is the interim storage and final disposal of the product. Once through the reactor, the fuel bundle ( the rods containing fissionable material that fuel nuclear reactors) must be taken from the reactor and stored underwater in a spent fuel pool. Spent fuel is hot as radioactive materials decay, which is generally remnant elements from fission. The pool cools the fuel, but it also blocks the release of radiation from the fuel.
After a couple of years, spent fuels are removed from the pool and put into a dry cask container at the plant site, or it is stored outside in a special container with air cooling.
Between 1968 and 2013, more than 241,460 fuel assemblies (bundles) have been discharged and stored within 118 nuclear reactor sites in the United States.
Plants Around the U.S.
Most of the 30 commercial nuclear reactors locations in the United States are east of the Mississippi River. Illinois has almost half of the total count, with 11 reactors across six plants. Illinois is a major nuclear generator. In 2018, the state has the largest net summer electricity generation capacity with about 11,580. (The net summer capacity reflects the maximum output that generating equipment can supply between June 1 and September 30).
However, further south, Mississippi is home to the largest nuclear reactor in the United States. The Grand Gulf Nuclear Station in Gibson, Mississippi has an electric generating capacity of 1,400 megawatts. The smallest power generators are at the Prairie Island nuclear plant in Minnesota.
On the other side of the Mississippi River, the Grand Coulee Dam in the state of Washington has the most electricity generation capacity of any electric power plant in the United States. Its total electricity generating capacity is 7,079 megawatts from a single plant. Second to the Grand Coulee Dam is the Palo Verde nuclear plant in Arizona. Its generating capacity is about 3,937 megawatts.
A single reactor does not make up a power plant. In some cases, nuclear power plants also host non-nuclear generating units. Nuclear reactors require attentive maintenance, and often there is a specific set of personnel and equipment for each reactor. About one-third of the nuclear power plants in the U.S. have two reactors minimum. The exceptions have three reactors. These plants are the Palo Verde Nuclear Generating Station in Arizona, Browns Ferry Nuclear Power Plant in Alabama, and Oconee Nuclear Station in South Carolina.
Benefits to Nuclear Energy
The United States has put a strong hand on its research and development of nuclear energy, something that is apparent during the early days of nuclear discovery. Many attribute the United States’ position in nuclear as a safety net in its national security. The Nuclear Energy Institute claims that national security experts recognize nuclear as a way to make the U.S. grid resilient without carbon emissions and support national defense.
America is a leader in the nuclear sector, which has given the country an advantage in setting international rules and standards for using nuclear technologies/materials. This is one way, experts claim, to keep nuclear weapons from the hands of “bad actors” (NEI).
The Nuclear Energy Institute reports that nuclear power is the most reliable source of electricity in the United States. The organization calls it an “emissions-free workhorse” that adds far more value than energy generation.
Nuclear power accounts for more than half of carbon-free electricity in the United States, and it’s gaining more ground. Specifically, in Pennsylvania, five nuclear power plants make up 93 percent of the state’s total carbon-free electricity. Although there has been pushback from environmentalists and other activists, who scorn nuclear as a haphazard ticking-time-bomb, the numbers are pretty revealing. In places that have closed nuclear power plants, emissions have skyrocketed. For example, in Vermont, the Yankee plant closed, which caused a 650,000-metric-ton increase in carbon inputs in just two months.
Cons to Nuclear Energy
Nuclear power is not harmless, especially when it is not controlled by a reactor or its handlers. If an uncontrolled nuclear reaction occurs, there is a serious threat of water and air contamination. However, the risk of this happening is counteracted by diverse and abundant safety systems at nuclear power plants, as well as specialized training for personnel. In addition, many have containment vessels that are able to withstand extreme weather, such as strong storms and hurricanes. Nuclear fuel is radioactive and could turn dangerous quickly. It cannot be dumped in a landfill. Spent nuclear takes hundreds of years to decompose to safe levels for the environment.
Although nuclear energy is inexpensive and efficient once in operation, building new plants is a different story. New construction can take up to a decade (or more) to build for the price of several million dollars.
It is also tied to a skewed perspective. With disasters such as Chernobyl in Russia or Fukushima in Japan, or threats of terror such as nuclear bombs, the public is afraid of this energy source. Uranium, unlike solar and wind power, is mined and synthesized for production. This is an expensive process.
The power of nuclear energy has been showcased around the world; however, in the wrong hands, it could challenge the fate of a country or even the world. As mentioned above, nuclear energy is non-renewable — though its carbon-free processing may confuse some on that fact. Despite uranium’s abundance throughout the world, reserves will eventually run out. Some compare nuclear energy to fossil fuels, claiming nuclear energy is not a sustainable power source.
Energy Information Administration. “Nuclear Explained”
World Nuclear Association. “Nuclear Power in the USA”
World Nuclear Association. “Outline History of Nuclear Energy”
Office of Nuclear Energy, Science and Technology. “The History of Nuclear Energy” U.S. Department of Energy
Renewable Resources Coalition (2016). “Nuclear Energy: Pros & Cons”