Nuclear fission produces low-carbon electricity, with significant contributions from power plants and ongoing advancements in safety and sustainability.
The McGuire Nuclear Station
By Joshua Peters
Nuclear energy is produced from the nucleus of atoms, consisting of protons and neutrons. This energy can be released in two ways: fission, where the nucleus of an atom splits, or fusion, where nuclei merge. Nuclear power plants produce electricity with very low greenhouse gas emissions, making them a key component in efforts to reduce carbon footprints and combat climate change. Nuclear power is a low-carbon energy source because, unlike coal, oil, or gas power plants, nuclear plants do not produce CO2 during operation. Nuclear reactors generate nearly one-third of the world’s carbon-free electricity.
Nuclear Fission
Currently, the global production of electricity from nuclear energy is done through fission, while fusion technology is still in the research and development stage. Nuclear fission occurs when the nucleus of an atom splits into two or more smaller nuclei, releasing energy. For example, when a neutron strikes a uranium-235 nucleus, it splits into smaller nuclei, such as barium and krypton, along with two or three neutrons. These neutrons then strike other uranium-235 atoms, causing them to split and release more neutrons, creating a chain reaction almost instantly. Each fission reaction releases energy as heat and radiation. This heat can be converted into electricity in a nuclear power plant, similar to how fossil fuels like coal, gas, and oil are used to generate electricity. Nuclear power plants use reactors to control chain reactions, typically fueled by uranium-235, to generate heat through fission. This heat warms the reactor’s cooling agent, usually water, to produce steam. The steam spins turbines, which activate an electric generator to produce low-carbon electricity.
In North Carolina, the state is home to three significant nuclear power plants contributing to its energy infrastructure. The Brunswick Nuclear Plant, located near Southport, has two reactors, which have been operational since 1975 and 1977. The McGuire Nuclear Station, situated near Huntersville, also consists of two reactors, operational since 1981 and 1984. The Shearon Harris Nuclear Plant, located near New Hill, has one reactor that has been operational since 1987. Additionally, the Catawba Nuclear Station, although located near York, South Carolina, serves customers in both North and South Carolina, including Mecklenburg County. This station, near the North Carolina border, has two reactors, which have been operational since 1985 and 1986. In 2023, approximately 32.9% of the state's electricity was generated from nuclear power.
The nuclear plants in North Carolina are regulated by the U.S. Nuclear Regulatory Commission (NRC). These plants have met all safety standards and operated safely according to recent NRC inspections.
Uranium, a metal found in rocks worldwide, has several isotopes, with uranium-238 and uranium-235 being the most significant. While uranium-238 is more abundant, it cannot sustain a fission chain reaction. Uranium-235, though less than 1% of the world's uranium, can be used to produce energy through fission. To make uranium more effective for fission, the proportion of uranium-235 is increased through a process called enrichment. Once enriched, uranium can be used as nuclear fuel in power plants for three to five years. After this period, it remains radioactive and must be disposed of following strict safety guidelines. Spent fuel can also be recycled into new fuel for specific nuclear power plants.
North Carolina does not have significant deposits of uranium minerals. There are no known large-scale deposits of pitchblende and carnotite, the principal ores of uranium, in the state. However, there are some areas with minor occurrences of uranium. For example, a preliminary geological investigation suggested that the Triassic sedimentary rocks of the Sanford basin and the Colon cross structure in North Carolina could potentially host uranium deposits. The most favorable sites for further investigation were identified near the contacts between various formations and faults in the region.
Nuclear Cycle
The nuclear fuel cycle is the series of industrial processes to produce electricity from uranium in nuclear power reactors. It starts with uranium mining and ends with the disposal of nuclear waste. Nuclear power plants produce waste with varying levels of radioactivity, managed differently based on their radioactivity levels and purposes. For more information on this topic, see the animation below. Radioactive waste, a small portion of all waste, is a by-product of medical procedures, industrial and agricultural applications using radiation, and nuclear reactors, which generate about 11% of global electricity. This animation explains how radioactive waste is managed to protect people and the environment from radiation now and in the future.
In North Carolina, the management of nuclear waste involves several key processes to ensure safety and compliance with federal regulations. Initially, spent nuclear fuel is stored in large pools of water located at each of the nuclear power plant sites. This method cools the fuel and provides radiation shielding. Typically, the spent fuel remains in these pools for at least five years to reduce its radioactivity levels. After sufficient cooling in wet storage, the spent fuel is moved to dry storage casks. These casks are made of steel or concrete and are designed to safely contain the fuel. Dry storage is considered a safer long-term storage method compared to wet storage.
The Nuclear Regulatory Commission (NRC) oversees the safety and regulation of spent nuclear fuel storage, ensuring that all safety standards are met and that the storage facilities are properly maintained and monitored. Additionally, North Carolina is a member of the Southeast Compact Commission for Low-Level Radioactive Waste Management. This commission manages low-level radioactive waste (LLRW) by facilitating the disposal of such waste generated within the member states, helping in the efficient use of resources and protection of public health and the environment.
Ongoing monitoring of stored nuclear waste is critical, and future costs for disposal and long-term monitoring of waste, such as carbon-14, are also considered. These activities are necessary to manage the waste effectively and mitigate any potential risks to public health and safety. However, there are concerns about the safety of wet storage, especially if the pools are overfilled beyond their design capacity. Watchdog groups have raised issues regarding the transportation and storage of radioactive waste, emphasizing the need for stringent safety measures and better emergency preparedness. North Carolina's approach to nuclear waste management involves a combination of wet and dry storage, strict regulatory oversight, and regional collaboration through the Southeast Compact Commission, ensuring that the waste is handled safely and efficiently, minimizing risks to the public and the environment.
Next Generation of Nuclear Systems
North Carolina State University (NCSU) is at the forefront of research and development in Generation IV (Gen-4) nuclear systems, which represent the next wave of advanced nuclear technology. These Gen-4 systems are designed to be safer, more efficient, and more sustainable compared to current nuclear reactors. NCSU boasts state-of-the-art research facilities, including the Nuclear Reactor Program, which operates the PULSTAR Reactor. This research reactor is a critical tool for conducting experiments and testing new technologies relevant to Gen-4 systems. The PULSTAR Reactor's capabilities allow researchers to explore innovative reactor designs and materials under controlled conditions.
The university promotes interdisciplinary collaboration through initiatives like the Consortium for Advanced Simulation of Light Water Reactors (CASL). By bringing together experts in nuclear engineering, materials science, and computational modeling, NCSU is able to address complex challenges associated with Gen-4 systems, such as fuel performance and reactor safety. NCSU researchers are working on advanced safety features and efficiency improvements for Gen-4 reactors, including the development of passive safety systems that can operate without human intervention or electrical power, significantly reducing the risk of accidents. Additionally, NCSU is exploring new fuel cycles and materials that can enhance reactor performance and reduce waste.
A key focus of Gen-4 research at NC State is the sustainability of nuclear energy. Researchers are investigating closed fuel cycles that can recycle spent nuclear fuel, reducing the amount of long-lived radioactive waste. This not only addresses environmental concerns but also makes nuclear energy more sustainable in the long term. NC State actively collaborates with industry partners and secures grants from organizations such as the Department of Energy (DOE) to fund its research. These partnerships provide valuable resources and real-world applications for the university's research, accelerating the development and deployment of Gen-4 technologies.
NCSU is committed to educating the next generation of nuclear engineers and scientists. The university offers comprehensive programs that prepare students for careers in the nuclear industry, with a strong emphasis on Gen-4 technologies. This ensures a steady pipeline of skilled professionals who can continue advancing nuclear technology. Additionally, NCSU is involved in the conceptualization and testing of innovative Gen-4 reactor designs, such as molten salt reactors and high-temperature gas-cooled reactors. These designs promise greater efficiency, improved safety margins, and the ability to utilize a broader range of fuel types, including thorium.