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| Fig. 1: Nuclear waste barrels. (Source: Wikimedia Commons) |
Since 1990, nearly 20% of the electricity used in the United States has come from a nuclear power plant. To generate energy, nuclear power plants split atomic nuclei of heavy isotopes such as Uranium-235 (U-235) or Plutonium-239 (Pu-239) to release large amounts of energy in the form of heat, known as a controlled nuclear fission chain reaction. Through these reactions, nuclear power plants are able to heat water, producing steam and powering turbines to harvest energy. Different from other primary energy sources such as coal or oil, nuclear energy does not release greenhouse gasses and therefore is a clean, nearly carbon-neutral energy alternative which can be leveraged to reduce the environmental impact of energy consumption. [1]
Nuclear waste remains a growing concern in the practice of nuclear energy production. Defined as waste produced during the nuclear fuel cycle, nuclear waste is classified into low, intermediate, and high levels. Notably, nuclear waste is hazardous due to its radioactive nature, creating potential risks for human and environmental health. Thus, its management is paramount in ensuring the long-term safety and sustainability of nuclear energy production (see Fig. 1). [2]
Radioactive waste management decisions have economic, environmental, political, and societal stakeholders, often landing the topic at the center of nuclear energy debates. As the world's largest producer of nuclear power, the United States faces a unique responsibility to establish robust policies and regulations governing the management of radioactive waste, balancing the imperative of public safety with the need for continued sustainable energy production. Various legislations oversee the possession, use, disposal, and management of facilities that produce radioactive waste. The Atomic Energy Act of 1954, Nuclear Regulatory Commission (NRC), Department of Energy Organization Act (DOE), and Environmental Protection Agency (EPA) take on this responsibility and ensure comprehensive oversight and regulation of radioactive waste management practices in the United States. [3-5]
Effective nuclear waste management strategies in the United States include containment, storage, and disposal in secure facilities designed to isolate the waste from the environment. Low level waste is stored at an isolation facility called the Waste Isolation Pilot Plant (WIPP), where it sits underground in an ancient salt dome. This facility hosts transuranic radioactive waste and is regulated by a variety of agencies including the EPA to ensure its adherence to waste management standards. 70,000 tons of high level waste was previously disposed of in a deep geological repository at the Yucca Mountain in Nye County, Nevada. The decision to store waste at Yucca Mountain was originally vetoed by Nevadas state governor, yet overridden by Congress in 2002. Seven years later, President Obama terminated this program and its use has remained a topic of discussion since.
It is important to note the harm that spent fuel presents to human and environmental health. It is fatally radioactive for at least 1,000 years, a potential groundwater health hazard for far longer than 1,000 years, and a proliferation danger due to the Plutonium it contains. The DOE mandates that all nuclear waste is exclusively handled by the DOE itself. Yet, it currently does not have a place to store this hazardous waste. Thus, the fundamental physical properties of the waste leaves the use of nuclear energy at a standstill.
2018 data are used for the following calculation. [6,7] The 98 nuclear reactors in the United States produced ~20 tons of spent fuel per year apiece. This created a total of
| 98 reactors × 20 tonnes y-1 reactor-1 | = | 1960 tonnes y-1 |
of spent fuel/year. 7.60 exajoules of nuclear energy was consumed in 2018. The total fuel consumed per eajoule was then
| 1960 tonnes y-1 7.60 EJ y-1 |
= | 258 tonnes EJ-1 |
Alternately, assuming that 5% of the Uranium atoms are fissioned, we have
| 0.05 × | 230 × 106 eV atom-1
× 1.602 × 10-19 J eV-1
× 6.022 × 1023 atoms mole-1 0.238 kg mole-1 |
|
| = | 4.66 × 1012 J kg-1 | |
| 1.0 × 1018 J
EJ-1 4.66 × 1012 J kg-1 × 1000 kg tonne-1 |
= | 215 tonnes EJ-1 |
© Mia Bennett. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] "Nuclear Energy Factsheet," Center for Sustainable Systems, University of Michigan. Pub. No. CSS11-15, July 2023.
[2] S. V. Stefanovsky et al., "Nuclear Waste forms," in Energy, Waste and the Environment: a Geochemical Perspective, ed. by R. Gieré and P. Stille (Geological Society of London, 2004).
[3] M. C. Sanders and C. E. Sanders, "A World's Dilemma 'Upon Which the Sun Never Sets' - The Nuclear Waste Management Strategy (Part I): Western European Nation States and the United States of America," Prog. Nucl. Energy 90, 69 (2016).
[4] R. C. Ewing and F. N. von Hippel, "Nuclear Waste Management in the United States - Starting Over," Science 325, 151 (2009).
[5] "Analysis of the Total System Life Cycle Cost of the Civilian Radioactive Waste Management Program, Fiscal Year 2007," U.S. Department of Energy, DOE/RW-0591, July 2008.
[6] "Reset of America's Nuclear Waste Management: Strategy and Policy," Stanford Univesity Center for International Security and Cooperation, October 2018.
[7] "BP Statistical Review of World Energy 2018," British Petroleum, June 2018.
