|Fig. 1: Yucca Mountain South Portal entrance. (Source: Wikimedia Commons)|
In 1982, Congress passed the Nuclear Waste Policy Act (NWPA), tasking the Department of Energy (DOE) to construct a central geological repository in the United States by 1998. The Act was passed to address the buildup of hazardous nuclear waste, a byproduct of the growing use of nuclear power for its otherwise relatively clean, reliable, and cost-competitive energy. The proposed deep geological repository would exist to safely store and dispose of high-level nuclear waste.
Nuclear waste can be categorized into two broad classifications: low-level or high-level waste. Low-level waste generally consists of operational items used around a nuclear plant or other site that uses radioactive materials in some way.  The level of radioactivity ranges from slightly above background levels found in nature to much higher, such as, in certain cases, parts from inside the reactor vessel of a power plant. Low-level waste is typically stored on-site in near-surface facilities. This waste accounts for approximately 90% of all nuclear waste by volume, yet only contains 1% of the overall radioactivity.  High-level radioactive waste is primarily uranium fuel that has been used in a nuclear power reactor and is spent (no longer useful for producing electricity).  This fuel is both highly radioactive and thermally hot, so it requires stringent safety measures such as shielding and remote handling. The radioactive isotopes will eventually decay or disintegrate into harmless material, but the time this takes depends on the isotope: for example, Sr-90 and Cs-137 have half-lives of around 30 years, whereas Pu-239 has a half-life of 24,000 years.  Every nuclear power plant in the United States stores spent fuel in "spent fuel pools" made of steel liners and reinforced concrete several feet thick. The water in these pools shields the radiation and cools the rods. Generally, around five to ten years later, the spent fuel is moved into "dry cask" storage (stainless steel canisters surrounded by concrete). Storage of spent fuel at power plant sites is considered temporary as the ultimate goal is permanent disposal. As of today, however, there are no facilities intended for permanent disposal of high-level waste in the United States.  A centralized deep underground repository, such as the one indicated in the 1982 NWPA, would mitigate risk for all the other nuclear facilities in the United States. Thus, the absence of such a repository is one of the largest obstacles facing the nuclear power industry in America.
In 1987, Congress enacted the Nuclear Waste Policy Amendments Act. This Act declared that Yucca Mountain would be the site of the geological repository outlined in the NWPA. Yucca Mountain was selected based on many empirical factors related to its location, dry climate, rock type, and distance to the nearest water basin.  Political influences also played a role: the Department of Energy's initial evaluation considered repository sites in 21 states, where Congress members adopted "Not in My Backyard" rhetoric.  The final three potential candidate sites for the repository were in Washington, Texas, and Nevada. A member of the House-Senate conference committee explained to Nevada Congressman James Bilbray, "I hope you understand what is going on here. There are three sites under review Texas, Nevada, and Washington. And the speaker (of the House, Jim Wright) is a Texan and the (House) majority leader (Tom Foley) is a Washingtonian. It is not going to Washington. And it is not going to Texas."  A 2019 Nevada Commission on Nuclear Projects report outlines the case against Yucca Mountain, highlighting the ways political science triumphed over earth science, the extensive number of remaining requirements, as well as geological contentions that challenge the site's suitability to isolate radioactive waste from the biosphere longterm.  Approximately $15 billion has been spent on the Yucca Mountain project. The Obama administration pulled the program's funding altogether in 2011; there are still no waste disposal tunnels, no receiving and handling facilities, or approved waste disposal container designs. [3,5] Fig. 1 shows the South Portal entrance to Yucca Mountain. In December 2012, the DOE estimated the Yucca Mountain project would require another $82.5 billion for construction, operation, and closure, equating to a total cost estimate of slightly under $97 billion. 
Once successfully constructed, a repository at a site like Nevada's Yucca Mountain would serve to centralize the storage of high-level nuclear waste. This would provide much-needed relief to facilities around the nation that are currently storing nuclear waste and act as a security measure to the U.S. as a whole, so long as it is effectively constructed, protected, and maintained long-term. The challenge with a deep geological repository is that it must remain functional and retain its structural, geological, and hydrological integrity for over 10,000 years to guarantee that thousands of tons of hazardous substances remain contained.  This poses an immense challenge to constructing such a repository, a considerable risk to the region, and pains politicians to tackle such a long-term, yet long overdue, issue waiting to be solved. In a Senate Committee on Energy and Natural Resources hearing on January 27, 2021, the Biden Administration's Energy Secretary nominee, Jennifer Granholm, expressed the administration supports examining the recommendations from the "Blue Ribbon Commission on America's Nuclear Future," which recommend taking a consent-based approach to siting a safe and workable location for our nation's high-level radioactive waste.  Approaching forty years since the Nuclear Waste Policy Act was passed by Congress, the demand for safe, enduring storage of high- level nuclear waste has never been higher, and a long-term solution remains a pressing issue that must be solved.
© Nick Barber. 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.
 "Backgrounder: Radioactive Waste," U.S. Nuclear Regulatory Commission, April 2015.
 N. Ioannou, "Nuclear Waste Disposal," Physics 241, Stanford University, Winter 2019.
 A. Chun, "Geological Repositories: Yucca Mountain," Physics 241, Stanford University, Winter 2019.
 B. Halstead, "Nevada Is Winning the War, But Yucca Mountain is Not Dead," Las Vegas Sun, 23 Oct 20.
 R. H. Bryan et al., "Report and Recommendations Of the Nevada Commission on Nuclear Projects," Nevada Commission on Nuclear Projects, November 2019.
 A. Winter, "Responses to Questions for the Record Submitted to the Honorable Jennifer M. Granholm," U.S. Senate Committee on Energy and Natural Resources, 27 Jan 21, p. 18.