|Fig. 1: Nuclear Regulatory Commission (NRC) staff at the Yucca Mountain Repository. (Source: Wikimedia Commons)|
The United States has the most nuclear reactors in the world and the question remains that once the nuclear fuel is full processed, it is a non-reusable, radioactive, and potentially dangerous material that remains radioactive for hundreds of thousands of years. According to the BP Statistical Review of World Energy, the USA consumed 191.8 MTOE of nuclear energy in 2016 with roughly 38% of this consumed energy being electric energy.  Converting to SI units, one obtains
with roughly 4% of the fuel rod burns up by fission.  Each atom fissioned produces 230 MeV of energy; thus, the amount of energy produced per fuel rod kilogram is
The amount of spent fuel rod mass produced per year is thus
or 2,160 tonnes/year. From this, we can estimate that twenty years of nuclear energy production results in roughly 40,000 tonnes of spent fuel rods.
These spent fuel rods as well as waste products from the used fuel are classified as high level nuclear waste due to their dangerously highly radioactive levels.  This waste is not only highly radioactive, but has high thermal heat. Because of the waste's high radioactive levels, this material is too dangerous to move from the reaction site. As a result, it is generally stored in water cooling pools, near the reactor, within the nuclear site, to cool and decay to safer levels until being moved into metal special containers. Given that high-level nuclear waste can remain radioactive for hundreds of thousands of years, neither the cooling pools nor the metal containers are a permanent disposal method. One possible method is space disposal given that the sun would be able to proper decay the nuclear waste; however, the danger of an unsuccessful rocket launch and the subsequent radioactive exposure to our atmosphere has for now eliminated this possibility.  As a result, geographic isolation, while an uncertain method at best, has been the mainly studied option. The U.S. Department of Energy's has used the Yucca Mountain Nuclear Waste Repository in southwestern Nevada, as its main isolation storage faculty and test case, pictured above. While the site was advantageous due engineering and low-moisture climate, the site began to reach capacity in the late 2000's and as of 2010, the U.S., nor any country in the world, had an active repository.
By 2035, estimates have shown that the U.S. nuclear waste levels would be nearly twice the capacity of Yucca Mountain, we must continue to search for a solution.  Given that geographic isolation has proven to not be a sufficient solution coupled with a renewed interest in space travel, driven by SpaceX's Elon Musk - a man known for wanting to solve the world's toughest energy problems, the possibility of space disposal becomes more of a possibility as time progresses.
© Daniel Cohn. 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.
 "BP Statistical Review of World Energy," British Petroleum, June 2017.
 "Commercial Spent Nuclear Fuel," U.S. Nuclear Waste Technical Review Board, November 2017.
 B. Madres, "Storage and 'Disposal' of Nuclear Waste," Physics 241, Stanford University, Winter 2011.
 S. Ali, "Nuclear Waste Disposal Methods," Physics 241, Stanford University, Winter 2011.