Communicating with an academic audience

Literature Review: Advancements in Nuclear Waste Disposal Technologies

Nuclear power accounts for 19% of electricity generated in the United States and is projected to generate increase in the future (U.S. Energy Information Administration, 2013). However, ever since the Yucca Mountain Nuclear Waste Repository was dismantled by the Department of Energy (GAO, 2014a), no waste disposal plan is currently being pursued, which means it is all sitting in an indefinite temporary storage. Currently, 80,000 metric tons of nuclear waste awaits disposal, and another 60,000 metric tons will be generated by 2050 (GAO, 2014a; GAO, 2014b). To assist in finding a permanent disposal solution, recent studies in fields related to nuclear waste disposal have been analyzed to understand the current state of the field and potential future research. First is an examination of public perception of nuclear waste and its effect on waste disposal. Then advancements in reprocessing techniques are discussed. Finally, an analysis of deep borehole disposal will be contrasted with the feasibility of space disposal.

Public Perception

An integral part of nuclear waste disposal is public acceptance. Studies have been completed internationally to identify analyze public opinion and identify key opposition points. Several common themes emerged. The lack of communication between public and authorities created a rift between them (Gallardo, 2014). The rift manifests as a belief scientists are too sterile and fail to consider the human element, causing the public to distrust findings (Ramana, 2013). Additionally, a distrust in government (Gallardo, 2014) was exacerbated by interest groups effectively using social media to motivate protests and sway opinion (Ramana, 2013; GAO, 2014b). Besides distrust in authorities, public concerns included environmental safety, radiation leaks (Gallardo, 2014), and terrorism during transportation or at storage sites (Ramana, 2013).  While the level of concern fluctuated between nations, one particular phenomenon was always present.

While the level of concern fluctuated between nations, one particular phenomenon was omnipresent: the “not in my backyard” — or NIMBY— phenomenon. People are willing to store nuclear waste in their country, but the prospect of the waste stored near them is not acceptable (Gallardo, 2014; Ramana, 2013; GAO, 2014b). The extent NIMBY was observed varied; in nations where geologic waste sites have not been attempted the effect was not particularly motivating (Gallardo, 2014) but in the United States the effect was strong enough to shut down Yucca Mountain (GAO, 2014a; GAO, 2014b). The powerful opposition mounted against the Yucca Mountain Nuclear Waste Repository has demonstrated the necessity of working with the public, not around them. Social issues are only one part of the challenges faced by nuclear waste disposal.

Reprocessing

Raw nuclear waste from reactors needs to be reprocessed before disposing. While originally developed for creating nuclear weaponry, the PUREX process has been adapted to remove viable fuel and to decrease the amount of waste. However, the process is politically undesirable for its potential in nuclear proliferation. A number of new techniques have been developed to decrease the purity of the plutonium stream while maintaining the integrity of the material. The plutonium stream must be diluted with uranium, but not with waste. The COEXtraction process modifies PUREX to create a plutonium stream with more than 20% uranium, decreasing proliferation risks. (Herbst, 2013).

In further processing of the waste, vitrification shows promise for long term storage. Single phase ceramics work well with single phase wastes, whereas more complicated glass and glassy materials are needed for mixture wastes (Lee, 2013), such as those resulting from the PUREX process. A variety of models are available to approximate the transfer of active radionucleotides into the environment but fundamental processes must be better understood before models accurately predict behavior into the tens of thousands of years.

Permanent Disposal Options

Most scientists agree deep boreholes are the optimal method for disposing nuclear waste (Gallardo, 2014; Ramana, 2013; Bates 2014). The costs are relatively cheap and the safety risks are reasonable. Additionally, a large portion of the US is made of a favorable crystalline basement which would tolerate multiple borehole sites (Bates, 2014). The problem with deep boreholes is in proving they are safe for the long term (Kim, 2016). No deep boreholes have been made or tested with waste which means the models used to justify them are only partially validated (Grambow, 2014). Boreholes are safe in the short-term with the data known, but after thousands of years the predictions are not accurate enough (Grambow, 2014). Additionally, the social implications of legal guidelines for deep borehole stability are unknown. Public fear of boreholes might be exacerbated by the 10,000-year stability required by the EPA, making it even harder for deep boreholes to be tested. (Grambow, 2014).

On the other hand, space disposal is almost unanimously viewed as the wrong option (Kim. 2016). Originally deemed not feasible due to safety and costs (Burns, 1978), a modern analysis suggests space disposal should be reconsidered. Space launches are safer today than in 1970, and cost has decreased from $20,000 per pound to $200 per pound making it nearly comparable to geologic storage. (Kim, 2016). For space disposal, proving the safety nuclear waste in space is trivial, but getting it there is where the concerns lie (Kim, 2016).

Conclusion

While some technical roadblocks exist, public acceptance of geologic disposal is the current gatekeeper towards progress. As a result, further research should be placed into understanding public perception and how to properly inform them of the safety and technical aspects in an appropriate manner. Coordinated social media campaigns have worked against nuclear waste management; thus, an analysis of their success could identify key traits that could be used to promote waste management. A deep borehole should be created to collect data and validate models. Finally, a formal study should reevaluate space disposal, since new technologies have rendered that original analysis obsolete.

References

Bates, E.A., Driscoll, M.J., Lester, R.K., & Arnold, B.W. (2014). Can deep boreholes solve America׳s nuclear waste problem?. Energy Policy, 72, 186-189. http://dx.doi.org.ezproxy.neu.edu/10.1016/j.enpol.2014.03.003

Burns, R. E., Causey, W. E., Galloway, W. E., & Nelson R. W. (1978).  Nuclear Waste Disposal in Space. Huntsville, Al: National Aeronautics and Space Administration

U.S. Energy Information Administration. (2013, April 25). “Long-term outlook for nuclear generation depends on lifetime of existing capacity” Retrieved from https://www.eia.gov/todayinenergy/detail.php?id=10991

U. S. Government Accountability Office. (2014a). Commercial Nuclear Waste: Effects of a Termination of the Yucca Mountain Repository Program and Lessons Learned. Washington, DC: United States Government Accountability Office.

U. S. Government Accountability Office. (2014b). Spent Nuclear Fuel Management: Outreach Needed to Help Gain Public Acceptance for Federal Activities That Address Liability. Washington, DC: United States Government Accountability Office.

Gallardo, A.H., Matsuzaki, T., & Aoki., H. (2014). Geological storage of nuclear wastes: Insights following the Fukushima crisis. Energy Policy, 73, 391-400.

Grambow, B., Bretesché S. (2014). Geological disposal of nuclear waste: II. From laboratory data to the safety analysis – Addressing societal concerns. Applied Geochemistry, 49, 247–258.

Herbst, R. S., Baron, P., & Nilsson, M. (2011). Standard and advanced separation: PUREX processes for nuclear fuel reprocessing. In Nash, K. L. & Lumetta, G. J. (Eds.), Advanced Separation Techniques for Nuclear Fuel Reprocessing and Radioactive Waste Treatment (pp. 141-175). Cambridge, UK: Woodhead Publishing

Kim, H., Park, C., & Kwon, O.J. (2016). Conceptual design of the space disposal system for the highly radioactive component of the nuclear waste. Energy, 115 (1), 155-168. http://dx.doi.org.ezproxy.neu.edu/10.1016/j.energy.2016.09.012

Lee W. E., Ojovan, M. I., Stennett, M. C., & Hyatt, N. C. (2013). Immobilisation of radioactive waste in glasses, glass composite materials and ceramics. Advances in Applied Ceramics, 105 (1), 3-12. DOI: 10.1179/174367606X81669

Ramana. M. V. (2013). Shifting strategies and precarious progress: Nuclear waste management in Canada. Energy Policy, 61. 196-206

Vienna, J. D., Ryan, J. V., Gin, S., & Inagaki, Y. (2013). Current Understanding and Remaining Challenges in Modeling Long-Term Degradation of Borosilicate Nuclear Waste Glasses. International Journal of Applied Glass Science, 4 (4), 283–294. DOI:10.1111/ijag.12050