Abstract: Since their conception in the 1950s, thorium reactors have been promoted as a promising technology for nuclear energy generation, though they have not yet been successfully commercialized. Proponents of thorium reactors argue that they are safer, produce less waste, and are proliferation-resistant, compared with uranium-fueled light water reactors used around the world today. The central question guiding this research concerns the final claim. Is the thorium fuel cycle inherently more resistant to nuclear weapons proliferation than the traditional uranium fuel cycle?
Advocates argue that the thorium fuel cycle is less vulnerable to proliferation of nuclear weapons technology because little or no plutonium is produced. Additionally, fissile U-233 is claimed to be “self-protected” by U-232, which is produced with U-233 and decays through Tl-208, emitting highly energetic gamma radiation. But the amount of U-232 generated depends on reactor operation. Furthermore, the U-232 content can be further decreased by conducting chemical separations at the back-end of the fuel cycle.
This presentation will discuss the proliferation risks of the thorium fuel cycle. The potential for generating large stockpiles of isotopically pure U-233 by conducting protactinium separations at the back end of the fuel cycle is examined as a new proliferation pathway that current IAEA safeguards may not be prepared to address.
About the Speaker: Eva C. Uribe is a Stanton Nuclear Security Postdoctoral Fellow at CISAC for the 2016-2017 academic year. Her research involves identifying proliferation pathways in the thorium fuel cycle and assessing the potential impact and implications of U-233 stockpile generation on the international nonproliferation regime. Eva received a Ph.D. in Chemistry from the University of California, Berkeley in 2016. Her dissertation research focused on structural analysis of organically-modified porous silica surfaces for the extraction of uranium from aqueous solutions using nuclear magnetic resonance spectroscopy. In 2011 Eva received a B.S. from Yale University with a double major in Chemistry and Political Science. She served as a Next Generation Safeguards Initiative intern with the Nonproliferation Division at Los Alamos National Laboratory in 2008 and 2009.