Burnup Performance of Sodium-Cooled Fast Reactor by Utilizing Thorium-Based Fuels

Thorium-based fuels are investigated to improve fast reactor fuel burnup. Such new sources of fuel will have to ensure that the projected expansion of nuclear power is achieved in conjunction with a reduced risk of nuclear weapons proliferation. Thorium fuel cycles have many incentives such as reduction of plutonium generation and consumption of light water reactor actinides, high-performance burnup, and conservation of 235U resources. This study provides the insight needed to judge the limitations of the thorium fuel system. This work examines burnup reactivity loss and depletion analysis of thorium-versus uranium-based metal fuels. When compared, the thorium-based metallic fuel outperformed uranium-based fuel with respect to higher actinide burnup and higher depletion rate of plutonium isotopes. The results of this paper help ascertain the limitations based on the long-term performance and behavior of the fuel under core operating conditions. Additionally, the resulting knowledge gained and techniques developed during this project support reestablishing the domestic infrastructure in the U.S. fast reactor development program. The thorium cycle offers an alternative, innovative concept for fast reactor fuels to better burn transuranics, and this study provides test cases for comparisons between options.