Sodium-Cooled Fast Reactor (SFR)
The Sodium-Cooled Fast Reactor (SFR) system features a fast-spectrum, sodium-cooled reactor and a closed fuel cycle for efficient management of actinides and conversion of fertile uranium.
A range of plant size options is available for the SFR, from small modular systems of 50 MWe to large monolithic reactors of approximately 1,500 MWe. The primary coolant system in a SFR can either be arranged in a pool layout - where all primary system components are housed in a single vessel or in a compact loop. For both options, there is a relatively large thermal inertia of the primary coolant. A large margin to coolant boiling is achieved by design and is an important safety feature of these systems. Another major safety feature is that the primary system operates at essentially atmospheric pressure. A secondary sodium system acts as a buffer between the radioactive sodium in the primary system and the energy conversion system in the power plant.
The two main fuel options for the SFR are: (1) mixed uranium-plutonium oxide (MOX) or (2) mixed uranium-plutonium-zirconium metal alloy (metal). The international experience with MOX fuel is more extensive, while the metal fuel offers advantages in safety performance. Other advanced options being considered are nitride, carbide, or dispersion fuels.
The primary mission for the SFR is actinide management for improved waste disposal and uranium resource utilization. With innovations to reduce capital cost, the mission can extend to electricity production and/or heat supply alternatives (hydrogen production, desalination, etc.).