MSR – Molten Salt Reactor System

MSR – Molten Salt Reactor System
The MSR system produces fission power in a circulating molten salt fuel mixture with an epithermal-spectrum reactor [shown below] and a full actinide recycle fuel cycle. In the MSR system, the fuel is a circulating liquid mixture of sodium, zirconium and uranium fluorides. The molten salt fuel flows through graphite core channels, producing an epithermal spectrum. The heat generated in the molten salt is transferred to a secondary coolant system through an intermediate heat exchanger, and then through a tertiary heat exchanger to the power conversion system. The reference plant has a power level of 1000 MWe. The system has a coolant outlet temperature of 700°C, possibly ranging up to 800°C, affording improved thermal efficiency.
The closed fuel cycle can be tailored to the efficient burnup of plutonium and minor actinides. The MSR’s liquid fuel allows addition of actinides such as plutonium and avoids the need for fuel fabrication. Actinides and most fission products form fluorides in the liquid coolant. Molten fluoride salts have excellent heat transfer characteristics and a very low vapor pressure, which reduce stresses on the vessel and piping.