Enhanced molten salt purification by electrochemical methods: feasibility experiments with flibe
Molten salts are considered within the Very High Temperature Reactor program as heat transfer media because of their intrinsically favorable thermo-physical properties at temperatures starting from 300 C and extending up to 1200 C. In this context two main applications of molten salt are considered, both involving fluoride-based materials: as primary coolants for a heterogeneous fuel reactor core and as secondary heat transport medium to a helium power cycle for electricity generation or other processing plants, such as hydrogen production. The reference design concept here considered is the Advanced High Temperature Reactor (AHTR), which is a large passively safe reactor that uses solid graphite-matrix coated-particle fuel (similar to that used in gas-cooled reactors) and a molten salt primary and secondary coolant with peak temperatures between 700 and 1000 C, depending upon the application. However, the considerations included in this report apply to any high temperature system employing fluoride salts as heat transfer fluid, including intermediate heat exchangers for gas-cooled reactor concepts and homogenous molten salt concepts, and extending also to fast reactors, accelerator-driven systems and fusion energy systems. The most important initial requirement for heat transfer test of molten salt systems is the establishment of reference coolant materials to use in the experiments. An earlier report produced within the same project (INL/EXT-10-18297) highlighted how thermo-physical properties of the materials that directly impact the heat transfer behavior are strongly correlated to the of composition and impurities concentration of the melt. It is therefore essential to establish laboratory techniques that can measure the melt composition, and to develop purification methods that would allow the production of large quantities of coolant with the desired purity. A companion report titled ‘An experimental test plan for the characterization of molten salt thermo-chemistry properties in heat transport systems’ describes the options available to reach such objectives and contains extended references to published work. The report highlights how electrochemical methods are the most promising techniques for the development of instrumentation aimed at the measurement of melts composition and for enhanced purification systems. The purpose of this work is to summarize preliminary experimental activities performed at the INL Safety and Tritium Applied Research facility in support of the development of electrochemistry based instrumentation and purification systems. The experiments have been focused on the LiF-BeF2 eutectic (67 and 33 mol%, respectively), also known as flibe.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- DOE - NE
- DOE Contract Number:
- DE-AC07-05ID14517
- OSTI ID:
- 1000530
- Report Number(s):
- INL/EXT-10-19963; TRN: US1100211
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COOLANTS
ELECTRICITY
ELECTROCHEMISTRY
EUTECTICS
FAST REACTORS
FLIBE
FLUORIDES
GAS COOLED REACTORS
HEAT EXCHANGERS
HEAT TRANSFER
HEAT TRANSFER FLUIDS
HELIUM
HYDROGEN PRODUCTION
IMPURITIES
MOLTEN SALTS
PROCESSING
PURIFICATION
REACTOR CORES
SAFETY
THERMONUCLEAR REACTORS
TRANSPORT
TRITIUM
molten salt
VHTR
VHTR TDO