Engineering tests of the metal transfer process for extraction of rare-earth fission products from a molten-salt breeder reactor fuel salt

In the metal transfer process for removal of rare-earth fission products from the fuel salt of a molten-salt breeder reactor (MSBR), the rare earths are extracted from the molten fuel salt into a molten bismuth solution containing lithium and thorium metal reductants, transferred from the bismuth into molten lithium chloride and, finally, recovered from the lithium chloride by extraction into molten bismuth containing lithium reductant. Engineering experiments using mechanically agitated, nondispersing contactors with salt and bismuth flow rates [approximately 1 percent of those required for processing the fuel salt from a 1000-MW(e) MSBR] have been conducted (1) to study this process, (2) to measure the removal rate of a representative rare-earth fission product (neodymium) from MSBR fuel salt, and (3) to evaluate the mechanically agitated contactor for use in a plant processing fuel salt from a 1000-MW(e) MSBR. The experimental equipment and procedures are described. Results obtained during five experiments in which the rare earth neodymium was extracted from MSBR fuel salt are presented. Removal rates and mass-transfer coefficients between the salt and bismuth phases were determined for neodymium and are discussed in terms of the processing requirements for a 1000-MW(e) MSBR