ChBE Seminar Series: Supathorn Phongikaroon
Tuesday, April 29, 2008
11:00 a.m.-12:00 p.m.
Room 2110 Chemical & Nuclear Engineering Bldg.
Professor Richard Calabrese
Development of New Chemical Engineering Applications in Pyroprocessing Technology
Presented by Supathorn Phongikaroon
Department of Chemical Engineering
Nuclear Engineering Program
University of Idaho
Spent fuel from the Experimental Breeder Reactor-II (EBR-II) is currently being treated in electrorefiners at the Idaho National Laboratory (INL) in a process known as pyroprocessing of spent nuclear fuel. In electrorefining, uranium is oxidized at the anode while simultaneously being reduced and deposited at the cathode. Plutonium, sodium, and fission products are oxidized to form chlorides in the electrolyte, which consists primarily of eutectic LiCl-KCl. The overall objective of pyroprocessing is to separate uranium from fission products and other actinides, both groups of elements of which can be placed into waste forms for long term storage in geological repository.
This work presents the progress in chemical engineering development for the three areas in pyroprocessing technology: (1) ion exchange, (2) oxide reduction, and (3) electrorefinery. The first part focuses on the two-site equilibrium model for ion exchange between multivalent cations and zeolite-A in a molten salt, a process being considered for concentrating nuclear fission products into high-level waste forms. The second topic concentrates on a head-end process in reduce an oxide fuel to metal in order to extend the electrometallurgical treatment technology to oxide-based fuels. The issue regarding the generation of oxygen bubbles around the anode, which provides the motivation to perform a mock-up study on the effect of physical properties and device geometry on bubble size distribution for gas-liquid interaction in this electrolytic reduction process. The last topic presents the development of a new modeling approach of the Mk-IV electrorefiner focusing on the fuel basket/salt interface. These three research areas show the significant development of new chemical applications in pyroprocessing, which can impact and improve the spent fuel cycle area, providing the new way for nuclear energy in the 21st century.