Physics Department Colloquia
Events on Friday, October 27th, 2017
- UNDERSTANDING THE SCIENCE OF MOLTEN SALT COOLANTS FOR THEIR APPLICATION TO ADVANCED NUCLEAR REACTORS
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall
- Speaker: Raluca Scarlat, Engineering Physics, UW-Madison
- Abstract: Molten salt technology that has the possibility of being a sustainable source of energy that does not produce atmospheric pollution and that is competitive with energy from fossil fuels. There are more than a dozen start-up companies pursuing molten salt technology, both U.S. and internationally. Some are driven by sustainability characteristics of molten salt reactors, which can recycle spent fuel from conventional nuclear reactors. Other companies are driven by the economic advantages that arise from the inherent safety features of molten salts as coolants for nuclear reactors. For example, molten salt mixtures have low vapor pressure and can operate at atmospheric pressure without boiling up to very high temperature (1000 oC and above). The atmospheric pressure operation significantly reduces costs and material testing timelines for advanced nuclear reactors. The high temperature operation enables coupling to high-efficiency modern gas turbines (open air Brayton cycles with combined cycle efficiencies of >60%), compared to steam turbines that are used by conventional, water-cooled nuclear power plants that operate below 350 oC (with efficiencies of ~35%). The high temperature operation also enables a broader market for process heat applications, and the use of gas turbines enables the production of rapidly-deployable peaking power by the use of gas co-firing.
Development of advanced nuclear reactors that use molten salts requires an understanding of the physics and chemistry of the molten salts as coolants, as solvents, as containment barriers for radioactive isotopes, as optically-transparent media through which in-service inspection of components is to be performed. In my research, I investigate the interaction of molten 2LiF-BeF2 with graphite and transport of tritium between the two, the heat transfer behavior of the fluids with liquid-solid phase change, and the physical chemistry of molten fluoride salts. The talk will provide an overview of advanced nuclear reactors and a discussion of the fundamental unknowns and the experimental challenges of studying high temperature molten fluoride salts.
- Host: Pupa Gilbert