Magnetic Bearing Supported Impeller for Molten Salt Reactor Pump

Molten salt reactors (MSR) use molten salts as both a carrier of dissolved fission materials and coolant. High temperature molten salts require highly reliable and robust components, especially, pump. The mechanical pump is considered to be ideal for pumping high temperature and corrosive molten salts compared to the electromagnetic pump because of its efficiency. However, the mechanical pump requires mechanical rolling ball bearings and dynamic sealing, which causes the maintenance issue. Electron Energy Corporation (EEC), collaborating with University of Wisconsin-Madison, will develop a high-performance pump using a magnetic bearing supported impeller for MSR. The levitated and rotating impeller-type pump with no mechanical bearings and sealing parts can move any liquid (e.g., liquid salts or liquid metals), which enables improved pump performance and reliability. Compared to the conventional pumps with rolling-element bearings, the proposed in-line pump design is much simpler and cost-effective in terms of maintenance and system integration. In particular, using EEC’s magnetic bearing and coupler technology will improve the pump performance. In Phase I, the technical objective is to design a magnetic bearing supported impeller using EEC magnet materials and technology. The capability, reliability, and complexity associated with development and implementation of the pump and magnetic designs will be studied and compared. Based on various strengths and weaknesses of each design option, a final pump design will be selected for the technology demonstration of Phase I with special attention focused on identifying the primary developmental issues (high-temperature mechanical strength, corrosion resistance, radiation resistance, levitation stability, vibration) for MSR applications. A suite of multiphysics analysis/design tools (Maxwell, Opera, Solidworks, Flow, Mag_Brg_TRC, ANSYS, and EES) will be used for electromagnetic, fluid, and thermodynamics analysis/design/optimization of the pump. Reliable high temperature impeller type pump is indispensable for the safe operation of future MSR. Concentrating solar power (CSP) plant use molten salts as heat transfer and storage medium. Generation 3 CSP operates at very high temperatures of about 700°C which is achieved at the solar receiver. The proposed pump is crucial for reliable pumping of high-temperature molten salts over high pressure head over high elevation and a long distance. In industrial melt applications, since the impeller is levitated, this pump has a unique advantage that no direct contact of moving parts with the chemically aggressive melt is necessary.