The Design of a Small Annular Linear Induction EM Pump for the Transportation of Liquid Sodium in the SFR

The linear annular induction electromagnetic (EM) pump was designed for the purpose of transporting the electrically conducting liquid sodium that is used as a coolant in the Sodium cooled Fast Reactor (SFR) in the high temperature of 550 °C. The EM pump was designed by using an equivalent circuit method which is commonly employed to the design of the induction machines. The mathematical equations on the developing pressure and efficiency was found out by using Laithewaite’s standard design formula. The main geometrical parameters for the design were a pump core length, a diameter of the pump and an annular gap size. The dominant electromagnetic variables were the input frequency, magnetic pole pitch and number, and coil turns. Especially, it was shown that the developing pressure and efficiency were maximized at the range of the low frequency less than 60 Hz of the commercial frequency. Also, the size of an annular gap was suitably selected considering the hydraulic frictional loss at the narrow annular channel. The P-Q characteristic was theoretically predicted according to the change of the input current, voltage and power. The functional and structural components of the pump consisted of the material compatible with the high temperature and chemical reactivity of the liquid sodium. The designed pump was predicted to have the nominal flowrate of 10 L/min and the developing pressure of 4 bar.