Coolant circulation pump for pool type nuclear reactor - incorporates gas-filled bell enclosing submerged motor and flywheel, minimising shaft length and flywheel size

摘要

An appts. for circulating a liq., pref. water, in a nuclear reactor of the pool type incorporates a motor, an inertia fly-wheel and a pump connected to the motor by a vertical shaft. The pump is in the lower, vessel part of the reactor and the motor is in the upper, pool, part, the parts being sepd. by a horizontal partition, with an orifice through which the shaft passes. The motor and the fly-wheel are in the pool part, in a bell-shaped structure, open below. The lower opening is vertically over the orifice and closed by a support plate. The motor and the fly-wheel are in the upper part of the bell and the support plate is fixed on the partition so as to be fluid-tight. The arrangement avoids problems which arise with existing ways of mounting the motor. These include placing it above the surface of the water, in which case the shaft has to be very long, or putting it and the fly-wheel under water, in which case the fly-wheel has to be large, or using a magnetic coupling, which is not economic and is less reliable. The arrangement allows easy dismantling of the pump part.