Primary coolant inflow reducing device for Main Coolant Pump

摘要

PURPOSE: An apparatus is provided to reduce primary cooling water introduced into a coolant circulation pump by using natural circulation force generated due to a temperature difference. CONSTITUTION: An annular space(2) is formed in an upper portion of a fluid guide(1). An annular cap(4) connected to a lower bearing fixing nut(3) is inserted into the annular space(2), thereby forming three annular passages(5). Upper and lower portions of three annular passages(5) are maintained with lower and higher temperature by means of heat transferring action, respectively. Due to the temperature difference between the upper and lower portions of three annular passages(5), natural circulation flow is created at three annular passages(5). The natural circulation flow shields mass exchange between three annular passages(5), thereby reducing cooling water introduced into the coolant circulation pump.