| 摘要 |
A boiling water reactor comprises a water recirculating pump unit 9 disposed in the pressure vessel 1 of the reactor, a motor case 14 projected downwardly from the bottom of the pressure vessel, a motor 15 encased by the motor case, a pump shaft 16 through which the pump unit 9 is drivingly connected to the motor, a stretch tube 24 by which the pump unit is fixed to the motor case, and a sealing structure 28 including an annular inflatable seal 34 disposed in the motor case at the lower end of the stretch tube and adapted to be inflated by a pressurized fluid to make a close contact with the outer peripheral surface of the pump shaft. Opposing annular grooves 35 and 36 are formed in the inner peripheral surface of the motor case and the outer peripheral surface of the sealing structure. A radially expandable and contractable cut ring member 37 is received by these annular grooves so as to detachably secure the sealing structure to the motor case. |
