Nuclear reactors

Purpose: To enable fuel assembly immersion in coolants irrespective of the coolant's depth in a reactor container upon fuel exchange by sucking the coolants in the reactor container to the inside of a reception cylinder. Constitution: A reception cylinder is passed through a rotary shielding plug and the lower end of the cylinder is opened to a reactor container. The rotary shielding plug is appropriately rotated to move the reception cylinder above a fuel assembly to be exchanged. Then, a pressure adjuster is operated to lower the pressure in the reception cylinder thus to attract the coolants in the reactor container to the inside of the reception cylinder. Then, the fuel exchanger is actuated to pull up the fuel assembly. Then, by an appropriate rotation of the rotary shielding plug, the reception cylinder is displaced above a fuel storage pot and then the fuel assembly is placed in the fuel storage pot by the actuation of the fuel exchanger. Thereafter, the fuel assembly is discharged together with the fuel storage pot by a fuel loader and unloader. (Kawakami, Y.)