Fuel exchange device in LMFBR type reactors

Purpose: To enable exact fuel exchange in LMFBR type reactors by lowering the temperature for coolants, removing an upper plug and an upper cover and then using a simple plug upon fuel exchange. Constitution: After lowering the temperature for coolant sodium, lifting a regular shielding plug and transporting it along a transporting rail to another position in a pit chamber, a simple plug mounted to a cylindrical body is placed on the upper opening to close it. Then, cover gas is fed from a gas pressure regulator to the inside of the cylindrical body to increase the pressure whereby the coolant level in the cylindrical body is reduced. When the upper portion of the reactor core appears above the coolant level, fuel exchange is conducted while monitoring the handling head of the fuel assemblies by a television camera. The fuel exchange work can thus be facilitated and the misoperation can be prevented. (Seki, T.)