Patent Number: 039487245
Section: summary

This invention relates to a device for handling rod-shaped members of a nuclear reactor and more particularly refers to a new and improved traveling device for transfer of rod-shaped members in and from a nuclear reaction vessel. Devices for handling rod-shaped elements in nuclear reactors usually have a hoisting unit which together with a gripping device operates via a number of connecting members such as rods, ropes, chains and the like to move fuel, breeder or absorber rods in and out of the reactor. To be effective, it is necessary to place the gripping device and of course the hoisting unit into a position perpendicular above the rod-shaped member to be moved. In the known devices of this type, this is accomplished via construction involving a main rotary cover with a second smaller rotary cover arranged eccentrically within the main rotary cover, and a hoisting unit disposed on the second smaller rotary cover. Through rotating motions of both rotary covers relative to each other and to the reactor vessel, the hoisting unit may be transported into position above the fission zone of the reactor. Other additional auxiliary equipment must also be affixed to the rotary cover. To accommodate the additional auxiliary equipment and the handling device without interfering with one another during rotary movements of the covers, it becomes necessary to employ large reactor containers with large rotary covers to properly space the appliances. This results in appreciably increased costs which are magnified by the presence of a plurality of rotary covers and their complicated drives. It is accordingly an object of the invention to provide a device for handling rod-shaped members in a nuclear reactor employing a single rotary cover. Another object of the present invention is to provide a handling device in conjunction with a small reaction vessel of a diameter not substantially greater than the fission zone which it encompasses. With the foregoing and other objects in view, there is provided, in accordance with the invention, a device for handling rod-shaped members of a nuclear reactor comprising a reaction vessel, a reactor core containing rod-shaped members in the reaction vessel, a rotary cover on the reaction vessel, means for rotating the rotary cover, a slot in said rotary cover, a hoisting unit arranged on said rotary cover, means for moving said hoisting unit along said slot, a grip for grasping a rod-shaped member, transmission means interconnected with said hoisting unit for movement of said grip in the slot, whereby through rotation of said rotary cover and movement of said hoisting unit along the slot, said grip may be moved into position for transfer of any desired rod-shaped member. In accordance with the invention, the device for handling rod-shaped members is provided with a rotary cover having a slot therein and the hoisting unit disposed on the rotary cover moves along the slot situated in the rotary cover. The intermediate transmission elements connected to the remote control grip move in this slot. The slot may extend over the entire rotary cover or only over a portion thereof, depending on whether the handling device is to be used only for relocating rod members within individual positions of the fission zone or depositing positions adjacent thereto or whether the entire cross section of the reactor vessel is to be accessible. In a preferred embodiment, the slot is arranged radially in the rotary cover thus obtaining a favorable relation between the length of the slot and the area which is swept by the slot during the rotation of the rotary cover. gas from shielding box or gas-tight hood is disposed on the rotary reactor cover sealed to the cover to prevent emission of radioactive radiation or protective from the reaction vessel and to prevent penetration of air thereinto. The shielding box should be of ample size to ensure the free mobility of the hoisting unit in its interior. Movement of the hoisting unit along the slot may be accomplished by means of a carriage or cart on which the hoisting unit rests. To prevent exposure of the hoisting unit and the gripping device to the corrosive effects of the reactor atmosphere particularly from reactors cooled with liquid metal, provision is made for preventing the gaseous atmosphere from the reactor vessel passing up through the slot into the area of the hoisting unit by means of two expansion members such as bellows or other pleated members, connected at one end with the wall of the shielding box and at the other end with the carriage which carries the hoisting unit. The bellows, by acting as a barrier to convection of gaseous currents from the atmosphere of the reaction vessel, protects the hoisting unit against impurities stemming from the reactor atmosphere, which contains for example gas, steam or coolant particles of metal. Another feature of the invention is the provision of a shielding block inserted from the side to seal the slot thereby making the hoisting unit and the bellows, following the removal of the shielding box, accessible for repair and maintenance work. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a device for handling rod-shaped members of a nuclear reactor, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.