Patent Number: 048866350
Section: summary

The invention relates to a gripping tool for a device for the remote-controlled removal of samples or specimens from a container, especially a pressure vessel of a reactor, including a guide bar disposed on a mast, and at least two catches in the form of a two-armed-lever disposed on the mast in pivots for surrounding a head of the sample housing like a clamp when activated. A conduit is provided on the outside wall of the core vessel of a reactor pressure vessel in which a radiation sample column disposed in a capsule is inserted after the first fuel assembly cycle. Following the second fuel assembly cycle, the capsule containing the sample is-removed from the reactor pressure vessel and is suspended under water at the edge of the fuel assembly reservoir. Removal of the sample takes place from the fuel assembly reservoir. Then a fresh radiation sample is inserted into the reactor pressure vessel. It is known to use a gripping tool for the removal of samples having a guide bar disposed on a mast, in which catches are each fixed on a pivot point in such way that they grasp a head of the housing like a clamp when activated. The gripping tool is suspended from a crane and lowered towards the reactor pressure vessel until it is seated on the head of the sample retainer, where the catches engage the sample head and grasp it like a clamp. It is possible for buckling or damage to the radiation sample to occur during the course of setting down the gripping tool, which must be done by remote control from a considerable height. It is accordingly an object of the invention to provide a gripping tool for a device for the remote-controlled removal of samples from a container, in particular from a pressure vessel of a reactor, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and which avoids a deformation of the housing and thus damage to the sample. With the foregoing and other objects in view there is provided, in accordance with the invention, a gripping tool for a device for the remote-controlled removal of samples in housings with heads from a container, in particular a pressure vessel of a reactor, comprising a mast having a first coupling part or connecting element, a second coupling part or connecting element opposite and associated with the first coupling part, a guide bar elastically bearing or being disposed on the second coupling part in a telescoping manner, pivots disposed on the guide bar, at least two catches of a two-armed lever being disposed on the pivots and having guide grooves formed therein, a bushing or sleeve surrounding the guide bar having guide pins each engaging a respective one of the guide grooves, and at least one remotely controlled linear drive moving the bushing in the direction of the longitudinal axis of the bushing for surrounding the head of the sample housing with the catches like tongs or a clamp. In this way the gripping tool can be placed on the head of the housing for the sample with the catches open. The forces acting on the head of the housing for the sample during placement are kept small due to the elastic mounting of the guide bar on the mast and damage to the radiation column is prevented. In accordance with another feature of the invention, the at least one remotely controlled linear drive is a pressure medium drive including at least one cylinder disposed on the guide bar having a piston with a piston rod connected to the bushing. In accordance with a further feature of the invention, there are provided control lines connected to the cylinder, and a return spring disposed in the cylinder for maintaining the catches in a closed position in case of pressure reduction in the control lines. In accordance with a concomitant feature of the invention, the first coupling part is an existing element provided for pulling fuel assemblies, and the second coupling part is adapted to and connected with the first coupling part. Due to this feature, the mast for pulling fuel assemblies which is provided in a nuclear power plant in any event, can be used for the gripping tool so that a separate mast for the gripping tool is not necessary. This results in a considerable simplification as compared to the prior art structure, since only the head need to be exchanged. 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 gripping tool for a device for the remote-controlled removal of samples from a container, in particular from a pressure vessel of a 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.