Abstract: A control rod drive contains a drive housing, in which a control rod carrying element is moveable between a basic position and an end position. The control rod carrying element is guided over a portion in a throttle bush. Formed across the throttle bush is a free flow cross section for a pressure fluid which varies in dependence on a position of the control rod carrying element. During an emergency shutdown, in which the control rod carrying element is moved hydraulically via a pressure fluid, the flow resistance for the pressure fluid is reduced, when the control rod carrying element reaches the end position. Therefore, a braking of the control rod carrying element takes place before it reaches the end position, thus reducing mechanical loads during braking. A flow resistance change takes place via a variable outside diameter of the control rod carrying element and/or by a bypass orifice.

Abstract: A control rod drive contains a drive housing, in which a control rod carrying element is moveable between a basic position and an end position. The control rod carrying element is guided over a portion in a throttle bush. Formed across the throttle bush is a free flow cross section for a pressure fluid which varies in dependence on a position of the control rod carrying element. During an emergency shutdown, in which the control rod carrying element is moved hydraulically via a pressure fluid, the flow resistance for the pressure fluid is reduced, when the control rod carrying element reaches the end position. Therefore, a braking of the control rod carrying element takes place before it reaches the end position, thus reducing mechanical loads during braking. A flow resistance change takes place via a variable outside diameter of the control rod carrying element and/or by a bypass orifice.

Abstract: A holder for fuel elements in a reactor, in particular in a boiling water reactor, is provided, as well as a method for repairing such a holder. A core grid is demounted from a core shroud and replaced by a new forged core grid for the purpose of repairing the holder. An adapter ring is to be inserted between the new core grid and the core shroud. There is provision for connecting the adapter ring to the core grid without a welding operation, for example by shrink fitting.