Method and device for ascertaining the deformation of a fuel assembly in a pressurized-water reactor

A device for measuring a deformation of a fuel assembly in a pressurized-water reactor having a plurality of control-rod guide tubes, the device comprising:

• a probe to be inserted into an interior of a control-rod guide tube and displaceable in a direction of a longitudinal axis of the control-rod guide tube and having at least one reference axis and is supported in at least one section of the control-rod guide tube against an inner wall of the control-rod guide tube such that an orientation of the at least one reference axis uniquely depends on an orientation of the longitudinal axis of the control-rod guide tube in the at least one section;
• and
• a measuring device, disposed in said probe, for determining the orientation of the at least one reference axis in the at least one section of the control-rod guide tube relative to the orientation of the longitudinal axis or a further reference axis of said probe in another section of the control-rod guide tube.