Abstract: A fuel element for a nuclear reactor has a fuel rod bundle, at least one spacer with cells defined by at least one web section made from a first material and several guide tubes each running through a cell and axially fixed thereto made from a second material. The first and second materials have differing thermal expansion coefficients. The connection between the guide tube and the spacer is embodied as follows: first and second projections are directly or indirectly fixed to the guide tube. The first projections are disposed in a first axial position and the second projections are arranged at a second axial position and the projections each engage in an opening through the web section to give an axially-acting undercut.

Abstract: A monitoring system for an inner area of a machine includes a radar source radiating or injecting radar radiation into the inner area and a radar receiver receiving radar radiation reflected in the inner area and emitting the reflected radar radiation as a received signal. A control and evaluation unit determines an actual signature from the received signal and compares the actual signature to a stored nominal signature representing a fault-free machine. An output unit outputs a fault error signal when a discrepancy between the actual signature and the nominal signature exceeds a tolerance value.

Abstract: A method and a device measure for a deformation of a fuel element of a pressurized water reactor having a plurality of control rod guide tubes. A probe displaceable in the direction of the longitudinal axis of the control rod guide tube is inserted in the interior of at least one control rod guide tube having at least one reference axis, and supported in at least one section of the control rod guide tube on the interior wall thereof, such that the orientation of the at least one reference axis is unambiguously a function of the orientation of the longitudinal axis of the control rod guide tube in the section. The orientation of the at least one reference axis in the section of the control rod guide tube is determined relative to the orientation of the or a further reference axis of the probe in a different section.