Abstract: A method for detecting the dropping of at least one control element in a reactor core of a power station by delaying signals output by detectors disposed along a fall path of the control element in such a way that they are approximately simultaneous. This improves a registration of the dropping of the control element by improving a ratio between a useful signal and a noise signal.

Abstract: A method and an apparatus detect the dropping of at least one control element in a reactor core of a power station by delaying signals output by detectors disposed along a fall path of the control element in such a way that they are approximately simultaneous. This improves a registration of the dropping of the control element by improving a ratio between a useful signal and a noise signal.

Abstract: A method and an apparatus are used for determining the neutron flux density of a neutron-emitting source, in particular a reactor core of a nuclear power facility. In the method, a first measurement signal and a second measurement signal, which differ from one another and are each monotonally dependent on the neutron flux density, are used to form a wide-range signal that depends uniquely on the neutron flux density. The wide-range signal is defined region-by-region, the wide-range signal is equated to the first measurement signal in a region where the values of the neutron flux density n are lower, n<n.sub.1, is equated to the second measurement signal in a region where the values of the neutron flux density are higher, n>n.sub.2, and is equated to a monotonal function of both measurement signals in an overlapping region located in between.

Abstract: A method for the location of shocks with a structure-borne sound monitoring system is used especially for pressurized enclosures in power plants, particularly nuclear power plants. Structure-borne sound monitoring systems were heretofore dependent upon assumptions regarding the propagation velocities of the structure-borne sound sensors. According to the invention an exact method of ascertaining the propagation velocities and the burst location is given. The invention begins with the realization that the frequency spectrum of the respective bursts of information for clarification of the dispersion behavior, for identifying the sound wave modes and for deriving the group velocity of these modes is self-evident. Burst signal-rise time differences, wave modes, especially s.sub.0 and a.sub.0 mode, as well as the pertaining group velocities are then ascertained.