Process surveillance in nuclear plants by methods using dynamic signals

Attention is drawn to process surveillance in nuclear plants by active and passive methods using dynamic signals. With respect to passive methods, experience is gained by means of noise diagnosis. A measuring system for research and routine investigations is described. Examples are the analysis of pressure vessel vibrations of a PWR using cross-correlation technique and the detection of a leak in a steam generator of an LMFBR employing statistic decision theory to find the performance criteria for a monitor conception. With respect to active measurements, a perturbation method is discussed. To overcome difficulties arising in the large PWR cores by space-time effects, detector positions have been determined for which these effects can be neglected. (author)