PROTECTIVE SUPERVISORY CONTROL WITH ADEQUATE INFORMATION FUNCTIONS IN PRESSURIZED WATER-REACTORS OF KRAFTWERK UNION

The most modern German nuclear power plants with pressurized water reactors feature full load-follow capability and abnormal operation with less than one scram per plant and year. This is to a significant extent achieved by the application of a ''Protective Supervisory Control'' in between the functional areas of control and protection systems. Because of the sophistication of the functions of this integrated concepts of ''defence-in-depth' a multiple VDU based 'Information System'' supports its understanding and maintenance; the operator remaining an observer of normal operation and a manager of long lasting accidents. History, development steps-by means of a special computer systems-and status of the added systems are mentioned. The different views of defence-in-depth (IAEA; IEC; KWU) are described. Several examples of condensed, human factor oriented information are given; single formats and format-sets using numerous icons and neighbouring information show the functional (event and symptom oriented) behavior of the plant and all of its C&I systems. Numerous (intelligent) format (-set) selection modes are implemented. A short outlook is given to further development ix digital technique with: use of analytical redundancy parallel processing diversity of event and symptom oriented identification and priority assignment to optimal countermeasures by identification judgement.