The scale and degree of sophistication of technological plants, e.g. nuclear powerplants, have been essentially increased during the last decades. Conventional disturbance analysis systems hove proved to work successfully in well-known situations. But in cases of emergencies, the operator staff needs a more advanced assistance in realizing diagnosis and therapy control. The significance of introducing Artificial Intelligence methods in nuclear power technology is emphasized. Main features of the on-line disturbance analysis system SAAP-2 are reported about. It is being developed for application in nuclear power plants. Problems related to man-machine-communication will be gone into more details, because their solution will influence end-user acceptance considerably.