German qualification and assessment of Digital I&C systems important to safety

The main steps of the qualification and assessment process as applied to digital I&C systems important to safety are discussed. Details are outlined with reference to the qualification of the Siemens Teleperm XS system specifically developed for safety applications in nuclear power plants. Type testing of hardware and software modules was performed by ISTec and TـV Nord. For the software modules an analog procedure as used for the hardware modules was applied. Adequate attention is given to the relevant standards, with a more detailed presentation of the revised guidelines of the German Reactor Safety Commission (published August 1996) which provide the basis for assessing digital systems.