Ageing of electronic equipment used in Cernavoda NPP

This paper presents some ageing mechanisms and an evaluation of systems and electronic equipment from Instrumentation and Control (I and C) system, taking into account their importance in command, control and safety operation of NPP. Concepts regarding lifetime, single and multiple stresses, experimental evaluation methods of lifetime, evaluation norms, measurement methods and constraints of lifetime evaluation techniques are also presented. The analysis highlights the factors that influence the operational safety, improvements in the methods of design, manufacture and operation, typical causes of failures and a case study on ASFD modules (Amplifier for Flux Detectors Self-supplied). In order to create a data base regarding the behaviour in time of modules and equipment in similar conditions as those of Cernavoda NPP, measurements of the operational parameters, without input current and with injection of current, depending on the type of module designed for each type of detector self-supplied (with vanadium or platinum ) were carried out. (authors)