Ageing monitoring and management for WWER steam generator and secondary circuit piping of WWER/213 NPPs

The report consists of two parts. Part I discusses the assessment of the effect of erosion-corrosion degradation on the reliability and service life of reactor components. The tasks and responsibilities are defined which should lead to the necessary level of quality assurance. Part II deals with the assessment of steam generator tube integrity. Experiments were carried out on tubes of titanium stabilized austenitic steel with cracks. The results lead to the following conclusions: leak rate increases with increasing crack cross section; no defined relation between leak rate and crack length was found due to crack blocking by corrosion products; when crack width corresponds to the size of corrosion product particles, due to clogging the leak rate decreases; for WWER-440 steam generator tubes a preliminary upper limit of 5 l/h was set for the leak rate. (A.K.) 5 figs., 9 tabs., 3 refs