Chemistry control analysis of lead alloys systems to be used as nuclear coolant or spallation target

This study presents the lead alloy system chemistry analysis for use as nuclear coolant or spallation target in ADS related systems in order to set down the needs for purification processes and monitoring. The study is limited here to the two main impurities, oxygen and iron. The analysis of the various potential pollution sources that may occur during the various operating modes is given, as well as a first pollution rate assessment. In order to limit the consequences in term of contamination (clogging) and corrosion, it is necessary to define specifications for operation as regards oxygen and iron content in the fluid. As iron cannot be measured and controlled up to now, the best specification is to set the oxygen as high as possible, defined by the cold leg interface temperature to ensure tolerable contamination, in order to maximize the oxidation area to ensure corrosion protection by self-healing oxide layer for the entire system.