The OSCAR V1.4 code: A new dissolution-precipitation model to better simulate the corrosion product transfer in nuclear cooling systems

Abstract : Predicting the radioactive contamination of nuclear reactor circuits is a significant challenge for plant designers and operators. To address this challenge, the French strategy has been focusing on performing experiments in test loops, measuring the PWR contamination and developing a simulation code so named OSCAR. The process governing the contamination by Activated Corrosion Products (ACPs) of a nuclear cooling system involves many different mechanisms that react with each other. One of the most important mechanisms is the dissolution-precipitation mechanism, which governs the behavior of soluble corrosion products and which is related to water chemistry specifications. The dissolution-precipitation model has been improved in the new version of OSCAR, OSCAR V1.4. Thanks to this improvement and to the OSCAR chemistry module, PHREEQCEA, the OSCAR V1.4 code can reproduce the impacts of pH and of Zn injection on $^{60}$Co contamination highlighted in a laboratory experiment and can better reproduced the volume activity variations during a cold shutdown.This new version of the OSCAR code is a powerful tool to predict the contamination of nuclear systems and to analyze the corrosion product behaviors in different conditions and thus to provide explanations of these behaviors.