Structural Material Anomaly Detection System Using Water Chemistry Data, (V)

Abstract

A water chemistry diagnosis model was developed which quantitatively evaluates ionic impurity behavior in case of equipment nonconformity or operating condition change by ana· lyzing the conductivity change along with the coolant flow in the primary cooling system in BWRs. The model propriety was evaluated using water chemistry data of the Tokai-2 plant.In the case of a sea water in-leak at the main condenser, the sea water in-leak flow rate of 31/h was the lower detection limit when searching for the leakage location in a condenser tube so as to repair it. The prediction trend of the reactor water conductivity agreed with the measured one within ± 10% error in the case of the CUW flow rate transient. The conductivity increase in the reactor obtained by conductivity balance evaluation was approximately found to correspond to the small chromate ion release rate from structural materials and it could be put to practical use as an index to understand the generation behavior of ionic impurity in the reactor.