Evaluation of Corrosion Product Activity in a Typical PWR with Extended Cycles and Flow Rate Perturbations

Abstract

Effect of flow rate perturbations has been studied using the modified computer program CPAIR-P for time dependent corrosion rates in Pressurized Water Reactors (PWRs) having extended cycles. In these simulations, a decrease in the corresponding saturation values of corrosion product activity (CPA) is observed for higher pH values. Comparison of CPA's behavior has been done for constant flow-rate case as well as for transients with elevated 10 B levels (~40%) in dissolved boric acid in coolant in two operating cycles. When the flow rate is decreased in the first cycle, the saturation value of CPA attains new higher values. Also, in the second operating cycle, the saturation values are about 12% higher when compared with the values in the first cycle.

Corrosion behavior of 304L stainless steel in a B-Li coolant for a nuclear power plant

“…It is reported that the amount of corrosion products in the coolant, the deposition rate in the core and the radiation field outside the core should be effectively reduced when the pH of the coolant increased from 6.9 to 7.2-7.4. 1 The operation experiences of the Sizewell B nuclear power plant showed that the corrosion product concentration decreased by two orders of magnitude when the pH of the coolant increased from 6.9 to 7.7 at 292°C. 2,3 The oxide film has a great influence on the corrosion rate of stainless steel in 290±0.5°C and 10 MPa water.…”