Effect of Ethanol Amine Injection on Flow-Accelerated Corrosion of PWR Secondary Systems

Abstract

  Some pressurized water reactor (PWR) plants have switched secondary system feed water treatment to ethanol-amine (ETA) injection from all-volatile treatment (AVT) to reduce iron transfer in the steam generator (SG). However, the effect of ETA injection on FAC rate has not been studied systematically. To assess the effect of ETA injection on FAC rate, the water chemistries in secondary systems were calculated by considering the thermal decomposition of hydrazine in SG and the vapor/liquid partition of ammonia, ETA, and hydrazine in SG and in a moisture-separator-and-reheater (MSR). Then, we measured the FAC rate experimentally by rotation tests to examine the effect of ETA injection. The high pH condition of ETA injection reduced the FAC rate more than the low pH condition of AVT. No chemical effect on the FAC rate was observed between ETA injection and AVT at 180°C. We also evaluated the FAC rate using magnetite solubility with and without ETA injection. The evaluation showed that ETA injection reduces the FAC rate of the secondary system.