The Reasons for the Frequently Exceeded Pressure Drop of Resin Bed in Steam Generator Blowdown System

Abstract

Steam generator blowdown (APG) system is a very important system for the steam generator water purification in PWR. However, the frequently exceeded pressure drop of resin bed in the APG system may cause excessive steam generator blowdown cut-off, or blowdown rate reducing, so that the steam generator water cannot be purified in optimization approach. At the same time, the real exceeded pressure drop of resin bed may also lead to the broken of resin, and then pollute the secondary water and block the related equipment of secondary cycle. So, these issues always bother the safety and stability of the system in operation. The frequent replacement of resin bed will increase unnecessary solid waste and economic losses. In order to find the main reasons for the frequently exceeded pressure drop of resin bed, the resin pressure drop in power station, the secondary water chemistry, the theoretical calculation for pressure drop, the deigned device structure and parameters, and the online instrument failure were be analyzed in this paper. After the theoretical analysis and the maintenance of resin bed during the outage, the main reasons for the frequently exceeded pressure drop of resin bed were be found, the blocked water cap of the resin bed.