Development of corrosion product behaviour and radiation fields at the Sizewell B PWR from 1995 to 2008

Since 1995 the standard 4-loop 3411 MWth Westinghouse PWR Sizewell B has completed nine fuel cycles. It has alloy 690 steam generator tubing, some stellite hard facing alloys eliminated, commissioned using a modified hot functional test passivation procedure and has operated either a modified or elevated chemistry with the pH (300 C) co-ordinated at 7.4 or 7.2. The paper reviews corrosion product behaviour, shutdown releases and radiation fields over the nine fuel cycles and discusses why the shutdown releases and radiation fields are low. It also discusses how the lower corrosion product releases have reduced occupational radiation exposure. (orig.)