Improving the feedwater purity of LWR plants by optimation of materials and concept

In all LWR plants, the allowable level of corrosion products in the feedwater is limited. The steam/water system has to be designed to meet these requirements. Experience from the Muehleberg and Leibstadt BWR plants and Beznau II PWR plant is reported. With appropriate materials choice and component design, it is possible to reduce the corrosion product level in the feedwater to well below specification limits. This approach has already been established by us more than 10 years ago to meet both the demands on water purity as well as on system integrity, and has recently been confirmed by other authors. In Leibstadt for example, with condensate polishers but uncleaned pumped forward heating condensates, a feedwater iron level of 1 μg/kg was achieved. 11 refs.