Determining the physical properties of steam generator tube scale using miniature specimens

Small flakes that consists primarily of magnetite have been discovered on the secondary side of the steam generator of the Three Mile Island Unit 1 plant. These iron oxide flakes are believed to cause significant increases in flow resistance, which in turn causes abnormal increases in steam generator water level. This article describes the measurement of the physical properties of the tube scale so that the maximum amount of loose flakes can be generated prior to hydrodynamic cleaning (water slap). The study of the flake properties to shed light on the flake formation and transport mechanisms