THE PASSIVATION EFFECTS OF MAGNESIUM-ION ON PHWR PRIMARY HEAT-TRANSFER SYSTEM STRUCTURAL-MATERIALS

Zinc ion injection passivation technique is being used in BWRs in orde r to reduce the radiation field build-up around the reactor coolant sy stem. In the case of PWRs and PHWRs, the chemistry of the primary cool ant system and the materials of construction are different from those of BWRs. In the present paper, the results of studies on the effect of magnesium ion in modifying the oxide layers formed under PHWR chemist ry conditions are reported. The experiments carried out at room temper ature and at 265 degrees C are described. Electron spectroscopy for ch emical analysis (ESCA) of the materials autoclaved at 265 degrees C in magnesium containing solution has also been reported.