Water-Related Corrosion

Scaling and corrosion are related phenomena. The properties of water influencing both are the calcium hardness, alkalinity, total dissolved solids, pH and temperature. Theoretically, the above conditions can be controlled so that the water is in equilibrium and neither corrosion nor scaling results. In practice, however, this equilibrium is difficult to achieve since it is a border condition, and a delicate balance must be maintained. 

In consideration of some operational difficulties, like biofouling and corrosion, directly related to the feed-water source, more reliable water sources have been evaluated by the Evides Industriewater that owns and operates this plant, like anaerobic groundwater and sweet tertiary wastewater. 

Corrosion Investigations Related to the Testing of the Diablo Canyon Unit 1 Cooling Water System, Report No. 733-129-75, Pacific Gas and Electric Company, San Ramon, CA, 1975. 

TF (temperature factor) shows the change in water corrosivity and associated corrosion rate related to temperature. 

As noted in the introduction to this chapter, a system that forced consumers to bear all of the liability associated with water-related lead poisoning might nominally have worked if it were predicated on good information. If consumers were able to discover for themselves with relative ease the possible dangers of lead in their particular locality, they could have chosen to use lead in those environments where water was not unduly corrosive, and avoided lead in those places where water supplies had the capacity to act on lead. Although it is not possible to go back in time and survey water consumers across the world about their... 

Gregory, R. 1993. Lead A Source of Contamination of Tap Water. In Corrosion and Related Aspects of Materials for Potable Water Supplies, ed. P. McIntyre and A. D. Mercer, 21-46. London Institute of Materials. 

S. M. Ah, "An Updated Version of Computer Code CORA II for Estimation of Corrosion Product Mass and Activity Migration ia PWR Primary Circuits and Related Experimental Loops," Eourth International Conference on Water Chemistry of Nuclear Systems, Bournemouth, U.K., Oct. 1986, pp. 107-109. 

Scaling is not always related to temperature. Calcium carbonate and calcium sulfate scaling occur on unheated surfaces when their solubiUties are exceeded in the bulk water. Metallic surfaces are ideal sites for crystal nucleation because of their rough surfaces and the low velocities adjacent to the surface. Corrosion cells on the metal surface produce areas of high pH, which promote the precipitation of many cooling water salts. Once formed, scale deposits initiate additional nucleation, and crystal growth proceeds at an accelerated rate. 

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