SEDL / STP / STP978-EB / STP26208S

Experience with Cathodic Protection of Power Plant Condensers Operating with High Performance Ferritic Stainless Steel Tubing

Redmerski, LS
Staff metallurgist, supervisor, and technical director, Crucible Materials Corporation, Crucible Research, Pittsburgh, PA

Eckenrod, JJ
Staff metallurgist, supervisor, and technical director, Crucible Materials Corporation, Crucible Research, Pittsburgh, PA

Pinnow, KE
Staff metallurgist, supervisor, and technical director, Crucible Materials Corporation, Crucible Research, Pittsburgh, PA

Kovach, CW
Consultant, Crucible Materials Corporation, Trent Tube Division, East Troy, WI

Pages: 13    Published: Jan 1988

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Abstract

Galvanic corrosion is an important consideration in brackish or seawater cooled power plant condensers containing dissimilar metal components. Cathodic protection is often used to minimize galvanic corrosion, but under certain conditions of operation, many condenser components, including high performance ferritic stainless steel tubing, can become susceptible to hydrogen embrittlement. Results of laboratory experiments indicate that conditions can be defined for the operation of a cathodic protection system, which will minimize corrosion of dissimilar, less noble, tubesheet, and waterbox materials and avoid embrittlement of high performance ferritic stainless steel tubing. These conditions are similar to those now recommended for use with condensers operating with titanium tubing. Several power plant condensers using SEA-CURE® (Unified Numbering System [UNS] S44660) ferritic stainless steel tubing are now successfully operating with impressed current cathodic protection systems, and no difficulties with hydrogen damage to the tubing have been encountered.