Tube sheet thickness, heat exchanger

Caution is also necessary when changing the metallurgy of tubes in a heat exchanger. Choosing more noble tubes may induce galvanic corrosion of the tube sheet. Problems can result if the tube sheet is not thick enough to accommodate the increased corrosion rate. 

Although there is almost no practical limit to the thickness of coatings that can be produced by cladding, the application of the process is limited to simple-shaped articles that do not require much subsequent mechanical deformation. Among the principal uses are lead and cadmium sheathing for cables, lead-sheathed sheets for architectural applications, and composite extruded tubes for heat exchangers. 

The PWS heat exchanger transfers heat generated in the reactor tank to the CWS. The heat exchanger has a 0.50-inch, wall-thickness shell with an inside diameter of 87.5 inches and an approximate length of 28 feet. Twelve evenly spaced baffle sheets and two tube sheets support the heat exchanger tubes which are cored with solid rods to provide a narrow (50 mil) annulus for coolant flow. The heat exchangers are mounted on saddles, which are supported on wheeled carriages. The saddles are provided with seismic supports. 

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