Solving raw water piping corrosion problems

This article describes how, with effective technology and revised flow calculations to monitor flow restrictions, TVA's engineers have tackled a chronic problem. The adequacy of flow and friction head loss equations came under scrutiny with the publication of ''A New Look at the Design of Raw Water Piping'' (Power Engineering, August, 1980) by Charles F. Bowman and W.S. Bain of the Tennessee Valley Authority (TVA). These standard equations were subjected to a rigorous analysis because about 20 years ago the pre-operational testing of safety-related raw service water piping systems in TVA's nuclear plants produced results that varied from the original design flow predictions of several heat exchangers in the system. In a TVA-initiated program, approximately 50 sections of carbon steel raw water pipe were removed from nine different TVA steam plants. Pressure drop tests also were performed at three of those steam plants. To aid the analysis, new analytical models were developed to conservatively predict the system flows based on test results