Finite element modeling of galvanic corrosion during chemical cleaning of westinghouse series 51 steam generator

Galvanic corrosion rates during the chemical cleaning of the Westinghouse Series 51 Steam Generator have been calculated using a finite element method. The results show that the galvanic action between the I-600 tube bundle and various carbon steel structures produces low galvanic corrosion rates on the base metal of the carbon steel surfaces, but high rates on the heat affected zones of welds. An explanation of the large difference in galvanic corrosion rates as well as methods to minimize the galvanic corrosion rate on the heat affected zones are discussed. Based on the modeling results, a test configuration to simulate the galvanic action in the steam generator is suggested.