Evaluation of Steam Generator Tube R12C66 from Indian Point No. 3. Final Report

摘要

In November 1981, inspection of steam generator No. 31 at Indian Point No. 3 produced an eddy current (EC) indication in a cold leg tube which was from row 12, column 66 (R12C66). The EC indication in tube R12C66 subsequently was confirmed in a laboratory test at Battelle. The indication was caused by pits on the OD surface of the tube. Numerous pits, small and large, were present on the tube between the 16- and 19-inch elevation from the secondary face of the tube sheet. The deepest pit found had penetrated 60% of the tube wall. Pitting most probably was caused by the presence of high concentrations of chloride ions, sulfur oxyanions and low pH water in the steam generator, particularly during long layups. Copper present in the sludge pile or in the water assisted the pit growth during startup and early periods of plant operation. (ERA citation 08:035803)