Study of A Sampling Method by Wiping for Analysis of Deposit on a Steel Surface

Abstract

In power plants, seawater may leak into the system due to corrosion or damage of the condenser cooling pipe, that is the cause of corrosion or stress corrosion cracking of stainless-steel applied to steam turbines. Contaminated areas are immediately investigated and cleaned when seawater leaks. The wiping method is general for the investigation of the contaminated area, however, there are few cases where the recovery rate of deposition component on the steel surface and the analytical accuracy have been examined, and the analytical method has not been standardized. Therefore, the sampling method of the surface deposition component by the wiping method was examined. The preparation method of the wiping gauze, the wiping pressure, the wiping direction, the effect of the surface roughness of the wiping area, and the effect of coexisting components were examined, and the wiping conditions in which the coefficient of variation was 10% and the recovery rate of the wiping was 89 % or more were clarified in the range of 0.2 ~ 500 mg/m2 of chloride ion deposition amount.