Abstract
The case cited here occurred in a waste heat boiler plant in 1993, which has many features in common with the case of Mihama nuclear power plant in 2004 in terms of piping materials, environmental conditions as well as in the location where the damage took place: very close to an upstream flow-meter. On this case, the cause was analyzed based on the best available knowledge and seemingly the best countermeasures for preventing a recurrence were taken. Seven years after the accident, in 2000, the effectiveness of these countermeasures was examined. The results of the examination and the newly obtained knowledge from the Mihama's case together confirmed the rationality of the opinion that the unusual thinning of pipe wall can be attributed not to the turbulence in fluid flow, but to a macro-cell corrosion.
