The liner structure in Nuclear Power Plants provides containment for the operation and therefore the study of its durability and integrity during its service life is an important issue. There are several -causes for the deterioration of the liner which in general involve corrosion due to its metallic nature.The aim of this paper is to present new non destructive techniques that have been used recently for the corrosion liner evaluation in some nuclear power plants. These techniques are based on electrochemistry and try to ensure the expected service life for this structure and have been already used in other nuclear structures.In this way the paper describes the assessment of corrosion problems of two liners from two different nuclear power plants which were evaluated using non-destructive electrochemical techniques. In spite of the testing difficulties arisen from the results extracted it can be concluded that the electrochemical techniques applied are adequate for the corrosion evaluation. They provide important information about the integrity of the structure and allow for its evolution with time to be assessed