The French National Agency for Radioactive Waste Management is in charge to develop an industrial centre for geological disposal of High Level Waste. The facility is based on a multi-barrier waste confinement concept which should be reversible for at least 100 years. First, vitrified waste are introduced in a stainless steel container and set into an overpack made of low alloyed steel. Then, overpacks are introduced into micro-tunnels drilled in the claystone and cased with a micro-alloyed steel pipe (API 5L X65 grade). A direct contact between the pipe casing and a cementitious bentonite grout material is established. Several environmental parameters will evolve during the operating phase, such as aeration conditions followed by a progressive consumption of oxygen by various processes, temperature, pH, water resaturation of the host rock…. During this period, different corrosion modes may occur, including uniform corrosion, crevice and pitting corrosion. The present work focuses on studying the abilities, limitations and complementarities between Acoustic Emission (AE) and Electrochemical Noise Measurements (ENM) to detect and distinguish pitting and crevice corrosion on API 5L X65 carbon steel. AE is known to be a sensitive technique to study corrosion elementary processes such as hydrogen evolution, thick corrosion products breakdown… [1] However, this technique presents some limitations since dissolution processes are not energetic enough to be detected by piezoelectric sensors. In contrast, ENM could allow the determination of the corrosion mode and the transitions from one mode to another. Nevertheless, the quality and reliability of EN records depends on the instrumentation used, the acquisition parameters [2], the size of electrodes [3]… Experimental procedures have been developed to produce localized corrosion processes using aerated chloride and hydrogenocarbonate containing environments. Analysis of ENM first requires the evaluation of the instrumentation noise using Power Spectral Densities which were compared with PSDs of ENM recordings of the corrosion system. After validation of the fact that the instrumentation noise could be neglected, ENM records were analyzed in the time domain. AE datas were processed by conventional analysis and more advanced methods of signal classification using a multivariable system. [1]S. Yuyama,“Fundamental Aspects of Acoustic Emission Applications to the Problems Caused by Corrosion”, Corrosion Monitoring in Industrial Plants Using Nondestructive Testing and Electrochemicals methods, ASTM STP 908 (1986) 43-74. [2] F. Huet, S. Ritter, “Electrochemical Noise Measurements with Dummy Cells. Evaluation of a Round Robin Test Series”, Corrosion 74 (2018) 1457-1475. [3J. Xiu, S. Nesic, F. Huet, B. Kinsella, B. Brown, D. Young, “Selection of Electrode Area for Electrochemical Noise Measurements to Monitor Localized CO2 Corrosion”, Journal of the Electrochemical Society 7 (2012) 283-288.