EDF is progressing steadily on the quality of structural health monitoring by taking advantage of the latest innovations in sensors. The construction of the Flamanville 3 EPR enabled to highlight significant advances in temperature, strain and moisture monitoring in concrete of the inner prestressed containment. A distributed measurement system with fiber optics embedded in concrete has been installed. Temperature and strain data is measured on a containment circumference. The challenge of holding the fragile concreting sensitive elements (silica) established over long lengths and in a dense reinforcement was successful. A remote optoelectronic device provides a measurement every meter all over the structure. First effects of concrete prestressing have been quantified. Another system for measuring the water content by Time Domain Reflectrometry was also setup. This allows to estimate the permittivity of the medium depending on the water content of the concrete. Five sensors were embedded at different depths to estimate the gradient of moisture in the wall. This information is one of the parameters that will predict more accurately the ageing of concrete. Effective cooperation from the lab to the field was required to transfer these technologies, while ensuring performance in long term operation.
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