IRSN opened the new ODE (Observatoire de la durabilité des enceintes - Containment durability observatory) facility at Cadarache on 12 October 2016, for research on the ageing of the concrete used for nuclear reactor containments and waste storage facilities. This new facility will be used for the experimental phase of the ODOBA (Observatoire de la durabilité des ouvrages en béton armé - Observatory for the durability of reinforced concrete structures) project launched in 2014.
The ODOBA project aims to study the impact of concrete pathologies on the behavior of nuclear structures (containment or waste storage cells), to validate non-destructive examination methods and develop predictive simulation tools. Concrete pathologies evolve over long periods and can modify the properties of the concrete, leading to cracks and even failure of the structure. These pathologies particularly depend on the chemical properties of the concrete and environmental conditions. This project is therefore of critical importance at a time when nuclear operators are planning to extend the operation of their facilities significantly.
The core project comprises tests carried out at the ODE site on large concrete blocks (2x1x4 metres). The site consists of a concrete slab, which is large enough to host up to 60 blocks and a facility able to subject these blocks to accelerated ageing (thermal cycles, humidification/drying cycles, etc.) representative of the operating period of the nuclear facility.
The first three blocks of concrete were successfully cast on 28 & 29 September and four more should be cast by end-2016. These seven concrete blocks vary in type and represent control blocks (exposed to natural ageing). From March 2017, six more blocks will be casted and subjected to accelerated ageing. All the blocks will be extensively instrumented (thermocouples, vibrating wire sensors, humidity meters, etc.) and periodically submitted to destructive and non-destructive testing, in order to define a containment monitoring program. Complementary laboratory tests will be used to improve the understanding of the pathologies detected.
Photo: from left to right, Jean-Christophe Niel, IRSN's Director General, Georges Nahas, scientific advisor for the project and Christophe Marquié, ODOBA project manager © IRSN