State-of-the-art of quantitative assessment of ageing of concrete SSC in NPPs
Corrosion assessment of embedded liners in concrete
Characterization, prediction and monitoring of internal swelling reactions in concrete
Delayed strains of containment buildings in operational and accidental conditions
Assessing the performance of irradiated concrete
Dissemination, communication and training
The ACES implementation plan consists of seven work packages. Figure illustrates the overall structure of the ACES work plan. The ACES work packages are:
The objectives of WP1 are (i) a critical review of AMPs across EU NPPs focusing on deterioration and ageing mechanisms of reinforced concrete, linked to decision-based assessment criteria of reinforced concrete performance and (ii) to identify the scientific basis that is required for assessing current and future condition for different ageing processes in nuclear power plants for the ageing processes and concrete SSCs.
NPP involve numerous concrete structures with embedded steel reinforcement, barrier and containment systems. Although concrete environment is particularly suitable for steel due to the alkaline nature that enables passivation of the steel surface, many corrosion processes take place in concrete structures, depending on the environmental conditions and geometry of the structure. This WP will concentrate on the parts of Nuclear Power Plants (NPP) where safety is the major concern, i.e. special conditions leading to chloride-induced corrosion of steel cylinder concrete pipes (SCCP) and to crevice corrosion of steel liner embedded in concrete of containment building. The aim is to provide background information for the modelling and non-destructive inspection as well as to facilitate proper prevention measures. The objectives include:
Internal Swellings Reactions (ISR) are pathologies that can degrade concrete by causing swelling, cracking and major disorders in the affected structures. ISR include the delayed ettringite formation (DEF), the alkali-silicate reaction (ASR) and the occurrence of both simultaneously. In nuclear facilities, the possibility of these phenomena cannot be ruled out. Matter of fact, they include massive reinforced concrete elements for which a significant heating could have occurred at the early age. Moreover, reactive aggregates may have been used during the construction phase. Therefore, those risks ought to be studied and quantified especially if the extension of the lifespan of these installations is envisaged. The aim is to contribute to the assessment of lifetime extension of NPP structures whose concrete is affected by ISR and to provide background information for the modelling and non-destructive inspection. The main objective include:
The aim of actions related to creep and shrinkage is to improve the modelling capability for drying and delayed strains of containment buildings:
For accidental phases and particular operational situations involving exposition of concrete to temperatures higher than 70°C, the material modelling is less mature. Hence, the project will focus on improving the understanding and modelling of the material behaviour. An ambitious experimental program has already started on VERCORS concrete at high temperatures. This experimental program will be completed and material modelling will be performed and shared between the project partners
The general objective of WP5 is to develop a comprehensive methodology to assess the effects of prolonged irradiation of LWRs CBSs using a holistic approach combining operating conditions, materials degradation and structural significance. This WP includes both gamma and neutron irradiation experiments in accelerated conditions; and materials (meso-scale) and structural modelling activities. The objective of the experimental activities is to address specific knowledge gaps identified in the open literature: (i) The effects of gamma irradiation of the reinforced concrete, and the risk of radiolysis-induced corrosion; and, (ii) The effects of neutron-irradiation of concrete-aggregate made of igneous and metamorphic rocks, common in Europe, and not or insufficiently characterized in previous research works. These experimental studies will provide input data to the (materials) meso-scale models which are to be benchmarked by different partners in coordination, with the International Committee on Irradiated Concrete (ICIC) activities, using open-literature data from Russia and Japan during the first stage of the project. The validation of the varied meso-scale models will provide the necessary inputs to develop a sound structural analysis of a prototypical water-cooled water-moderated reactor (VVER) CBS. The final output of this research will be the creation of methodological guidelines applicable to varied LWRs establishing the long-term operation conditions assessment of the CBS.
WP6 comprises the dissemination, training, innovation management and End-User activities within the ACES project. This WP supports the technical tasks carried out as part of WP2 to WP5 by the incorporation of tools designed to both enhance the progress of work and communicate the obtained results. The main goals of WP6 are to:
Work package 7 consists of the overall management, administration, and coordination of the consortium, meetings and communication actions to ensure a timely execution of the project in accordance with the proposal and its objectives. Additional gorals include:
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