Scope and objectives of this 2.5 day conference (talks and posters).
Cementation is a widely applied technique for the conditioning of low – and intermediate – level radioactive wastes. However, specific issues have still to be addressed, such as the limitation of adverse cement-waste interactions which may affect the quality of the resulting solidified waste form, or the understanding and prediction of long-term properties of the waste packages and cement barriers. There is also a need for safe processes minimizing the production of secondary wastes, and for monitoring techniques of cemented waste packages and cement barriers. Besides, most of the cements used nowadays have a high carbon footprint (e.g. Portland cement) or comprise supplementary mineral additions with limited availability in the near future (e.g. fly ash). In the same time, strong effort is made by the cement industry to reduce its environmental footprint. One consequence will be the progressive disappearance of binders with high clinker content (e.g. CEM I 52.5). Inversely, new cements are under development / standardization (CEM II/C-M, CEM VI), which may offer new prospects for nuclear waste management. The dismantling of old nuclear facilities will also produce waste with negligible or no contamination, which may be possibly reused as an alternative to primary aggregates. The design of novel cementitious materials with reduced environmental impact, but guaranteed long-term performance for surface or deep disposal, will thus be one of the challenges of the years to come.
The objective of the 5th edition of NUWCEM will be to promote the exchange of advanced information on the ongoing research and development activities dealing with cementation of nuclear wastes, from elaboration of waste packages with reduced carbon footprint to their final disposal.
Topics
– Performance requirements and implementation methods,
– Formulation for various kinds of wastes (legacy waste, waste from current and future nuclear power generation)
– Formulation methodologies
– Processes involved: mixing device designs, packaging options, engineering feasibility and implementation in real site
– Cement-waste interactions
– Factors influencing rheology, setting, hardening, hydration rate, heat production, pH and pore solution evolution
– Evolution of mineralogy and microstructure
– NEW! Low CO2 cements
– Calcium aluminate and sulfoaluminate cements
– Geopolymers
– Phosphate cements
– Magnesia-based cements
– Low pH cements
– NEW! Interactions between new binders and conventional construction materials
– Waste / cement / aggregate interactions
– Differed ettringite formation
– Effect of βγ and α irradiation: radiolytic gas production, stability of cement hydrates and admixtures
– Corrosion of metallic waste
– Gas evacuation
– Micro and macro-cracking
– NEW! Chemo-mechanical modelling
– Leaching by aggressive solutions (chloride, sulfate…), carbonation
– Effect of temperature
– Redox state evolution
– Radionuclides retention
– Liquid, gas, and contaminant transport under unsaturated or saturated conditions
– Interactions with other cement barriers
– Modelling of long-term behavior – saturated versus unsaturated transport
NEW!
– Monitoring techniques, remote monitoring, potential of robotics for monitoring the conditioning of waste packages and waste forms
– Methods for detecting and quantifying concrete contamination
– Methods for concrete decontamination and management of secondary waste
– Methodology for service life extrapolation
– Methods for reworking non-compliant cement waste forms
About Sfen
The French Nuclear Society is the French knowledge hub for nuclear energy. Created in 1973, the Sfen provides a space where all those who are interested in nuclear energy and its applications can obtain and exchange information.
