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Early-age thermo-mechanical behaviour of concrete Supercontainers for radwaste disposal
The Belgian concept for the disposal of vitrified high-level waste and spent fuel assemblies is founded on the use of cylindrical concrete Supercontainers. This concept is based on a multiple barrier system where every component has its own specific safety function requirements. It consists of encapsulating the heat-emitting waste in a watertight carbon steel overpack and surrounding it by a cylindrical concrete buffer that will then be disposed in a deep clay layer. Finally, the buffer is sealed with a concrete lid. Th concrete materials provide favourable chemical conditions for the overpack allowing it to confine the radionuclides during the thermal phase. In addition, they also ensure shielding protection during construction and transport. A self-compacting concrete (SCC) and a Traditional Vibrated Concrete (TVC) are bein considered for the choice of the cementious buffer, enclosing the radwaste. The use of SCC will ease considerably the precast process and complies with all other requirements regarding strength, durability, chemical interactions,. A laboratory characterization program, in order to obtain the mechanical and thermal properties of the SCC, and 2.5 D thermal and crack modelling simulations, has been conducted to predict the early-age thermo-mechanical behaviour of the concrete buffer during the different construction stages, i.e. the casing of the buffer, insertion of the high-level waste and closure of the Supercontainer. Also the effect of gamma radiation and elevated temperatures on hardening SCC based mortar and hardened SCC was investigated. Finally, the prediction of the avoidance of through-going cracks in the concrete buffer is ensured by means of simulations, after implementation of the obtained test results, and by means of large scale tests, with temperature measurements, displacement and deformation registrations, for the validation of the simulation results of the early-age behaviour of the Supercontainer.
Early-age thermo-mechanical behaviour of concrete Supercontainers for radwaste disposal
The Belgian concept for the disposal of vitrified high-level waste and spent fuel assemblies is founded on the use of cylindrical concrete Supercontainers. This concept is based on a multiple barrier system where every component has its own specific safety function requirements. It consists of encapsulating the heat-emitting waste in a watertight carbon steel overpack and surrounding it by a cylindrical concrete buffer that will then be disposed in a deep clay layer. Finally, the buffer is sealed with a concrete lid. Th concrete materials provide favourable chemical conditions for the overpack allowing it to confine the radionuclides during the thermal phase. In addition, they also ensure shielding protection during construction and transport. A self-compacting concrete (SCC) and a Traditional Vibrated Concrete (TVC) are bein considered for the choice of the cementious buffer, enclosing the radwaste. The use of SCC will ease considerably the precast process and complies with all other requirements regarding strength, durability, chemical interactions,. A laboratory characterization program, in order to obtain the mechanical and thermal properties of the SCC, and 2.5 D thermal and crack modelling simulations, has been conducted to predict the early-age thermo-mechanical behaviour of the concrete buffer during the different construction stages, i.e. the casing of the buffer, insertion of the high-level waste and closure of the Supercontainer. Also the effect of gamma radiation and elevated temperatures on hardening SCC based mortar and hardened SCC was investigated. Finally, the prediction of the avoidance of through-going cracks in the concrete buffer is ensured by means of simulations, after implementation of the obtained test results, and by means of large scale tests, with temperature measurements, displacement and deformation registrations, for the validation of the simulation results of the early-age behaviour of the Supercontainer.
Early-age thermo-mechanical behaviour of concrete Supercontainers for radwaste disposal
Craeye, Bart (Autor:in) / De Schutter, Geert
01.01.2010
Hochschulschrift
Elektronische Ressource
Englisch
DDC:
690
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| British Library Online Contents | 2003
| British Library Online Contents | 2003
Radwaste Treatment Technologies
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