USE OF CEMENT-BASED MATERIALS FOR RADIOACTIVE WASTE MANAGEMENT: COMPARATIVE STUDY OF OPC, BFS-PFA AND HFSC CEMENT PASTES LEACHING BEHAVIOUR

摘要

In the context of the nuclear long-lived ILW management, cement-based materials are cur-rently used for waste encapsulation and containers development. Such materials are also likely to be ued for engineered barriers in deep repositories. Various types of cement―OPC, blended cments―have been studied, mainly to evaluate materials long-term durability and confinement properties. Other types of ce-ment such as High Fly ash Silica fume Cement ( HFSC) have also been developed for specific needs like the mitigation of high pH plume effects on the clay engineered barrier and on the clay host rock of the disposal facility. The French Atomic Energy Commission (CEA) and the Japan Nuclear Cycle Development Institute (JNC) performed a comparative joint study on the leaching behaviour of hardened cement pastes based on these cements. Leaching experiments were carried out with a standard test developed at CEA. Experimental results were analysed and cross-calculations were made to estimate calcium fluxes and degraded thicknesses using CEA Diffu-Ca and JNC TRACE 1D codes. Experimental and modelling results were compared and modelling strategies were then disc'ussed.