CHARACTERIZATION AND CONDITIONING BY CEMENTATION AND COMPACTION OF ASHES COMING FROM SIMULATED RADWASTES

The statement and the results of a systematic programme of characteriz ation and evaluation of conditioning by cementation and supercompactio n of ashes coming from different simulated radwastes are presented. Th e main programme objectives are to define the influence of the most im portant operating parameters of conditioning methods on the mechanical properties of the conditioned products and to obtain the guidelines f or the optimization of their final storage, evaluating the achievable volume reduction and its relation with mechanical strength. The study is based on the physical and chemical characterization of the ashes an d the determination of their behaviour with respect to two conditionin g methods: cementation and high pressure compaction, to determine the strength development, the mechanical stability, and the volume reducti on achieved. The ashes are obtained by incineration of low activity si mulated radwastes, which represent different real wastes with high vol ume to activity ratio. The conditioning by cementation is tested over a series of cementitious pastes made with two cement types, changing i n ash and water content. Products are controlled by measuring volume, setting time, expansion, and strength. High pressure compaction tests are made at laboratory scale, measuring the ash volume reduction as a function of compacting pressure.