New binders, new trends, new potentialities in waste cementation - 15095

It has long been common practice to solidify and stabilize low- and intermediate-level radioactive wastes with calcium silicate cements (ordinary Portland cement, or composite cement). However, wastes produced by nuclear activities are very diverse and some of their components may chemically react with cement phases or mixing water, reducing in some cases the quality of the product. This paper reviews the potential of three kinds of alternative inorganic binders to treat problematic wastes: (i) calcium aluminate and sulpho-aluminate cements, (ii) magnesium and calcium phosphate cements, and (iii) alkali-activated binders. Their setting and hardening process is briefly presented, and their potential for waste conditioning is discussed and illustrated. The opportunity offered by these new binders opens a wide field of research which should be attractive and stimulating both for physico-chemists and nuclear industry in the years to come. (authors)