Silica-based materials for reclamation of exp 135 Cs at high temperatures

• Published in: Journal of materials science letters Vol. 21; no. 15; pp. 1175 - 1177
• Main Authors: Massiot, P, Centeno, M A, Gouriou, M, Laurent, Y, Odriozola, J A
• Format: Journal Article
• Language: English
• Published: 01-08-2002
• ISSN: 0261-8028

Nuclear waste from radio-elements requires special confinement due to its important radiological impact on human beings and their environment. In particular, nuclear waste with very high activity (C-class) presents a great hazard and is nowadays a real problem for society. Fission products are a type of nuclear waste. Even if they are generally less radiotoxic than minor actinides, their mobility caused by lixiviation seems potentially more critical. Efforts must be made to separate the fission products having long-life elements. In the case of cesium, the exp 135 Cs isotope possesses a period of 2,300,000 years. exp 135 Cs should be stored at great depth. Nevertheless, the stable exp 133 Cs isotope complicates the problem. Indeed, by neutronic irradiation, exp 133 Cs gives rise to exp 135 Cs. Thus, if separation of the different isotopes is not possible, exp 133 Cs could increase the exp 135 Cs content. The separation of the different isotopes of cesium is an important objective but it is very hard to achieve. For this reason, immobilization of cesium into crystalline networks must be studied. Alumino-silicate compounds are interesting due to their remarkable intrinsic properties but this composition does not match the composition of apatite. Silico-phosphate compounds could prove interesting because many apatites among the apatite family contain Si/P elements.