Crystallization of neodymium-rich phases in silicate glasses developed for nuclear waste immobilization
Crystallization of neodymium-rich phases in silicate glasses developed for nuclear waste immobilization
复制标题
DOI：
10.1016/j.jnucmat.2006.03.014
复制
发表时间：
2006-08-01
影响因子：
3.1
通讯作者：
Dussossoy, J. L.
中科院分区：
文献类型：
--
作者：
Caurant, D.;Majerus, O.;Dussossoy, J. L.
含有富钕晶相的微晶玻璃可以通过硅酸盐玻璃的结晶（成核+晶体生长热处理）或通过控制熔体的冷却来获得。如果废物在结晶相和残余玻璃之间的分配比高（双重密封屏障原理），则可以设想这种材料作为处理少量锕系元素和富铀核废料的耐用基质。在放射性废物形式中，Nd会被锕系元素和中子吸收剂（Gd）部分取代。在这项工作中，研究了两种硅酸盐玻璃成分，它们可以有效地形成锆石（Ca1-xNdxZrTi2-xAlO7,x < 1）或磷灰石（Ca2Nd8Si6O26）作为潜在的废物形式。研究了微晶玻璃的制备方法（熔体控制冷却或玻璃成核+晶体生长）对微晶玻璃微观结构和富钕晶相结构的影响。采用成核+晶体生长的方法得到的锆石或磷灰石晶体数量最多。然而，与更耐用的大块陶瓷相比，锆石晶体中钕的比例仍然太小，无法实际使用这种材料来调节锕系元素。(c) 2006 Elsevier B.V.版权所有
Glass-ceramics containing neodymium-rich crystalline phases can be obtained by crystallization of silicate glasses (nucleation + crystal growth heat treatments) or by controlled cooling of melts. Such materials could be envisaged as durable matrices for conditioning minor actinides- and Pu-rich nuclear wastes if the partitioning ratio of the wastes between crystalline phase and residual glass is high (principle of double containment barrier). In radioactive waste forms, Nd would be partially substituted by actinides and neutron absorbers (Gd). In this work, two silicate glass compositions leading to efficient nucleation and crystallization of either zirconolite (Ca1-xNdxZrTi2-xAlO7,x < 1) or apatite (Ca2Nd8Si6O26) in their bulk were studied as potential waste forms. The effect of the method used to prepare glass-ceramics (controlled cooling from the melt or nucleation + crystal growth from the glass) on both the microstructure and the structure of the neodymium-rich crystalline phase was studied. The highest number of zirconolite or apatite crystals in the bulk was obtained using the nucleation + crystal growth method. However, the percentage of neodymium incorporated in zirconolite crystals remained too small to make realistic the use of such materials for the conditioning of actinides in comparison with more durable bulk ceramics. (c) 2006 Elsevier B.V. All rights reserved.