Next-Generation Low-Carbon Cement Wasteforms for Safe Disposal of Radioactive Waste

在英国，到目前为止，已经产生了超过15万立方米的放射性废物(足以填满60个奥运大小的游泳池)。大多数放射性废物需要通过将其包裹在水泥中进行处理，以防止释放到生物圈。以波特兰水泥(PC)为基础的胶囊剂与辅助胶凝材料(SCM)混合，如飞灰(FA)和高炉矿渣(BFS)，对于胶结英国迄今产生的大部分放射性废物是必不可少的。然而，随着传统的SCM如飞灰和高炉矿渣变得越来越稀缺，利用大量和容易获得的SCM如石灰石、煅烧粘土和遗留矿渣等制备PC/SCM密封剂是确保供应安全的关键。目前关于哪些原材料参数对可靠应用至关重要的信息有限，特别是当这些密封剂是在核包覆工厂所要求的条件下与大量的SCM替代品如石灰石、煅烧粘土和遗留矿渣配制的时候。本文研究了用石灰石、煅烧粘土和废渣生产的PC/SCM密封剂中流体-颗粒和颗粒-颗粒相互作用的机理。通过研究基本粒子之间的相互作用，可以为前驱体粉末制定更可靠的规范，利用丰富的超临界流体，确保供应的安全。

In the UK, over 150,000m3 of radioactive waste (enough to fill 60 Olympic size swimming pools) has been produced to date. Most of this radioactive waste needs conditioning by encapsulating it in cement to prevent release to the biosphere.Encapsulants based on Portland cement (PC) blended with supplementary cementitious materials (SCM) such as fly ash (FA) and blast furnace slag (BFS) are essential to cementation of much of the radioactive waste produced in the UK to date. However, with traditional SCM such as fly ash and blast furnace slag becoming increasingly scarce, development of PC/SCM encapsulants produced using abundant and readily available SCM such as limestone, calcined clays, and legacy slags, etc., is critical to ensure security of supply.There is currently limited information on what parameters of raw materials are critical to reliable application, particularly when these encapsulants are formulated with abundant SCM alternatives such as limestone, calcined clays, and legacy slags, under conditions required on nuclear encapsulation plants.This proposal investigates the mechanisms of fluid-particle and particle-particle interactions in PC/SCM encapsulants produced using limestone, calcined clays, and legacy slags as more abundant replacements for BFS and PFA,and the effect of this replacement on composition-structure-property relationships, and reaction mechanisms and kinetics.Through investigating fundamental particle interactions more robust specifications can be developed for precursor powders utilising abundant SCMs, ensuring security of supply.